Journal articles on the topic 'Iron-containing sorption materials'
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1
Litynska, Marta, Tetiana Dontsova, Olena Yanushevska, and Volodymyr Tarabaka. "Development of iron-containing sorption materials for water purification from arsenic compounds." Eastern-European Journal of Enterprise Technologies 2, no. 10 (110) (April 30, 2021): 35–42. http://dx.doi.org/10.15587/1729-4061.2021.230216.
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The paper is devoted to the development of a method for obtaining and using iron-containing sorption materials for the effective removal of arsenic compounds of different oxidation states from an aqueous medium. It is known that arsenic compounds have a harmful effect on biota due to high toxicity. The paper theoretically and experimentally substantiates the choice of iron-containing materials as the main sorbent material for arsenic compounds removal from the aqueous medium. A series of iron-containing adsorbents, including powder, activated carbon-based granular and suspension sorbents, was synthesized by different methods (heterogeneous and homogeneous precipitation). Experimental studies have confirmed that the adsorption of arsenate ions on iron-containing sorption materials corresponds to the pseudo-second order of the reaction (R2=0.999), which is inherent in adsorption processes. It was determined that oxyhydroxide sorption materials obtained by the homogeneous precipitation demonstrate higher sorption activity (up to 70 mg/g for As(III) and over 70 mg/g for As(V)). It was found that activated carbon-based iron-containing sorption materials showed approximately 2 times lower efficiency than powder iron(III) oxide, iron(III) oxyhydroxide and amorphous iron(III) hydroxide. It was shown that the use of microfiltration membranes is promising for the removal of spent suspension iron-containing sorption materials. Experimental studies have confirmed that the use of the combination “fine-particle iron(III) oxyhydroxide/membrane” allows removing arsenic compounds from contaminated water to the sanitary requirements level (less than 10 μg As/l) and separating effectively the spent fine-particle sorbent from water
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Makovskaya, Olga Yu, and Nadezhda I. Bryantseva. "Nickel Sorption from Sulphate Solutions of Oxidized Nickel Ores Leaching." Defect and Diffusion Forum 410 (August 17, 2021): 394–99. http://dx.doi.org/10.4028/www.scientific.net/ddf.410.394.
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The possibility of sorption extraction of nickel from leaching solutions of oxidized nickel ores of the Buruktal deposit is considered. Ionite Lewatit TP220 with bis-picolylamine functional groups is effective for nickel recovery against the background of high iron contents. Lewatit TP220 is mechanically strong enough for use in the resin-in-pulp process. Nickel sorption with satisfactory performance occurs both in the variant of sorption leaching and extraction from clarified solutions. At sorption from the pulp, the capacity for nickel was 5.44 mg/g, for iron, 25.17 mg/g. The use of 20% sulfuric acid provides quantitative nickel desorption. To obtain a higher quality nickel-containing product, it is recommended to additionally purify the resulting eluates from iron.
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Bondarieva, A. I., V. Yu Tobilko, Yu M. Kholodko, B. Yu Kornilovych, and N. A. Zahorodniuk. "Efficient removal of arsenic(V) from water using iron-containing nanocomposites based on kaolinite." Voprosy Khimii i Khimicheskoi Tekhnologii, no. 1 (January 2022): 11–18. http://dx.doi.org/10.32434/0321-4095-2022-140-1-11-18.
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We studied the main physicochemical features of removing of arsenate from contaminated waters utilizing stabilized nanoscale iron. An inorganic kaolinite matrix was used for stabilization. The structure of adsorbents was studied using some physicochemical methods (X-ray powder diffraction and the low-temperature N2 adsorption-desorption method). It was found that the efficiency of the removal of arsenic (V) ions depends on the weight ratio of iron nanopowder to kaolinite, whereas it does not depend on the pH of the water systems in a wide range. Kinetics data were analyzed using pseudo-first-order and pseudo-second-order models. It was stated that the removal of arsenic by iron-containing composites based on kaolinite occurs relatively rapid. The adsorption kinetic was appropriately described by the pseudo-second-order model, indicating the high affinity of arsenates with the surface of the iron-containing nanocomposite. The results demonstrated that the obtained materials have a much higher sorption capacity to As(V) ions than natural silicates. The Langmuir and Freundlich isotherm equations provided good fittings for the experimental sorption data. It was shown that the sorbents based on stabilized nanoscale iron effectively remove toxic arsenic ions from contaminated water.
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Zemskova, Larisa, Andrei Egorin, Eduard Tokar, Vladimir Ivanov, and Svetlana Bratskaya. "New Chitosan/Iron Oxide Composites: Fabrication and Application for Removal of Sr2+ Radionuclide from Aqueous Solutions." Biomimetics 3, no. 4 (December 4, 2018): 39. http://dx.doi.org/10.3390/biomimetics3040039.
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Here, we discuss the fabrication and problems of application of chitosan-based composite materials for the removal of hazardous metal ions from tap water and wastewater. The chitosan-based composites containing iron oxides for the uptake of Sr2+ ions were fabricated via a co-precipitation method with variation of the iron/chitosan ratio and pH of the medium. The morphology and composition of the fabricated sorbents were characterized using scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM–EDX) and X-ray diffraction (XRD) analysis. We have shown that the suggested fabrication approach allows for a homogeneous distribution of the inorganic phase in the polymer matrix. Investigations of the sorption performance of the composites have shown that they are efficient sorbents for 90Sr radionuclides uptake from tap water. The composite sorbent containing amorphous iron oxide in a chitosan matrix and calcined at 105 °C showed the best sorption characteristics. We have also demonstrated that there is an optimal iron oxide content in the composite: with increasing oxide content, the efficiency of the sorbents decreases due to poor stability in solution, especially in alkaline media. The alternative approach yielding magnetic chitosan-based composites with sufficiently good sorption performance and stability in neutral and weakly alkaline media is suggested.
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Zhanabayeva, A. K., G. K. Bishimbayeva, D. S. Zhumabayeva, A. M. Nalibayeva, and Ye N. Abdikalykov. "A technology for producing electrode materials for lithium-ion batteries from Kazakhstan spodumene raw materials." Proceedings of Universities. Applied Chemistry and Biotechnology 12, no. 1 (April 1, 2022): 141–52. http://dx.doi.org/10.21285/2227-2925-2022-12-1-141-152.
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This study aims to develop a technology for producing innovative electrode materials for modern lithium batteries. An efficient technology for post-purifying of technical lithium carbonate to reach the level of battery quality (99.95%) was developed. This technology involves causticiziation of technical lithium carbonate, ultrafiltration and ion-exchange sorption of a lithium hydroxide solution, followed by precipitation of lithium carbonate with ammonium carbonate. Cation-exchange resins of the brands Purolite S930Plus, Purolite S940 and Purolite S950 were studied for sorption purification of lithium-containing solutions from calcium and magnesium impurities. Purolite S940 and Purolite S950 can be recommended as the most effective cation exchangers. The kinetic parameters of calcium and magnesium sorption were determined using a Purolite S940 cation exchanger. The bicarbonation mode was set at room temperature and a pressure of 0.3 atm. The synthesized samples of lithium-iron-phosphate studied by the sol-gel method. The structures of the obtained electrode materials corresponding to the standard profile of lithium-iron-phosphate were investigated by X-ray diffraction. The synthesized electrode materials in the structure of lithium half- and button cells confirmed their good electrochemical properties, stable operation of batteries and a high intercalation reversibility of lithium ions in the samples within the potential range of 2.5–4.3 V. The main research results are innovative cathode and anode materials of a new generation for modern lithium-ion batteries with significantly increased capacity and stability of operation, obtained from lithium precursors – battery grade lithium carbonate based on domestic mineral and technogenic raw materials.
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Flieger, Jolanta, Justyna Kawka, Wojciech Płaziński, Rafał Panek, and Jarosław Madej. "Sorption of Heavy Metal Ions of Chromium, Manganese, Selenium, Nickel, Cobalt, Iron from Aqueous Acidic Solutions in Batch and Dynamic Conditions on Natural and Synthetic Aluminosilicate Sorbents." Materials 13, no. 22 (November 21, 2020): 5271. http://dx.doi.org/10.3390/ma13225271.
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Zeolites are materials with known sorption properties. The sorption is thought to progress mainly by ion exchange with Na+, K+, Mg2+, Ca2+ or H+ from the zeolite exchange sites. The aim of the study was to compare the sorption properties of natural and synthetic zeolites on the example of the removal of selected metals from aqueous acidic solutions. Uptake experiments for selected ions of chromium, manganese, selenium, nickel, cobalt, and iron were performed using the batch and kinetic column methods. The sorption of the individual metal ions in mg per 1g of sorbent was determined for each sorbent. The relative affinity sequence of the examined cations toward the various sorbent was presented. The Langmuir model was used to model the adsorption equilibrium. Vermiculite under 1 mm of diameter (SF), Na-X, and Na-A were proved to be the most suitable for the individual uptake of studied metal ions. It was observed that the behavior of selenium ions differed from the remaining ones which was interpreted that selenium undergoes adsorption in the anionic form. The fixed-bed column studies were performed using Na-A, ensuring the sorption of selenium in the presence of iron(III) ions. The experiments were conducted using Na-X zeolite pre-loaded by Fe(III) as well as unmodified sorbent eluted by an equimolar mixture containing 100 ppm of Fe and Se. Obtained results prove that selenium sorption improves if other metal ions such as iron appear in the acidic solution. That efficient selenium sorption conditions can be applied to remove selenium which was recognized as toxic at higher levels.
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Navratil, J. D., and M. T. Shing Tsair. "Magnetic separation of iron and heavy metals from water." Water Science and Technology 47, no. 1 (January 1, 2003): 29–32. http://dx.doi.org/10.2166/wst.2003.0009.
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A magnetic separation device is being developed for removal of iron and heavy metals from water. The device consists of a column of supported magnetite surrounded by a movable permanent magnet. The mineral magnetite, or synthetically prepared iron ferrite (FeO.Fe2O3), is typically supported on various materials to permit adequate water passage through the column. In the presence of an external magnetic field, enhanced capacity was observed in using supported magnetite for removal of actinides and heavy metals from wastewater. The enhanced capacity is primarily due to magnetic filtration of colloidal and nanoscale particles along with some complex and ion exchange sorption mechanisms. This paper will review some previous work on the use of magnetite for wastewater treatment and discuss the development and potential of the magnetic nanoscale filtration/sorption process for water treatment. Recent research results are also presented on preliminary experimental studies using the process with water samples containing iron.
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Rahman, Md Lutfor, Zhi Jian Wong, Mohd Sani Sarjadi, Sabrina Soloi, Sazmal E. Arshad, Kawi Bidin, and Baba Musta. "Heavy Metals Removal from Electroplating Wastewater by Waste Fiber-Based Poly(amidoxime) Ligand." Water 13, no. 9 (April 30, 2021): 1260. http://dx.doi.org/10.3390/w13091260.
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An efficient and economical treatment technology for heavy metal removal from the electroplating wastewaters is needed for the water purification. Therefore, pure cellulosic materials were derived from two waste fiber (pandanus fruit and durian rind) and conversion of the cellulose into the poly(acrylonitrile)-grafted material was accomplished by free radical grafting system. Thereafter, poly(amidoxime) ligand was produced from the grafted materials. Sorption capacity (qe) of several toxic metals ions was found to be high, e.g., copper capacity (qe) was 298.4 mg g−1 at pH 6. In fact, other metal ions, such as cobalt chromium and nickel also demonstrated significant sorption capacity at pH 6. Sorption mechanism played acceptable meet with pseudo second-order rate of kinetic pattern due to the satisfactory correlation with the experimental sorption values. A significant correlation coefficient (R2 > 0.99) with Langmuir model isotherm showed the single or monolayer sorption occurred on the surfaces. The reusability study showed that the polymer ligand can be useful up to six cycles with minimum loss (7%) of efficiency and can be used in the extraction of toxic metal ions present in the wastewaters. Therefore, two types of electroplating wastewater were used in this study, one containing high concentration of copper (23 ppm) and iron (32 ppm) with trace level of others heavy metals (IWS 1) and another containing high concentration of copper (85.7 ppm) only with trace level of others heavy metals (IWS 2). This polymeric ligand showed acceptable removal magnitude, up to 98% of toxic metal ions can be removed from electroplating wastewater.
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Castro, Laura, Lesly Antonieta Ayala, Arevik Vardanyan, Ruiyong Zhang, and Jesús Ángel Muñoz. "Arsenate and Arsenite Sorption Using Biogenic Iron Compounds: Treatment of Real Polluted Waters in Batch and Continuous Systems." Metals 11, no. 10 (October 10, 2021): 1608. http://dx.doi.org/10.3390/met11101608.
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Arsenic pollution in waters is due to natural and anthropogenic sources. Human exposure to arsenic is associated with acute health problems in areas with high concentrations of this element. Nanometric iron compounds with large specific surface areas and higher binding energy produced by some anaerobic microorganisms are thus expected to be more efficient adsorbents for the removal of harmful metals and metalloids than chemically produced iron oxides. In this study, a natural consortium from an abandoned mine site containing mainly Clostridium species was used to biosynthesize solid Fe(II) compounds, siderite (FeCO3) and iron oxides. Biogenic precipitates were used as adsorbents in contact with solutions containing arsenate and arsenite. The adsorption of As(V) fitted to the Langmuir model (qmax = 0.64 mmol/g, KL = 0.019 mmol/L) at the optimal pH value (pH 2), while the As(III) adsorption mechanism was better represented by the Freundlich model (KF = 0.476 L/g, n = 2.13) at pH 10. Water samples from the Caracarani River (Chile) with high contents of arsenic and zinc were treated with a biogenic precipitate encapsulated in alginate beads in continuous systems. The optimal operation conditions were low feed flow rate and the up-flow system, which significantly improved the contaminant uptake. This study demonstrates the feasibility of the application of biogenic iron compounds in the treatment of polluted waters.
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Tatarintseva, E. A., and L. N. Olshanskaya. "Obtaining effective oil sorbents based on chemical industry waste for water treatment." Industrial processes and technologies 1, no. 1 (2021): 6–16. http://dx.doi.org/10.37816/2713-0789-2021-1-1-6-16.
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It was proposed new technologies for producing effective oil sorbents based on chemical industry waste. It was shown the possibility of using PET waste as a binder in the produc- tion of oil sorbents with specific properties (hydrophobicity, oleophilicity, magnetic proper- ties) using thermally expanded and oxidized graphite (TEG and OG) and ferritized iron- containing galvanic sludge (FGS). The presence of iron ions in the galvanic sludge allows one to obtain magnetite and ferrites during ferritization, which leads to the appearance of magnetic properties in FGS, established using a vibration magnetometer, the saturation induction was ~ 0.02 T. Electroplating sludge was carried out at t ≈ 1000 oC and τ = 1.5 hr with preliminary mechanical activation. The physicomechanical, chemical, and sorption properties of the obtained oil sorbents (bulk density, abrasion, grindability, particle size distribution, oil capacity, moisture capacity, wettability, buoyancy, specific surface area, chemical composition, adsorption capacity of materials under static and dynamic conditions) are studied. It was found that sorption ma- terials have 100% buoyancy, are highly active in cleaning water surface from films of oil products with different thicknesses (1–5 mm). It was shown that sorption capacity increases with increasing film thickness and reaches a maximum value at a thickness of 3 mm. The cleaning efficiency is 99.0%. It has been established that the sorption capacity of the sorption material (SM) depends on the nature of oil products, its viscosity, solubility and initial concentration in water. It is proved that the processes of sorption of oil products proceed by the physical mechanism, which can be represented as the oleophilic interaction of particles of the Sorption material and oil products, which is confirmed by the type of sorption isotherms, which are type II and IV according to the BDT theory and type L according to the Hills classification char- acteristic of polymolecular adsorption. The obtained adsorption isotherms were processed in the framework of the Langmuir and Dubinin – Radushkevich models, and the constants of the adsorption equations were calculated.
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Yang, Fan, Yankui Tang, Yuwei Mi, Lu Jiang, Penghong Luo, and Yang Yang. "Mn(II) Sorption on Stream Sediments Sampled in Manganese Mining Area: Dynamics and Mechanisms." Applied Sciences 12, no. 7 (March 25, 2022): 3368. http://dx.doi.org/10.3390/app12073368.
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The stream sediments that have been impacted by manganese (Mn) containing wastewater for decades contain not only abundant microorganisms but also organic/inorganic substances. To achieve effective treatment of manganese (Mn)-containing effluent and recovery of Mn from water/sediments, the Mn(II) sorption behaviors and mechanism on sediments of a stream in Mn mining areas were studied. In addition, the study analyzed the effects of various factors (initial concentration, solution pH, sediment dose, contact time, and coexisting cations) on the Mn sorption efficiency of Daxin sediments, and explored the contribution of microbial activity in the sediment sorption of Mn(II). The results showed that the sorption process of Mn(II) on the sediments was consistent with the Elovich and Freundlich models, and the removal of heavy metals was maximum at 40 °C (62.47–98.93%), pH = 8 (77.51%), initial concentration of 1 mmol·L−1 (95.37%) and sediment dosing of 12 g·L−1 (98.93%). The addition of 50 mM NaN3 inhibited the microbial activity in the Daxin sediment, reducing the sorption and removal rates of Mn(II) by 0.605 mg·g−1 and 8.92%, respectively. After sorption, the proportion of the Fe–Mn oxidation(iron–manganese) state in Daxin sediments decreased from 54% to 43%, while the proportion of the exchangeable state increased by 10.80%. Microorganisms in the sediment had a positive effect on inhibiting heavy metal migration and reducing the bioavailability of contaminants in the soil. Through this study, we hope to further understand the sorption and desorption mechanism of manganese by stream sediments in manganese ore areas, so as to provide a guide on the management and recovery of Mn from stream sediments in manganese mining areas.
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Palamarchuk, M. S., E. A. Tokar, M. V. Tutov, and A. M. Yegorin. "Deactivation of Spent Ion-exchange Resins Contaminated by Cesium and Cobalt Radionuclides." Ecology and Industry of Russia 23, no. 4 (April 3, 2019): 20–24. http://dx.doi.org/10.18412/1816-0395-2019-4-20-24.
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Simulation of iron oxide (magnetite and maghemite) and aluminosilicate (sillimanite and cyanite) deposits formed on the surface of spent ionexchange resins in the process of decontamination of liquid radioactive waste contaminated by cesium and cobalt radionuclides has been performed. A method of deep deactivation of spent ion-exchange resins contaminated by aluminosilicate and iron oxide deposits using alkaline and acidic solutions containing Zn-EDTA complexes has been suggested. The method of two-stage concentrating of cesium radionuclides using selective sorption materials (resorcinol-formaldehyde resin and Thermoxid-35 ferrocyanide sorbent) has been improved. The method advantage consists in using a solution containing EDTA complexes for elution of cesium radionuclides from the resorcinol-formaldehyde resin with their transition onto Thermoxid-35. High stability of the resorcinol-formaldehyde resin and Thermoxid-35 in the course of concentrating has been demonstrated. A scheme of deactivation of spent ion-exchange resins, which enables one to decrease the volume of secondary wastes due to utilization of a circulating water supply, has been suggested.
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Holford, I. C. R., C. Hird, and R. Lawrie. "Effects of animal effluents on the phosphorus sorption characteristics of soils." Soil Research 35, no. 2 (1997): 365. http://dx.doi.org/10.1071/s96048.
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Two groups of soils were examined to determine the effects of dairy, pig, or sewage effluent and other materials containing phosphorus (P) on their P sorption characteristics, using the Langmuir equation to estimate values of both sorption capacity and sorption strength. There were 19 soils (0-15 cm) from 6 sites in the Williams River catchment and 3 soils (0-100 cm) from Bermagui, all from coastal New South Wales. Effluent usually decreased P sorption capacities of the Williams River soils, and in 3 soils the capacities were reduced to zero. Sorption strength was reduced substantially by effluent treatment in all soils except one, which had received effluent for only 3 years. Sorption strength, but not necessarily capacity, was also lower after treatment with poultry manure or chicken litter than after treatment with superphosphate only. Where effluent did not decrease sorption capacity there was a substantial increase in total carbon and iron, both of which could increase sorption capacities. After 3 years of effluent treatment of the Bermagui soil, sorption capacities had been reduced in the top 70 cm depth, the extent of the reduction varying from 17% at 0-7 · 5 cm depth to 38% at 40-70 cm depth. Sorption strength was reduced in the top 40 cm depth only. After 12 years of effluent treatment, sorption capacities and strength had also decreased at the deeper sampling depths (to 100 cm), and the average reduction in capacity was about 40%. These results suggest that P leaching will begin well before the total sorption capacity has been saturated. There was a direct and significant correlation between the sorption strength of the untreated soil and the percentage saturation reached before leaching began. Further saturation of the sorption complex appears to be slow after this degree of saturation has been reached, and it seems that P leaching exceeds adsorption during this phase. There was also a negative correlation between sorption strength and KCl-soluble P in all soils, suggesting that soil P solubility and potential saturation are both controlled by this characteristic.
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Borkowski, Andrzej, Wojciech Kiciński, Mateusz Szala, Justyna Topolska, Paweł Działak, and Marcin D. Syczewski. "Interactions of Fe–N–S Co-Doped Porous Carbons with Bacteria: Sorption Effect and Enzyme-Like Properties." Materials 13, no. 17 (August 21, 2020): 3707. http://dx.doi.org/10.3390/ma13173707.
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Carbon-based (nano)materials doped with transition metals, nitrogen and other heteroatoms are considered active heterogeneous catalysts in a wide range of chemical processes. Recently they have been scrutinized as artificial enzymes since they can catalyze proton-coupled electron transfer reactions vital for living organisms. Herein, interactions between Gram-positive and Gram-negative bacteria and either metal-free N and/or S doped or metal containing Fe–N–S co-doped porous carbons are studied. The Fe- and N-co-doped porous carbons (Fe–N–C) exhibit enhanced affinity toward bacteria as they show the highest adsorption capacity. Fe–N–C materials also show the strongest influence on the bacteria viability with visible toxic effect. Both types of bacteria studied reacted to the presence of Fe-doped carbons in a similar manner, showing a decrease in dehydrogenases activity in comparison to controls. The N-coordinated iron-doped carbons (Fe–N–C) may exhibit oxidase/peroxidase-like activity and activate O2 dissolved in the solution and/or oxygen-containing species released by the bacteria (e.g., H2O2) to yield highly bactericidal reactive oxygen species. As Fe/N/ and/or S-doped carbon materials efficiently adsorb bacteria exhibiting simultaneously antibacterial properties, they can be applied, inter alia, as microbiological filters with enhanced biofouling resistance.
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Dinu, Maria Valentina, Doina Humelnicu, and Maria Marinela Lazar. "Analysis of Copper(II), Cobalt(II) and Iron(III) Sorption in Binary and Ternary Systems by Chitosan-Based Composite Sponges Obtained by Ice-Segregation Approach." Gels 7, no. 3 (July 24, 2021): 103. http://dx.doi.org/10.3390/gels7030103.
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With the intensive industrial activity worldwide, water pollution by heavy metal ions (HMIs) has become a serious issue that requires strict and careful monitoring, as they are extremely toxic and can cause serious hazards to the environment and human health. Thus, the effective and efficient removal of HMIs still remains a challenge that needs to be solved. In this context, copper(II), cobalt(II) and iron(III) sorption by chitosan (CS)-based composite sponges was systematically investigated in binary and ternary systems. The composites sponges, formed into beads, consisting of ethylenediaminetetraacetic acid (EDTA)- or diethylenetriaminepentaacetic acid (DTPA)-functionalized CS, entrapping a natural zeolite (Z), were prepared through an ice-segregation technique. The HMI sorption performance of these cryogenically structured composite materials was assessed through batch experiments. The HMI sorption capacities of CSZ-EDTA and CSZ-DTPA composite sponges were compared to those of unmodified sorbents. The Fe(III) ions were mainly taken up when they were in two-component mixtures with Co(II) ions at pH 4, whereas Cu(II) ions were preferred when they were in two-component mixtures with Co(II) ions at pH 6. The recycling studies indicated almost unchanged removal efficiency for all CS-based composite sorbents even after the fifth cycle of sorption/desorption, supporting their remarkable chemical stability and recommending them for the treatment of HMI-containing wastewaters.
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Pasinszki, Tibor, Melinda Krebsz, Deepak Chand, László Kótai, Zoltán Homonnay, István E. Sajó, and Tamás Váczi. "Carbon microspheres decorated with iron sulfide nanoparticles for mercury(II) removal from water." Journal of Materials Science 55, no. 4 (September 26, 2019): 1425–35. http://dx.doi.org/10.1007/s10853-019-04032-3.
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Abstract A new and simple method is developed to synthesize carbon microspheres decorated with iron sulfide nanoparticles for mercury ion removal from water. The synthesis is based on carbonizing polystyrene–divinylbenzene-based and iron(III) sulfate-loaded cation exchange resins between 500 and 1000 °C. The phase composition, surface area, and morphology of these materials are characterized by various spectroscopic and diffraction techniques, including Mössbauer spectroscopy, powder X-ray diffraction, Raman and scanning electron microscopy, and BET analysis. Pyrrhotite is found to be the dominant iron-containing phase. The adsorption performance of microspheres for mercury ion removal from water is studied as a function of adsorbent load and contact time at pH 6.5 using a solution of 40 mg dm−3 mercury ion. Pyrrhotite nanoparticles played a key role in mercury ion removal amounting to 70–90% of the extracted amount. A high adsorption capacity of 104 mg of mercury/g of adsorbent at an adsorbent load of 0.33 g dm−3 is achieved, and the removal kinetics could be well fitted with a pseudo-second-order kinetic model, indicating chemical sorption. The synthetic method is easy to scale up for large-scale production and materials are easy to handle, which is significant for large-scale environmental applications.
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Egorin, Andrei, Eduard Tokar, Anna Matskevich, Nikita Ivanov, Ivan Tkachenko, Tatiana Sokolnitskaya, and Larisa Zemskova. "Composite Magnetic Sorbents Based on Iron Oxides in Different Polymer Matrices: Comparison and Application for Removal of Strontium." Biomimetics 5, no. 2 (May 18, 2020): 22. http://dx.doi.org/10.3390/biomimetics5020022.
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Introduction of magnetic nanoparticles into composite sorbents based on polymer matrices has received great attention due to the possibility of using cheap iron oxides and removing spent sorbents by means of magnetic separation. In the present paper, we discuss the problem of creating magnetic sorbents using two types of matrices as host materials: synthetic cation exchange resin and natural aminopolysaccharide chitosan. The possibilities of applying matrices for the in situ formation of oxide phases of a specified composition with the required content of an inorganic component in a composite material were estimated. The composition of the oxide phase formed in the composite material was studied, and particle sizes were evaluated by the method of X-ray diffraction analysis. Magnetic characteristics were investigated. Sorption characteristics with respect to strontium for the composites containing iron oxides were determined.
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Yegorov, V. V., O. Yu Makovskaya, S. V. Mamyachenkov, and P. A. Kozlov. "SORPTION OF FLUORIDE IONS BY IRON OXYHYDRATE FIXED ON THE CARRIERS. Part 1. Organic carriers." Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy, no. 4 (August 16, 2018): 15–23. http://dx.doi.org/10.17073/0021-3438-2018-4-15-23.
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The article considers possibility of using inorganic sorbent – iron oxyhydrate (IOH) – to remove F– ions from process solutions of zinc production. The method of IOH synthesis is chosen. The results of scanning electron microscopy and X-ray phase analysis are presented. The principal possibility of using ion-exchange resins as IOH-modified carriers is considered. The paper studies active substance formation on anion and cation exchange resins. It is shown that the most durable composite sorbents are obtained using strongly acidic cation exchange resins with SO3– groups. A method for introducing IOH into the structure of carrier materials and obtaining composite sorbents is described. The KU-2×8 strongly acidic cation exchanger is recommended as a composite base. Cation exchangers saturated with iron were held in a sodium chloride solution with a concentration of 2,5 g/dm3 for 24 hours at 85 °C to ensure formation of β-modification IOH crystals distributed over the ion exchanger grain volume. Anion exchangers were held in an iron(III) sulfate solution with added sodium chloride for 24 hours at 85 °C. At the same time, iron oxyhydrate films formed on the surface of sorbent grains were observed. Fluorine sorption was carried out in a static mode from a standardized test solution with a concentration of F– = 100 mg/dm3 at 60 °C. Sorption on the AB-17×8 anionite was carried out at 20 °C. Absorbed fluorine was desorbed by the NaOH (0,1 M) solution at 60 °C for 2 hours. The synthesized KU-2×8-IOH composite sorbent has a fluorine capacity of 0,7–1,1 mg/g, and can be regenerated with resulting easily utilizable fluorine-containing eluate.
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Malka, Iwona, Tomasz Czujko, Jerzy Bystrzycki, and Leszek Jaroszewicz. "The role of Mg2FeH6 formation on the hydrogenation properties of MgH2-FeFx composites." Open Chemistry 9, no. 4 (August 1, 2011): 701–5. http://dx.doi.org/10.2478/s11532-011-0051-5.
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AbstractThe hydrogenation properties of magnesium hydride mechanically milled with iron fluorides (FeF2 and FeF3), were investigated by Temperature Programmed Desorption (TPD) and volumetric methods using a Sieverts-type apparatus, as prepared upon dehydrogenation and finally upon subsequent hydrogenation. The activation energy of hydrogen desorption (Ea), calculated from the Kissinger formula using TPD measurements obtained with different heating rates, showed significant decreases of Ea in comparison to that of milled MgH2 without any dopants. Moreover, the influence of these metal fluorides on the thermodynamics of the decomposition process was also examined. In the case of the FeF2 dopant, rehydrogenation following desorption caused the complete decomposition of the iron fluoride to BCC iron and the formation of a predominant MgH2 phase. In contrast to FeF2, the addition of FeF3 led to the formation of β-MgH2 as a major phase coexisting with Mg2FeH6 and MgF2 compounds. The presence of pure Fe in the MgH2+FeF2 composite, as opposed to MgH2+FeF3 containing Mg2FeH6 and MgF2, did not cause any significant influence on the sorption properties of MgH2. Moreover, the original material doped with FeF3 predominantly showed iron in the Mg2FeH6 compound, while the FeF2 dopant iron mostly showed the nearly pure BCC metallic phase
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Politaeva, Nataliya А., Irina V. Atamanyuk, Yuliya А. Smyatskaya, Tatiana A. Kuznetsova, Toumi Amira, and Pavel B. Razgovorov. "WASTE-FREE TECHNOLOGY OF CHLORELLA SOROKINIANA MICROALGAE BIOMASS USAGE FOR LIPIDS AND SORBENTS PRODUCTION." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 61, no. 12 (December 12, 2018): 137–43. http://dx.doi.org/10.6060/ivkkt.20186112.5795.
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In the present article we introduce application areas of Сhlorella sorokiniana microalgae biomass for national economy (feed and biologically active additives, etc). Here it is shown that thermal and chemical modification of plant material waste might result in obtaining of highly-efficient materials for water purification. Major stages of waste-free technology of microalga processing with further extraction of valuable lipids and obtaining of sorption materials are schematically shown. We have determined fatty-acid content of lipid fraction (77 mg/g), obtained by Soxhlet method from lyophilized microalga biomass. It was revealed, that it includes 83.7% of unsaturated fatty acids (generally, С18:1, С18:2, С18:3), whereas saturated fatty acids are mostly presented by С16 – С20 family. In lyophilized biomass we discovered α-linolenoic acid (Omega-3, 28.3%), which is one of the most valuable biologically active compounds, required for full-value human life and activities. Microstructure analysis of residual biomass of C. sorokiniana microalgae has shown pore surface, formed by destroyed cells. In the course of studying the sorption properties of residual biomass with the use of initial and final concentration parameters, the efficiency of purification of model water from Fe3+ ions (47.5%) was evaluated, which indicates the need to modify the sorption properties of biomass. It has been established that the degree of wastewater purification containing iron (III) compounds can be significantly increased (by 1.8 times) by forming from the residual biomass granular materials with additional introduction of chitosan in the composition, which using as a binder and a modifying additive (mass ratio 4:1).
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Rébiscoul, Diane, Emilien Burger, Florence Bruguier, Nicole Godon, Jean-Louis Chouchan, Jean-Pierre Mestre, Pierre Frugier, Jean-Eric Lartigue, and Stephane Gin. "Glass-Iron-Clay interactions in a radioactive waste geological disposal: a multiscale approach." MRS Proceedings 1518 (2013): 185–90. http://dx.doi.org/10.1557/opl.2013.67.
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ABSTRACTIn France, nuclear glass canisters arising from spent fuel reprocessing are expected to be disposed in a deep geological repository using a multi-barrier concept (glass/canister/steel overpack and claystone). In this context, glass - iron or corrosion products interactions were investigated in a clayey environment to better understand the mechanisms and driving forces controlling the glass alteration. Integrated experiments involving glass - metallic iron or magnetite - clay stacks were run at laboratory scale in anoxic conditions for two years. The interfaces were characterized by a multiscale approach using SEM, TEM, EDX and STXM at the SLS Synchrotron. Characterization of glass alteration patterns on cross sections revealed various morphologies or microstructures and an increase of the glass alteration with the proximity between the glass and the source of iron (metallic iron or magnetite) due to the consumption of the silica coming from the glass alteration. In case of magnetite, the silica consumption is mainly driven by a sorption of silica onto the magnetite. For experiments containing metallic iron, the silica consumption seems to be strongly driven by silicates precipitation including Fe and Fe/Mg when the Fe is not enough available. Moreover, in addition to Fe-silicates observed at the surface of the gel layers, iron is incorporated within the gel probably as nanosized precipitates of Fe-silicates which could affect its physical and chemical properties. Those results highlighted the impact of the distance between glass and iron source and the nature of the iron source which drive the process consuming the silica coming from the glass alteration.
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Filatova, D. G., A. A. Arkhipenko, M. A. Statkus, I. V. Mikheev, V. B. Baranovskaya, and Yu A. Karpov. "Sorption of As (III) and Se (IV) from aqueous solutions for subsequent determination by total reflection X-ray fluorescence." Industrial laboratory. Diagnostics of materials 87, no. 8 (August 21, 2021): 19–22. http://dx.doi.org/10.26896/1028-6861-2021-87-8-19-22.
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An approach to the simultaneous isolation of As (III) and Se (IV) from solutions on a new S,N-containing sorbent followed by determination of the analyte in the sorbent phase using total reflection X-ray fluorescence (TXRF) has been proposed. To match the goal, a sorbent with a branched structure was synthesized on the base of polyacrylamide modified with formaldehyde and hydrogen sulfide. This is a heteroatomic copolymer containing sulfide bridges in the chain and crosslinking by a tertiary amine. Conditions for the quantitative co-extraction of As (III) and Se (IV), i.e., sorption in solutions of 1 M HNO3 with calcium ions present, heating to 60°C and phase contact time of 1 h were determined. The mechanism of sorption interaction of the analytes under specified conditions is discussed. It is shown that a 100-fold excess of iron, zinc and copper does not interfere with the extraction of analytes, thus providing the possibility of As (III) and Se (IV) isolation from different types of raw materials and processed products using the synthesized sorbent. A method for the direct XRF quantification of arsenic and selenium with sr 0.09 and 0.08, respectively, in the sorbent phase has been developed. The correctness of the results was confirmed by the ICP-MS method in analysis of aqueous reference solution after dissolution of the sorbate in HNO3 (1:1).
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Damzina, Anna А., Lidia N. Skvortsova, and Konstantin A. Bolgaru. "Oxidative photo-catalytic destruction of eosine with the application of iron-contalning metal-ceramic composites with additive complex-forming reagents." Butlerov Communications 60, no. 11 (November 30, 2019): 21–30. http://dx.doi.org/10.37952/roi-jbc-01/19-60-11-21.
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Iron-containing metal-ceramic composites based on nitrogen and sialon nitrides, obtained by the method of self-propagated synthesis were studied in the process of photocatalytic oxidative destruction of eosin. The phase composition of the samples was established by the X-ray diffraction method. It was shown that, along with the main phases, the ceramic matrix of materials contains the phases of semiconductors: (SiC, TiN). The indicator method of Hammet and Tanabe assessed the surface acid-base centers of the composites. It was established that a large sorption of the dye is characteristic of samples based on silicon nitride and sialon and is associated with the participation of active Brensted acid sites. The photocatalytic activity of iron-containing composites was studied in the presence of H2O2 (photo-Fenton system), H2O2 and EDTA (peroxide-ferriccomplexon system), H2O2 and tartaric acid (peroxide-ferritartrate system). It was shown that the degree of oxidative destruction of eosin is significantly higher with the participation of Fe(II, III) complexes with EDTA and tartaric acid, than Fe(II, III) aquacomplexes in the photo-Feton system. The high activity of composites containing the semiconductor phase of titanium nitride (TiN) is due to the combination of homogeneous and heterogeneous catalysis with the participation of the ceramic matrix. The introduction of complexing agents shifts the optimal acidity (pH 2-4) for a homogeneous system of photo-Fenton with the participation of iron(II, III) aqua complexes in the weakly acidic region (pH 4-7) and leads to almost complete destruction of the dye in the peroxide-tartrate system.
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Ullah, Rafique, Biplob Kumer Deb, and Mohammad Yousuf Ali Mollah. "Studies on the Treatment of Wastewaters Containing Cr6+ with Iron Oxide-Silica Composite Materials Prepared by Different Methods." Defect and Diffusion Forum 353 (May 2014): 33–38. http://dx.doi.org/10.4028/www.scientific.net/ddf.353.33.
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Chromium (VI) is known to be carcinogenic to humans and thus it is important to ensure the removal of Chromium (VI) from aqueous solutions and industrial effluents. The present study introduces a good alternative method for Cr (VI) removal from aqueous solutions at ambient temperature by adsorption, allowing the development of newer, lower operational cost, and more efficient technology than other processes already in use. Adsorption was found to be dependent on pH and initial concentration of Cr (VI) solution. Results of adsorption studies suggest that pristine iron oxide and silicon (IV) oxide removes 72.10% and 24.73%, respectively. The iron oxide – silicon (IV) oxide composite, prepared in this work, removes 93.88% Cr (VI) in 20 minutes from aqueous solution at an initial concentration of 50 mgL-1at pH 4.8 ± 0.2. The effect of concentration, contact time, adsorbent dose and solution pH on the adsorption of Cr (VI) were studied in detail in batch experiments. Studies of the sorption kinetics shows that equilibrium adsorption was attained in 20 minutes depending on other experimental conditions. The kinetic data justified Lagergren’s first-order kinetic equation. Adsorption isotherm study showed that the results fulfilled the Langmuir Model of adsorption isotherm. The maximum adsorption (98.28%) was recorded at pH 3 in 90 minutes for the initial Cr (VI) concentration of 50 mg L-1. Therefore, it can be concluded that iron oxide – silicon (IV) oxide composite is a potential adsorbent for adsorption of Cr (VI) from aqueous solution.
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Polotskaya, Galina, Maia Putintseva, Alexandra Pulyalina, Iosif Gofman, and Alexander Toikka. "Impact of Endometallofullerene on P84 Copolyimide Transport and Thermomechanical Properties." Polymers 10, no. 10 (October 7, 2018): 1108. http://dx.doi.org/10.3390/polym10101108.
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Novel polymer composite materials, including unique nanoparticles, contribute to the progress of modern technologies. In this work, the endohedral fullerene C60 with incapsulated iron atom (endometallofullerene Fe@C60) is used for modification of P84 copolyimide. The impact of 0.1, 0.5, and 1 wt % endometallofullerene on the structure and physicochemical properties of polymer films is studied through scanning electron microscopy, thermogravimetric analysis, and thermomechanical tests. Transport properties are estimated through sorption and pervaporation techniques toward methanol and methyl acetate mixture. The inclusion of endometallofullerene into the copolyimide matrix improves membrane permeability and selectivity in the separation of methanol—methyl acetate mixtures. The maximal effect is achieved with a composite containing 0.5 wt % Fe@C60. The developed composites are effective for energy and resource saving purification of methyl acetate by pervaporation.
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Zhang, Xiaoran, Lei Yan, Junfeng Liu, Ziyang Zhang, and Chaohong Tan. "Removal of Different Kinds of Heavy Metals by Novel PPG-nZVI Beads and Their Application in Simulated Stormwater Infiltration Facility." Applied Sciences 9, no. 20 (October 10, 2019): 4213. http://dx.doi.org/10.3390/app9204213.
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Polyvinyl alcohol and pumice synthetized guar gum-nanoscale zerovalent iron beads (PPG-nZVI beads) were synthesized, and their adsorption towards Pb2+, Cu2+, and Zn2+ ions was evaluated. The adsorption kinetics of metal ions was well fitted by the pseudo-second-order model. The adsorption rate decreased followed in the order of Cu2+ > Pb2+ > Zn2+, consistent with the reduction potential of the ions. The sorption isotherm was well fitted by Langmuir model. The maximum adsorption capacity decreased followed in the order of Pb2+ > Cu2+ > Zn2+, which suggested that the strength of covalent bonds between the metal ions and surface functional groups substituted to the beads is one of the major factors in the adsorption process. Adsorption increased with the increase of pH and the largest sorption occurred at pH 5.5, while ionic strength did not significantly influence the adsorption process. The application of PPG-nZVI beads as filling materials in the simulated stormwater infiltration facility shows good removal efficiency in treating the contaminated water containing Pb2+, Cu2+, Zn2+, Cr6+, and Cd2+ and the removal rate was more than 65% at least. The results indicated that the PPG-nZVI beads could be applied as promising sorbents for purification of heavy metal contaminated water.
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Bishimbayeva Gaukhar Kozykeevna,, Zhumabayeva Dinara Sarsenovna,, Zhanabaeva Asem Kaldybekkyzy,, Nalibayeva Arailym Muratovna,, Abdikalykov Yerlan Nurzhanuly,, and Bakenov Zhumabay Bekbolatovich,. "PROSPECTS FOR CREATING A FULL CYCLE OF LITHIUM PRODUCTION IN KAZAKHSTAN – FROM ORE PROCESSING TO LITHIUM BATTERIES." SERIES CHEMISTRY AND TECHNOLOGY 5, no. 443 (October 15, 2020): 38–45. http://dx.doi.org/10.32014/2020.2518-1491.78.
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Today, lithium is becoming a new strategic material capable of influencing the sustainable development of the world economy. The results of developments in the production of innovative electrode materials from lithium carbonate on the basis of domestic lithium-containing raw materials with the creation of a full cycle of the technological line of lithium production: from ores to modern lithium batteries are pesented. Analysis of the explored reserves, mineral and material composition of domestic spodumene raw materials and lithium-containing dumps of the Belogorsk GOK indicate the prospects and expediency of their development for the production of the ever-increasing needs of the world market for lithium materials. As a result, the sulfuric acid technology for obtaining high-grade lithium carbonate directly from spodumene was optimized, bypassing the stage of obtaining a technical grade product, in a single technological process for processing spodumene with a reduction in the number of technological operations, excluding the expensive operation of concentrating a lithium sulfate solution by stripping. An efficient technology of purification and post-treatment of technical lithium carbonate to battery quality of 99.95% has been developed, including the processes of causticization of technical lithium carbonate, ultrafiltration and ion-exchange sorption of a solution of lithium hydroxide, followed by precipitation of lithium carbonate by ammonium carbonate. Cathode materials - lithium iron-phosphate , obtained from high-purity lithium carbonate by aerosol pyrolysis (MAP) and the sol-gel method (SGM), showed good electrochemical characteristics. The end result is innovative electrode materials for modern LIBs with significantly increased capacity and stability. The practical implementation of a full cycle of technologies from lithium-containing raw materials to modern lithium batteries opens up prospects for the creation in Kazakhstan of a high-tech lithium cluster according to the Scheme: Spodumene ores → Lithium concentrate → Lithium carbonate → Lithium cathode materials → Batteries.
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Lutyński, Marcin, Piotr Sakiewicz, and Sylwia Lutyńska. "Characterization of Diatomaceous Earth and Halloysite Resources of Poland." Minerals 9, no. 11 (October 31, 2019): 670. http://dx.doi.org/10.3390/min9110670.
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The mining industry of Poland is based mostly on coal and copper ores. Strict carbon emissions and the depletion of deposits will slowly phase out coal. Therefore, metallic ores and other mineral raw materials will dominate the extractive industry of Poland. Current measured resources of the largest deposits of halloysite and diatomaceous earth in Poland are over 0.5 Mt and 10 Mt, respectively. Halloysite and diatomaceous earth samples from halloysite Dunino deposits and Jawornik diatomaceous earth deposits (composed mostly of diatomaceous skeletons (frustules)) were subjected to mineralogical analysis, scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM-EDS) nanostructural, chemical, elemental, and mineral content analysis. Both these minerals have similar properties, i.e., sorption capacity and cation exchange capacity, and are used mostly for the same purposes, e.g., adsorbents, filler material, and filtration. Samples of Dunino halloysite consist of minerals such as halloysite, kaolinite, hematite, magnetite, quartz, magnesioferrite, rutile, ilmenite, geikielite, goyazite, gorceixite, and crandallite, with little impurities in the form of iron oxides. Occasionally, halloysite nanoplates (HNP) nanotubes (HNT) were found. Diatomaceous earth is composed mainly of silica-containing phases (quartz, opal) and clay minerals (illite and kaolinite). The frustules of diatoms are mostly centric (discoid) and have radius values of approximately 50–60 μm. Large resources of these minerals could be used in the future either for manufacturing composite materials or highly advanced adsorbents.
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Комаров, М. А., and Т. В. Камлюк. "Synthetic gypsum prepared from natural water coagulation sludge." Vodosnabzhenie i sanitarnaia tehnika, no. 1 (January 17, 2022): 38–43. http://dx.doi.org/10.35776/vst.2022.01.06.
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Представлены результаты исследований получения гипса из отходов отработанной серной кислоты производства химических волокон и отходов кальцийсодержащего осадка коагуляции природных вод. При синтезе отработанной серной кислоты и осадка коагуляции образуется дигидрат сульфата кальция с заданными размерами и формой кристаллов, а также побочный продукт – фильтрат с высоким содержанием Mg, Na, S и Ca. Наличие данных элементов открывает возможность использования фильтрата в качестве микроудобрения, а наличие сульфата железа (около 11 масс. %) – в качестве коагулянта. Наличие железа в фильтрате также открывает перспективы его использования в качестве прекурсоров для получения каталитических материалов для фотокаталитической очистки сточных вод от растворенных органических веществ или получения сорбционных материалов для очистки сточных вод от нефтепродуктов. Железо в составе данных материалов позволит дополнительно придать им магнитные свойства, что облегчит их извлечение из обрабатываемых водных сред. Технико-экономический анализ показал, что при использовании фильтрата значительно повышается эффективность капиталовложений предлагаемого технологического процесса. The results of studies on the preparation of gypsum from waste sulfuric acid from the production of chemical fibers, and calcium-containing waste sludge generated in the process of natural water coagulation, are presented. During the synthesis of spent sulfuric acid and coagulation sludge, calcium sulfate dihydrate with crystals of a given size and shape is formed, as well as a by-product – a filtrate with a high concentration of Mg, Na, S and Ca. The availability of these elements opens up the potential of using the filtrate as a microfertilizer, and ferrous sulfate (about 11 wt. %) as a coagulant. The availability of iron in the filtrate also opens up the doors to using it as a precursor for the production of catalytic materials for removing dissolved organic substances from wastewater by photocatalytic treatment, or for the production of sorption materials for removing oil products from wastewater. Iron in these materials will give them additional magnetic properties to enhance their extraction from the treated aqueous media. The technical and economic analysis showed that using the filtrate significantly increases the investment efficiency of the proposed technological process.
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Mofa, N. N., and Z. A. Mansurov. "Mechanochemical Synthesis of Composite Magnetic Materials on the Basis of Quartz-Containing Systems." Eurasian Chemico-Technological Journal 12, no. 1 (November 10, 2009): 55. http://dx.doi.org/10.18321/ectj27.
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Mechanochemical treatment of quartz and its mixtures with ash-slag and iron oxides in the presence of various modifying organic additives was carried out. Quartz and mixtures based on it exhibit ferromagnetic properties and are distinguished by good sorption ability toward organic substances. Crystalline silica assumes the role of the matrix during development of structure and functional properties of the magnetic adsorbent. It was found, that the polymer film, which is used to cover the quartz particles, includes regions with embedded iron nanoparticles as well as other regions enriched with active carbon. The synthesized sorbents were used to collect petroleum spill over water; high water purification degree<br />(up to 98 %) was achieved.
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Vlasovskikh, Natalia S., Ruslan Kh Khamizov, Lilia P. Moroshkina, Anna N. Krachak, Aleksandra N. Gruzdeva, and Sultan Kh Khamizov. "Acid Retardation method of separation for closed-circuit processing of alumina-containing raw materials with the use of salt-acid digestion." Сорбционные и хроматографические процессы 17, no. 6 (February 22, 2018): 877–85. http://dx.doi.org/10.17308/sorpchrom.2017.17/448.
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A brief overview and critical analysis of acid and acid-salt methods for processing alumina raw materials, including high-silica bauxite, nepheline and clay is presented. The basic approaches to the creation of closed and reagent-less or low-reagent-consumption processes are demonstrated. The results obtained in the course of long-term systematic laboratory and bench studies are presented, and they display the prospects for the creation of new technologies for the production of alumina from high silica bauxite and aluminum silicates with the use of different nitrate and sulfate reagents. In the case of using acids, the sorption method of «Acid Retardation» in nano-porous media is shown to be successfully used for recycling them into the process head and to ensure soft conditions for the removal of iron components. This stage is realized with the use of strong base anion exchanger, preliminarily equilibrated with the macro-anion composition of solutions to be processed and washed with water or diluted acid solution. The AR process in three phase systems including organic liquids immiscible with water solutions (“New Chem” method) is also described, a this is also important to provide the complete insulation of concentrated salt solution and to simplify its farther treatment. A circular process with the recovery and consumption of the same amount of salt reagent in each cycle is demonstrated. A comparison of digestion methods is given in terms of the completeness of reagent recycling, the quality of product and the complexity of the process. Advisable conditions for the production of alumina from non-traditional raw with salt-acid decomposition are shown. As it is shown, the most in demand are the processes, which fully or partially can be «inscribed» in modern equipment design and process conditions corresponding to the standard Bayer method or its industrial modifications
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Fujita, T., M. Tsukamoto, T. Ohe, S. Nakayama, and Y. Sakamoto. "Modeling of Neptunium(V) Sorption Behavior onto Iron-Containing Minerals." MRS Proceedings 353 (1994). http://dx.doi.org/10.1557/proc-353-965.
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AbstractSorption behaviors of neptunium (V) on naturally-occurring magnetite (Fe3O4) and goethite (α-FeOOH) in 0.1M NaN03 electrolyte solution under aerobic conditions were interpreted using the surface complexation model (SCM). The surface properties of these materials were experimentally investigated by C02-free potentiometric titration, and SCM parameters for the constant capacitance model, such as protonation/deprotonation constants of the surface hydroxyl group, were determined. The number of negatively charged sorption sites of goethite rapidly increased with the increase of the bulk solution pH compared with that of magnetite and this tendency was similar to the pH dependence of neptunium sorption. This implies that the neptunyl cation, NpO2+, plays a dominant role in possible sorption reactions. Assuming that the dominant surface complex is XO-NpO2, modeling by means of SCM was carried out, and the results were found to agree with experimental data.
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Smith, Robert W., John C. Walton, and Masudur Rahman. "Effects of Recrystallization on Time Variant Sorption of Radionuclides onto Steel Corrosion Products." MRS Proceedings 333 (1993). http://dx.doi.org/10.1557/proc-333-713.
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ABSTRACTCorrosion products resulting from the oxidation of steel containers and iron-containing waste can alter the local geochemical environment in radioactive waste disposal vaults and trenches. In addition, corrosion products can enhance the retention of radionuclides by providing a highly sorptive media. Initial hydrous corrosion products are poorly crystalline with large surface area, high sorption capacity, and large Kds. Over time, corrosion products recrystallize by step-wise dehydration to phases with significantly smaller surface areas. The decreased surface area results in decreased sorption and the potential for remobilization of previously sorbed radionuclides. The impact of time-dependent variation in sorption on radionuclide transport is a complex function of the rate of recrystallization and the radionuclide half-life.A mathematical model has been developed, which coupling mass transport with corrosion product recrystallization and equilibrium sorption of radionuclides. The model is applied release of radionuclides with a range of half-lives (year to 100,000s of years) from radioactive waste disposal facilities to illustrate the significance of corrosion product recrystallization on release.
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Foltynowicz, Zenon, Andrzej Maranda, Bogdan Czajka, Leszek Wachowski, and Tomasz Sałaciński. "The effective removal of organic and inorganic contaminants using compositions based on zero-valent iron nanoparticles (n-ZVI)." Materiały Wysokoenergetyczne / High Energy Materials, December 14, 2020, 37–74. http://dx.doi.org/10.22211/matwys/0172e.
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For almost three decades, the engineered nanomaterials (ENMs) due to their reactivity, unique sorption, catalytic, electronic, optical and magnetic properties, have been the subject of extensive research. The results show that these materials can provide a new tool for the remediation of contaminated aquatic ecosystems (surface and groundwater), sediments, soils, military training grounds and waste recycling areas, including electronic waste. In-situ remediation technologies using composites containing metal nanoparticles, mainly zero-valent iron particles (n-ZVI) are becoming more common. The solutions disclosed in numerous publications and patent applications show their applicability, igher effectiveness and lower costs of remediation processes compared to the conventional methods.