Articoli di riviste: "Bentonite"

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Pan, Yi, Xinyue Zhang, Chengcheng Ji, Qianru Zhan, Zhaoxuan Li, Jian Guan e Jian Huang. "Modification Method of High-Efficiency Organic Bentonite for Drilling Fluids: A Review". Molecules 28, n. 23 (30 novembre 2023): 7866. http://dx.doi.org/10.3390/molecules28237866.

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The requirements for drilling bentonites are tightening due to ever-increasing demands for petroleum resources, coupled with cost and reaction technology constraints. In addition to raising the risk of drilling, bentonite’s poor performance also raises the possibility of safety incidents and significant financial losses. Organically modified bentonites effectively reduce the consumption of drilling fluids, conserve resources, and lessen environmental effects. This paper aims to provide an overview of the several organic modification methods of bentonite for drilling fluids. It also evaluates the characteristics and application impacts of bentonite. We primarily describe the three popular modification methods represented by intercalation, coupling, and grafting. Also, this review provides the effect of molecular simulation on the investigation of structure in microconfined conditions. Through microlearning, organically modified bentonite with exceptional performance is to be further developed.

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Aji, Navela Rahma, Emas Agus Prastyo Wibowo, Resti Ujiningtyas, Hestin Wirasti e Nuni Widiarti. "Sintesis Komposit TiO2-Bentonit dan Aplikasinya untuk Penurunan BOD dan COD Air Embung UNNES". Jurnal Kimia VALENSI 2, n. 2 (30 novembre 2016): 114–19. http://dx.doi.org/10.15408/jkv.v2i2.3620.

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Abstrak Telah disintesis komposit TiO2-bentonit untuk penurunan BOD dan COD. Penelitian ini bertujuan untuk mengetahui proses pembentukan komposit TiO2-Bentonit serta mengetahui katalis terbaik dalam proses fotodegradasi air embung. Penelitian diawali dengan preparasi TiO2-Bentonit. Hasil pembentukan komposit dikarakterisasi dengan menggunakan X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) dan Scanning Electron Microscope (SEM). Katalis yang diuji adalah TiO2, bentonit, TiO2-bentonit yang diaplikasikan ke air embung dengan waktu penyinaran selama 30 menit.Terbentuknya komposit TiO2-Bentonit ditunjukkan dengan refleksi TiO2 pada 2 25. Hasil analisis menggunakan FTIR yakni Ti-O antara range 400-700 cm -1 dalam hal ini ditunjukkan dalam peak 478.35 dan 594.08. Puncak serapan-serapan utama pada bentonit beradi di bilangan gelombang 3626.17 cm-1, 3448.72 cm-1 dan 1635.64 cm-1. Spektra TiO2-Bentonit tidak menunjukkan adanya pergeseran serapan pada bilangan gelombang 3448.72 cm-1 yang belum menunjukkan ikatan O-H yang semakin lemah karena adanya TiO2 di dalam antar lapis bentonit.Penurunan nilai BOD dan COD terbesar diperoleh dengan menggunakan TiO2-Bentonit yakni untuk BOD 18.40 ppm dan COD 10.05ppm. Kemampuan komposit TiO2-Bentonit lebih besar dibandingkan katalis TiO2 dan bentonit. Kata kunci: air embung, fotodegradasi, TiO2-bentonit Abstract Have done synthesized composite TiO2-bentonite to decrease BOD and COD. This study aims to determine the process of form he composite TiO2-bentonite and determine the best catalyst in the process of photodegradation water reservoir. The study begins with the preparation of TiO2-bentonite. Results composite formation characterized using X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) and Scanning Electron Microscopy (SEM). The catalyst is tested TiO2, bentonite, TiO2-bentonite which is applied to the water reservoir with the exposure time for 30 menit.Terbentuknya composite TiO2-bentonite indicated by TiO2 reflection on the 2θ ≥ 25. FTIR analysis results using the Ti-O between the range 400-700 cm-1 in this case is shown in peak 478.35 and 594.08. The main absorption peak-absorption on bentonite beradi at wavenumber 3626.17 cm-1, 3448.72 and 1635.64 cm-1. TiO2-bentonite spectra did not indicate any shift in absorption at wavenumber 3448.72 cm-1 which has not shown the OH bond is weakened by the existence of TiO2 in between layers of bentonite. Impairment The BOD and COD obtained using the TiO2-bentonite for BOD 18.40 ppm and 10.05 ppm COD. TiO2-bentonite composite capability greater than TiO2 catalyst and bentonite. Keyword: air embung, photodegradation, TiO2-bentonite DOI: http://dx.doi.org/10.15408/jkv.v0i0.3620

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Brezovska, Snezana, Biljana Marina, Donco Burevski, Biljana Angjuseva, Vasa Bosevska e Lepa Stojanovska. "Adsorption properties and porous structure of sulfuric acid treated bentonites determined by the adsorption isotherms of benzene vapor". Journal of the Serbian Chemical Society 70, n. 1 (2005): 33–40. http://dx.doi.org/10.2298/jsc0501033b.

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In a previous paper, adsorption isotherms of benzene vapor on natural bentonite from Ginovci, Macedonia, and forms acid activated with 10% and 15% solutions of hydrochloric were interpreted by means of the Dubinin-Radushkevich-Stoeckli and Dubinin-Astakhov equations; the investigation has been continued with bentonites acid activated with 10% and 15% solutions of sulfuric acid where X-ray analysis indicates smaller structural changes. Using the above equations, the heterogeneity of the micropores and the energetic heterogeneity of the bentonites were determined from the differential distribution of the micropore volume with respect to the structural parameter of the equations characterizing the microporous structure and to the molar free energy of adsorption. Activated bentonites obtain bigger pores but also a certain quantity of new small pores appear during acid activation with the higher concentration of acid. The micropore volumes, determined from the adsorption of benzene vapor, of bentonites activated with 10 % and 15 % solution of hydrochloric acid (144.60 cm3 kg-1 and 110.06 cm3 kg-1, respectively), decrease in comparison with that of natural bentonite (162.55 cm3 kg-1). In contrast, the values of the micropore volume for bentonities treated with 10 % and 15 % solutions of sulfuric acids increase (169.19 cm3 kg-1 and 227.74 cm3 kg-1). That is due to the difference in the structural changes occurring during activation with hydrochloric and sulfuric acids. The values of the free energy of adsorption of benzene vapor for natural bentonite are higher than those of the acid activated bentonities, what is in accordance with the structural and porosity changes.

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Lathifah, Tiva, Nia Yuliani e Gladys Ayu Paramita Kusumah Wardhani. "BENTONIT TERAKTIVASI ASAM SULFAT SEBAGAI ADSORBEN DALAM PEMURNIAN PELUMAS BEKAS". Jurnal Sains Natural 9, n. 1 (28 marzo 2019): 1. http://dx.doi.org/10.31938/jsn.v9i1.170.

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Activated Bentonits of Sulfatic Acid as Adsorben in Purchase of Used Lubricants Recycling of used lubricating oil is one of the alternatives in the framework of efficiency, saving oil consumption, and reducing pollution. One effort to purify used lubricating oil is to separate impurities through the adsorption method. The adsorbent that can be used is bentonite. Activation of bentonite using acid will produce adsorbent with an active side and greater surface acidity so that the adsorption ability is higher than before activated. Characteristics of lubricating oil produced are: kinematic viscosity 40 °C and 100 °C at 109.94 cSt and 14.57 cSt recently; viscosity index is 136; specific gravity 15 °C is 0.8872; and the resulting color is L5.0. Activated sulfonic bentonite can be an optimum adsorbent in purifying used lubricating oil, with optimum bentonite concentration is 30% and optimum adsorption temperature is 70 °C resulting in a 49% increase in viscosity efficiency of 40 °C and 30.79% for temperatures of 100 °C.Keywords: Bentonite, Lubricants, Adsorption ABSTRAK Daur ulang minyak pelumas bekas merupakan salah satu alternatif dalam rangka efisiensi, penghematan konsumsi minyak bumi, serta mengurangi pencemaran. Salah satu upaya menjernihkan minyak pelumas bekas adalah dengan memisahkan zat-zat pengotor melalui metode adsorpsi. Adsorben yang dapat digunakan adalah bentonit. Aktivasi bentonit menggunakan asam akan menghasilkan adsorben dengan sisi aktif dan keasaman permukaan yang lebih besar sehingga kemampuan adsorpsinya lebih tinggi dibandingkan dengan sebelum diaktivasi. Karakteristik minyak pelumas yang dihasilkan yaitu: viskositas kinematik 40 °C dan 100 °C sebesar 109,94 cSt dan 14,57 cSt secara berturut-turut; indeks viskositas sebesar 136; specific gravity 15 °C sebesar 0,8872; serta warna yang dihasilkan adalah L5,0. Bentonit teraktivasi asam sulfat mampu menjadi adsorben yang optimum dalam pemurnian minyak pelumas bekas, dengan konsentrasi bentonit optimum adalah 30% dan suhu adsorpsi optimum adalah 70 °C menghasilkan % efisiensi kenaikan viskositas sebesar 49,15% untuk suhu 40 °C dan 30,79% untuk suhu 100 °C.Kata kunci : adsorpsi, bentonit, pelumas

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Liu, Hao, Bing Xie e Yue-lin Qin. "Effect of Bentonite on the Pelleting Properties of Iron Concentrate". Journal of Chemistry 2017 (2017): 1–6. http://dx.doi.org/10.1155/2017/7639326.

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The physical and chemical properties such as particle size, montmorillonite content, swelling degree, water absorption, and blue absorption of A, B, and C bentonites were studied under laboratory conditions. The effects of adding different quality and different proportion of bentonite on falling strength, compression strength, and shock temperature of green pellet were investigated. The experimental results show that the montmorillonite content, water absorption, and methylene blue absorption of bentonite-B are the highest. And the quality of bentonite-B is the best, followed by bentonite-C and bentonite-A poor quality. When the amount of bentonite-B reduced from 1.5% to 1.0%, the strength of green pellets and the shock temperature both decrease. As the same proportion of A, B, and C bentonites, the green-ball strength and shock temperature are as follows: bentonite-A > bentonite-B > bentonite-C.

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Buzetzky, D., E. M. Kovács, M. N. Nagy e J. Kónya. "Sorption of pertechnetate anion by cation modified bentonites". Journal of Radioanalytical and Nuclear Chemistry 322, n. 3 (16 ottobre 2019): 1771–76. http://dx.doi.org/10.1007/s10967-019-06852-8.

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Abstract Pertechnetate anion sorption was investigated on modified bentonites. Mn-, Cr-, Sn-bentonites were prepared by ion exchange process to sorb radioactive pertechnetate ions. In the case of Mn-, Cr-bentonite the sorb amount of metal ion was 70–90% of the cation exchange capacity of the bentonite which is expected. Interestingly in the case of Sn-bentonite this amount was 1.42 times higher than the cation exchange capacity. On Mn-bentonite the sorption was 35% at pH 5. The removal of pertechnetate ions was 100% on Cr-, Sn-bentonites and the significant sorption was achieved below 650 mV/SHE.

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Wijayanto, Sofian, e Sunyoto Sunyoto. "Variasi Komposisi Bentonit pada Cetakan Pasir Blok Silinder Mesin Pemotong Rumput". Jurnal Dinamika Vokasional Teknik Mesin 4, n. 1 (1 aprile 2019): 31–38. http://dx.doi.org/10.21831/dinamika.v4i1.24281.

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Purpose of this research is to find out how the influence of variation of bentonite composition on the sand mold to casting defect, hardness, and microstructure. Variations of bentonite composition used were 0%, 8%, and 16%. The data of the research were analyzed directly using graphs and micro photographs which were then drawn conclusions from the results of the study. Needle-hole defects are found in all variations of bentonite composition. The porosity defect was found only in the variation of 0% and 16% bentonite compositions. The highest hardness value was obtained from the 8% bentonite composition variation is 84.26 VHN and the lowest hardness value was obtained from 0% VHN bentonite composition variation is 68.02 VHN. The best microstructure is indicated by the variation of 8% bentonite composition as evidenced by the formation of Al and Si elements that are evenly distributed and closer to the grain.Tujuan penelitian ini adalah untuk mengetahui bagaimana pengaruh variasi komposisi bentonit pada cetakan pasir terhadap cacat coran, kekerasan dan struktur mikro. Variasi komposisi bentonit yang digunakan adalah 0%, 8% dan 16%. Data hasil penelitian dianalisis secara langsung menggunakan grafik dan foto mikro yang kemudian ditarik kesimpulan dari hasil penelitian tersebut. Cacat lubang jarum ditemukan di semua variasi komposisi bentonit. Sedangkan cacat porositas hanya ditemukan pada variasi komposisi bentonit 0% dan 16. nilai kekerasan tertinggi diperoleh dari variasi komposisi bentonit 8% sebesar 84.26 VHN dan nilai kekerasan terendah diperoleh dari variasi komposisi bentonit 0% sebesar 68.02 VHN. Struktur mikro terbaik ditunjukkan oleh variasi komposisi bentonit 8% dibuktikan dengan pembentukan unsur Al dan Si yang merata dan lebih merapat letak antar butirnya.

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LV, Yiyan, Haoqing XU, Pengming JIANG e Tao WU. "Effect of Bentonite Admixture Content on Effective Porosity and Hydraulic Conductivity of Clay-based Barrier Backfill Materials". Materials Science 29, n. 3 (24 agosto 2023): 340–46. http://dx.doi.org/10.5755/j02.ms.32075.

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Clay-based barrier wall has been diffusely employed as vertical barriers. Nevertheless, there were few project practices of these walls in China. And few research have been performed to study the impact on the permeability of the addition of domestic bentonites. To solve this problem, the influences of bentonite level on hydraulic conductivity, porosity and clay-bound water of soil-bentonite admixtures have been assessed employing a flexible-wall test and water centrifugal dewatering experiment with various bentonites. The outcomes revealed that as barrier walls are constructed by blending bentonite and Fujian standard sandy soil, there is a critical bentonite level of the smallest porosity. If the bentonite level is less than the critical bentonite content, hydraulic conductivity is reduced quickly, while if the bentonite level is greater than the critical bentonite content, hydraulic conductivity is reduced gently. Additionally, as the bentonite level grew, the clay-bound water centage of the admixtures continually improved. Supposing that the clay-bound water enclosed the clay grains, a near computation approach of the effective porosity is put forward and showed that the effective porosity decreased with bentonite content. Additionally, an exponential relationship was found between the effective porosity and the permeability.

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Gerasin, Viktor A., e Viktor V. Kurenkov. "JOINT TREATMENT OF BENTONITES WITH INORGANIC POLYELECTROLYTES AND CATIONIC SURFACTANTS IN ORDER TO PROMOTE ORGANOCLAY EXFOLIATION". IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 62, n. 5 (21 maggio 2019): 71–77. http://dx.doi.org/10.6060/ivkkt.20196205.5746.

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A new approach to production of organomodified bentonites is offered. Bentonites are consecutively treated with inorganic polyelectrolyte (sodium silicate solution) and quaternary ammonium salts, as a result exfoliated organoclays are obtained. An ejector set up has been used for treatment of natural bentonites. Samples of activated bentonites treated in the ejector set up with sodium silicate solution (up to 21 g of sodium silicate per 100 g of bentonite) were prepared. Structure of the obtained bentonite and organoclay samples was established by X-ray diffraction analysis. It has been shown that treatment of the activated bentonite with sodium silicate does not influence the structure of the non-modified bentonite particles, but facilitates exfoliation of clay after organomodification. Polymer composites based on EVA containing 5% wt. of bentonites were prepared by extrusion mixing. In case of non-modified bentonites microcomposites are formed. In case of organomodified bentonites, not treated with sodium silicate, intercalated nanocomposites are formed. Treatment of bentonite with sodium silicate solution and subsequent organomodification ensures the production of exfoliated nanocomposite. Mechanical properties of obtained polymer composites were determined. Incorporation of 5% wt. clays or organoclays into the polymer material leads to increase in Young modulus (up to 50%), tensile strength (up to 20%); elongation at break decreases by 10% or less. In order to ensure the more significant reinforcing effect in EVA composites optimization of the organomodified bentonite composition (selection of surfactant and its content in the organoclay) has to be carried out with account for the polymer properties.

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Al-Asheh, Sameer, Fawzi Banat e Leena Abu-Aitah. "The Removal of Methylene Blue Dye from Aqueous Solutions Using Activated and Non-Activated Bentonites". Adsorption Science & Technology 21, n. 5 (giugno 2003): 451–62. http://dx.doi.org/10.1260/026361703769645780.

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An improvement in the adsorption capacity of naturally available bentonite towards water pollutants such as Methylene Blue dye (MBD) is certainly needed. For this purpose, sodium bentonite was activated by two methods: (1) treatment with sodium dodecyl sulphate (SDS) as an ionic surfactant and (2) thermal treatment in an oven operated at 850°C. Batch adsorption tests were carried out on removing MBD from aqueous solution using the above-mentioned bentonites. It was found that the effectiveness of bentonites towards MBD removal was in the following order: thermal-bentonite > SDS-bentonite > natural bentonite. X-Ray diffraction analysis showed that an increase in the microscopic bentonite platelets on treatment with SDS was the reason behind the higher uptake of MBD. An increase in sorbent concentration or initial pH value of the solutions resulted in a greater removal of MBD from the solution. An increase in temperature led to an increase in MBD uptake by the bentonites studied in this work. The Freundlich isotherm model was employed and found to represent the experimental data well.

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My Linh, Nguyen Le, Duc Hoang Van, Tran Duong, Mai Xuan Tinh e Dinh Quang Khieu. "Adsorption of Arsenate from Aqueous Solution onto Modified Vietnamese Bentonite". Advances in Materials Science and Engineering 2019 (11 aprile 2019): 1–13. http://dx.doi.org/10.1155/2019/2710926.

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In this study, pillared layered clays were prepared by modifying Vietnamese bentonite with polymeric Al and Fe. The obtained materials were characteristic of X-ray diffraction analysis, thermal analysis, and nitrogen adsorption/desorption isotherms. The results indicated that hydroxy-aluminum ([Al13O4(OH)24(H2O)12]7+) and poly-hydroxyl-Fe or polyoxo-Fe cations were intercalated into layers of clay, resulting in an increase of d001 values and of the specific surface areas compared with those of initial bentonite. Modified bentonites were employed to adsorb As(V) from aqueous solution. The adsorption of As(V) was strongly dependent on solution pH, and the maximum adsorption of modified bentonites was obtained in the pH 3.0 for Fe-bentonite and the pH 4.0 for Al-bentonite. The equilibrium adsorption study showed that the data were well fit by the Langmuir isotherm model. The maximum monolayer adsorption capacity of As(V) at 30°C derived from the Langmuir equation was 35.71 mg/g for Al-bentonite and 18.98 mg/g for Fe-bentonite. Adsorption kinetics, thermodynamics, and reusability of modified bentonites have been addressed.

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Wijaya, Martin, Eng Choon Leong e Hossam Abuel-Naga. "Shrinkage Curves for Powder and Granular Bentonites". E3S Web of Conferences 92 (2019): 07009. http://dx.doi.org/10.1051/e3sconf/20199207009.

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Bentonite is one of the most commonly used materials in geotechnical engineering applications especially for isolation purposes due its low permeability and its highly expansive nature. For instance, Geosynthetic Clay Liners (GCL) self-healing ability relies on the swelling properties of the bentonite to close any holes in the GCL while the low permeability of the bentonite serves to reduce the infiltration of leachate to the surrounding soil. However, different types of bentonite have different shrinkage or swelling properties and hence affects the effectiveness of the GCL. A method to assess the wetting/drying induced volume change of the bentonite is through its shrinkage curve. This paper focuses on the shrinkage behaviour of reconstituted granular and powder bentonites which are used in GCL. Photogrammetry method is used to measure the volume change of specimen during drying. The shrinkage curves of the bentonites are then compared with other bentonites from the literature.

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Åhman, Birgitta. "Intake and excretion of water in reindeer - effects of supplements of potassium and bentonite". Rangifer 8, n. 2 (1 giugno 1988): 38. http://dx.doi.org/10.7557/2.8.2.749.

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Supplements of potassium and bentonite are used to reduce absorption and increase excretion of radiocesium in reindeer. In a feeding experiment with 6 reindeer calves the effects of these supplements on water consumption and water excretion were measured. The experiment was made in three separate parts. During the first part (period I) the reindeer were fed pellets. Two reindeer god not supplements, two got 15 g K/day and two got 15 g K and 80 g bentonite/day. Supplements of K about doubled both the consumption of water and the excretion of urine. Bentonite gave no additional effect. During a period of 5 days all the reindeer were given 180 g of bentonite/day. The animals had trouble keeping their body temperature and the appetite went down. During period II the reindeer ate lichens in combination with pellets. Two reindeer got no supplements. Two got 23 g bentonite/day and two got 46 g/day. The average intake of water was not affected. Intake of water and excretion of urine was higher during collecting periods in three of the reindeer that had received bentonite. In period II the reindeer fed pellets and supplements of 23 g or 46 g of bentonite/day. The average water consumption was not affected. The intake of water and excretion of urine during collecting periods was higher in two of the three animals that had received the higher amount of bentonite. Supplements of 1% potassium or 3% of bentonite when feeding reindeer for slaughter should not cause any problems if fresh drinking water is available. The supplements cannot be recommended to reindeer on pasture in late winter and early spring.Intag och utsondring av vatten hos renar vid utfodring med foder innehållande tillsatser av kalium eller bentonit.Abstract in Swedish / Sammanfattning: Tillskott av kalium och bentonit anvånds for att minska upptaget och oka utsondringen av radioaktivt cesium hos renar. I ett utfodringsforsok med 6 renkalvar testades också dessa tillsatsers effekt på intaget och utsondringen av vatten. Forsoket utfordes i tre delar. Under forstå delen (period I) fick renarna pelleterat foder. Två renar fick inget tillskott, två fick 15 g K/dag och två 15 g K + 80 g bentonit/kg. K okade vattenforbrukningen och urinutson-dringen till ungefår det dubbla. Bentoniten gav ingen ytterligare effekt. Under 5 dagar fick samtliga renar ett tillskott av 180 g bentonit per dag. Vattenkonsumtionen okade mycket kraftigt. Renarna hade svårt att hålla kroppstemperaturen och aptiten minskade. Under period II fick renarna lav i kombination med pellets. Två renar fick inget tillskott, två fick 23 g bento-nit/dag och två fick 46 g/dag. Det genomsnittliga vattenintaget under perioden påverkades inte nåmnvårt av bentonittillskottet. Vattenintaget och urinutsondringen var dock mycket hog under uppsamlingsperioderna hos tre av de renar som fått bentonit. Under period III fick renarna åter enbart pellets. Tre renar fick 23 g bentonit/dag och tre fick 46 g. Den genomsnittliga vattenkonsumtionen påverkades inte. Vattenintaget och urinutsondringen under uppsamlingsperioderna var hogre for två av de renar som fått den storre mångden bentonit. Tillsatser av 1% kalium eller 3% bentonit vid utfodring av slaktren bor inte orsaka problem om man ser till att renarna har tillgång till vatten. Tillsatserna kan inte rekommenderas vid tillskottsutfodring av livren under vårvintern.

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Zhang, Rong Bin, Liu Jing Yao e Yan Ju. "Preparation of Au and Au-Ce Catalysts Supported on Acid-Activated Bentontie and its Catalytic Performance". Advanced Materials Research 287-290 (luglio 2011): 1704–7. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.1704.

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Acid-activated by H2SO4was applied to modify bentonite. Acid-activated bentonite supported Au catalyst was prepared by deposition-precipitation and compared with SiO2supported one. CTAB was used to modify the surface of acid-activated bentonite. Au-Ce/bentontie catalyst was prepared by adding Ce into catalyst as assistant. CO oxidation was used to evaluate the catalytic activity of samples. These samples were characterized by BET, XRD, ICP and CO-TPD. The activity results showed that Au/Bentonite was more active than Au/SiO2. The BET results showed that the surface area and pore volume of acid-activated bentontie had a substantial improvement. Using the bentontie acid-activated by 30wt%H2SO4as supporter，the Au-Ce catalyst has a better catalytic performance than Au catalyst.

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Muslimah, Muslimah, Puji Wahyuningsih e Yusnawati Yusnawati. "Effectiveness of Hydrochloric Acid Activated Bentonite in Local Salt Purification". Elkawnie 9, n. 1 (30 giugno 2023): 71. http://dx.doi.org/10.22373/ekw.v9i1.15229.

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Abstract: Various purification techniques have been developed to improve the quality of local salt, especially the NaCl content of more than 94%. One of the binding materials used in salt purification is bentonite. This study aims to synthesize modified bentonite using hydrochloric acid (HCl) solution and measure the metal content of NaCl, Pb, Ca, and Mg using AAS. The synthesis of activated bentonite was carried out using the hydrolysis method using 0.1 M HCl (1:10). Bentonite was separated from the filtrate and dried at 110°C for 2 hours. Bentonite, which had been activated with HCl, was dried again at 170°C for four hours. Analytical methods such as XRD, FTIR, and SEM were used to characterize HCl-activated bentonite. The results of the analysis showed that the acid activation process did not change the basal spacing d001 on the bentonite diffractogram. FTIR analysis showed that there was a shift in the -OH stretching vibration towards a lower wave number and a decrease in the absorption intensity. The activation process will reduce the pore size and increase the surface area and porosity of the bentonite. The results of the AAS analysis showed that the NaCl content in the salt increased after the purification process using acid-activated bentonite, followed by a decrease in the metal content of Mg. Based on the results of the analysis, it can be concluded that HCl-activated bentonite is effectively used in the salt purification process to improve salt quality.Abstrak:Berbagai teknik pemurnian telah dikembangkan untuk meningkatkan kualitas garam lokal, khususnya kandungan NaCl besar dari 94%. Salah satu zat pengikat yang digunakan dalam pemurnian garam adalah bentonit. Penelitian ini bertujuan untuk mensintesis bentonit termodifikasi menggunakan larutan asam klorida (HCl), dan mengukur kadar logam NaCl, Pb, Ca, dan Mg menggunakan metode SSA. Sintesis bentonit teraktivasi dilakukan menggunakan metode hidrolisis menggunakan 0,1 M HCl (1:10).Bentonit dipisahkan dari filtrat dan dikeringkan pada suhu 110°C selama 2 jam. Bentonit yang telah diaktivasi dengan HCl dikeringkan kembali pada suhu 170°C selama empat jam. Metode analisis seperti XRD, FTIR, dan SEM digunakan untuk mengkarakterisasi bentonit teraktivasi HCl. Hasil analisis menunjukkan bahwa proses aktivasi asam tidak mengubah basal spacing d001 pada difraktogram bentonit. Analisis FTIR menunjukkan terjadi pergeseran vibrasi ulur -OH ke arah bilangan gelombang yang lebih rendah dan penurunan intensitas serapan. Proses aktivasi akan memperkecil ukuran pori dan memperbesar luas permukaan serta porositas pada bentonit. Hasil analisis SSA menunjukkan bahwa kandungan NaCl pada garam mengalami peningkatan setelah proses pemurnian menggunakan bentonit teraktivasi asam yang diikuti dengan penurunan kadar logam Mg. Berdasarkan hasil analisis dapat disimpulkan bahwa bentonit teraktivasi HCl efektif digunakan dalam proses pemurnian garam untuk meningkatkan kualitas garam.

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16

Bourliva, A., K. Michailidis, C. Sikalidis e A. Filippidis. "Spectroscopic and thermal study of bentonites from Milos Island, Greece". Bulletin of the Geological Society of Greece 47, n. 4 (5 settembre 2013): 2020. http://dx.doi.org/10.12681/bgsg.11030.

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Bentonitic clays, currently in use in over hundred areas, are among the most important industrial raw materials. In most of the cases, bentonites predominantly consist of montmorillonite which is a 2:1 layer clay mineral formed by one alumina octahedral sheet placed between two silica tetrahedral sheets. Three bentonite composite samples (BN1, BN2, BN3) with some differences in mineralogical and chemical composition from Milos island (“Miloan”), Greece were investigated by X-ray diffraction (XRD), atomic absorption spectrometry (AAS), differential thermal analysis (DTA), thermogravimetric analysis (TG), Fourier transform infrared (FTIR) and surface area (BET) measurements techniques. Mineralogically, bentonite samples were characterized by high concentrations of smectite (>85%) and minor amounts of other clay minerals (illite and kaolinite). Nonclay minerals such as quartz, calcite and pyrite were also identified. The infrared spectrum of the bentonites also revealed the presence of dioctahedral smectite as the major component and quartz as the main impurity in all the samples. The stretching vibration at 3698cm-1 in the sample BN3 could be ascribed to kaolinite. DTA-TG curves of all samples were measured in the temperature range 75-1000oC. The total weight losses for the bentonite samples BN1, BN2 and BN3 were determined as 16.25, 12.32 and 13.35% respectively.

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Kuchkorov, Lochinbek, Nodirjon Tursunov e Anna Avdeeva. "Improving physical and mechanical properties of bentonite clay from Navbahar clay deposit". E3S Web of Conferences 401 (2023): 05020. http://dx.doi.org/10.1051/e3sconf/202340105020.

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Different compositions of mixtures of sand and clay with medium-grade bentonite for molding of critical large parts of a freight car bogie are examined in the article. Different compositions to improve bentonite’s physical and mechanical properties, such as gas permeability and compressive strength with the addition of soda ash, are considered. As a material for the study of sand and clay mixtures were taken quartz sand grade 1K2O2025, medium strength bentonite Navbaharskogo birthplace, and for improving the physical and mechanical properties of bentonite - soda ash. One possible way to increase bentonite's stability at high temperatures is to treat it with sodium-containing powder like soda ash. The treatment is performed by adding soda ash in powder form to dried bentonite. Experimental results are given in the form of tables and diagrams. Experimental studies were carried out in the production conditions of the central plant laboratories at ES “Liteyno-mechanical plant”. The experiments were carried out following the normative documents. The basis of the results was plotted, and the assumed composition of sand and clay mixtures was established.

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18

Zhuravlev, F. M., E. V. Chuprinov, V. P. Lyalyuk, D. A. Kassim e I. A. Lyakhova. "Material composition and characteristics of bentonite clays used as a binder in the production of iron ore pellets". Ferrous Metallurgy. Bulletin of Scientific , Technical and Economic Information 76, n. 1 (7 febbraio 2020): 30–40. http://dx.doi.org/10.32339/0135-5910-2020-1-30-40.

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In the production of iron ore pellets, binding additives are used, in particular, bentonite clays. At present, instead of alkaline bentonite clays used before, the alkaline-earth bentonite clays modified by soda ash are used, supplied from abroad. There is a whole number of bentonite clays deposits in Russia and Ukraine having reserves of the raw material accounting hundreds of million tons, which are not used in the industry because of absence of planned and proper studies of their applicability for pellets production. The analysis of chemical composition carried out and requirements to rheological characteristics of bentonite clays used in the iron ore pellets production at steel-works of Russia and Ukraine determined. Indicators of swelling and water absorption of mono-ionic forms of bentonite of some deposits in water of various hardness presented. Quality of pellets with bentonites, having different exchange complex when using technical water of various hardness considered. Analysis of mineralogical and chemical compositions, as well as value and content of exchange complex of alkaline-earth bentonite clays of Cherkassk deposition, Ukraine, accomplished. The deposition has the largest reserves of such clays in CIS. It was shown, that clays suitable for pellets production, are located near the earth surface. Comparative analysis of strength indicators of pellets, produced with bentonite application with alkaline and alkaline-earth complexes, carried out. It was shown, that despite the low swelling of alkaline-earth bentonites, the quality of pellets, produced with those bentonites is sometimes a little lower, but under definite conditions does not yield to the quality of pellets with alkaline bentonites at the same their consumption.

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19

Chukwu, U. J., I. P. Okoye e E. I. Awosu. "Impact of acid activated Bentonites on foster swelling capacity and sorption dynamics of hydrocarbons, phenol and water". Scientia Africana 20, n. 1 (23 aprile 2021): 101–8. http://dx.doi.org/10.4314/sa.v20i1.9.

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The successful protonation of the dissociable 𝐻 + from different organic acids (with varying alkyl chains) to supplant sodium ions in the inter layers of bentonites resulting in increased surface area has been carried out. The resultant materials were characterized using foster swelling and adsorption capacity techniques. Results show that the foster capacities of acid activated bentonites were greater than the un-activated bentonite (UAB) upon interaction with petroleum hydrocarbons. The bentonite activated with the organic acid having the most alkyl chain, hexanoic acid activated bentonite (HAAB) showed high affinity for all petroleum hydrocarbons. This demonstrates the hydrophilicity of UAB and upon activation, the hydrophobic properties of HAAB. The adsorption capacity result records that bentonites and HAAB adsorbed more petroleum hydrocarbon solvents than other lower alkyl chain acid activated bentonites and UAB. This study shows that HAAB is an excellent adsorbent for the removal of hydrocarbons from industrial wastes. Keywords: Acid Activated Bentonite, Foster Swelling, Adsorption Capacity, Organic Acids, Phenol

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20

Liu, Xiao Dong, Xian Jun Lu, Jun Qiu, Zhi Ming Wang e Peng Wu. "Purification of Low Grade Ca-Bentonite for Iron Ore Pellets". Advanced Materials Research 454 (gennaio 2012): 237–41. http://dx.doi.org/10.4028/www.scientific.net/amr.454.237.

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According to the bentonites properties and mineral composition, three bentonites with 32-36% montmorillonite content(MC) from Laiyang, Shandong, China, are purified for utilizing low grade bentonite sufficiently. Research shows that the purification is effective by separating –325 mesh products from raw bentonite after soaking, stirring and rubbing in water. Firstly, the three bentonites are combined into one and soaked in water for 24h with the ratio of liquid and solid 15:1, and then, the bentonite is purified using –325 mesh sieve after stirring and rubbing in water for 1h with pulp density of 26%. Methylene blue index(MBI) of the product is 22.52g/100g, swell index(SI) is 5.5mL/2g, water absorption(WA) is 184.3%, water content(Wa.C) is 9.7%, and the indexes meet the stantard of three grade Ca-bentonite(TGCB)applying to iron ore pellets.

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21

Komine, Hideo, e Nobuhide Ogata. "Prediction for swelling characteristics of compacted bentonite". Canadian Geotechnical Journal 33, n. 1 (25 marzo 1996): 11–22. http://dx.doi.org/10.1139/t96-021.

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Compacted bentonites are attracting greater attention as back-filling (buffer) materials for high-level nuclear waste repositories. For this purpose, it is very important to quantitatively evaluate the swelling characteristics of compacted bentonite. New equations for evaluating the relationship between the swelling deformation of compacted bentonite and the distance between two montmorillonite layers are derived. New equations for evaluating the ion concentration of pore water and the specific surface of bentonite, which significantly influence the swelling characteristics of compacted bentonite, are proposed. Furthermore, a prediction method for the swelling characteristics of compacted bentonite is presented by combining the new equations with the well-known theorectical equations of repulsive and attractive forces between two montmorillonite layers. The applicability of this method was investigated by comparing the predicted results with laboratory test results on the swelling deformation and swelling pressure of compacted bentonites. Key words: bentonite, diffuse double-layer theory, van der Waals force, nuclear wastes disposal, swelling deformation, swelling pressure.

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22

Tan, Yunzhi, Hui Li, De’an Sun e Huajun Ming. "Granular Bentonite Preparation and Effect of Granulation Behavior on Hydromechanical Properties of Bentonite". Advances in Civil Engineering 2020 (10 settembre 2020): 1–13. http://dx.doi.org/10.1155/2020/8879792.

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Compacted bentonite is regarded as a suitable buffer/backfill material in a high-level radioactive waste disposal repository due to its low permeability, high swelling, and strong adsorption capacity, but the bentonite powder is difficult to compact to a high density only by increasing the compaction energy. Hence, a proposal is made to improve the compactness of bentonite by changing its grain size distribution. To obtain bentonite granules with different sizes, a granulation method is proposed in this paper, in which bentonite powders experience the processes of wetting and drying into plate bentonites, which are then crushed into granules. Furthermore, in this paper, the hydromechanical behavior of granular bentonite is evaluated to verify the feasibility of the method for preparing granules. For this purpose, the granular and original bentonite powder with similar grain sizes were prepared; then, various laboratory tests, including measurements of free swelling ratio, swelling pressure, water retention capacity, and compactness, were carried out. The test results show that the free swelling ratio, swelling pressure, permeability coefficient, and water retention capacity of granular bentonite are almost similar to those of original bentonite, and after compaction, the maximum dry densities of granular and original bentonites are 1.72 and 1.64 g/cm3 at the optimum moisture content (20%) and the energy consumption was reduced by 38% with the void ratio decreased from 1.30 to 0.8 compared with the original bentonite. It indicates that, compared with the original bentonite, the hydromechanical behavior of granular bentonites changed a little, but its compaction performance has been significantly improved. To investigate the differences in pore size distributions of granular bentonite and original bentonite, MIP and NA tests were performed on samples produced with the wetting-drying agglomerate method, and the results show that the pores with a size of 10.0 μm almost disappear and the pores mainly exist with a size of approximately 1.0 μm. It can be verified that preparing granules by the wetting-drying agglomeration method is feasible, the granulation process has little effect on the hydromechanical properties of bentonite, and after granulation, not only the compactness is improved but also the energy consumption is saved.

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23

Izosimova, Yulia, Inna Tolpeshta, Irina Gurova, Michail Karpukhin, Sergey Zakusin e Victoria Krupskaya. "Sorption of Cu2+ Ions by Bentonite Modified with Al Keggin Cations and Humic Acid in Solutions with pH 4.5". Minerals 10, n. 12 (14 dicembre 2020): 1121. http://dx.doi.org/10.3390/min10121121.

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The sorption of Cu2+ onto bentonite modified with Al Keggin cations and humic acid from CuCl2 solutions at pH 4.5 was studied. Modification of Na-bentonite with Al Keggin cations was found to result in an increase in the basal spacing of montmorillonite from 1.29 nm for N-form to 1.85 and 1.78 nm for HAl13 and Al13 forms respectively, in a reduction of CEC (cation exchange capacity) and in the formation of additional sites with a variable charge with pHPZC 4.2. Al13-bentonite is not affected by heat. Under the conditions of the experiments at pH of 4.5 Na-bentonite adsorbs more Cu2+ from CuCl2 solutions then Al13 forms of bentonites. The main mechanism of copper sorption on Na-bentonite is the cation exchange Cu2+–Na+. The reduction of CEC of Na-bentonite after modification with Al Keggin cations leads to a decrease in the Cu2+ sorption. pH-dependent sorption sites on Al13-bentonites have a pHPZC of 4.2 and, therefore, under conditions of the experiment have positive charge which prevents Cu2+ sorption. Na-bentonite adsorbs more humic acid solution (HA) then Al13-bentonite and the proportion of adsorbed HA remains constant over the entire concentration range. Treatment of the Al13-bentonite with HA leads to the formation of the additional sorption sites. The amount of sorbed Cu2+ and the percentage of their extraction from solutions by HAAl13-bentonite is similar to those values for Na-bentonite.

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Jeon, Han Yong. "Temperature Effects and pH Value on Free Swell Behaviors of Bentonite Solutions". Advanced Materials Research 983 (giugno 2014): 44–51. http://dx.doi.org/10.4028/www.scientific.net/amr.983.44.

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Swelling behaviors of powder and granular type sodium bentonites in permeate solutions such as NaCl, KCl, MgCl2, CaCl2, distilled water and in HCl and NaOH (with different pH values) under different temperatures were investigated. Swelling behaviors of these bentonites were dependent on strength, reactivity power and physical form of ion, and temperature and pH value of permeate solution. +1 ion solution showed higher swell volumes than +2 ion solution. Distilled water showed highest swell volumes among these tested solutions. Powder type sodium bentonite showed higher swells volume than granular type bentonite. Higher temperatures brought quickly the bentonite to a stable swell volume state. The pH value also affected on swelling volumes of bentonite as lower pH values (pH<3) increased and higher pH values (11<pH<12) decreased the swell volume of powder and granular type sodium bentonite.

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25

Ahmad Fauzi, A. A., Azlin Fazlina Osman, M. A. A. Abdullah e S. Mandal. "Destabilization of Natural and Commercial Bentonite Interlayers by Ultrasonication, pH Control and Salt Addition". Solid State Phenomena 280 (agosto 2018): 115–20. http://dx.doi.org/10.4028/www.scientific.net/ssp.280.115.

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Natural and commercial bentonites can act as efficient fillers to reinforce a polymer matrix if their strong interlayer binding forces are weakened to reduce tactoid formation. In this research, interlayers destabilization process was applied to gain a loosely packed, swelled and disorganized clay layered structure for better polymer intercalation and filler dispersion during the polymer/clay composite fabrication. Three different destabilization methods were applied to the natural and commercial bentonites and their effects on swelling and platelets ordering/stacking of the clays were observed. The pristine and destabilized natural and commercial bentonites were characterized and compared based on their chemical component (XRF), chemical structure (XRD) and morphology (FESEM). Chemical analysis revealed that alumina content in the natural bentonite is less than in the commercial bentonite while silica content in natural bentonite is more than in the commercial bentonite. XRD results suggest that basal spacing (d001) of both natural and commercial bentonites reduced when single destabilization process (by salt addition) was applied but increased when destabilization was done by the combination of pH control and salt addition processes. These show that the destabilization process through combination of pH control and salt addition is more efficient in swelling both natural and commercial bentonite clays. This is supported by FESEM analysis where smaller, more loosely packed and uniform platelets were observed due to swelling and weakening of the interlayer binding forces of both natural and commercial bentonite clays.

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Jovic-Jovicic, Natasa, Danica Bajuk-Bogdanovic, Tatjana Novakovic, Predrag Bankovic, Aleksandra Milutinovic-Nikolic e Zorica Mojovic. "Electrochemical properties of carbonized bentonite". Journal of the Serbian Chemical Society, n. 00 (2022): 30. http://dx.doi.org/10.2298/jsc220127030j.

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Organomodified bentonites were obtained by modification of bentonite clay from local mine Bogovina with four different alkylammonium ions in the amounts that correspond to cation exchange capacity. Carbonized bentonites, obtained by pyrolyzing the organomodified bentonites in the flow of nitrogen, were characterized using the XRD, low-temperature N2 physisorption, and Raman spectroscopy. Structural and textural properties of carbonized bentonites depended on the arrangement of alkylammonium cations in the paternal organomodified bentonite, while the Raman spectroscopy confirmed the presence of amorphous carbon. The obtained carbonized bentonites were used for modification of the carbon paste electrode. The modified electrodes were investigated using cyclic voltammetry and electrochemical impedance spectroscopy. The electrosorption of chloride and sulfate anions on carbonized bentonites was studied by chronocoulometry. The results were interpreted in the terms of surface groups and textural properties of the carbonized bentonites.

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Barker, Ivan R., Desmond E. Moser, Sandra L. Kamo e A. Guy Plint. "High-precision U–Pb zircon ID–TIMS dating of two regionally extensive bentonites: Cenomanian Stage, Western Canada Foreland BasinThis article is one of a series of papers published in this Special Issue on the theme of Geochronology in honour of Tom Krogh." Canadian Journal of Earth Sciences 48, n. 2 (febbraio 2011): 543–56. http://dx.doi.org/10.1139/e10-042.

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The stratigraphy of Cretaceous rocks in the Western Canada Foreland Basin is well constrained by dense borehole data that allow three-dimensional mapping of transgressive–regressive events, paleogeography, and subsidence patterns. However, it is difficult to estimate rates of change or to place events in a precise temporal framework because very few of the many bentonite beds have been dated using modern techniques. In this study, two bentonites, of at least regional extent, were dated using isotope dilution – thermal ionization mass spectrometry (ID–TIMS) U–Pb methods on chemically abraded zircon crystals. The older bentonite correlates with the “X” bentonite of the late middle Cenomanian and yields an age of 95.87 ± 0.10 Ma. The Bighorn River Bentonite, which lies just below the Cenomanian–Turonian boundary, yields an age of 94.29 ± 0.13 Ma and is interpreted to equate with the “B” bentonite and bed 80 at Pueblo, Colorado. Both bentonites dated here are older than the previously reported 40Ar/39Ar ages from correlative United States samples, supporting the observation that 40Ar/39Ar ages may systematically underestimate ages of Cretaceous bentonites by ∼1%, as suggested by other recent studies. The X bentonite immediately precedes a major late middle Cenomanian eustatic transgression that inundated the Dunvegan delta complex. The new ages for the X and Bighorn River bentonites indicate an average minimum subsidence rate of ∼0.27 mm/year in the most proximal part of the Cenomanian foredeep in northeast British Columbia during this time. The new age of the Bighorn River Bentonite, coupled with the orbitally tuned time scale of Sageman et al. (2006) , suggests a Cenomanian–Turonian boundary age of 94.12 ± 0.13 Ma.

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Yildiz, A., e M. Kuscu. "Origin of the Basoren (Kutahya, W Turkey) bentonite deposits". Clay Minerals 39, n. 2 (giugno 2004): 219–31. http://dx.doi.org/10.1180/0009855043920132.

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AbstractBentonite deposits in Basoren Kutahya, West Anatolia, Turkey formed from alteration of perlite and pyroclastic rocks of Pliocene age. The distribution of bentonite deposits along faults in the study area indicates that the alteration solutions were hydrothermal. Although lateral zonation is observed in bentonite deposits in some regions (i.e. Demirli, Akyokus, Seklice- Sarıokuz, etc.), alteration zones are extremely irregular in the Cayırlık bentonite deposit.X-ray diffraction studies have shown that Basoren bentonites contain dioctahedral Ca-smectite.The Greene-Kelly test (Li-saturation and heating) showed that the Demirli and Akyokus bentonites consist of montmorillonite and that the Cayırlık bentonite consists of montmorillonite and/or beidellite. Spherulitic or hemispherical ‘crystals’ of opal-CT minerals formed from hydrothermal alteration of volcanic glass. The MgO, CaO and total Fe2O3 enrichment in bentonites, compared to parent rocks, is related to the chemical composition of hydrothermal solutions that passed through the ophiolitic rocks such as serpentinite.

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Piluarto, Bambang, Yusril Ihza Mahendra e Novita Andarini. "HYBRID KITOSAN/BENTONIT SEBAGAI MATRIKS UNTUK PELEPASAN ION AMONIUM DALAM AIR". Jurnal Kimia Riset 1, n. 1 (1 giugno 2016): 42. http://dx.doi.org/10.20473/jkr.v1i1.2441.

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AbstrakHybrid kitosan/bentonit dalam bentuk bead telah berhasil dibuat dengan berbagai rasio komposisi kitosan dan bentonit. Dalam penelitian ini, bead dari hybrid ini digunakan sebagai matriks untuk ion amonium. Bead dibuat dengan pengendapan suspensi kitosan dan bentonit menggunakan koagulan NaOH. Bead hybrid yang diperoleh dikarakterisasi daya serap air (DSA) dan pelepasan ion amonium dalam air. Hasil yang diperoleh menunjukkan bahwa bentuk bead dipengaruhi oleh kandungan bentonit dalam hybrid. Peningkatan kandungan bentonit dalam hybrid menurunkan nilai DSA, namun meningkatkan pelepasan ion amonium dalam air. Sisa basa pada permukaan bead hybrid mempengaruhi deteksi pelepasan ion amonium dalam air. Kata kunci: hybrid, bead, suspensi, daya serap air, pelepasan ion AbstractChitosan/bentonite hybrid in the form of beads was successfully prepared in various of chitosan and bentonite composition ratio. In this study, beads of hybrid play role as matrix for ammonium ions. Beads prepared by precipitation of chitosan and bentonite suspension using NaOH as coagulant. Characterization beads obtained were carried out on water uptake and release of ammonia ions in the water. The results showed that forms of bead were affected by bentonite content in the hybrid. Increasing of bentonite content decreased water uptake of hybrid, however the release of ammonia ions in the water increased. Remaining base in the beads surface affected detection of release of ammonia ions in the water. Keywords: hybrid, beads, suspension, water uptake, release of ions

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Sudheer Kumar, Ritwick, Carolin Podlech, Georg Grathoff, Laurence N. Warr e Daniel Svensson. "Thermally Induced Bentonite Alterations in the SKB ABM5 Hot Bentonite Experiment". Minerals 11, n. 9 (18 settembre 2021): 1017. http://dx.doi.org/10.3390/min11091017.

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Pilot sites are currently used to test the performance of bentonite barriers for sealing high-level radioactive waste repositories, but the degree of mineral stability under enhanced thermal conditions remains a topic of debate. This study focuses on the SKB ABM5 experiment, which ran for 5 years (2012 to 2017) and locally reached a maximum temperature of 250 °C. Five bentonites were investigated using XRD with Rietveld refinement, SEM-EDX and by measuring pH, CEC and EC. Samples extracted from bentonite blocks at 0.1, 1, 4 and 7 cm away from the heating pipe showed various stages of alteration related to the horizontal thermal gradient. Bentonites close to the contact with lower CEC values showed smectite alterations in the form of tetrahedral substitution of Si4+ by Al3+ and some octahedral metal substitutions, probably related to ferric/ferrous iron derived from corrosion of the heater during oxidative boiling, with pyrite dissolution and acidity occurring in some bentonite layers. This alteration was furthermore associated with higher amounts of hematite and minor calcite dissolution. However, as none of the bentonites showed any smectite loss and only displayed stronger alterations at the heater–bentonite contact, the sealants are considered to have remained largely intact.

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Osacky, M., V. Šucha, M. Miglierini e J. Madejová. "Reaction of bentonites with pyrite concentrate after wetting and drying cycles at 80°C: relevance to radioactive waste (Radwaste) storage". Clay Minerals 47, n. 4 (dicembre 2012): 465–79. http://dx.doi.org/10.1180/claymin.2012.047.4.06.

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AbstractThe mineral stability of two bentonites was studied in the presence of pyrite concentrate to simulate the possible reactions between the bentonite barrier used in a high-level nuclear waste (HLW) repository and host rock containing up to 5 wt.% of admixed pyrite. Smectite was the only bentonite mineral affected by pyrite treatment under the experimental conditions used. Bentonites reacted differently with pyrite due to the different nature of the smectites. The distinct crystal chemistry of the smectites controlled by the composition of the parent rocks influenced the smectite surface properties (cation exchange capacity and layer charge distribution) which resulted in a different response of the bentonites to pyrite treatment. A partial transformation of the original smectites into H-smectites represented the initial stage of smectite destabilization on acid attack. Rising non-equivalent isomorphous substitution in the octahedral sheets of the smectites enhanced smectite reactivity and thus the reaction between bentonite and pyrite, causing lower stability of the bentonite containing high-charge smectite.

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Sari, Nerry Puspita, e Pirim Setiarso. "PEMBUATAN ELEKTRODA KERJA GRAPHENE OXIDE TERMODIFIKASI NANO BENTONIT UNTUK ANALISIS ASAM NIKOTINAT SECARA VOLTAMETRI SIKLIK MAKING OF GRAPHENE OXIDE NANO BENTONITE MODIFIED WORKING ELECTRODE FOR ANALYSIS NICOTINIC ACID USING CYCLIC VOLTAMMETRY". Unesa Journal of Chemistry 9, n. 3 (29 novembre 2020): 170–78. http://dx.doi.org/10.26740/ujc.v9n3.p170-178.

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Pada penelitian ini telah dilakukan penelitian pengukuran asam nikotinat menggunakan elektroda kerja Graphene oxide termodifikasi nano bentonit dengan metode voltametri siklik. Elektroda kerja Graphene oxide termodifikasi nano bentonit dibuat dengan cara mencampurkan Graphene oxide, parafin, dan nano bentonit dengan perbandingan 3:5:2, 3:4:3, 3:3:4, 3:2:5. Parameter optimasi yang diuji yaitu kondisi optimum (pH, waktu deposisi, dan laju pindai), komposisi modifier nano bentonit yang ditambahkan. Elektroda kerja Graphene oxide termodifikasi nano bentonit pada kondisi pengukuran optimum digunakan untuk menentukan analisis asam nikotinat secara voltametri siklik. Hasil penelitian menunjukkan komposisi terbaik diperoleh 3:3:4 dengan nilai puncak katodik -0.00375A. pH optimum diperoleh 5 dengan nilai puncak katodik -0.00337A. Waktu deposisi optimum diperoleh selama 5 detik dengan nilai puncak katodik -0.00144A dan laju pindai optimum diperoleh 100 mV/detik dengan nilai puncak katodik -0.00272A. Perbandingan persen perolehan kembali asam nikotinat secara voltametri siklik dengan elektroda kerja Graphene oxide termodifikasi nano bentonit lebih besar yaitu 96.164% dibandingkan dengan metode HPLC adalah 88.332%.Kata kunci : graphene oxide, nano bentonit, asam nikotinat, voltametri siklik In this research modified Graphene oxide electrode with nano bentonite has been prepared, for determination of nicotinic acid using cyclic voltammetry. Graphene oxide electrode modified by nano bentonite was made by with mixing Graphene oxide, paraffin, and nano bentonite with 3:5:2, 3:4:3, 3:3:4, 3:2:5. The observed parameters includes pH, deposition time, scan rate at modified Graphene oxide electrode with nano bentonite, and composition of modifier in modified Graphene oxide Graphene oxide electrode with nano bentonite. The results showed the best composition obtained 3:3:4 with an peak of cathodic value of -0.00375A. The optimum pH obtained 5 with an peak of cathodic value of -0.00337A.The optimal deposition time obtained for 5 seconds with an peak of cathodic value of -0.00144A and optimal scanning rate obtained 100 mV/second with an peak of cathodic value -0.00272A. Comparison of the results of nicotinic acid recovery using Graphene oxide nano bentonite modified electrode using the cyclic voltammetry method is greater that is 96.164% compared to the method HPLC is 88.332%.Key words: graphene oxide, nano bentonite, nicotinic acid, cyclic voltammetry

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Safitri, Rahayu Puji, Mochammad Arief Budihardjo e Budi Prasetyo Samadikun. "Sistematik Review: Perbandingan Penggunaan Kaolin dan Bentonit dalam Penelitian Remediasi Elektrokinetik untuk Penyisihan Logam Berat". Jurnal Kesehatan Lingkungan Indonesia 21, n. 3 (27 luglio 2022): 301–10. http://dx.doi.org/10.14710/jkli.21.3.301-310.

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Latar belakang: Perbedaan mekanisme remediasi elektrokinetik salah satunya disebabkan oleh distribusi gugus ≡SOH yang berbeda beda pada jenis lempung yang dapat mengontrol muatan permukaan lempung. Bentonit dan kaolin merupakan jenis lempung yang seringkali digunakan dalam penelitian remediasi elektrokinetik tanah terkontaminasi logam berat. Oleh karenanya, tujuan dari review jurnal ini adalah mengkaji perbandingan penggunaan kaolin dan bentonit dalam remediasi elektrokinetik tanah terkontaminasi logam berat, baik dalam publikasi penelitiannya, karakteristiknya dan pengaruhnya terhadap mekanisme remediasi elektrokinetik.Metode: Metode yang digunakan dalam review jurnal ini adalah systematic literature review, yang terdiri dari tahap identifikasi kata kunci, screening dokumen terpublikasi dan pemilihan jurnal berdasarkan kriteria-kriteria tertentu. Data base yang digunakan berasal dari Scopus, Science Direct dan Springer. Dokumen yang telah terpilih selanjutnya dianalisis dan dibandingkan. Hasil: Sebanyak 92% dari dokumen terpilih menggunakan kaolin dalam peneltian EKR, sedangkan 8% lainnya menggunakan bentonit. Berdasarkan karakteristiknya, bentonit memiliki daya adsorbsi yang lebih tinggi dari kaolin, namun, memiliki efisiensi penyisihan yang lebih rendah dari kaolin. Dalam pengaruhnya terhadap mekanisme remediasi elektrokinetik, arah aliran EOF kaolin maupun bentonit pada umumnya menuju katoda, namun bentonit dapat menyerap elektrolit lebih banyak dari kaolin, sehingga memiliki kadar air yang lebih tinggi. Sedangkan untuk konsumsi energi, remediasi elektrokinetik pada kaolin memerlukan energi yang lebih rendah dari bentonit.Simpulan: Bentonit dan kaolin memiliki perbedaan karakteristik pada kapasitas adsorbsi, efisiensi penyisihan logam berat, dan konsumsi energi. Meskipun arah aliran EOF pada bentonit dan kaolin sama, namun kapasitas penyerapan elektrolit pada bentonit lebih besar dari kaolin. ABSTRACTTitle: Research Study on the Use of Kaolin and Bentonite in Electrokinetic Remediation for Heavy Metal RemovalBackground: One of the differences in the electrokinetic remediation mechanism is caused by the distribution of different ≡SOH groups on the type of clay that can control the surface charge of the clay. Bentonite and kaolin are types of clay that are often used in the study of electrokinetic remediation of heavy metal contaminated soils. Therefore, the purpose of this journal review is to compare the use of kaolin and bentonite in the electrokinetic remediation of heavy metal contaminated soils, both in their research publications, their characteristics and their effect on the electrokinetic remediation mechanism. Method: The method used in this journal review is a systematic literature review consisting of keyword identification, screening published documents and selecting journals based on certain criteria. The database used comes from Scopus, Science Direct and Springer. The selected documents are then analyzed and compared.Result: As many as 92% of the selected documents used kaolin in the EKR study, while 8% used bentonite. Based on its characteristics, bentonite has a higher adsorption capacity than kaolin. However, it has a lower removal efficiency than kaolin. In its influence on the electrokinetic remediation mechanism, the flow direction of kaolin and bentonite EOF is generally towards the cathode, but bentonite can absorb more electrolytes than kaolin, so it has higher water content. As for energy consumption, electrokinetic remediation on kaolin requires lower energy than bentonite.Conclusion: Bentonite and kaolin have different characteristics in adsorption capacity, heavy metal removal efficiency, and energy consumption. Although the direction of EOF flow in bentonite and kaolin is the same, the electrolyte absorption capacity of bentonite is greater than that of kaolin.

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Zhang, Bing Bing, Ming Yue Miao, Jing Bai, Guang Jin Yuan, Yan Yan Jia, Zhe Xiang Han, Zhi Guo Zhao e Hai Quan Su. "Researches on Purification and Sodium-Modification of Ca-Bentonite by Tri-Roller Grinder". Advanced Materials Research 962-965 (giugno 2014): 809–13. http://dx.doi.org/10.4028/www.scientific.net/amr.962-965.809.

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To fully evaluate the usability of a raw Ca-bentonite source and to deeply understand the property of bentonite mineral are critical for applications of these special layered materials. Due to sodium bentonites have several advantages over calcium bentonites, especially in expansibility, cation exchange capacity, cohesive force, dispersibility, and thermostability, sodium-modification of Ca-bentonite is regarded as a top priority of effective utilization of abundant Ca-bentonite source in China. In present work, the purified Na-montmorillonite was synthesized by purification and sodium-modification of a raw Ca-bentonite source (Liaoning, China) by tri-roller grinder. Important influencing factor rolling times in purification and sodium modification process was investigated. Mineral compositions, microscopic morphology, and thermal stability were characterized by using different techniques. The crystalline phases and compositions were identified by X-ray powder diffraction (XRD). The morphology and structure were evaluated by scanning electron microscopy (SEM). The thermal properties were investigated using differential thermal gravity analysis (DTG) and differential thermal analysis (DTA) analysis.

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Kaufhold, Stephan. "Discussion of parameters used to distinguish suitable from less suitable HLRW bentonites". Safety of Nuclear Waste Disposal 1 (10 novembre 2021): 125–26. http://dx.doi.org/10.5194/sand-1-125-2021.

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Abstract. Bentonites will be used in the construction of some high-level radioactive waste (HLRW) repositories mostly in combination with crystalline host rocks. They will be used both as a geotechnical barrier (compacted bentonite blocks) around the canisters and for backfilling. The bentonite should be stable in contact with cement pore water, minimize metal corrosion, be stable against erosion and various salt solutions, retard radionuclides, prevent canister displacement, possess high thermal conductivity, be stable against radioactive radiation, keep its swelling capacity even when dried, and, most importantly, should have a low hydraulic conductivity. Bentonites are natural materials (clays) which are dominated by swelling clay minerals called smectites. All bentonites, therefore, possess high water uptake capacity, swelling, and cation exchange properties. Different bentonites from different deposits worldwide differ with respect to their chemical and mineralogical composition, composition and charge distribution of the smectites, particle size and morphology, microstructure (arrangement of particles relative to each other), and interlayer population. All these parameters affect the performances of bentonites in different applications. The bentonite industry, therefore, compares different bentonites based on empirical investigations to produce superior products. Specifications which could be used to select a suitable HLRW bentonite were discussed by Kaufhold and Dohrmann (2016). Additional information has been published later (Kaufhold et al., 2020a, b). First of all, some of the above listed desired bentonite properties depend more on the degree to which it is compacted compared to the natural variability. High compaction decreases the hydraulic conductivity and increases thermal conductivity. In order to prevent canister displacement only a small swelling pressure is needed which is easily achieved by compaction with all bentonites. Generally, the type of exchangeable cation is the most important parameter determining bentonite properties such as swelling and rheology. Large scale deposition tests, however, proved that the cation population will readily equilibrate with the surrounding water. The initial type of exchangeable cation is, therefore, less relevant. More important is the Fe content which negatively affects the thermal and chemical stability. Structural Fe of the smectites can be reduced or oxidized by bacteria and radiation. The Fe content of the bentonite should therefore be low. Highly charged smectites proved to be less corrosive in combination with iron canisters because they provide more reducing conditions compared to low charged ones. Bentonites containing highly charged smectites should be preferred if Fe canisters are used. In the case of Cu canisters no effect of the charge could be found. Also, soluble or at least partly soluble components such as sulphates, sulphides, carbonates, and organic matter should be absent since their possible dissolution would decrease the dry density and hence the swelling pressure. The presence of reactive silica in some bentonites proved to buffer the dissolution reactions at the cement bentonite interface and hence could have a beneficial effect.

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Mota-Heredia, Carlos, Jaime Cuevas e Raúl Fernández. "Effect of Iron Chloride (II) on Bentonites under Hydrothermal Gradients: A Comparative Study between Sodium Bentonite and Calcium Bentonite". Minerals 14, n. 2 (25 gennaio 2024): 132. http://dx.doi.org/10.3390/min14020132.

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This study investigates the performance of two bentonite materials, specifically MX-80 (Na-bentonite) and FEBEX (Ca-Mg-Na-bentonite), employed as engineered barriers in deep geological disposal facilities for the isolation of high-level radioactive waste, contained in metallic canisters. Experiments conducted at the laboratory scale focused on the interaction of these bentonites with FeCl2 powder, used as a soluble iron source, to observe enhanced alteration of the bentonite. The experiments were carried out under a hydrothermal gradient. A dominant Na-Cl-SO4 saline solution was put in contact with the compacted bentonites from the top, while a constant temperature of 100 °C was maintained at the bottom using a heater in contact with the layer of FeCl2. The experimental cells were examined after six months of interaction. Various changes in the physical and chemical properties of the bentonites were observed. An increase in the water content, a reduction in the specific surface area and cation exchange capacity, changes in the distribution of aqueous species, and the formation of secondary minerals were observed. Reaction products formed at the bentonite interface with FeCl2, primarily comprising akaganeite, goethite, and hematite. The smectites showed evident structural modifications, with an enrichment in iron content, and a shift in the exchangeable ion distribution in the case of MX-80 bentonite. This work provides valuable insights into the complex interactions between bentonite barriers and materials that dissolve iron, serving as proxies for deep geological disposal environments and indicating the potential long-term behavior, taking into account higher concentrations of dissolved iron than those expected in a real repository.

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E, Chuprinov, Lyalyuk V, Zhuravlev F, Kassim D e Lyakhova I. "The potential of using of alkaline earth bentonite clays of Ukraine in the production of iron ore pellets". Theory and practice of metallurgy 1,2020, n. 1,2020 (124) (21 gennaio 2020): 36–43. http://dx.doi.org/10.34185/tpm.1.2020.05.

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Objective: to analyze and determine the potential of alkaline earth bentonite clays of Ukraine for use as a binder in the production of iron ore pellets. Methods: performing rheological studies of bentonite clay samples and their chemical analysis, electron microscopic studies of samples. Results: the analysis of the chemical composition and requirements for the rheological characteristics of bentonite clays used in the production of iron ore pellets at metallurgical enterprises of Russia and Ukraine is carried out. The swelling indicators and water absorption of monoionic forms of bentonites of some deposits in water of different hardness are given. The quality of pellets with bentonites, that have a different exchange complex, during an industrial water of various hardness usage is examined. The analysis of the mineralogical and chemical composition, as well as the size and composition of the exchange complex of alkaline-earth bentonite clays of the Cherkassk deposit (Ukraine), which has the largest reserves of such clays in the CIS is carried out. It is shown that clays suitable for the production of pellets are located near the surface of the earth. A comparative analysis of the strength characteristics of pellets using bentonites with an alkaline and alkaline-earth exchange complex is presented. Scientific novelty: it was shown that despite the low swelling of alkaline-earth bentonites, the quality of pellets with these bentonites, in some cases, is slightly lower, and in certain conditions is not inferior to the quality of pellets with alkaline bentonites at the same flow rate. Practical significance: for real industrial conditions it is shown that the increase in water hardness leads to partial or complete (depending on the value of hardness) replacement of alkaline exchange complex with alkaline earth and conversion of alkaline bentonite clay into alkaline earth with corresponding rheological characteristics, deterioration of lumps and the need to increase the content of bentonite in the charge. In the case of increased hardness of water in the concentrate, it is economically feasible to use in the production of alkaline earth pellets bentonite clay, if it is cheaper than alkaline.

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Zaimahwati, Zaimahwati, Yuniati Yuniati, Ramzi Jalal, Syahman Zhafiri e Yuli Yetri. "Isolasi Dan Karakterisasi Bentonit Alam Menjadi Nanopartikel Monmorillonit". Jurnal Katalisator 3, n. 1 (27 aprile 2018): 12. http://dx.doi.org/10.22216/jk.v3i1.2729.

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Pada penelitian ini telah dilakukan isolasi dan karakterisasi bentonit alam menjadi nanopartikel montmorillonit. Bentonit alam yang digunakan diambil dari desa Blangdalam, Kecamatan Nisam Kabupaten Aceh Utara. Proses isolasi meliputi proses pelarutan dengan aquades, ultrasonic dan proses sedimentasi. Untuk mengetahui karakterisasi montmorillonit dilakukan uji FT-IR, X-RD dan uji morfologi permukaan dengan Scanning Electron Microscopy (SEM). Partikel size analyzer untuk menganalisis dan menentukan ukuran nanopartikel dari isolasi bentonit alam. Dari hasil penelitian didapat ukuran nanopartikel montmorillonit hasil isolasi dari bentonit alam diperoleh berdiameter rata-rata 82,15 nm.In this research we have isolated and characterized natural bentonite into montmorillonite nanoparticles. Natural bentonite used was taken from Blangdalam village, Nisam sub-district, North Aceh district. The isolation process includes dissolving process with aquades, ultrasonic and sedimentation processes. The characterization of montmorillonite, FT-IR, X-RD and surface morphology test by Scanning Electron Microscopy (SEM). Particle size analyzer to analyze and determine the size of nanoparticles from natural bentonite insulation. From the research results obtained the size of montmorillonite nanoparticles isolated from natural bentonite obtained an average diameter of 82.15 nm.

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Tanjaya, Ailen, S. Sudono, Nani Indraswati e Suryadi Ismadji. "Aktivasi bentonit alam pacitan sebagai bahan penyerap pada proses pemurnian minyak sawit". Jurnal Teknik Kimia Indonesia 5, n. 2 (2 ottobre 2018): 429. http://dx.doi.org/10.5614/jtki.2006.5.2.4.

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Application of pacitan's bentonite as adsorbent in purification process of palm oil. Bentonite is one of the widely use adsorbent which is usually used in the bleaching process of edible palm oil to remove pigments color and other impurities which can improve the sensory quality and the oxidative stability of the oil. Bleaching capacity from bentonite can be improved by acid activation, to modified the structure as well as to improve the sorptive surface area. The aim of this research was to determine the optimum acid concentration for the activation of bentonite from Pacitan, East Java. The bleaching capacity of activated bentonite was evaluated based on color, free fatty acid (FFA) and peroxide value (PV) contents of bleached palm oil. The activation was carried out using sulfitric acid (HSO) and hydrochloride acid (HCI) as activating agents at a ranges of concentrations from 1 N to 10 N. The bleaching process of crude palm oil was conducted at 100 C for 10 mins. The bleached palm oil were analyzed for its colur, free fatty acid (FFA) and peroxide value (PV) contents. From this study it can be concluded that the activation process using HCl 5 N gave the optimum bleaching capacity.Keywords: Bleaching earth; Acid activation; Bentonite; Color; Free fatty acid; Peroxide value AbstrakBentonit merupakan salah satu jenis adsorben yang sering digunakan pada proses bleaching minyak kelapa sawit untuk menyerap zat warna dan pengotor-pengotor dalam minyak. Kemampuan bleaching dari bentonit dapat ditingkatkan dengan aktivasi dengan asam untuk meningkatkan luas permukaan dan memodifikasi struktur bentonit. Tujuan dari penelitian ini adalah menentukan jenis dan konsentrasi asam yang optimum pada proses aktivasi bentonit Pacitan. Kemampuan bleaching bentonit dievaluasi berdasarkan parameter warna, kadar asam lemak bebas (Free Fatty Acid, FFA) dan bilangan peroksida (Peroxide Value, PV) pada bleached palm oil. Proses aktivasi bentonit dilakukan menggunakan asam sulfat (H2SO4) dan asam klorida (HCl) dengan variasi konsentrasi 1-10 N. Bentonit yang telah diaktivasi digunakan untuk proses bleaching degummed palm oil pad a suhu 100 C selama 10 menit. Bleached palm oil dianalisa warna (dengan lovibond tintometer), kadar FFA dan PV Dari hasil penelitian diperoleh bahwa bentonit Pacitan yang diaktivasi menggunakan HCl 5 N, memberikan hasil bleaching yang optimum.Kata kunci : Bleaching earth; Aktivasi asam; Bentonit; Wama; Asam lemak bebas; Bilangan peroksida

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DOLATI, Samira, e Mohsen KALANI. "STRUCTURAL CHARACTERIZATION OF A BENTONITE DEPOSIT FROM THE EASTERN IRAN; COMPARISON WITH TWO REFERENCE BENTONITES". Carpathian Journal of Earth and Environmental Sciences 16, n. 1 (2021): 151–62. http://dx.doi.org/10.26471/cjees/2021/016/163.

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Mineralogically, bentonites are dominated by smectites and due to characteristic textural and physicochemical properties of smectites (e.g. very small particle sizes, high cation exchange capacity) are of a great use in industrial applications. In this study, a bentonite sample was characterized with regard to the particle size distribution, mineralogical composition and cation exchange capacity in comparison with the data for the two internationally well-known bentonites representative for Na- and Ca-bentonites: the Mx-80 bentonite of Wyoming, USA and that of Milos, Greece, respectively. Results show a high fraction of fine-grained particles, which demonstrates high yield of purified clay. Mineralogically, the studied bentonite comprises mainly smectites and expandable illite-smectite mixed layer clay minerals. Main accessory minerals are calcite, silica polymorphs and zeolites. The specific surface area and cation exchange capacity values are 330.3 (m2g-1) and 42.2 (meq/100 g), respectively. It is concluded that the mineralogical, textural and the measured physicochemical properties of the studied bentonite is applicable to the applications in oil industry and its related environment maintenance related issues.

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My Linh, Nguyen Le, Tran Duong, Hoang Van Duc, Nguyen Thi Anh Thu, Pham Khac Lieu, Nguyen Van Hung, Le Thi Hoa e Dinh Quang Khieu. "Phenol Red Adsorption from Aqueous Solution on the Modified Bentonite". Journal of Chemistry 2020 (28 luglio 2020): 1–14. http://dx.doi.org/10.1155/2020/1504805.

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In the present work, the modified bentonites were prepared by the modiﬁcation of bentonite with cetyltrimethylammonium bromide (CTAB), both cetyltrimethylammonium bromide and hydroxy-Fe cations and both cetyltrimethylammonium bromide and hydroxy-Al cations. X-ray diffraction (XRD), thermal analysis (TG-DTA), infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and nitrogen adsorption/desorption isotherms were utilized to characterize the resultant modified bentonites. The modified bentonites were employed for the removal of phenol red dye from aqueous solution. Phenol red adsorption agreed well with the pseudo-second-order kinetic model. The equilibrium data were analyzed on the basis of various adsorption isotherm models, namely, Langmuir, Freundlich, and Dubinin‒Radushkevich models. The highest monolayer adsorption capacity of phenol red at 30°C derived from the Langmuir equation was 166.7 mg·g−1, 125.0 mg·g−1, and 100.0 mg·g−1 for CTAB‒bentonite, Al‒CTAB‒bentonite, and Fe‒CTAB‒bentonite, respectively. Different thermodynamic parameters were calculated, and it was concluded that the adsorption was spontaneous (∆G° < 0) and endothermic (∆H° > 0), with increased entropy (∆S° > 0) in all the investigated temperature ranges.

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Yulanda, Andesta, Lisna Wahyuni, Rahmi Safitri, Abu Bakar e Muhammad Dani Supardan. "Pemanfaatan Bentonit sebagai Penyerap Air pada Proses Transesterifikasi Minyak Jelantah Menjadi Biodiesel". Jurnal Teknologi dan Industri Pertanian Indonesia 10, n. 2 (1 ottobre 2018): 14–19. http://dx.doi.org/10.17969/jtipi.v10i2.10577.

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ABSTRAK. Transesterifikasi merupakan salah satu proses dalam pembuatan biodiesel. Metode transesterifikasi secara konvesional tanpa penambahan adsorben memiliki kekurangan pada rendemen dan mutu biodiesel sehingga dikembangkan metode transesterifikasi menggunakan adsorben secara simultan. Penelitian ini bertujuan untuk pemanfaatan bentonit sebagai penyerap air untuk meningkatkan rendemen biodiesel pada proses transesterifikasi minyak jelantah. Pertama dilakukan pengecilan ukuran bentonit menjadi 100 hingga 120 mesh dan dilanjutkan dengan aktivasi bentonit menggunakan asam sulfat 98% pada suhu 80oC. Hasil analisis Scanning Electron Microscope menunjukkan bentonit aktivasi memiliki permukaan yang lebih halus dan bersih dibandingkan dengan bentonit tanpa aktivasi. Selanjutnya, bentonit digunakan pada proses transesterifikasi minyak jelantah dengan variasi massa adsorben (1, 2, 3 dan 4 %-berat minyak) dan kadar air minyak jelantah (2, 3, 5 dan 6 %-berat minyak). Hasil penelitian menunjukkan bahwa penggunaan bentonit teraktivasi menghasilkan rendemen yang lebih tinggi dibandingkan bentonit tanpa aktivasi dan proses tanpa menggunakan bentonit. Hasil penelitian terbaik diperoleh pada massa adsorben 3% dan kadar air 2% yaitu rendemen biodiesel sebesar 81%, massa jenis 865 kg/m3, viskositas 2,90 mm2/s, angka asam 0,1675 mg KOH/gram dan kadar air 0,70%.ABSTRACT.Transesterification is one of process in production of biodiesel. Conventional transterification method without adding adsorbent has deficiency in the yield and quality of biodiesel, therefore transesterification using adsorbent simultaneously is developed. The purpose of this research is to utilize bentonit as the adsorbent of water to increase yield of biodiesel in the waste cooking oil transesterication process. The first step to do in this research was bentonite crushing to the size of 100 to 120 mesh and then bentonite activation using sulfuric acid 98% at 80 oC. The result of SEM analysis showed that activated bentonite surface was smoother and more clean than bentonite without activation. Bentonite is used to transesterification process by varying mass of adsorben (1, 2, 3 and 4 %-wt. of waste cooking oil) and water content (2, 3, 5 and 6 %-wt. of waste cooking oil). The result of this research showed that activated bentonite has better yield than without adsorbent and activation. The best result from this research is at adsorbent mass 3% and water content 2% with biodiesel yield 81%. The biodiesel produced have density of 865 kg/m3, viscosity of 2.90 mm2/s, acid number of 0.1675 mg KOH/gram and water content of 0.7%.

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Kussainova, Bakytgul, Gaukhar Tazhkenova, Ivan Kazarinov, Aisha Nurlybayeva, Anna Lamichova, Lyazat Kusepova, Togzhan Mashan et al. "Comparative Study of the Physico-Chemical Properties of Sorbents Based on Natural Bentonites Modified with Iron (III) and Aluminium (III) Polyhydroxocations". Coatings 13, n. 11 (20 novembre 2023): 1974. http://dx.doi.org/10.3390/coatings13111974.

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A comparative study of the physicochemical properties of natural bentonite clays of Pogodayevo (Republic of Kazakhstan, mod. 1) and Dash-Salakhli (Republic of Azerbaijan, mod. 2) deposits and modification of the bentonite clay with polyhydroxocations of iron (III) and aluminium (III). The amount of bentonite in the concentration of iron (aluminum) was 5 mmol Me3+/g. It was established that the modification of natural bentonites using polyhydroxocations of iron (III) (mod. 1_Fe_5-c, mod. 2_Fe_5-c) and aluminum (III) (mod. 1_Al_5-c, mod. 2_Al_5-c) by the method of “co-precipitation” leads to a change in their chemical composition, structural and sorption properties. The results showed that hydroxy-aluminum cations ([Al3O4(OH)24(H2O)12]7+) and poly-hydroxyl-Fe or polyoxo-Fe were intercalated into clay layers, which led to an increase in the values of d001 and specific surface areas compared to those of the original bentonite, from 37 to 120 m2/g for the Pogodaevo bentonite and from 51 to 172 m2/g respectively, for bentonite from the Dash-Salakhli deposit. It is shown that modified sorbents based on natural bentonite are finely porous objects with a predominance of pores of 1.5–8.0 nm in size. As a result, there is a significant increase in the specific surface area of sorbents. Modification of bentonite with polyhydroxocations of iron (III) and aluminum (III) by the “co-precipitation” method also leads to an increase in the sorption capacity of the sorbents obtained with respect to nickel (II) cations. Modified bentonites were used for the adsorption of Ni (II) ions from the model solution. Ni (II) was absorbed in a neutral pH solution. The study of equilibrium adsorption showed that the data are in good agreement with the Langmuir isotherm model. The maximum adsorption capacity of the Ni (II) obtained from the Langmuir equation was 25.0 mg/g (mod. 1_Al_5-c), 18.2 mg/g (mod. 2_Al_5-c) for Al-bentonite and 16.7 mg/g (mod. 1_Fe_5-c), 10.1 (mod. 2_Fe_5-c) for Fe-bentonite. The kinetics of adsorption is considered. The high content of Al-OH anion exchange centers in them determines the higher sorption activity of Al-modified bentonites.

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Haerudin, Hery, Nino Rinaldi e Adel Fisli. "CHARACTERIZATION OF MODIFIED BENTONITE USING ALUMINUM POLYCATION". Indonesian Journal of Chemistry 2, n. 3 (9 giugno 2010): 173–76. http://dx.doi.org/10.22146/ijc.21913.

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The modification of bentonite by pillarization using aluminum polycation type Keggin [Al13O4(OH)24(H2O)12]7+ has been carried out, by exchange of cation from interlayer with aluminum polycation. The amount of aluminum polycation, which was used for the pillaring of bentonite was varied, i.e. 5 mmol/gram, 10 mmol/gram, and 20 mmol/gram of bentonite. After drying, the pillared bentonite was calcined at 400 oC for 6 hour with temperature rate of 5 oC/min. The cationic exchange capacity (CEC) of starting bentonite was 98.3 meq/100 gram. The concentration ratio of Al/Si increased from 0.27 to 0.34 for pillared bentonite and of Ca/Si was decreased from 0.06 to 0.006 for pillared bentonite. The basal space for pillared bentonit increased significantly from 7.30 Å to about 18 Å . The measured specific surface area (by BET) of pillared bentonite was also increased significantly from 46 m2/g to about 162 m2/g. It was concluded that bentonite has been pillared by aluminum polication successfully. Keywords: aluminum polycation, bentonite

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45

Andrejkovičová, Slávka, Martin Pentrák, L'uboš Jankovič e Peter Komadel. "Sorption of heavy metal cations on rhyolitic and andesitic bentonites from Central Slovakia". Geologica Carpathica 61, n. 2 (1 aprile 2010): 163–71. http://dx.doi.org/10.2478/v10096-010-0008-1.

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Sorption of heavy metal cations on rhyolitic and andesitic bentonites from Central SlovakiaThe main purpose of this work was to determine adsorption characteristics of heavy metal cations on two Slovak bentonites. Adsorption of Pb2+, Zn2+, Cu2+and Cd2+on Jelšový Potok (JP) and Lieskovec (L) bentonites was studied by the batch equilibration technique using solutions of different concentrations. Higher smectite content (81 mass %) and higher cation exchange capacity (CEC) (105 mmol M+/100 g) of JP bentonite cause higher adsorption of all heavy metals in comparison with L bentonite. JP adsorbed heavy metals in the order Pb2+» Cd2+> Zn2+> Cu2+while sorption on L was slightly different, Pb2+» Cd2+> Cu2+≥ Zn2+. The Freundlich model of adsorption is more appropriate for adsorption of Pb2+and Cd2+while lower uptake of Cu2+and Zn2+is better described by the Langmuir model. Negative ΔG° values indicate that the adsorption process of all cations on both bentonites is feasible, spontaneous and exothermic. The decrease in thed001spacings from 14.8-14.9 Å in natural dominantly Ca2+-saturated samples to 13.2-12.6 Å for both bentonites saturated with four heavy metal cations shows the effect of less hydrated exchangeable cations on interlayer spacing. Jelšový Potok bentonite of higher montmorillonite content and greater CEC is the more effective candidate for removal of Pb2+, Zn2+, Cu2+and Cd2+from waste water than Lieskovec bentonite.

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46

Rodríguez-Ameijide, Vanina, Andrea Maggio, Manuel Pozo, M. Belén Gómez, Pablo M. Naranjo e M. Eugenia Roca-Jalil. "Assessment of Sorption of Anthocyanins from Red Cabbage onto Bentonites from Patagonia (Argentina)". Minerals 14, n. 2 (25 gennaio 2024): 133. http://dx.doi.org/10.3390/min14020133.

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In the northern Patagonian region of Argentina, some of the largest bentonite deposits exist. Four bentonite samples (B1, B2, B3, and B4) from two deposits were thoroughly characterised and evaluated as potential adsorbents of anthocyanins extracted from red cabbage. Anthocyanins (ACys) are natural colourants obtained from fruits and plants and have shown excellent antioxidant properties that have promising applications in health. The adsorption of ACys onto bentonites enhances their stability relative to that observed in aqueous solutions. Material characterisation showed that three of the samples are soFdium bentonites (Na-bentonites: B2, B3, and B4), while the fourth exhibits a large quantity of magnesium and calcium in its interlayer, classifying it as a Mg-Ca-Na-bentonite (B1). Na-bentonites demonstrated higher ACy adsorption capacities, occurring through cation exchange, while Mg-Ca-Na-bentonite adsorption occurs by another type of interaction and a cooperative adsorption mechanism, resulting in the lowest ACy adsorption. The highest adsorption capacity was noted for B3, characterised by the highest smectite content, cation exchange capacity, and proportion of monovalent cations in its interlayer. Under the conditions studied, sodium smectites proved to be capable of retaining red cabbage ACys, thereby introducing a novel avenue for potential applications of regional materials with potential implications for health-related uses.

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47

Komine, Hideo, e Nobuhide Ogata. "New equations for swelling characteristics of bentonite-based buffer materials". Canadian Geotechnical Journal 40, n. 2 (1 aprile 2003): 460–75. http://dx.doi.org/10.1139/t02-115.

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Compacted bentonite and sandbentonite mixtures are attracting greater attention as buffer material for repositories of high-level nuclear waste. This buffer material is expected to fill up the space between the canisters containing the waste and the surrounding ground by swelling. To produce the specifications, such as dry density, sandbentonite mass ratio, and dimensions, of the buffer material, the swelling characteristics of compacted bentonite and sandbentonite mixtures must be evaluated quantitatively. New equations for evaluating the swelling behavior of compacted bentonite and sandbentonite mixtures are presented that can accommodate the influences of the sandbentonite mass ratio and the exchangeable-cation composition of bentonite. The new method for predicting swelling characteristics is presented by combining the new equations with the theoretical equations of the GouyChapman diffuse double layer theory and of the van der Waals force, which can evaluate the repulsive and attractive forces of montmorillonite mineral (i.e., the swelling clay mineral in bentonite). Furthermore, the applicability of the new prediction method has been confirmed by comparing the predicted results with laboratory test results on the swelling deformation and swelling pressure of compacted bentonites and sandbentonite mixtures.Key words: bentonite, diffuse double layer theory, van der Waals force, nuclear waste disposal, swelling deformation, swelling pressure.

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48

Osacký, Marek, Miroslav Honty, Jana Madejová, Thomas Bakas e Vladimír Šucha. "Experimental interactions of Slovak bentonites with metallic iron". Geologica Carpathica 60, n. 6 (1 dicembre 2009): 535–43. http://dx.doi.org/10.2478/v10096-009-0039-7.

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Experimental interactions of Slovak bentonites with metallic ironThe experimental stability of four bentonites and one K-bentonite from Slovak deposits in the presence of iron was studied to simulate the possible reactions of clays (bentonite barrier) in the contact with Fe containers in a nuclear waste repository. The batch experiments were performed at 60 °C for 30 and 120 days in aerobic conditions. The reaction products were examined by XRD, FTIR, and Mössbauer spectroscopies and CEC (cation exchange capacities) were determined. Reaction solutions were analysed for selected elements using AAS (atomic absorption spectrometry). The results show that bentonites do not interact equally with metallic iron. Bentonites from the Jelšový Potok, Kopernica and Lieskovec deposits reacted similarly whereas the interaction between the bentonite from Lastovce and the iron was less intensive. The lower reactivity of the bentonite from Lastovce can be explained by its low content of smectite. During iron-clay interactions the iron was consumed and Fe oxides (magnetite, lepidocrocite) were formed. Decrease of the smectite diffraction peaks intensity and CEC values during the experiments show rather the rearrangement of the original smectite crystals than dissolution of smectite. In the K-bentonite from the Dolná Ves deposit where the mixed-layer illite-smectite is present instead of smectite, the dissolution of illite-smectite was observed along with the neoformation of smectite. The structure of illite-smectite deteriorated more than the structure of smectites which suggests that this mixed-layer illite-smectite is much less stable in the presence of iron than smectites.

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Hamad, Gamal M., Hussein A. El-Makarem, Marwa G. Allam, Osama S. El Okle, Marwa Ibrahim El-Morsy Ibrahim El-Morsy El-Toukhy, Taha Mehany, Yasser El-Halmouch et al. "Evaluation of the Adsorption Efficacy of Bentonite on Aflatoxin M1 Levels in Contaminated Milk". Toxins 15, n. 2 (26 gennaio 2023): 107. http://dx.doi.org/10.3390/toxins15020107.

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The existence of aflatoxin M1 (AFM1) in raw milk results in economic losses and public health risks. This research aims to examine the capability of bentonite to adsorb and/or eliminate AFM1 from various raw milk types. In addition, the effects of numerous bentonites (HAFR 1, 2, 3 and 4) on the nutritional characteristics of the milk were studied. Our findings revealed that goat milk had the highest value of AFM1 (490.30 ng/L) in comparison to other milks. AFM1 adsorption was influenced by applying bentonite (0.5 and 1 g) in a concentration-dependent manner for different time intervals (from 0 to 12 h). The percentage of AFM1 reached the maximum adsorption level after 12 h to 100, 98.5 and 98% for bentonites HAFR 3, 1 and 2, respectively. HAFR 3 (1 g bentonite) presented higher adsorption efficiency than other bentonites used in the phosphate buffer saline (PBS) and milk. Residual levels of AFM1 reached their lowest values of 0 and 1.5 ng/L while using HAFR 3 in PBS and milk, respectively. With regard to the influence of bentonite on the nutritional characteristics of milk, there was an increase in fat, protein and solid non-fat ratio while using HAFR 3 and 4, yet decreased lactose in comparison with the control. Scanning Electron Microscopy and Fourier Transform-Infrared Spectroscopy both identified bentonites as superior AFM1 binders. The results demonstrated that bentonite, particularly HAFR 3, was the most effective adsorbent and could thus be a promising candidate for the decontamination of AFM1 in milk.

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Nugroho, Aprilian Adi, Sri Sumarsih e Bambang Sulistiyanto. "Kandungan Total Bakteri dan Total Fungi pada Pellet Limbah Penetasan yang Dibuat dengan Penambahan Bentonit". Jurnal Agripet 16, n. 2 (1 ottobre 2016): 69. http://dx.doi.org/10.17969/agripet.v16i2.3192.

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ABSTRAK. Penelitian efek penambahan bentonit dalam proses pelleting terhadap total bakteri dan total fungi dari produk pellet limbah penetasan sebagai bahan pakan alternatif, telah dilaksanakan di Laboratorium Teknologi Pakan, Fakultas Peternakan dan Pertanian, Universitas Diponegoro. Penambahan bentonit pada proses pelleting diharapkan mengurangi total bakteri dan total fungi pada pellet olahan limbah penetasan, sehingga aman digunakan sebagai bahan pakan alternatif. Pada penelitian ini limbah penetasan yang berupa cangkang telur, telur infertile, telur gagal menetas, serta DOC afkir dan mati dihancurkan, dicampur dengan bentonit dan dibuat pellet, untuk kemudian dianalisis kandungan total bakteri dan total fungi pada produk pellet. Perlakuan bentonit dilakukan dengan aras 0, 2, 4 dan 6% (B/B). Penelitian dilakukan dengan rancangan acak lengkap (RAL) 4 perlakuan dan 5 ulangan. Data dianalisis dengan analisis ragam dan dilanjutkan dengan uji wilayah ganda Duncan untuk mengetahui perbedaan antar perlakuan. Hasil menunjukkan bahwa pemberian bentonit dari berbagai level berpengaruh sangat nyata (P<0,01). Pemberian bentonit pada tingkat tertinggi (6%) mampu menekan total bakteri dan total fungi pada kisaran 105 cfu/g. Disimpulkan bahwa bentonit mampu menekan kandungan total bakteri dan total fungi pada produk pellet limbah penetasan. (Numbers of total bacteria and total fungi of hatchery waste pellets that made by adding bentonite) ABSTRACT. A Research about the effect of bentonite addition in the pelletizing process on total bacteria and total fungi of pellet product of hatchery waste as an alternative feedstuff, was done at Feed Technology Laboratory, Faculty of Animal and Agricultural Sciences, Diponegoro University. The addition of bentonite was expected to reduce the number of bacteria and fungi in the pellet product of hatchery waste, therefore, it could be used safely as an alternative feedstuff. In this experiment, the hatchery waste in the forms of eggshell, infertile eggs, un-hatched eggs, dead and culled DOC were blended, mixed with bentonite and pelleted,and then the number of total bacteria and total fungi of pellet was analyzed. The treatment was carried out with the level of bentonite i.e. 0, 2, 4 and 6% (w/w). Completely randomized design (CRD)was applied by 4 treatments and 5 replications of each. Data analyzed by analysis of variance (ANOVA), and followed by Duncan multiple range test (DMRT) to determine differences among the treatments. The results showed that administration of bentonite at various levels significantly affect the number of bacteria and fungi in the hatchery waste pellets (P <0.01). Administration of bentonite at the level of 6% shows the highest value on suppressing the content of total bacteria as well as fungi up to the range of total content 105cfu/g. In conclusion, the bentonite was able to suppress the total amount of bacteria and total fungi in the hatchery waste pellets.

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