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1
Osacky, M., V. Šucha, M. Miglierini, and 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, no. 4 (December 2012): 465–79. http://dx.doi.org/10.1180/claymin.2012.047.4.06.
Повний текст джерелаАнотація:
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.
2
Sudheer Kumar, Ritwick, Carolin Podlech, Georg Grathoff, Laurence N. Warr, and Daniel Svensson. "Thermally Induced Bentonite Alterations in the SKB ABM5 Hot Bentonite Experiment." Minerals 11, no. 9 (September 18, 2021): 1017. http://dx.doi.org/10.3390/min11091017.
Повний текст джерелаАнотація:
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.
3
Chen, Li, Yanbo Zhou, Xiaoqian Wang, Thomas Zwicker, and Jun Lu. "Enhanced oil–mineral aggregation with modified bentonite." Water Science and Technology 67, no. 7 (April 1, 2013): 1581–89. http://dx.doi.org/10.2166/wst.2013.013.
Повний текст джерелаАнотація:
The application of modified-bentonite-enhanced oil dispersion in water and oil–mineral aggregate (OMA) formation was studied in the laboratory. The effect of modification on the surface properties of bentonite was characterized. The hydrophobicity and surface electric properties of bentonite were significantly improved by attaching cetyltrimethyl ammonium bromide to its surface. The results showed that surface properties of bentonite played an important role in OMA formation. Spherical droplets of OMAs were formed with natural bentonite and elongated solid OMAs and flake OMAs were formed with modified bentonite as observed by fluorescence microscopy. The effects of shaking time, oil concentration and mineral content were also studied. It was suggested that oil concentration and mineral content were critical factors and OMA formed rapidly with both types of bentonite. Modified bentonite had better performance on OMA formation than hydrophilic natural bentonite.
4
Sun, Yongshuai, and Anping Lei. "Enhanced Compressive Strength of the Bentonite-Amended Cement via Bio-Mineralization." Advances in Materials Science and Engineering 2022 (September 27, 2022): 1–9. http://dx.doi.org/10.1155/2022/7220528.
Повний текст джерелаАнотація:
Bentonite, a supplementary cementitious material for Portland cement, has greatly contributed to environmental sustainability. However, few studies have investigated mortar samples produced by substituting bentonite for cement, and cement strength may be adversely affected when cement is replaced with bentonite in larger proportions. Therefore, this paper investigates and discusses the effect of microbially induced calcium carbonate precipitation (MICP) on improving the strength of bentonite-amended cement. The bio-mineralization process of MICP was characterized by SEM-EDS, while the biominerals formed in bentonite-amended mortar were identified by FIIR and XRD analysis. The results showed that: at bentonite concentrations of 0%, 10%, 20%, 30%, and 40% in cement, the bacterial suspension and reaction solution enhanced the compressive strength of bentonite-amended cement by 17%, 20%, 79%, 78%, and 38%, respectively, after 28 days, compared to control specimens; With the increased bacterial concentration in the presence of the reaction solution, the strength of the bentonite-amended cement (20% bentonite) increased remarkably compared to the control specimen (without bacteria). When the bacterial concentration was OD600 2.0, the compressive strength of bentonite-amended cement (20% bentonite) increased by 80% after 28 days; MICP process has a great effect on improving the strength of bentonite-amended cement. It is a green and economical choice to use MICP to improve the strength of bentonite-amended cement.
5
Annan, Ebenezer, Emmanuel Nyankson, Benjamin Agyei-Tuffour, Stephen Kofi Armah, George Nkrumah-Buandoh, Joanna Aba Modupeh Hodasi, and Michael Oteng-Peprah. "Synthesis and Characterization of Modified Kaolin-Bentonite Composites for Enhanced Fluoride Removal from Drinking Water." Advances in Materials Science and Engineering 2021 (January 16, 2021): 1–12. http://dx.doi.org/10.1155/2021/6679422.
Повний текст джерелаАнотація:
Fluoride-contaminated drinking waters are known to cause severe health hazards such as fluorosis and arthritis. This paper presents the encapsulation of iron oxide nanoparticles in kaolin-bentonite composites adsorbents (KBNPs) for the removal of fluoride from drinking water by adsorption compared with kaolin-bentonite composite (KB). Adsorbents with an average weight of ∼200 mg and ∼7 mm diameter (granules) were prepared in the ratio of 10 : 10 : 0.1 for kaolinite, bentonite, and magnetite nanoparticles, respectively. The granules were air-dried and calcined at 750°C and contacted with 2 mg/L sodium fluoride solution at varying time periods. The adsorbents were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) formulation, and Brunauer–Emmett–Teller (BET), whereas the adsorption mechanism and the kinetics were explained using the Langmuir isotherm, Freundlich models, and pseudo-first-order and pseudo-second-order models. The results showed that the BET surface areas for the granules were 10 m2/g and 3 m2/g for KBNPs and KB, respectively. The SEM images for the adsorbents before and after adsorption confirm the plate-like morphology of kaolin and bentonite. The FTIR analyses of bentonite (3550 cm−1–4000 cm−1) and kaolin (400–1200 cm−1) correspond to the structural hydroxyl groups and water molecules in the interlayer space of bentonites and the vibrational modes of SiO4 tetrahedron of kaolin, respectively. The KBNPs composites also recorded a fluoride removal efficiency of ∼91% after 120 minutes compared with 64% for KB composites without Fe3O4 nanoparticles. The adsorptions of fluoride by the KBNPs and KB granules were found to agree with the Freundlich isotherm and a pseudo-second-order kinetic model, respectively. The results clearly show that the impregnation of clays with magnetite nanoparticles has significant effect in the removal of fluoride, and the implication of the results has been discussed to show the impact of clay-magnetite nanoparticles composites in the removal of fluoride from contaminated water.
6
Zunic, Marija, Aleksandra Milutinovic-Nikolic, Natasa Jovic-Jovicic, Predrag Bankovic, Zorica Mojovic, Dragan Manojlovic, and Dusan Jovanovic. "Modified bentonite as adsorbent and catalyst for purification of wastewaters containing dyes." Chemical Industry 64, no. 3 (2010): 193–99. http://dx.doi.org/10.2298/hemind091221023z.
Повний текст джерелаАнотація:
Modification and characterization of bentonite from location Bogovina, Serbia was performed in order to obtain material applicable in wastewater purification. The <75?m bentonite fraction was used in organobentonite synthesis while the <2?m bentonite fraction, obtained by hydroseparation was used in pillaring procedure. Organo-modification of bentonite was performed with (1-hexadecyl)trimethylammonium bromide (HDTMA-Br). Pillared bentonite was obtained using standard procedure. Al3+ and Fe3+ ions were incorporated in pillars in 4:1 ratio and applied as catalyst in catalytic wet peroxide oxidation. Differences in structure of starting and modified bentonites were established by XRD analysis and nitrogen physisorption on -196 ?C. The (001) smectite peak around 2? = 6? shifts during the modification process. The Na-exchange process lowered d001 from 1.53 nm (2? = 5.78?) for starting clay to 1.28 nm (2? = 6.92?), but the clay retained its swelling properties. The pillaring process increased and fixed the basal spacing to 1.74 nm. Intercalation of HDTMA ions into smectite structure increased d001 to 2.00 nm for organobentonite. Specific surface area, SBET, was affected by particle size and type of modification. The samples with finer bentonite fraction had higher SBET due to increased smectite content. Na-exchanged bentonite samples had higher SBET value than starting clay samples of same granulation. Organomodification caused dramatic decrease in SBET value, while the pillaring process lead to an increase of SBET value. Adsorptive and catalytic purification of wastewaters containing dyes was tested using Acid Yellow 99 as a model dye. Na-exchanged bentonite had greater adsorption affinity for dye adsorption than raw bentonite owing to higher SBET. By organomodification this affinity was enhanced more than 70 times due to transition of bentonite surface from hydrophilic to organophilic. Al,Fe pillared bentonite was proven to be efficient in catalytic wet peroxide oxidation of Acid Yellow 99 dye at room temperature.
7
Liu, Qian, Ruihua Huang, Bingchao Yang, and Yanping Liu. "Adsorption of fluoride from aqueous solution by enhanced chitosan/bentonite composite." Water Science and Technology 68, no. 9 (October 19, 2013): 2074–81. http://dx.doi.org/10.2166/wst.2013.456.
Повний текст джерелаАнотація:
In this work, enhanced chitosan/bentonite composite was prepared by treating chitosan/bentonite composite with concentrated hydrochloric acid (HCl). The adsorption of fluoride ions from aqueous solution onto the enhanced chitosan/bentonite composite was investigated. Adsorption studies were performed in a batch system, and the effects of various parameters, such as the pH value of the solution, adsorbent dosage and initial fluoride concentration, were evaluated. The optimum operating conditions for fluoride removal by the enhanced chitosan/bentonite composite were pH = 7 or so, and adsorbent dosage =1.2 g. Increasing initial fluoride concentration reduced the adsorption of fluoride onto the enhanced chitosan/bentonite composite. Furthermore, the presence of other co-anions weakened the adsorption of fluoride onto this adsorbent. The equilibrium adsorption isotherms were well described by both the Freundlich and Langmuir models. The maximum monolayer adsorption capacity was 2.95 mg/g at 293 K.
8
Mollins, L. H., D. I. Stewart, and T. W. Cousens. "Drained strength of bentonite-enhanced sand." Géotechnique 49, no. 4 (August 1999): 523–28. http://dx.doi.org/10.1680/geot.1999.49.4.523.
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9
Zhou, Feng-shan, Jie Li, Lin Zhou, and Yang Liu. "Preparation and Mechanism of a New Enhanced Flocculant Based on Bentonite for Drinking Water." Advances in Materials Science and Engineering 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/579513.
Повний текст джерелаАнотація:
Bentonite is characterized by the large specific surface, good adsorption, ion exchange ability, and nontoxicity. An enhanced bentonite base composite flocculant (BTA) can be prepared from treating the calcium base bentonite and compositing various functional additives. Bentonite was firstly treated by citric acid, then the talc and activated carbon turned to be acid part and simultaneously the part that was treated by sodium bicarbonate and calcium hydroxide turned to be alkaline part, and finally the acid bentonite part and alkaline bentonite part were mixed up with preground powder of polymeric chloride aluminium (PAC), cationic polyacrylamide (CPAM), ferrous sulfate, and aluminum sulfate, and after all of the processing flocculant BTA was obtained. The optimum preparation process of flocculant BTA has shown 29.5% acid bentonite part, 29.5% alkaline bentonite part, 15% PAC, 1% CPAM, 5% ferrous sulfate, and 20% aluminum sulfate. BTA was used to treat drinking water with high turbidity and metal ion in Karamay City, Xinjiang. The treated water was surely up to the drinking water standard of China in decolorization rate, deodorization rate, heavy metal ion removal rate, and so forth, and contents of residual aluminum ions and acrylamide monomer in drinking water were considerably decreased.
10
Liu, Xue Gui, Chang Feng Liu, Hong Shao, and En De Wang. "Studies on a New Type of Crosslinked Polyacrylamide Bentonite Composite." Advanced Materials Research 152-153 (October 2010): 666–69. http://dx.doi.org/10.4028/www.scientific.net/amr.152-153.666.
Повний текст джерелаАнотація:
In this paper, a peroxide-tertiary amine oxidation-reduction initiator system was used to synthesize a cross-linked polyacrylamide/bentonite composite at room temperature. The composite could contain up to 50% bentonite. Performance studies showed that the salt tolerance of the composite was enhanced compared to bentonite. The structure of the composite was characterized and analyzed by XRD, FTIR, and TG. Other than a slight increase in the interlamellar spacing, the structure of bentonite did not change during its aggregation. The composite therefore had enhanced dispersion properties and improved thermal stability.
11
Handayani, H., M. I. Fathurrohman, A. Ramadhan, and N. A. Sutisna. "Effect of Organomodified Bentonite/Silica Hybrid Filler Compound System on Mechanical Properties and Sealing Performance of NR/NBR Rubber Seal for LPG Tube Valve." Asian Journal of Chemistry 34, no. 11 (2022): 2879–86. http://dx.doi.org/10.14233/ajchem.2022.23881.
Повний текст джерелаАнотація:
Organomodified bentonite and silica were used as hybrid fillers in natural rubber (NR)/nitrile butadiene rubber (NBR) seal for liquified petroleum gas (LPG) tube valve compound to evaluate their interaction and influence on mechanical properties and sealing performance. In this work, the NR-organomodified bentonite were prepared by the in situ organomodified and latex compounding method with varying amounts of bentonite then applied in the silica-NR/NBR rubber seal compounds with mixing process held in two rolls open mill. Silanization reaction, Payne effect, curing characteristics, tensile properties, compression set, hardness, uniaxial compression and sealing performance were assessed. The study obtained that NR/NBR-silica/organomodified bentonite show improved silica dispersion physically, as analyzed by Payne effect. The presence of organomodified bentonite decreases the vulcanization reaction. The cure rate index, apparent crosslink density and hardness tend to decrease with addition of organomodified bentonite, while tensile strength and elongation at break are enhanced with increasing organomodified bentonite. With an appropriate amount of organomodified bentonite (organomodified bentonite below 4 phr), the introduction of organomodified bentonite enhances the elastic response of the material, as shown by increasing of tensile properties. The rubber seal’s sealing performance analysis revealed that B4 (4 phr organomodified bentonite) performed the best, with contact stress higher than the actual working pressure and Misses stress lower than the actual working pressure, making it difficult to crack.
12
He, Haijie, Tao Wu, Xiaole Shu, Kuan Chai, Zhanhong Qiu, Shifang Wang, and Jun Yao. "Enhanced Organic Contaminant Retardation by CTMAB-Modified Bentonite Backfill in Cut-Off Walls: Laboratory Test and Numerical Investigation." Materials 16, no. 3 (February 1, 2023): 1255. http://dx.doi.org/10.3390/ma16031255.
Повний текст джерелаАнотація:
Adding organically modified bentonite into impervious wall materials may improve the adsorption of organic pollutants. In this study, cetyltrimethylammonium bromide organically modified bentonite (CTMAB bentonite) was mixed with sodium bentonite and kaolin to obtain two materials, which were then used as cut-off walls for typical pollutants. Soil column consolidation tests, diffusion tests, and breakdown tests were conducted to study migration of organic pollutants in soil columns. The parameter sensitivity of pollutant transport in the cut-off wall was analysed by numerical simulation. The sodium bentonite mixed with 10% CTMAB bentonite and kaolin-CTMAB bentonite showed the greatest impermeability: with a consolidation pressure of 200 kPa, the permeability coefficients were 1.03 × 10−8 m/s and 3.49 × 10−9 m/s, respectively. The quantity of phenol adsorbed on sodium bentonite-CTMAB bentonite increased with increasing water head height. The kaolin-CTMAB bentonite column showed the best rhodamine B adsorption performance, and the adsorption rate reached 98.9% on day 67. The numerical results showed that the permeability coefficient was positively correlated with the diffusion of pollutants in the soil column. The quantity adsorbed on the soil column was positively correlated with the retardation factor, and the extent of pollutant diffusion was negatively correlated with the retardation factor. This study provides a technical means for the optimal design of organic pollutant cut-off walls.
13
Sellin, Patrik, Mary Westermark, Olivier Leupin, Simon Norris, Antonio Gens, Klaus Wieczorek, Jean Talandier, and Johan Swahn. "Beacon: bentonite mechanical evolution." EPJ Nuclear Sciences & Technologies 6 (2020): 23. http://dx.doi.org/10.1051/epjn/2019045.
Повний текст джерелаАнотація:
The aim of Beacon is to develop the understanding of fundamental processes that lead to material homogenisation, as well as to improve capabilities for numerical modelling. In earlier assessments of bentonite EBS, the mechanical interaction between the installed bentonite components has been neglected and an “ideal” final state has generally been assumed. Key features of the project are (1) re-evaluation of the available knowledge to extract the crucial data to compile the qualitative and quantitative data and to enhance the conceptual understanding. (2) Enhanced, robust and practical numerical tools based on a good scientific understanding, which have the expected predictive capabilities regarding the evolution of engineered barriers and seals. (3) A developed database with experimental data needed by the quantitative models. (4) Verified calculation tools based on experimental results in different scales. The Beacon project is required for the pan-European objectives at building confidence amongst regulators and stakeholders regarding the performance of the engineered barriers in a geological repository.
14
Cao, Benyi, Yunhui Zhang, and Abir Al-Tabbaa. "SEBS-Polymer-Modified Slag–Cement–Bentonite for Resilient Slurry Walls." Sustainability 14, no. 4 (February 12, 2022): 2093. http://dx.doi.org/10.3390/su14042093.
Повний текст джерелаАнотація:
In spite of the well-established design and construction approaches of slag–cement–bentonite slurry walls, the materials deteriorate inevitably in contaminated land. The development of effective materials which are sustainable, resilient and self-healing over the lifetime of slurry walls becomes essential. This study, for the first time, adopts a styrene–ethylene/butylene–styrene (SEBS) polymer to modify slag–cement–bentonite materials to enhance mechanical and self-healing performance. The results show that the increase in SEBS dosage results in significantly increased strain at failure, indicating the enhanced ductility thanks to the modification by the deformable polymer. The increased ductility is beneficial as the slurry wall could deform to a greater extent without cracks. After the permeation of liquid paraffin, the SEBS exposed on the crack surface swells and seals the crack, with the post-healing permeability only slightly higher than the undamaged values, which exhibits good self-healing performance. Scanning electron microscopy and micro-computed tomography analyses innovatively reveal the good bonding and homogeneous distribution of SEBS in slag–cement–bentonite. SEBS acts as a binder to protect the slag–cement–bentonite sample from disintegration, and the swollen SEBS particles effectively seal and heal the cracks. These results demonstrate that the SEBS-modified slag–cement–bentonite could provide slurry walls with resilient mechanical properties and enhanced self-healing performance.
15
Jiang, Yuexiu, Tongxia Huang, Lihui Dong, Tongming Su, Bin Li, Xuan Luo, Xinling Xie, Zuzeng Qin, Cuixia Xu, and Hongbing Ji. "Mn Modified Ni/Bsentonite for CO2 Methanation." Catalysts 8, no. 12 (December 10, 2018): 646. http://dx.doi.org/10.3390/catal8120646.
Повний текст джерелаАнотація:
To enhance the low-temperature catalytic activity and stability of Ni/bentonite catalyst, Ni-Mn/bentonite catalyst was prepared by introducing Mn into Ni/bentonite catalyst and was used for CO2 methanation. The results indicated that the addition of Mn enhanced the interaction between the NiO and the bentonite carrier, increased the dispersion of the active component Ni and decreased the grain size of the active component Ni, increased the specific surface area and pore volume of the Ni/bentonite catalyst, and decreased the average pore size, which suppressed the aggregation of Ni particles grown during the CO2 methanation process. At the same time, the Mn addition increased the amount of oxygen vacancies on the Ni/bentonite catalyst surface, which promoted the activation of CO2 in the methanation reaction, increasing the low-temperature activity and stability of the Ni/bentonite catalyst. Under the reaction condition of atmospheric pressure, 270 °C, V(H2):V(CO2) = 4, and feed gas space velocity of 3600 mL·gcat−1·h−1, the CO2 conversion on the Ni-Mn/bentonite catalyst with 2wt% Mn was 85.2%, and the selectivity of CH4 was 99.8%. On the other hand, when Mn was not added, the CO2 conversion reached 84.7% and the reaction temperature only raised to 300 °C. During a 150-h stability test, the CO2 conversion of Ni-2wt%Mn/bentonite catalyst decreased by 2.2%, while the CO2 conversion of the Ni/bentonite catalyst decreased by 6.4%.
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Stewart, D. I., Y. Y. Tay, and T. W. Cousens. "The strength of unsaturated bentonite-enhanced sand." Géotechnique 51, no. 9 (November 2001): 767–75. http://dx.doi.org/10.1680/geot.2001.51.9.767.
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17
Al-Essa, Khansaa. "Activation of Jordanian Bentonite by Hydrochloric Acid and Its Potential for Olive Mill Wastewater Enhanced Treatment." Journal of Chemistry 2018 (2018): 1–10. http://dx.doi.org/10.1155/2018/8385692.
Повний текст джерелаАнотація:
Jordanian bentonite was activated by hydrochloric acid at room temperature. FTIR, XRD, TGA, and BET surface area analyses of the samples were carried out to examine the structure of bentonite before and after acid activation. It is found that the octahedral cations were removed, which altered the chemical composition of the bentonite. Difference of surface area was noticed (66.2 to 287.8 m2 g−1), which was caused by structural changes in the bentonite. We aimed to investigate the effectiveness of activated bentonite in OMWW treatment. Batch and column techniques were applied. Crude and treated OMWW samples were characterized; physiochemical parameters, total phenolic compounds, and heavy metal ions concentrations were measured. Several parameters that affected the adsorption capacity were studied: the pH value of the solution, temperature, and the adsorbent dose. It was found that the maximum removal of total phenolic compounds and heavy metal ions (Zn, Fe, and Mn) was at pH 6. Adsorption capacity of phenolic compounds was enhanced with an increase in the temperature of the solution and also with the adsorbent dose. The optimum adsorbent concentration needed for the maximum removal of total phenolic compounds is 1 g of activated bentonite/0.01 L of OMWW. The percentage removal exceeded 99% for Zn, Fe, and Mn ions, while it reached 65.2 and 61.5 for K+ and Na+ ions, respectively. Finally, the percentage removal of pollutants was increased by using activated bentonite. This study will provide valuable insight into the effect of activated bentonite towards the treatment and recyclability of OMWW, which is essential for the local olive mill industry.
18
Wang, Guang Hua, Dong Wan, Wen Bing Li, and Kun Chen. "Preparation and Adsorbability for Orange II of CTAB Modified Bentonite." Advanced Materials Research 807-809 (September 2013): 530–33. http://dx.doi.org/10.4028/www.scientific.net/amr.807-809.530.
Повний текст джерелаАнотація:
Surfactant modified bentonite was prepared using cetyltrimethylammonium bromide (CTAB) by a simple ion exchange method, and the organification of bentonite was proved by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron micrographic (SEM). The adsorption of Orange II(OII) dye onto CTAB modified bentonite was carried out. Compared with natural bentonite, the adsorption capacity of CTAB-Bent for OII was greatly enhanced. The adsorption isotherm of OII was in good agreement with the Langmuir equation.
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Assi, Amel Habeeb, Ramzi Riyadh Khazeem, Ahmed Salah Salem, and Alaa Tahseen Ali. "Studying the Effects of Different Polymers on Rheological Properties of Water Base Muds." Journal of Engineering 24, no. 12 (December 3, 2018): 12–25. http://dx.doi.org/10.31026/j.eng.2018.12.02.
Повний текст джерелаАнотація:
This research is focusing on finding more effective polymers that leads to enhance the rheological properties of Water Base Muds. The experiments are done for different types of mud for all substances which are Polyacrylamide, Xanthan gum, CMC (Carboxyl Methyl Cellulose). This study shows the effect of add polymer to red bentonite mud, effect of add polymer to Iraqi bentonite mud, the effect of add bentonite to polymer mud. The mud properties of Iraqi bentonite blank are enhanced after adding the polymers to the blank mix, CMC gives the highest value of plastic viscosity and Gel strength than others; X-anthan gives the highest value of yield point and gel strength than others. For the red bentonite mud, Polyacrylamide has the highest shear stress and yield point than the others polymers, but Xanthan has the highest effect on plastic viscosity than other polymers. All polymers reduce filtration loss. The polymer solution mud failed to suspend the barite so we cannot use it as drilling fluid even so this mud has good Rheological properties (PV and YP). The maximum amount of each polymer is founded for the studied clay types.
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Tong, Shan, and Kristin M. Sample-Lord. "Coupled solute transport through a polymer-enhanced bentonite." Soils and Foundations 62, no. 6 (December 2022): 101235. http://dx.doi.org/10.1016/j.sandf.2022.101235.
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21
Rao, Sudhakar M., A. Sridharan, and M. R. Shenoy. "Influence of starch polysaccharide on the remoulded properties of two Indian clay samples." Canadian Geotechnical Journal 30, no. 3 (June 1, 1993): 550–53. http://dx.doi.org/10.1139/t93-047.
Повний текст джерелаАнотація:
The reported presence in marine clays and the recognized role of polysaccharide as a bonding agent provided the motivation to examine the role of starch polysaccharide in the remoulded properties of nonswelling (kaolinite) and swelling (bentonite) groups of clays. The starch polysaccharide belongs to a group of naturally occurring, large-sized organic molecules (termed polymers) and is built up by extensive repetition of simple chemical units called repeat units. The results of the study indicate that the impact of the starch polysaccharide on the remoulded properties of clays is dependent on the mineralogy of the clays. On addition to bentonite clay, the immensely large number of segments (repeat units) of the starch polysaccharide create several polymer segment – clay surface bonds that cause extensive aggregation of the bentonite units layers. The aggregation of the bentonite unit layers greatly curtails the available surface area of the clay mineral for diffuse ion layer formation. The reduction in diffuse ion layer thickness markedly lowers the consistency limits and vane shear strength of the bentonite clay. On addition to kaolinite, the numerous polymer segment – clay surface bonds enhance the tendency of the kaolinite particles to flocculate. The enhanced particle flocculation is responsible apparently for a small to moderate increase in the liquid limit and remoulded undrained strength of the nonswelling clay. Key words : soil organics, polysaccharides, starch, polymers, bentonite, kaolinite, Atterberg limits, vane strength, interparticle forces.
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Mohammedi, N., F. Zoukrami, and N. Haddaoui. "Preparation of Polypropylene/Bentonite Composites of Enhanced Thermal and Mechanical Properties using L-leucine and Stearic Acid as Coupling Agents." Engineering, Technology & Applied Science Research 11, no. 3 (June 10, 2021): 7207–16. http://dx.doi.org/10.48084/etasr.4148.
Повний текст джерелаАнотація:
The compatibilization of raw bentonite (bent) with a polymer matrix of polypropylene (PP) can improve the performance of the material in terms of thermal and mechanical properties. In this study, two kinds of untreated bentonite, bentonite-Maghnia (bent-m) and bentonite-Mostaganem (bent-M), that differ in the proportion of Al2O3 and in the particle size distribution were coupled to typical maleic anhydride grafted polypropylene PP-MA. Stearic Acid (SA) and L-leucine Amino Acid (AA) were selected as new coupling modifiers at a 5/5 ratio of bentonite/coupling agent. All PP/bent composites were prepared by melt mixing at 190°C. Morphological observation revealed a good dispersion of bentonite into the PP matrix in the presence of AA, SA, and PP-MA. Mechanical properties showed an increase in stiffness as bent-m or bent-M were associated with AA. For instance, PP/bent-m/AA composite underwent an improvement of about 13% in Young’s modulus as compared to neat PP. On the other hand, the addition of SA into bent-m maintained stiffness and tensile strength at an acceptable level. An increase of around 40°C and 37% in the decomposition temperature and elongation at break was respectively observed for the PP/bent-m/SA composite. All coupled composites showed high degradation temperatures.
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Xu, Sifa, Yajun Fu, Jun Wang, Jianwei Lv, Xiaobing Xu, Weiwei Wei, and Zhe Wang. "Effect of Zeolite Content on Permeability of Stone Chip-Bentonite-Zeolite Mixture Using a Single Solution." Applied Sciences 12, no. 22 (November 18, 2022): 11732. http://dx.doi.org/10.3390/app122211732.
Повний текст джерелаАнотація:
Bentonite is frequently utilized as a landfill lining material due to its high impermeability. Due to the fact that heavy metal ions in leachate can alter the permeability of bentonite liner, the impermeability and metal adsorption effect of bentonite liner is typically enhanced by the use of external admixtures. In this investigation, zeolite was combined with stone chips and bentonite. Using a flexible wall permeation test, zeta potential test, and X-ray diffraction test, the effect of zeolite on the permeability and adsorption properties of the mixture was investigated. The results indicate that the addition of zeolite can enhance the impermeability of the mixed soil. The permeability coefficient of the mixed soil in DIW is 3.74 × 10−7 cm/s when bentonite is incorporated at 11% and decreases to 6.55 × 10−8, 4.65 × 10−8, and 5.10 × 10−8 cm/s when 12.50%, 25%, and 50% of zeolite are incorporated; the permeability coefficient of the mixed soil in DIW was 3.74 × 10−7 cm/s when the permeate concentration was 0.01 mol/L of ZnCl2 solution, the permeation coefficients were 5.73 × 10−7, 5.98 × 10−8, 5.8 × 10−8, and 5.7 × 10−8 cm/s when the zeolite doping was 0, 12.50, 25, or 50%, respectively, and the Zn2+ concentration of the leachate decreased compared to the no-zeolite case by 92.48, 97.29, and 98.65%, respectively; the competitive adsorption of metal ions by zeolites in ionic solutions of different concentrations reduced the ionic concentration in the solution and decreased the inhibition of bentonite swelling, while the adsorption characteristics of stone chip-bentonite-zeolite mixture on Zn2+ were measured by the Langmuir and Freundlich et al. model.
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Ling, Wanting, Qing Shen, Yanzheng Gao, Xiaohong Gu, and Zhipeng Yang. "Use of bentonite to control the release of copper from contaminated soils." Soil Research 45, no. 8 (2007): 618. http://dx.doi.org/10.1071/sr07079.
Повний текст джерелаАнотація:
A decrease in release and availability of heavy metals in soil has been of worldwide interest in recent years. Bentonite is a type of expandable montmorillonite clay, and has strong sorption for heavy metals. In this work, the control of amended bentonite on the release of copper (Cu2+) from spiked soils was investigated using a batch equilibrium technique. Sorption of Cu by bentonite was pH-dependent, and could be well described using the Langmiur model. Maximum sorption capacity of the bentonite used in this study was 5.4 mg/g, which was much greater than soils reported in the literature. The extent of Cu2+ release from spiked soils was correlated with slurry concentrations, pH, and soil ageing process. In all cases, the amendment of bentonite was observed to effectively decrease the release of Cu2+ from soils. The apparent aqueous concentrations of Cu2+ released from soils devoid of bentonite treatment were 113–1160% higher than those from the soils amended with bentonite. Moreover, the magnitude of Cu2+ release decreased with increasing amount of bentonite added to soils. The bentonite added was more effective in retaining Cu2+ in sorbents for aged contaminated soils. Such enhanced retention resulting from the presence of bentonite was observed within a wide pH range from 2.5 to 7.0. Bentonite, as one of the most abundant minerals in soils, is regarded to improve the soil overall quality. The results obtained from this work provide useful information on utilisation of bentonite to control the release of heavy metals from contaminated soils.
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Zhou, Feng-shan, Tian-qi Li, Yun-hua Yan, Can Cao, Lin Zhou, and Yang Liu. "Enhanced Viscosity of Aqueous Palygorskite Suspensions through Physical and Chemical Processing." Advances in Materials Science and Engineering 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/941580.
Повний текст джерелаАнотація:
Palygorskite has remarkable rheological properties and was used to increase the stability and viscosity of aqueous suspensions. The effects of different physical and chemical processing methods on the apparent viscosity and plastic viscosity of the palygorskite suspensions such as pressing, ultrasound scattering, acidification, and chemical additives have been released. The pressing and ultrasound scattering indicated that the dispersed state of palygorskite could be increased effectively after treatment, and the apparent viscosity of treated-palygorskite samples increased almost 2-3 times compared to that of before. The viscosity of the acid-treated palygorskite suspension was not increased. The viscosity increased with the content of bentonite in the mixture of bentonite and palygorskite in fresh water. It seemed to be not worthy to add a certain amount of bentonite to palygorskite in order to enhance viscosity and vice versa. Chemical additives appeared to have good effects on the rheological behavior of palygorskite suspension. Magnesium oxide revealed great contribution to viscosity enhancement. The main mechanism was the electrostatic attractive interaction between magnesium oxide particles with positive charges and the palygorskite rods with negative charges. This interacted force has an impact on the structural inversion of palygorskite rods and even caused the reinforcing of flocculation.
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Stepova, K., L. Sysa, A. Kontsur, and O. Myakush. "Adsorption of Copper Ions by Microwave Treated Bentonite." Physics and Chemistry of Solid State 21, no. 3 (September 30, 2020): 537–44. http://dx.doi.org/10.15330/pcss.21.3.537-544.
Повний текст джерелаАнотація:
Changes of bentonite surface structure under the influence of direct microwave irradiation during adsorpion of Cu2+ from concentrated solutions were investigated by X-ray and EDS analysis. The microwave treated bentonite (MTB) has been proved to have enhanced adsorption capacity for copper due to improved pore structure and some peculiarities of adsorption mechanism. The non-linear fitting of experimental data to the theoretical isotherms have demonstrated that the adsorption on natural bentonite fitted the Toth model, whilst microwave-treated bentonite fitted the Langmur-Freundlich model. The isotherm modeling allowed predicting the maximal adsorption capacities 44.8 mg/g. XRD and SEM analysis of MTB sample after adsorption indicated formation of microcrystals of individual copper compound. The adsorption on MTB sample takes place not only in pores or in monomolecular layer on the bentonite surface, but the prevalent mechanism is surface-induced co-precipitation of copper as microcrystals of individual copper compound.
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Hosney, Mohamed, and Ronald Kerry Rowe. "Polymer-enhanced bentonite–sand to cover calcium-rich soil." Environmental Geotechnics 6, no. 3 (May 2019): 155–61. http://dx.doi.org/10.1680/jenge.17.00001.
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Zhong, Cheng, Rui Deng, Meng Gao, Yunpeng Cao, Pan Weiliang, Li Gu та Qiang He. "Enhanced bromate adsorption by using ɑ-FeOOH pillared bentonite". DESALINATION AND WATER TREATMENT 213 (2021): 248–58. http://dx.doi.org/10.5004/dwt.2021.26677.
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Wang, Guang Hua, Kun Chen, Wen Bing Li, Dong Wan, Qin Hu, and Lu Lu Lu. "Synthesis of Magnetic Modified Organobentonite as Adsorbent for Degradation of Orange II." Advanced Materials Research 838-841 (November 2013): 2306–9. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.2306.
Повний текст джерелаАнотація:
Magnetic modified organobentonite (Fe3O4/CTAB–Bent) was synthesized by chemical co-precipitation method in which CTAB–Bent was firstly achieved via ion–exchange.The composite materials have been characterized by powder X–ray diffraction (XRD), Fourier transform infrared spectroscopy (FT–IR) and Scanning electron microscopy (SEM) . The results revealed that basal spacing of bentonite was increased through organic modification and the Fe3O4 particles synthesized which covering the surfaces of bentonite .Compared with natural bentonite, the adsorption capacity of Fe3O4/CTAB–Bent for Orange II was greatly enhanced and can be easily separated from the reaction medium by an external magnetic field after the treatment.
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Assi, Amel Habeeb. "The Effect of Weighting Materials on the Rheological Properties of Iraqi and Commercial Bentonite in Direct Emulsion." Iraqi Geological Journal 54, no. 1F (June 30, 2021): 110–21. http://dx.doi.org/10.46717/igj.54.1f.10ms-2021-06-30.
Повний текст джерелаАнотація:
Numerous drilling additives and materials are used continuously because they are necessary to support and give the required properties of the drilling fluid so that to ensure the stability of the borehole. This paper aspires to evaluate the rheological properties of bentonite (montmorillonite) Trefawey as an alternative to using commercial bentonite. Monitoring and evaluating of the rheological and filtration properties were prepared. This exertion aims to focus on the effect of hematite, and barite on the rheological properties of the three aforementioned bentonite types. An improvement in the rheological properties of bentonite (montmorillonite). Trefawey was observed after adding the previous heavy materials. Hematite has by some means better ability to improve rheological properties compared to other heavy materials. The emulsifying agent used was Carboxyl Methyl Cellulose (HOCH2COONA), as it has provided excellent results parallel to the lignite. The rheological properties of bentonite (montmorillonite) Trefawey are enhanced by doubling the amount of carboxyl methyl cellulose (HOCH2COONA). The results have proved that the use of weighting materials and emulsifying agent affected the rheological properties of bentonite (montmorillonite) Trefawey in a direct emulsion. The results have shown that it is more appropriate to use carboxyl methyl cellulose as an emulsifying agent to prepare a direct emulsion than bentonite (montmorillonite) Trefawey due to its excellent effect in improving the rheological properties of bentonite (montmorillonite) Trefawey. And it can be said that this effort has succeeded in studying two effects simultaneously. In other words, both heavy substances and emulsifying agent have effects on bentonite (montmorillonite) Trefawey, in order to obtain a stable emulsion and a clearer view of the behavior of Iraqi bentonite. The above effort has focused on making bentonite (montmorillonite) Trefawey suitable for the nature of geological layers such as oil shale, limestone and sandstone. This means preparing drilling fluid using bentonite (montmorillonite) Trefawey to drill the above structures. The study has concluded that it is better to use bentonite (montmorillonite) Trefawey in preparing direct oil emulsions as a stable and successful alternative of imported bentonite.
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Li, Shan Ping, and Jiang Jie Cui. "Adsorption of Congo Red Dye onto Raw and Chitosan-Modified Bentonite." Advanced Materials Research 156-157 (October 2010): 217–24. http://dx.doi.org/10.4028/www.scientific.net/amr.156-157.217.
Повний текст джерелаАнотація:
We studied the effects of surface modification of bentonite with chitosan on its ability to adsorb Congo Red (CR) dye. The adsorption behavior of CR from aqueous solution onto raw (RB) and chitosan-modified (CMB) bentonite samples was investigated as a function of parameters such as initial CR concentration, contact time, pH and temperature. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to confirm the surface modification. Compared with RB, the adsorption capacity of CMB for CR was greatly enhanced. Kinetic studies indicated that the adsorption of CR on both RB and CMB followed the pseudo-second-order kinetic model. From the thermodynamic parameters, the adsorption of CR on RB and CMB is spontaneous and endothermic. The results indicate that chitosan-modified bentonite provides an important advantage for CR dye adsorption over raw bentonite.
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Adjei, Stephen, Salaheldin Elkatatny, and Abdulaziz Al-Majed. "Effect of Bentonite Prehydration Time on the Stability of Lightweight Oil-Well Cement System." Geofluids 2021 (June 12, 2021): 1–8. http://dx.doi.org/10.1155/2021/9957159.
Повний текст джерелаАнотація:
Lightweight cement systems are used in the weak intervals of petroleum wells. Sodium bentonite is used as an extender in lightweight oil-well cement systems as it prevents excess water and sedimentation of particles, thereby ensuring the formation of homogenous and stable cement sheaths. The extending ability of sodium bentonite is enhanced when prehydrated. However, the optimum bentonite prehydration time and its effect on the stability of lightweight cement systems have not been well established. The objective of this study is to investigate the optimum sodium bentonite prehydration time and correlate it to the stability of lightweight oil-well cement systems. Bentonite suspensions were prepared by vigorous preshearing at 12000 rpm for 5 minutes, followed by aging times of 0, 30, 60, and 120 minutes. The swelling behavior of bentonite was investigated using a laser particle size analyzer. The Herschel-Bulkley model was used to determine the rheological parameters of the experimentally measured shear stress vs. shear rate data of the aged suspensions. The effect of calcium chloride salt on aged bentonite suspensions was investigated. Density measurements and pore space analysis with the nuclear magnetic resonance (NMR) technique were used to investigate the homogeneity of cement-based cores. It was observed that bentonite swells with time and, after 30 minutes, the swelling is insignificant; however, the swelling property did not have any observed impact on the properties of cement systems designed with the bentonite aged at different times. In general, all the lightweight cement slurries exhibited similar properties, in terms of rheology, stability, and homogeneity, regardless of the bentonite prehydration time. These findings indicate that aging bentonite suspension after vigorous preshearing in lightweight cement design is unnecessary and would only contribute to nonproductive time.
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Ozhan, H. O. "Sodium Carboxymethyl Cellulose-Enhanced GCLs in Freshwater Reservoirs." IOP Conference Series: Materials Science and Engineering 1260, no. 1 (October 1, 2022): 012006. http://dx.doi.org/10.1088/1757-899x/1260/1/012006.
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Abstract Biopolymers that are environmentally friendly organic products are increasingly used in geotechnical applications instead of synthetic polymers and other chemical additives. Cellulose is a biopolymer that is obtained from the cell walls of plants. In order to evaluate its effect on internal erosion, triaxial permeability tests were performed on a sodium carboxymethyl cellulose-enhanced geosynthetic clay liner (GCL) with Ca bentonite that was placed over a coarse gravel with an average grain diameter of 2.5 cm and permeated with tap water. Furthermore, unconfined compression tests were conducted on the cellulose-added bentonite component of the GCL in order to evaluate the mechanical effect of sodium carboxymethyl cellulose addition to the GCL on internal erosion. Test results indicated that 2% cellulose addition by dry weight maintained sufficient hydraulic and mechanical performances with almost 2.5 orders of magnitude decrease in permeability and 10 times increase in unconfined compressive strength. However, cellulose addition had only a slight enhancement against internal erosion. All the tested GCLs resisted against internal erosion up to a hydraulic head of 25 m. But 30 m hydraulic head resulted in internal erosion for the GCLs enhanced with up to a content of 2% cellulose.
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Xi, Huan, Qingqing Li, Yan Yang, Jianfeng Zhang, Feng Guo, Xiaogang Wang, Shikai Xu, and Shiping Ruan. "Synergistic modification of bentonite by acid activation and hydroxyl iron pillaring for enhanced dye adsorption capacity." Water Science and Technology 81, no. 7 (April 1, 2020): 1518–29. http://dx.doi.org/10.2166/wst.2020.239.
Повний текст джерелаАнотація:
Abstract Despite the fact of natural abundance, low cost and environmental friendliness, the far-from-sufficient adsorption capacity of natural bentonite (BT) has limited such a promising application to remove dye pollutants. In this paper, we proposed a facile modification strategy to enhance adsorption performance of bentonite utilizing synergistic acid activation and hydroxyl iron pillaring, by which the adsorbent (abbreviated as S-Fe-BT) exhibited the highest adsorption capacity (246.06 mg/g) and a high rapid adsorption rate for a typical organic dye, Rhodamine B (RhB). This could be ascribed to the increased interlayer spacing, the increased specific surface area, and the optimized OH/Fe ratio after the synthetic modification of the pristine BT. The adsorption behavior of RhB onto S-Fe-BT was well described by the pseudo-second-order kinetic model, indicating a chemical-adsorption-controlled process. Furthermore, its adsorption isotherm matched well with the Langmuir model due to a monolayer adsorption process. This paper opens a promising direction to remove the dye pollution using low cost bentonite adsorbents treated by such a convenient modification strategy.
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Yu, Tao, Chengtun Qu, Daidi Fan, and Renjun Xu. "Effects of Bentonite Activation Methods on Chitosan Loading Capacity." Bulletin of Chemical Reaction Engineering & Catalysis 13, no. 1 (April 2, 2018): 14. http://dx.doi.org/10.9767/bcrec.13.1.1040.14-23.
Повний текст джерелаАнотація:
The adsorption capacity of bentonite clay for heavy metal removal from wastewater can be significantly enhanced by a high loading of chitosan on the surface. In order to enhance the chitosan loading, we tested activating bentonite clay by three methods prior to chitosan loading: sulfuric acid, calcination, and microwave treatments. Meanwhile, several parameters during chitosan loading, namely the initial chitosan concentration, stirring speed, reaction time, temperature, and pH value were investigated. Our results indicate that chitosan is attached to bentonite clay through intercalation and surface adsorption according to X-ray Diffraction (XRD), Scanning Eelectron Microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR) analyses. The maximum chitosan loading on 200-mesh raw bentonite clay (126.30 mg/L) was achieved under the following conditions: the initial chitosan concentration of 1000 mg/L, the stirring speed of 200 rpm, pH of 4.9, 60 min of reaction time, and temperature of 30 °C. The chitosan loading was further increased to 256.30, 233.70, and 208.83 mg/g, when using bentonite clay activated through 6 min of microwave irradiation (800 W), 10 % sulfuric acid treatment, and calcinations at 600 °C, respectively. When the chitosan loading was increased from 34.76 to 233.7 mg/g, the removal percentages of Cu(II), Cr(VI), and Pb(II) were improved, respectively from 78.90 to 95.5 %, from 82.22 to 98.74 %, from 60.09 to 86.18 %. Copyright © 2018 BCREC Group. All rights reservedReceived: 14th March 2017; Revised: 17th July 2017; Accepted: 18th July 2017; Available online: 22nd January 2018; Published regularly: 2 April 2018How to Cite: Yu, T., Qu, C., Fan, D., Xu, R. (2018). Effects of Bentonite Activation Methods on Chitosan Loading Capacity. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (1): 14-23 (doi:10.9767/bcrec.13.1.1040.14-23)
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Jablonovská, Katarína, and Iveta Štyriaková. "Application Possibility of Bentonite and Zeolite in Bioremediation." Advanced Materials Research 20-21 (July 2007): 295–98. http://dx.doi.org/10.4028/www.scientific.net/amr.20-21.295.
Повний текст джерелаАнотація:
This paper investigates Zn2+ and Cu2+ adsorption capability of bentonite and zeolite taken from the non-raw metallic deposits of Slovakia. Viable biomass of an Bacillus pumilus and Bacillus megaterium enhanced the efficiency of Zn2+ and Cu2+ adsorption from model solution. Initial concentration of Cu and Zn in model solutions initially containing 32.3 mg.Cu.L-1and 42.9 mg Zn.L-1 after six hours sorption and desorption at 25°C, it was observed that 1g bentonite whit bacteria inokulum was found to remove 0.195 mg Zn2+ and 0.17 mg Cu2+ from the solution and 1g zeolite was found to remove 0.088 Zn2+ and 0.051 Cu2+. The ability for Zn and Cu sorption was bentonite > zeolite. The adsorption of metal ions on bentonite and zeolite depends on pH. Between pH 4 and 6, the main mechanism is by ion exchange. In order to prevent contamination of subsoil and groundwater by leachates containing heavy metals, bentonite and zeolite are widely used as cost-effective treatments barriers. For this reason it is important to study the adsorption of metals by these materials.
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Abnisa, Faisal. "Enhanced Liquid Fuel Production from Pyrolysis of Plastic Waste Mixtures Using a Natural Mineral Catalyst." Energies 16, no. 3 (January 23, 2023): 1224. http://dx.doi.org/10.3390/en16031224.
Повний текст джерелаАнотація:
Since plastic wastes are commonly found and accumulate in numerous types and forms, the pyrolysis of plastic waste mixtures seems more feasible to be selected for large-scale production. However, the process typically produces less liquid than individual plastic pyrolysis. This study proposed a viable approach for catalytic pyrolysis by using natural mineral catalysts without modification. Bentonite was selected as a natural mineral catalyst while HZSM-5 was used for performance comparison. The process was evaluated in situ using a fixed-bed reactor at temperatures between 400 °C and 500 °C. The mixture of plastic waste composition was designed based on the non-recycled plastics data. The results showed that 42.55 wt% of liquid yield was obtained from thermal pyrolysis using Malaysia’s non-recycled plastics data. It was then found that using HZSM-5 and bentonite catalysts significantly boosted liquid products to about 56 and 60%, respectively. The presence of catalysts also positively minimized tar formation and eliminated wax formation in the liquid product. Furthermore, the catalytic process showed remarkable improvements in aromatics and alkane compounds in the liquid while only alkenes were found to be high when bentonite was used.
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Veréb, G., V. E. Gayır, E. N. Santos, Á. Fazekas, Sz Kertész, C. Hodúr, and Zs László. "Purification of real car wash wastewater with complex coagulation/flocculation methods using polyaluminum chloride, polyelectrolyte, clay mineral and cationic surfactant." Water Science and Technology 80, no. 10 (November 15, 2019): 1902–9. http://dx.doi.org/10.2166/wst.2020.008.
Повний текст джерелаАнотація:
Abstract In the present study, real car wash wastewater was purified by different coagulation/flocculation methods. As coagulant, polyaluminum chloride (‘BOPAC’), conventional iron(III) chloride, iron(III) sulfate, and aluminum(III) chloride were used, while as flocculant non-ionic and anionic polyelectrolytes were investigated. The effects of added clay mineral (Na-bentonite) and cationic surfactant (hexadecyltrimethyl ammonium bromide – ‘HTABr’) were also investigated. The use of BOPAC was significantly more effective than conventional coagulants. Extra addition of clay mineral was also beneficial in relation to both the sediment volume and sedimentation speed, while polyelectrolyte addition enhanced further the sedimentation. Moreover, the simultaneous addition of HTABr significantly enhanced the color removal efficiency due to the successful in-situ generation of organophilic bentonite. In summary, the application of 100 mg L−1 Na-bentonite with 20 mg L−1 Al3+ (from BOPAC) and 0.5 mg L−1 anionic polyelectrolyte resulted in the efficient reduction of the turbidity (4–6 NTU), the COD (158 mg L−1) and the extractable oil content (4 mg L−1) with efficiencies of 98%, 59%, and 85%, respectively. By applying organophilic bentonite in high concentration (500 mg L−1) with identical concentrations of BOPAC and anionic polyelectrolyte, significant color removal (5 times lower absorbance at λ = 400 nm) and 27% lower sediment volume were achieved.
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Stewart, D. I., Y. Y. Tay, P. G. Studds, and T. W. Cousens. "Design parameters for bentonite-enhanced sand as a landfill liner." Proceedings of the ICE - Geotechnical Engineering 137, no. 4 (October 1, 1999): 189–95. http://dx.doi.org/10.1680/geng.1999.137.4.189.
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Stewart, D. I., T. W. Cousens, P. G. Studds, and Y. Y. Tay. "Design parameters for bentonite-enhanced sand as a landfill liner." Proceedings of the Institution of Civil Engineers - Geotechnical Engineering 137, no. 4 (October 1999): 189–95. http://dx.doi.org/10.1680/gt.1999.370404.
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Liu, Yanjun, Junjie Jia, Huifeng Zhang, and Shujuan Sun. "Enhanced Cr(VI) stabilization in soil by chitosan/bentonite composites." Ecotoxicology and Environmental Safety 238 (June 2022): 113573. http://dx.doi.org/10.1016/j.ecoenv.2022.113573.
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Stewart, D. I., P. G. Studds, and T. W. Cousens. "The factors controlling the engineering properties of bentonite-enhanced sand." Applied Clay Science 23, no. 1-4 (August 2003): 97–110. http://dx.doi.org/10.1016/s0169-1317(03)00092-9.
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Iravanian, Anoosheh, and Huriye Bilsel. "Tensile Strength Properties of Sand-bentonite Mixtures Enhanced with Cement." Procedia Engineering 143 (2016): 111–18. http://dx.doi.org/10.1016/j.proeng.2016.06.015.
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Feriancová, A., A. Dubec, J. Pagáčová, I. Labaj, and M. Pajtášová. "The influence of silane on the physico-mechanical properties of vulcanizates using bentonite fillers." IOP Conference Series: Materials Science and Engineering 1199, no. 1 (November 1, 2021): 012040. http://dx.doi.org/10.1088/1757-899x/1199/1/012040.
Повний текст джерелаАнотація:
Abstract Layered phyllosilicate fillers have received attention in the polymer industry due to their unique nanoscale sheet-like structure. Adding a small amount of bentonite nanofiller gives rise to improved mechanical, thermal, and gas barrier properties of rubber mixtures. Depending on the application, natural bentonite is often modified by physical processes or by chemical processes (intercalation, cation exchange process, functionalization, pillaring, etc.). Chemical modification increases the size of the interlayer spaces and provides a hydrophobic environment. Functionalization (e.g., silanization), which encompasses the chemical grafting of thermally stable silane coupling agents onto the clay platelets, make inorganic bentonite and the organic polymer matrix compatible. In the introduced study, commercial bentonite P130 from Lieskovec deposit was modified by silane (3-aminopropyl trietoxysilane) treatment. Different techniques such as infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to characterize modified and raw bentonite sample. Silanized P130s and raw product P130 were added to the natural rubber matrix to examine the influence of chemically functionalized bentonite on curing characteristic (M H, M L, t s2, t 90, ΔM) and mechanical properties (TSb, Eb, hardness) of rubber vulcanizates. Organo-bentonite was mixed into a rubber blend in particular ratio of 5, 10, 15, 20 phr in various combination with silane (3-aminopropyl triethoxysilane), Perkasil and carbon black. The highest maximum torque values were obtained with the sample using 20 phr of silanized P130s. The tensile strength (TSb) values decreased with increasing P130 content, as well as non-silanized and silanized P130. However, when 20 phr P130s was used, value of TSb was higher. The most enhanced properties of rubber blends were found with the addition of 20 phr of silanized bentonite P130s.
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Nigiz, F. U., A. I. Yucak, and N. D. Hilmioglu. "Purification of emulsified oil by Bentonite loaded polyvinylidene fluoride/polyvinylpyrrolidone membrane." Water Practice and Technology 15, no. 2 (March 31, 2020): 394–403. http://dx.doi.org/10.2166/wpt.2020.026.
Повний текст джерелаАнотація:
Abstract In this study, a Bentonite clay incorporated polyvinylfluoride (PVDF) and polyvinyl pyrrolidone (PVP) based adsorbent membrane was produced for the selective separation of oils from simulated wastewater. This membrane was produced as an intelligent material that selectively separates emulsified oils from water when it is used as adsorbent and purifies water when it is used in continuous membrane filtration. The affinity of the membrane to oil components was determined by water-oil uptake tests. The uptake experiments were conducted for soybean oil, hazelnut oil, lubricant oil and other volatile oils. As a result, membranes absorbed greater than 200 wt.% of oil when the membranes were immersed in the soybean oil, hazelnut oil and lubricant oil. When the same membranes were used for continuous filtration, greater than 85% of oil rejection values were obtained. As the PVP ratio in the membrane increased, flux values enhanced gradually. Bentonite incorporation simultaneously improved flux values and oil rejection remarkably. The soybean rejection increased from 69.1% to 90.9%, hazelnut oil rejection increased from 78% to 99.98%, and lubricant oil rejection enhanced from 80.5% to 96.5% when the bentonite amount was increased from 0 wt.% to 15 wt.%.
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Xu, Sifa, Cuifeng Li, Jizhuang Liu, Mengdan Bian, Weiwei Wei, Hao Zhang, and Zhe Wang. "Deformation and Hydraulic Conductivity of Compacted Clay under Waste Differential Settlement." Processes 6, no. 8 (August 8, 2018): 123. http://dx.doi.org/10.3390/pr6080123.
Повний текст джерелаАнотація:
Landfill is still the most important process to dispose of municipal solid waste in China, while landfill closure aims for pollution control, security control, and better land reuse. However, uneven settlement of landfill cover system is very likely to cause deformation and cracking. The objective of this paper is to examine the effects of geogrid reinforcement on the deformation behaviour and hydraulic conductivity of the bentonite-sand mixtures that are subjected to differential settlement. The laboratory model tests were performed on bentonite-sand mixtures with and without the inclusion of geogrid reinforcement. By maintaining the type and location of the geogrid within the liner systems as constant, the thickness of the bentonite-sand mixtures is varied. The performation of the liner systems with and without the inclusion of geogrid reinforcement was assessed by using jack to control differential settlement. Un-reinforced bentonite-sand mixtures of 100 mm and 200 mm thickness were observed to begin cracking at settlement levels of 2.5 mm and 7 mm, respectively. When settlement reached 25 and 42.5 mm, cracks for 100 mm and 200 mm thick bentonite-sand mixtures without geogrid penetrated completely. The settlement levels for bentonite-sand mixtures of 100 mm thickness with and without geogrid reinforcement was found to be 10 mm and 15 mm, respectively, when its hydraulic conductivity was around 5 * 10−7 cm/s. In comparison, geogrid reinforced bentonite-sand mixtures was found to sustain large deformation with an enhanced imperviousness. The results from the present study can provide theory evidence of predicting deformation and hydraulic conductivity of the landfill cover system.
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Benhacine, Fayçal, Farida Yahiaoui, and Assia Siham Hadj-Hamou. "Thermal Stability and Kinetic Study of Isotactic Polypropylene/Algerian Bentonite Nanocomposites Prepared via Melt Blending." Journal of Polymers 2014 (April 16, 2014): 1–9. http://dx.doi.org/10.1155/2014/426470.
Повний текст джерелаАнотація:
Isotactic polypropylene (iPP)/bentonite nanocomposites were prepared via melt blending using bentonite clay originated from Maghnia (Algeria). This clay was, at a first stage, used in its pure form (PBT) and then organically modified by Hexadecyl ammonium chloride (OBT). The effect of Maghnia bentonite dispersion on the iPP matrix was investigated by X-ray diffraction (XRD) and transmission electronic microscopy (TEM). DSC results evidenced that unmodified or organomodified bentonite can act as a nucleating agent increasing the rate of crystallites formation. Moreover, a thermogravimetry analysis confirmed a significant enhanced thermal stability of IPP/clay nanocomposites compared to pure IPP. The Flynn-Wall-Ozawa and Tang methods were applied to determine the activation energy Ea of the degradation process. The apparent activation energy Eα of thermal degradation for IPP/clay nanocomposites was much higher than that of virgin iPP. Comparatively to PBT, results indicate that OBT has an important effect on pure iPP thermal stability. Tensile modulus, tensile strength, and elongation at break were also measured and compared with those of pure iPP.
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Mutahir, Sadaf, Tayyaba Irfan, Nimra Nadeem, Muhammad Humayun, Muhammad Asim Khan, Moamen S. Refat, Chundong Wang, and Tahir Ali Sheikh. "Synthesis and Micromechanistic Studies of Sensitized Bentonite for Methyl Orange and Rhodamine-B Adsorption from Wastewater: Experimental and DFT-Based Analysis." Molecules 27, no. 17 (August 29, 2022): 5567. http://dx.doi.org/10.3390/molecules27175567.
Повний текст джерелаАнотація:
This work reports the formation of a novel adsorbent, prepared by activating bentonite with cinnamic acid, which is highly efficient to remove dyes from wastewater. The adsorption efficiency of the cinnamic acid activated bentonite was compared with unmodified bentonite by removing methyl orange and rhodamine-B from polluted water. The characterization was performed through X-ray diffraction (XRD) Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The results indicated that acidic pH and low temperature were more suitable for the selected dyes adsorption. The analysis of the data was done by the Langmuir and Freundlich isotherms; the Freundlich isotherm showed more suitability for the equilibrium data. The data were further analyzed by pseudo-first and pseudo-second-order models to study adsorption kinetics. The results showed that methyl orange and rhodamine-B adsorption obeyed pseudo-order kinetics. The results obtained from this research suggested that acid activation of bentonite with cinnamic acid increased the surface area of the clay and hence enhanced its adsorption efficiency. The maximum adsorption efficiency for the removal of methyl orange and rhodamine-B was up to 99.3 mg.g−1 and 44.7 mg.g−1, respectively, at 25 °C. This research provides an economical modification technique of bentonite, which makes it cost-effective and a good adsorbent for wastewater treatment.
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Suleimanov, B. A., E. F. Veliyev, and N. V. Naghiyeva. "Preformed particle gels for enhanced oil recovery." International Journal of Modern Physics B 34, no. 28 (October 27, 2020): 2050260. http://dx.doi.org/10.1142/s0217979220502604.
Повний текст джерелаАнотація:
This study refers to the synthesis of new advanced preformed particle gels (PPGs) based on 2-acrylamido-2-methylpropane sulfonic acid (AMPS), Polyvinyl Pirrolidone (PVP) and bentonite clay. For the synthesis, [Formula: see text], [Formula: see text]-methylenebisacrylamide was used as crosslinker and ammonium persulphate as initiator. As a consequence of the inclusion of clay into the polymer matrix and the intercalation of AMPS between the layers as well as the presence of hydrophilic interactions occurring between partners, the final PPGs possessed greater swelling degrees, slower de-swelling process, high thermal stability and enhanced mechanical properties in comparison with pure PPG.
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Svensson, Margareta, and Bert Allard. "Diffusion tests of mercury through concrete, bentonite-enhanced sand and sand." Journal of Hazardous Materials 142, no. 1-2 (April 2007): 463–67. http://dx.doi.org/10.1016/j.jhazmat.2006.08.046.
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