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Iron and manganese oxides/biochar composite materials (Fe/Mn-BC) are promising catalysts in the field of advanced oxidation. High purity chemical reagents are popular precursors for preparing Fe/Mn-BC, while the potential of low-cost natural minerals as precursors has been neglected. In this study, high-efficiency Fe/Mn-BC was synthesized by one-step pyrolysis method using hematite, phosphoromanganese, and bagasse. The synthesized Fe/Mn-BC removed 83.7% 2, 4-dichlorophenol (2, 4-DCP) within 30 min, about 8.8 and 10.6 times better than biochar (BC) and Fe/Mn complex, respectively. The removal of 2, 4-DCP in the Fe/Mn-BC + peroxydisulfate (PDS) system was influenced by catalyst dosage, PDS concentration, initial pH, organic acids, and chromium. Sulfate radical (SO 4 •-) and hydroxyl radicals (•OH) generated by Fe/Mn-BC-activated PDS have similar contribution to the degradation of 2,4-DCP. A possible removal mechanism of 2, 4-DCP in the Fe/Mn-BC + PDS system was proposed based on Electron Spin Resonance spectroscopy, free radical quenching experiments, X-ray photoelectron spectroscopy, X-ray diffraction, and electrochemical measurement. Fe0 and Fe(II) in Fe/Mn-BC play significant role in catalytic degradation of 2, 4-DCP at the early stage of the reaction (within 0–5 min). Then, the interaction between Mn and BC or structural Mn and structural Fe gradually became dominant in the later stage. Similarly, the electron transfer promoted by biochar also played an important role in this catalysis. This discovery provided a new strategy for developing iron and manganese oxides/biochar composite materials to activate PDS for the elimination of refractory organic pollutants. [Display omitted] • Fe/Mn@BC was fabricated by a one-step pyrolysis method using natural minerals. • The Fe/Mn@BC-PDS system had efficient and sustained 2,4-DCP degradation capacity. • Fe(0) and Fe(II) in Fe/Mn@BC played key roles at the early stage of the reaction. • The interaction between Mn and Fe enhanced the catalysis in later stage reaction. • The electron transfer promoted by biochar contributed to 2,4-DCP degradation. [ABSTRACT FROM AUTHOR]

Chemical-looping with oxygen uncoupling (CLOU) is considered a promising technology to burn solid fuels with improved CO2 capture and has the potential to improve fuel conversion and reaction rates. Cu-based oxygen carriers (Cu-OC) are often used in solid fuel CLOU. This study focused on investigating Cu-OC derived from a natural mineral for solid fuel CLOU because of their potentially lower cost compared to synthetic OCs. Reactivity and recyclability of a natural ore-derived Cu-OC on coal char (Powder River Basin sub-bituminous coal) were studied at 900 °C in Ar and air using TGA-QMS and fixed-bed reactor-QMS for five cycles. Cu-OC was prepared by simply heating chalcopyrite in air. Chalcopyrite is one of the principle copper sulfide ores and one of the primary ores for copper. The prepared Cu-OC had primarily CuO and CuFe2O4 (CuOFe2O3) as active compounds based on XRD analysis and an oxygen capacity 3.3% from oxygen uncoupling. The carbon conversion efficiency Xc was 0.94 for reduction at a ratio of Cu-OC to char ϕ = 75 and the product gas was primarily CO2 with trace O2. The reactivities and the rates were similar for five redox cycles. These results indicate that the natural ore-derived material with low cost has potential as a competitive oxygen carrier in solid fuel CLOU based on its reactivity in this study.

The heat capacity of natural chalcanthite (copper sulfate pentahydrate, CuSO 4 ·5H 2 O) from the deposit Kosmurun has been measured by the method of low-temperature adiabatic calorimetry over the temperature range of (4.3–320) K. The identity of the mineral was proved by methods of XRD, EMPA, IR and Raman spectroscopy. The thermodynamic functions have been calculated based on the experimental data on the heat capacity. The lattice component of heat capacity below 20 K was extracted. The standard values of the heat capacity and entropy for natural chalcanthite are as follows: C ° p ,m = 288.0 ± 0.4 J·mol −1 K −1 , S ° m = 295.2 ± 0.8 J mol −1 K −1 . [ABSTRACT FROM AUTHOR]

Our previous work has revealed the feasibility of natural hematite as an electrolyte material for solid oxide fuel cells (SOFCs), tailoring SOFCs to be a more economically competitive energy conversion technology. In the present work, with the aim of exploring more practical uses of natural minerals, a novel composite hematite/LaCePrO x -La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (hematite/LCP-LSCF) has been developed from natural hematite ore, rare-earth mineral LaCePr-carbonate, and perovskite oxide LSCF as a functional membrane in SOFCs. The heterogeneity, nanostructure and mixed-conductive property of the composite were investigated. The results showed that the hematite/LCP-30 wt% LSCF composite possessed balanced ionic and electronic conductivities, with an ionic conductivity as high as 0.153 S cm −1 at 600 °C. The as-designed fuel cell using the hematite/LCP-LSCF membrane exhibited encouraging power outputs of 303 – 662 mW cm −2 at 500 – 600 °C. These findings show that the hematite/LCP-LSCF based fuel cell is a viable strategy for developing cost-effective and practical low-temperature SOFCs (LTSOFCs). [ABSTRACT FROM AUTHOR]

The existence of excessive concentrations of iron and manganese in water results in economic, technological and health problems. The adsorption characteristics of four clay minerals collected from different localities of Saudi Arabia, Osfan (OS1 and OS2) and Gholaa (GH1 and GH2), on the adsorption of Fe3+ and Mn7+ ions were investigated. The quantitative phase composition of the selected samples was calculated from their X-ray diffraction technique, while the chemical constitution was determined through X-ray fluorescence technique. The adsorption of Fe3+ onto different clays was complied with Langmuir isotherm (R2 = 0.9996, 0.9956, 0.9840 and 0.9932, respectively). OS1 and OS2 (Qmax = 6.872 and 8.258; 1/b = 0.315 and 0.296, respectively) have higher adsorption capacity than GH1 and GH2 (Qmax = 2.109 and 3.457; 1/b = 0.596 and 0.465, respectively). The adsorption of Fe3+ onto OS1, OS2, GH1 and GH2 clay minerals cannot be described by Freundlich isotherm model where R2 = 0.831, 0.92, 0.70 and 0.52, respectively. The mean adsorption energy recorded indicates that the sorption process is physisorption. [ABSTRACT FROM AUTHOR]

Natural minerals from different localities in the Republic of Macedonia are selected for elimination of Cr(VI) ions from water resources. For that aim are selected: aksil (Kriva Palanka), trepel (Bitola), SiO2 amorphous (Kozuf), pemza (Bojanciste). In this study, their adsorption capacity is analyzed using spectrophotometric method (UV/VIS Spectrophotometer). Results from the spectrophotometric analysis in all used examples gave us insight for the starting concentration of Cr(VI) before adsorption and concentration after adsorption. The physical, chemical and mineralogical characteristics of adsorbents are studied. XRD, TGA-DTA and FT-IR analysis are used for characterization of natural mineral materials. The surface area of the sorbents were measured by BET method. With aim to determine the optimum pH value for maximal removal of Cr(VI) ions, the point of zero charge, pHPZC, for investigated materials were obtained. The aim of the study is to select which adsorbent is more efficient for elimination of Cr(VI) from water resources. According to obtained results all of them were successful in elimination of Cr(VI), but more effi cient and economic is trepel. [ABSTRACT FROM AUTHOR]

Spilled oil slicks are likely to break into droplets in the subtidal and intertidal zones of seashores due to wave energy. The nonliving suspended fine particles in coastal ecosystems can interact with the dispersed oil droplets, resulting in the formation of Oil Particle Aggregates (OPAs). Many investigations assumed that these aggregates will settle due to the particles' high density. Recent studies, however, reported that some particles penetrate the oil droplets, which results in further breakup while forming smaller OPAs that remain suspended in the water column. Here, we investigated the interaction of crude oil droplets with intertidal and subtidal sediments, as well as artificial pure kaolinite, in natural seawater. Results showed that the interaction between oil droplets and intertidal sediments was not particularly stable, with an Oil Trapping Efficiency (OTE) < 25%. When using subtidal sediments, OTE reached 56%. With artificial kaolinite, OPA formation and breakup were more significant (OTE reaching up to 67%) and occurred faster (within 12 h). Oil chemistry analysis showed that the biodegradation of oil in seawater (half-life of 485 h) was significantly enhanced with the addition of sediments, with half-lives of 305, 265, and 150 h when adding intertidal sediments, subtidal sediments, and pure kaolinite, respectively. Such results reveal how the sediments' shape and size affect the various oil-sediment interaction mechanisms, and the subsequent impact on the microbial degradation of petroleum hydrocarbons. Future studies should consider investigating the application of fine (several microns) and sharp (elongated-sheeted) sediments as a nondestructive and nontoxic technique for dispersing marine oil spills.

Jordanian phosphate mine wastes (PMW) at Ruseifa City was fully characterized and tested for its PO4removal capacity by batch experiments using prepared phosphate solutions and domestic wastewater. PMW particles are positively charged with median particle size of 0.625 μm. Mineralogical and chemical analyses of PMW showed that it is mainly composed of calcite, fluorapatite, and quartz with high concentrations of calcium and phosphorous. The phosphate concentrations in PMW range from 11 to 24% expressed as P2O5. PMW as a sorbent has a very high PO4removal efficiency from wastewater and prepared solutions. PO4solutions with concentrations ranging from 5 to 5,000 mg L−1were prepared and utilized in batch experiments in the presence of PMW as a sorbent. The concentration of PO4in the solution phase and pH were the main parameters influencing the PMW sorption capacity of PO4. The PO4removal efficiency from prepared solutions was up to 99%. Moreover, Langmuir sorption model was able to describe the observed data for PO4sorption by PMW. The sorption data at PO4concentrations >50 mg L−1were highly fitted to Langmuir model. The estimated sorption maximum capacity (bmax) of PMW was 46,620 mg kg−1. On the other hand, domestic wastewater samples obtained from six Jordanian wastewater treatment plants were subjected to PO4removal by PMW, and the results showed that the PO4removal efficiency exceeded 97%. The adverse environmental impacts and human health risks associated with PMW presence are briefly discussed. [ABSTRACT FROM PUBLISHER]

Naturally occurring sulfosalt minerals of the tetrahedrite-tennantite series ((Cu,Fe,Zn,Ag,Hg)(Sb,As)S) are studied because of their potential use as basic components in the manufacture of thermoelectric devices for moderate-temperature applications. In the work reported herein, the chemical, crystallographic, thermoelectric, and magnetic properties of four specimens from different ores from Europe and America were exhaustively characterized. Our study revealed that these natural tetrahedrites usually behave as low-to-moderately doped p-type semiconductors with low mobility. Their carrier charge transport is thus located at the edge between hopping and itinerant mechanisms. The magnetic study, probing the behavior of the constituent iron species, revealed that an insignificant part of the iron occurs as ferromagnetic impurities. The dominant iron species is Fe ions with antiferromagnetic interactions. The maximum value of ZT observed was 0.13 at 700 K; this value is impaired, primarily, by high electrical resistivity. [ABSTRACT FROM AUTHOR]

A field experiment was carried out for two seasons 2001 and 2002 at Ismailia Agric. Res. Station to study the comparative effect of farmyard manure (FYM) application, individually or in combination with natural minerals, as sources of micronutrients. Such effect was studied during successive growth stages of wheat (vegetative stage, flowering stage and harvest stage), as well as after maize harvesting, on plant growth, nutrients uptake and wheat - maize productivity. The experiment was designed in a randomized complete block design with three replications. Two levels of FYM (2 % and 3 %) and three natural minerals, i.e., magnetite (iron oxide, Mag.), basic slag (Bas.) and manganese dust (Md.) at three rates 0.02 %, 0.05 % and 0.07%, respectively. Obtained results revealed that, at vegetative stage, mineral fertilizers (MF) treatment positively affected the dry matter of both shoots and roots of wheat plants along with contents of nitrogen and potassium in both shoots and roots as well as shoot/root ratios. At flowering stage, obtained data showed that applied farmyard manure at the rate of 3 % (F2) significantly affected the dry matter of both shoots and roots as well as their contents of N, P and K. A similar trend was obtained for micronutrients uptake at the two indicated growth stages of wheat, which recorded high values when FYM, at a rate of 3 % (F2), was applied. On the other hand, obtained results indicated that applied FYM at the rate of 2 % (F1) with high rate (0.07 %) of each of the used natural minerals and FYM at the rate of 3 % (F2) in combination with the moderate rate (0.05 %) of such minerals recorded high values of all tested parameters. In addition, Basic slag (Bas.), generally, gave the highest values, over control, of dry matter content and macronutrients uptake during the studied two growth stages of wheat, (vegetative and flowering stages). The agronomic yield components of wheat (straw, grains and weight of 1000 grains) were increased when MF was applied; such significant increases were obtained in maize yield (residual effect) as a result of applied FYM individually or combined with natural minerals.

Special production footwear is the primary means of personal protection from harmful factors, which purpose is to guarantee human safety in the workplace. Accordingly, shoe materials that are used in the production of the shoes should have increased protective properties. The results of tests of leather materials obtained using ecologically safe mineral compositions of natural origin have been presented in the article. The influence of the mineral content of semi-finished leather on operational, environmental and safety properties of finished leather and suitability for the manufacture of top of special protective footwear have been determined. During the studies the environmental safety of researched skins for external and internal parts of uppers by setting exposure Cr (VI), formaldehyde and heavy metals and their comparison with MPC for materials of the first category that have contact with the skin of the foot have been evaluated. Moisture, water resistance and hygroscopic properties of skin have been defined by setting parameters of moisture, water yielding capacity, water adsorption in dynamic conditions, moisture soaking in static and dynamic conditions, wet and moisture content of leather for 2 and 24 hours. Thermal resistance of leather has been determined by determining the thermal resistance of the material to burning with hot metal, heat exposure 200 °С in air-dry condition and to the influence of hot surfaces. To predict the sustainability and reliability of footwear without loss of functional properties, changes of physical and mechanical properties have been defined after aging of researched skins at low and high temperatures. Also defects have been evaluated on samples after repeated bending at ambient and low (-15 °С) temperatures. The results show the feasibility of using animal skins with mineral filling for making comfortable, environmentally friendly footwear with high humidity, water and thermal resistant properties. [ABSTRACT FROM AUTHOR]

Immobilization of Ро on natural minerals (magnetite, glauconite), rocks (basalt, dunite), and synthesized manganese dioxide of the composition MnO was studied. Basic and ultrabasic rocks (basalts, dunites) widely occurring in the nature can be used for making artificial geochemical barriers for the removal of Po from weakly acidic and neutral liquid radioactive wastes. Dunite ensures the most efficient Ро immobilization from acidic solutions, and basalt, from neutral solutions. The degree of Ро removal upon 48-h interaction with dunite and basalt was 93 and 80% relative to its initial content in solutions with initial pH 3.0 and 7.0, respectively. With all the samples except MnO, the Ро immobilization in the initial step (0-5 h) is more efficient in the initially neutral solutions, but with time the degree of the Ро removal from the initially acidic solutions becomes higher. The rate of the Ро immobilization on MnO does not appreciably depend on pH in the examined acidity range. [ABSTRACT FROM AUTHOR]

Purpose. To study the effect of composition of the coating composition for forming a coating on the leather filled natural minerals. Methodology. The use of physical and mechanical methods for determining the quality of the coating on natural leathers. Findings. To study of possibility forming of coats on the leather filled natural minerals. Influence of components and their flow on complex coating. We studied the influence of synthetic dyes and protein oxidation on the coating quality. Originality. The process of forming a coating on the leather filled with natural minerals. Practical value. Simplifying the process of preparation covering stores and schemes for forming a coating on the leather. [ABSTRACT FROM AUTHOR]

The ability of the skin to the formation and preservation of form in service depends on its ability to stretch and balance of the elastic and plastic (permanent) deformation. The values of the components of the deformation of the skin with the mineral content in the test mode, one full cycle "loading - unloading - rest" indicates that the type of mineral filler significantly affects the elastic- plastic properties of the skin. Dependence of residual elongation of tested leather with repeated uniaxial stretching on the degree of hydration of the skin, stretching size and number of repeated stretching have been considered in this paper. Experimentally confirmed hypothesis and mathematical model of stretching adjustment of the leather with multisycle stretching and fixing of material in a stretched state. Patterns of change and the quantitative value of the residual elongation of skin samples with montmorillonite dispersion mineral content have been obtained. The most appropriate treatment process of tricyclic stretching mode and optimum humidification have been proposed. It has been proved that after 2-3 fold prior stretching of the leather the strength is not reduced, but rather strengthens, the value of which depends on the relative size of tensile and relative amount of dampening material before stretching. [ABSTRACT FROM AUTHOR]

Shoe shape stability is one of the most important indicators of quality which depends primarily on the deformation properties of the skin, its stretching. It is possible to increase shoe shape stability using the technological process of adjustment operations of stretching the skin to optimal values, which are necessary for the production of high quality footwear. Ductility index influences the percentage of leather waste in the performance of recover and last operations, i.e. material resource saving and cost of shoes. We present a mathematical model of stretching adjustment of the skin with mineral content to accurately calculate the area of parts of the work piece in this paper. The proposed concept of stretching adjustment method involves iterative process of skins preliminary tensile elongation with fixation of each cycle. The physical model of the process has been built, including hydration operations, stretching, drying in a stretched state and relieve of tension. By means of mathematical analysis and the theory of sets, the dependence of the residual elongation size of the researched skins on the degree of hydration of the skin, stretching the size and number of repeated stretching has been found. Implementation of the correction stretching process of shoe leather will reduce the material and energy resources while improving the competitiveness of shoes. [ABSTRACT FROM AUTHOR]

Purpose. Investigation of the nature of the strain distribution on the vamp area of men leather shoes with mineral filling. Methods. Well-known method of tightening on the lasting machine on hot melt adhesive has been used. Before tightening process humidification of pieces was performed, and then - damp- heat treatment at a facility flow-through type. Deformation of materials has been measured by the total length of lines and squares with drawing-compass under a microscope with an accuracy of 0.1 mm. Results. In the course of the experiment it has been revealed that the distribution of strains in almost all samples of vamps is almost the same and even at max total value (12.3%) is ~ 50% of that recommended for other skins. Type of mineral filler did not significantly affect the transverse and longitudinal tensile strain at two-dimensional stretch. In addition, the nature of the redistribution of fiber structure does not depend on the locations of parts on the skin and the direction of force. Scientific novelty. The nature of the effect of mineral fillers on the deformation properties of men's shoes vamps at two-dimensional stretch has been studied. The practical significance. The results will make it possible to predict good shape stability of the shoes made of leather with mineral filling. [ABSTRACT FROM AUTHOR]

Highlight: [•] Adding tourmalines, Na-bentonite and medical stone can make the total sulfur retention increase during coal pyrolysis. [•] Adding tourmalines, Na-bentonite and medical stone also can make organic sulfur retention higher. [•] These natural minerals are beneficial for sulfate sulfur to remove during coal pyrolysis. [•] Na-bentonite, tourmaline 2 and medical stone are all good for pyritic sulfur to decompose and remove. [•] Tourmaline 2 and medical stone are beneficial for sulfur to convert into H2S and then escape, and medical stone is also good for sulfur to turn into COS during coal pyrolysis. [ABSTRACT FROM AUTHOR]

Abstract: The heat capacity of natural zinc carbonate (smithsonite, ZnCO3) has been measured by the method of low-temperature adiabatic calorimetry over the temperature range of (4.4 to 320)K. Its thermodynamic functions have been calculated based on the experimental data on the heat capacity. The standard values of the heat capacity and entropy for smithsonite are as follows: Cp , m =80.36±0.09J·mol−1 ·K−1, Sm =81.28±0.09J·mol−1 ·K−1. [Copyright &y& Elsevier]

Based on the experimental data obtained, the processes proceeding in electric energy accumulators based on mineral-water composites are classified. A model assuming an exponential character of the processes proceeding in the system mineral - water - coal electrodes in the process of electric energy production by this system was used for processing and retrieval of the data on the electroaccumulation properties of the composite. An example of model application to an explanation of the experimental data is demonstrated. The characteristic relaxation times of these processes are determined. The contribution of each process of electric energy production to the total charge is estimated. [ABSTRACT FROM AUTHOR]

Abstract: Norwegian industrial tailings and by-products, as well as naturally occurring minerals and ores have been surveyed with the purpose of identifying candidate oxygen carrier materials for use in a chemical looping combustion process. Nine materials, based on manganese and/or iron oxide, were selected for an initial screening test; six were deemed promising and were hence investigated further. Thermogravimetric experiments were performed to investigate the oxygen capacity, the reaction kinetics and reversibility of the oxygen absorption reaction. A manganese ore with a reversible capacity of 4.9wt% oxygen at 1000°C was selected as the most promising for chemical looping combustion applications. This material was modified by addition of calcia to explore the possibility of enhancing the kinetic, catalytic and mechanical properties. The addition of excess calcium relative to manganese resulted in formation of calcium manganite and related phases. The oxygen capacity of the modified material was 4.5wt% at 1000°C, but it has potential advantages in terms of kinetics and chemical and mechanical stability relative to the pure ore. [Copyright &y& Elsevier]

The paper examines the mechanochemical activation of starting minerals (kaolin, pyrophyllite, and talcum) and their effect on the solid-phase synthesis and properties of cordierite. Binary oxide compounds (spinel, mullite, enstatite, forsterite) are synthesized. It is established that binary compounds and crystalline silica should be minimized to decrease the synthesis temperature of cordierite. Processes for synthesis and production of cordierite ceramics with lower thermal expansion coefficient ((1.0-1.2) ⋅ 10 °C) are developed. [ABSTRACT FROM AUTHOR]

The study was carried out in the Territorial Research Station of Sugar Cane on the Inceptisol soil. It was established 9 treatments with organic materials and natural minerals. The soil structure was improved significantly when natural minerals and organic materials were applied in comparison with the chemical fertilization. The application of the sugar cane filter cake 15 t.ha + Zeolith 2 t.ha and the compost 4 t.ha-1 + calcareous phosphate rock 2 t.ha-1 caused a positive residual effect on the soil structure factor and the agricultural and industrial yield for more than 3 years. A proportional relationship existed between the soil quality and the agricultural yield of the sugar cane. [ABSTRACT FROM AUTHOR]

The study was carried out in the Territorial Research Station of Sugar Cane on the Inceptisol soil, and in the soil lab. of Agricultural Research Institute. It were established 9 treatments with organic materials and natural minerals. The structural state of soil was improved with the application of the organic and organic-minerals variants expressed in the increment of stable aggregates, soil structure factor and permeability. The soil consistency was modified with tendency to be bigger the inferior limit of plasticity in the organic and organic-minerals variants. The biggest yield in Pol (t.ha ) and -I - agricultural one was obtained when was applied compost 4 t.ha-1 + calcareous phosphate rock 2 t.ha-1(with 110.38 t.ha ) and sugar cane filter cake 15 t.ha -1+ calcareous phosphate rock 2 t.ha (with 96.27 t.ha-1) surpassing the chemical fertilization in 16,50% and 1,60% respectively. [ABSTRACT FROM AUTHOR]

Abstract: The only stable NMR-active isotope of strontium, 87Sr, is a spin-9/2 quadrupolar nucleus that has a low gyromagnetic ratio, a low natural abundance, and a large nuclear electric quadrupole moment. In this work, we utilize the quadrupolar Carr-Purcell-Meiboom-Gill (QCPMG) pulse sequence and a 21.14T NMR spectrometer at the Pacific Northwest National Laboratory to characterize the strontium sites in the natural minerals strontianite (SrCO3) and celestine (SrSO4). QCPMG at 21.14T was found to provide sensitivity enhancements of roughly two orders of magnitude over Hahn-echo experiments at an 11.74T magnetic field. We extracted the quadrupolar parameters for the strontium nuclei through iterative simulations of the experimental spectra with the SIMPSON program by Bak, Rasmussen, and Nielsen. The data show that the quadrupolar parameters of 87Sr appear to be highly sensitive to the symmetry of the strontium coordination environment and can thus provide information about the strontium binding environment in complex systems. [Copyright &y& Elsevier]

Incommensurate (INC) phases as a special, one-dimensional case of quasi-crystals were found in natural minerals of plagioclase and pyroxene solid solutions, as well as in quartz and in telluriumantimony (Sb2Te3). A relationship between the chemical composition of the mineral and its ability to be in the metastable state of INC was justified based on the transmission electron microscopic (conventional and high-resolution) data. Namely, the amphoteric elements adjacent to the large diagonal of amphoters of the Mendeleev table favor the formation and prolonged life-time of INC. Telluriumantimony proved to display the most pronounced INC state. Its features suggest that the red/ox transition provides the generation of energy in chemical systems. [Copyright &y& Elsevier]

This study tested the technical feasibility of pyrite and/or persulfate oxidation system for arsenic (As) removal from aqueous solutions. The effects of persulfate on As removal by the pyrite in the integrated treatment were also investigated. Prior to the persulfate addition into the reaction system, the physico-chemical interactions between As and the pyrite alone in aqueous solutions were explored in batch studies. The adsorption mechanisms of As by the adsorbent were also presented. At the same As concentration of 5 mg/L, it was found that As(III) attained a longer equilibrium time (8 h) than As(V) (2 h), while the pyrite worked effectively at pH ranging from 6 to 11. At optimum conditions (0.25 g/L of pyrite, pH 8.0 and 5 mg/L of As(III) concentration), the addition of persulfate (0.5 mM) into the reaction promoted a complete removal of arsenic from the solutions. Consequently, this enabled the treated effluents to meet the arsenic maximum contaminant limit (MCL) of <10 μ g/L according to the World Health Organization (WHO)'s requirements. The redox mechanisms, which involved electron transfer from the S 2 2− of the pyrite to Fe3+, supply Fe2+ for persulfate decomposition, oxidizing As(III) to As(V). The sulfur species played roles in the redox cycle of the Fe3+/Fe2+ of the pyrite by giving its electrons, while the As(III) oxidation to As(V) was attributed to the pyrite. Overall, this work reveals the applicability of the pyrite as an adsorbent for water treatment and the importance of persulfate addition to promote a complete As removal from aqueous solutions. [Display omitted] • SO.• 4 - is the predominant active species at acidic conditions; • SO 4.•- intensified FeS 2 oxidation by yielding iron oxide to co-precipitate arsenic; • As(V) sorption capacity of pyrite was higher than that of As(III). • Complete As removal was attained by integrated pyrite and persulfate oxidation. • Treated effluents met the discharge limit of <10 μ g/L set by the WHO. [ABSTRACT FROM AUTHOR]

Natural zeolites have been employed to adsorb contaminants in water. This study is aimed to evaluate the cation and anion leaching from the zeolite after the wastewater was passed through filters packed with a natural zeolite (heulandite-CaAl 2 Si 7 O 18 ·6H 2 O). Eight treatments were evaluated in a 2 × 2 × 2 factorial treatment design. Factor A was the zeolite with two levels: 127 g and 80.4 g. Factor B was the nanoparticles with two levels: one bag (3.19 g) and two bags (6.39 g); and Factor C was the use of a magnet: with and without. There were two replications; hence, a total of 16 filters were employed. The water was obtained from a municipal wastewater treatment plant (MWTP). The cations (Na + , K + ; Mg +2 and Ca +2 ) and anions (F - , Cl - and SO 4 2- ) were measured before (influent = IW) and after filtering (effluent = EW) three times. All treatments leached the cations Na + (EW in a range of 175 to 232 ppm), K + (EW in a range of 15.4 to 33.2 ppm), and Mg +2 (EW in a range of 7.40 to 10.8 ppm) but did not leach Ca +2 . Likewise, the treatments leached the anions F - (EW in a range of 7.59 to 8.87 ppm), Cl - (EW in a range of 85.9 to 120 ppm), and SO 4 2- (EW in a range of 139 to 146 ppm). We conclude that this natural zeolite leaches cations (except Ca +2 ) and anions in MWTP passed through filters. Therefore, its application in wastewater treatment should be considered for purposes such as agriculture and animal production and not for drinking water.

The cost-effective recovery of phosphate is of great significance to the mitigation of phosphorus resource depletion crisis. The electrochemical-decomposition of dolomite was developed to recover phosphate and ammonium from aqueous solution. The dolomite ore is mainly composed of CaMg(CO 3) 2 (53.73%), CaCO 3 (28.93%) and SiO 2 (16.59%). The continuous release of Mg2+ and Ca2+ were achieved by electrochemically decomposing dolomite ore, accompanied by the generation of base solution (9.0–10.5). The main factors affecting the recovery performance of phosphate (PO 4 –P) and ammonium (NH 4 –N) are current, initial concentration of PO 4 –P and NH 4 –N, initial pH of feed solution and feed rate. For a 30-d operation, the recovery rate of PO 4 –P was maintained at 90–97% and that of NH 4 –N at 50–60% under optimized operating conditions. The recovered product had low water solubility but high citric-acid-soluble, and was proposed as a slow-release fertilizer for crops. The proposed process as a simple, effective and green route may serve as a new strategy for recovering PO 4 –P and NH 4 –N from wastewaters. Image 1 • Mg2+ and Ca2+ can be released from dolomite ore by electrochemical decomposition. • A high alkaline solution can be created by the electrochemical process. • Phosphate can be efficiently recovered as well as ammonium. • The precipitates did not give any environmental burden, which can be as a fertilizer. [ABSTRACT FROM AUTHOR]

• Highly crystalline FeCu-SSZ-13 was one-pot synthesized from natural minerals. • Neither silicon, aluminum, and iron-containing chemicals were used. • The synthesized zeolite has small crystallize size and large specific surface area. • More iron and copper species are incorporated into the framework of FeCu-SSZ-13. • The resultant FeCu-SSZ-13 shows outstanding catalytic performance in NH 3 -SCR. Heterobimetallic zeolites have been considered as highly efficient catalysts to reduce nitrogen oxide emissions, but economic and sustainable preparation methods have been lacking. This paper presents an economic and sustainable one-pot synthesis strategy to prepare the heterobimetallic FeCu-SSZ-13 zeolite (FeCu-SSZ-13M) with high crystallinity via the mesoscale depolymerization-reorganization of natural aluminosilicate minerals without the use of any synthetic silicon-, aluminum-, and iron-containing chemicals. Systematic characterization results reveal that the resultant FeCu-SSZ-13M sample has smaller crystallize size, larger specific surface area and pore volume (especially external specific surface area and mesopore volume), lower acid strength and more isolated Cu2+ and framework Fe3+ ions when compared with Cu-SSZ-13C and FeCu-SSZ-13C prepared from conventional precursors. Therefore, it exhibits outstanding catalytic performance (such as super-wide reaction temperature window, excellent hydrothermal stability, high H 2 O and SO 2 tolerance, and good gaseous hourly space velocity flexibility) in the selective catalytic reduction of NO by NH 3. Our research contributes to the design and synthesis of an efficient environmental protection catalyst in an economic and sustainable manner. [ABSTRACT FROM AUTHOR]

In situ immobilization of heavy metal cations in contaminated soil using natural minerals is an attractive remediation technique. However, little research has focused on the remediation of arsenic (As) and cadmium (Cd) co-contaminated. In this work, three different crystal structures and chemical compositions minerals, zeolite; bentonite; and dolomite, were applied to simultaneously reduce the uptake of As and Cd in Brassica chinensis L. , and the mechanism on reducing As and Cd bioavailability in soil were also investigated. The results showed that the three minerals decreased the bioavailability of As and Cd and restrained their uptake by Brassica chinensis L. with the order followed bentonite > zeolite > dolomite. Particularly, bentonite decreased the exchangeable As and Cd by 4.05% and 32.5% and the concentrations of As and Cd in shoots of Brassica chinensis L. by 36.2% and 64.6%, as compared with the controls. Moreover, with the addition of minerals increased, the dry biomass of Brassica chinensis L. and the rhizosphere microbial functional diversity increased significantly, and the highest biomass increased by 289% at 4.0% addition of bentonite. Correlation analysis indicated that the uptake of As and Cd was positive with the available Cd and As in soil, and was negative with soil pH and available N. Furthermore, the Scanning Electron Microscopy-Energy Dispersive Spectroscopy and Fourier Transform Infrared Spectroscopy analysis illustrated the interaction between minerals and Cd mainly involved ion-exchange and adsorption, while As was mainly immobilized by calcium and magnesium through forming precipitation. In conclusion, this present study implied that the bentonite can be recommended as the more effective amendment to immobilize metal (loid)s in soil and thereby reduce the exposure risk of metal (loid)s associated with grains consumption. Image 1 • The three minerals can simultaneous alleviate As and Cd bioavailability efficiently. • Effects of minerals on the uptake of As and Cd in Brassica chinensis L. were quantified. • Soil pH and available N should be priority controlled in As and Cd remediation. • The mechanism of reducing the available As and Cd in soil were investigated. [ABSTRACT FROM AUTHOR]

Ulcerative colitis (UC) affects millions of people worldwide and is currently incurable. As such, there is an urgent need for effective drugs that will promote UC remission. This study investigated the therapeutic effects of five typical natural minerals on UC induced by dextran sulfate sodium (DSS): kaolinite (Kaol), halloysite (Hal), diatomite (Dia), montmorillonite (Mt), and palygorskite (Pal). These minerals were characterized by lamellar, tubular, columnar porous, and fibrous morphologies, as well as centered size distribution and negative charge. In vivo experiments indicated that natural minerals had a remission effect on UC and altered gut flora, especially Kaol. These results suggest that natural minerals can serve as drugs, or drug carriers, to attain synergistic effects with other drugs for UC therapy. Unlabelled Image • Five natural minerals for ulcerative colitis (UC) therapy were in vivo evaluated. • Natural minerals exhibited different therapeutic efficiency on ulcerative colitis. • Microflora in UC mice colon could be altered toward balance by clay minerals. [ABSTRACT FROM AUTHOR]

Chemical-looping with oxygen uncoupling (CLOU) is considered a promising technology to burn solid fuels with improved CO2 capture and has the potential to improve fuel conversion and reaction rates. Cu-based oxygen carriers (Cu-OC) are often used in solid fuel CLOU. This study focused on investigating Cu-OC derived from a natural mineral for solid fuel CLOU because of their potentially lower cost compared to synthetic OCs. Reactivity and recyclability of a natural ore-derived Cu-OC on coal char (Powder River Basin sub-bituminous coal) were studied at 900 °C in Ar and air using TGA-QMS and fixed-bed reactor-QMS for five cycles. Cu-OC was prepared by simply heating chalcopyrite in air. Chalcopyrite is one of the principle copper sulfide ores and one of the primary ores for copper. The prepared Cu-OC had primarily CuO and CuFe2O4 (CuOFe2O3) as active compounds based on XRD analysis and an oxygen capacity 3.3% from oxygen uncoupling. The carbon conversion efficiency Xc was 0.94 for reduction at a ratio of Cu-OC to char ϕ = 75 and the product gas was primarily CO2 with trace O2. The reactivities and the rates were similar for five redox cycles. These results indicate that the natural ore-derived material with low cost has potential as a competitive oxygen carrier in solid fuel CLOU based on its reactivity in this study. [ABSTRACT FROM AUTHOR]