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Novel process for facile preparation of mesoporous silica-based materials with controllable pore structure from coal fly ash Author links open overlay panel

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Particuology 2024年第8期91卷 128-137页

作者： Jian-ming Gao Zhen Li Shujia Ma Yuanyuan Zhang Fangqin Cheng Institute of resources and Environment engineering State Environmental Protection Key Laboratory of Efficient Utilization Technology of Coal Waste ResourcesShanxi Collaborative Innovation Center of High Value-added Utilization of Coal-related WastesShanxi UniversityTaiyuan 030006China

Extraction of silica from fly ash to produce mesoporous silica materials is one of the most important utilization *** silica could not be synthesized on a large-scale by conventional sol-gel *** this paper,facile preparation of mesoporous silica with controllable pore structure from fly ash by the template-free process via two steps of mineral phase transformation and selective acid etching was *** influence of crystalline structure and acid etching degree on structure of as-synthesized mesoporous silica materials was revealed,as well as mechanism of crystalline structure transformation and pore structure *** results show that mullite and quartz could be transformed into acid-soluble kaliophilite when fly ash reacted with K_(2)CO_(3)at temperature of 800-1100℃.The hexagonal kaliophilite would be transformed into orthorhombic KAlSiO_(4)-O1 phase when the temperature is controlled at 1100℃.Mesoporous silica with specific surface area of 475.93 m^(2)/g and 642.57 m^(2)/g could be synthesized from activated fly ash with kaliophilite and KAlSiO_(4)-O1 phase crystalline *** controlling the degree of acid etching,mesoporous silica materials with different pore structures can be *** paper provides a cost-effective and large-scale process for the preparation of mesoporous silica materials with controllable pore structure from solid waste fly ash.

关键词： Fly ash Mesoporous silica Crystal transformation Acid etching Controllable pore structure

Enhanced remediation of chlorpyrifos-contaminated soil by immobilized strain Bacillus H27

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Journal of Environmental Sciences 2024年第10期144卷 172-184页

作者： Changrui Liu Shengfang Wen Shuhan Li Yu Tian Lanjun Wang Lusheng Zhu Jun Wang Young Mo Kim Jinhua Wang National engineering research center for efficient utilization of Soil and Fertilizer resources Key Laboratory of Agricultural Environment in Universities of ShandongCollege of Resources and EnvironmentShandong Agricultural UniversityTaian 271018China Department of Civil and Environmental engineering Hanyang UniversitySeongdong-guSeoul 04763Korea

Chlorpyrifos is a pesticide widely used in agricultural production with a relatively long residual half-life in *** the problem of residual chlorpyrifos is of universal *** this study,rice hull biochar was used as an immobilized carrier to prepare the immobilized strain H27 for the remediation of chlorpyrifos-contamination *** microorganisms after remediation were investigated by ecotoxicological *** immobilized strain H27 had the highest removal rate of chlorpyrifos when 10%bacterial solution was added to the liquid medium containing 0.075-0.109 mm diameter biochar cultured for 22 *** study on the removal of chlorpyrifos by immobilized strain H27 showed that the initial concentration of chlorpyrifos in solution was 25mg/L,and the removal rate reached 97.4%after 7 days of *** the soil,the removal rate of the immobilized bacteria group increased throughout the experiment,which was significantly higher than that of the free bacteria and biochar treatment *** Biolog-ECO test,T-RFLP and RT-RCR were used to study the effects of the soil microbial community and nitrogen cycling functional genes during chlorpyrifos *** was found that ICP group had the highest diversity index among the four treatment *** microflora of segment containing 114 bp was the dominant bacterial community,and the dominant microflora of the immobilized bacteria group was more evenly *** influence of each treatment group on ammonia-oxidizing bacteria(AOB)was greater than on ammonia-oxidizing archaea(AOA).This study offers a sound scientific basis for the practical application of immobilized bacteria to reduce residual soil pesticides.

关键词： Chlorpyrifos Immobilized microorganisms Soil remediation Soil microorganism

Mn-doped LiFePO_(4)@C as a high-performance cathode material for lithium-ion batteries

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Particuology 2024年第7期90卷 418-428页

作者： Wenjing Chen Fangxiang Song Yumei Yang Qianlin Chen School of Chemistry and Chemical engineering Guizhou UniversityGuiyang550025China Collaborative Innovation center of Guizhou Province for efficient utilization of Phosphorus and Fluorine resources Guizhou UniversityGuiyang550025China

In this work,LiFe_(1-x)MnxPO_(4)@C(x=0,0.01,0.02,0.03)cathode materials were obtained by a simple co-precipitation method and heat treatment,and the influence of Mn-doped modification on the electrochemical performance of LiFePO_(4)@C cathode materials was *** show that by doping an appropriate amount of Mn,the cell volume became larger,and the electronic conductivity increased,which improved the Li+diffusion rate and thus its rate capability and cycle performance of Li-ion *** them,LiFe_(0.98)Mn_(0.02)PO_(4)@C showed superior lithium storage capability;the discharge capacity can reach 150.7 mAh g^(−1)at 0.1 *** cell could discharge up to 155.9 mAh g^(−1)at 1 C under high temperature at 45°C,which was higher than LiFePO_(4)@C(142 mAh g^(−1))under the same test *** discharge capacity of 1 C at room temperature was 139.9 mAh g^(−1),and the cycle stability was 95.9%after 200 *** showed that it had good rate capability and excellent cycle *** results indicate that Mn-doped LFP is a simple and effective strategy for developing high-performance cathode materials.

关键词： Mn-doped LiFePO_(4) Lithium-ion battery High temperature

Recent process developments in beneficiation and metallurgy of rare earths:A review

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Journal of Rare Earths 2024年第4期42卷 629-642页

作者： Shaokai Cheng Wenbo Li Yuexin Han Yongsheng Sun Peng Gao Xiaolong Zhang School of resources and Civil engineering Northeastern UniversityShenyang110819China National-local Joint engineering research center of High-efficient Exploitation Technology for Refractory Iron Ore resources Shenyang110819China

Rare earth elements(REEs)are irreplaceable materials supporting low-carbon technology and equip-ment,and their commercial demand and strategic position are becoming increasingly *** the continuous depletion of rare earth(RE)resources,developing high-efficiency beneficiation and eco-friendly metallurgical processes has attracted widespread *** paper reviews the major minerals exploited for RE production and their deposits,as well as the beneficiation and metallurgical processes of RE ***,monazite,mixed RE ores,and ion-adsorption clays are the main raw materials in the world to ***-bearing ores(except ion-adsorption minerals)are generally beneficiated by flotation,gravity and magnetic separation *** mainstream metallurgical processes for bastnaesite,monazite and mixed RE concentrates are oxidation roasting-HCl leaching,caustic soda decomposition and high-temperature concentrated sulfuric acid roasting,***-adsorption clays are directly processed by in situ leaching-precipitation/solvent *** achieve the sustainable development of RE resources,it is essential to further explore innovative techniques to achievecomprehensive utilization and cleaner production.

关键词： Rare earths Beneficiation processes Metallurgical processes Cleaner production

Thermal decomposition mechanism and kinetics of bastnaesite in suspension roasting process:A comparative study in N_(2) and air atmospheres

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Journal of Rare Earths 2024年第9期42卷 1809-1816,I0006页

作者： Wenbo Li Jijia Chen Shaokai Cheng Junyan Sun Xiaolong Zhang School of resources and Civil engineering Northeastern UniversityShenyang110819China National-Local Joint engineering research center of High-efficient Exploitation Technology for Refractory Iron Ore resources Shenyang110819China

To investigate the thermal decomposition behavior and reaction kinetics of bastnaesite in suspension roasting,the gas and solid products of bastnaesite roasted in N2 and air atmospheres were examined using a gas analyzer,X-ray diffraction(XRD),scanning electron microscopy(SEM),and energy dispersive spectrometry(EDS).Subsequently,the kinetic parameters of bastnaesite in the suspension roasting process were derived and calculated using the isothermal *** results show that the decomposition product of bastnaesite in N_(2) is ***,once the roasting temperature exceeds 600℃,CO is generated in addition to CO_(2),and all the XRD diffraction peaks of CeOF are shifted to the right,indicating that CO_(2) can oxidize CeOF and lead to the transformation of Ce(Ⅲ) into Ce(Ⅳ).When roasted in air,the decomposition product CeOF can be completely converted to CeF3 and Ce_(7)O_(12) as it easily ***,the reaction rate of bastnaesite in air is higher than that of N_(2),and the starting reaction temperature is lower than that of N_(2).A large number of irregular cracks and holes appear on the surface of solid-phase products following suspension roasting,which are due to the thermal decomposition of bastnaesite that produces CO_(2) as well as the reconstruction of the lattice of the solid-phase *** reaction kinetic model of bastnaesite roasted in N_(2)(temperature range 600-750℃) and air(temperatu re range 500-575℃) confo rms to the A_(3/2) model with the mechanism function G(α)=-ln(1-α)^(2/3),and the reaction activation energy is 59.78 kj/mol and lnA is 1.65 s^(-1) in N_(2) *** air,the reaction activation energy is 100.30 kj/mol and lnA is 9.63 s^(-1).

关键词： Rare earths Bastnaesite Suspension roasting Thermal decomposition mechanism Reaction kinetics

Effect of temperature on suspension magnetization roasting of hematite using biomass waste as reductant:A perspective of gas evolution

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Journal of Central South University 2024年第6期31卷 1870-1887页

作者： CAO Yue SUN Yong-sheng HAN Yue-xin GAO Peng LI Yan-jun School of resources and Civil engineering Northeastern UniversityShenyang 110819China National-local Joint engineering research center of High-efficient Exploitation Technology for Refractory Iron Ore resources Shenyang 110819China

The magnetization reduction of hematite using biomass waste can effectively utilize waste and reduce CO_(2) emission to achieve the goals of carbon peaking and carbon *** effects of temperatures on suspension magnetization roasting of hematite using biomass waste for evolved gases have been investigated using TG-FTIR,Py-GC/MS and gas composition *** mixture reduction process is divided into four *** the temperature range of 200-450℃ for mixture,the release of CO_(2),acids,and ketones is dominated in gases *** yield and concentration of small molecules reducing gases increase when the temperature increases from 450 to 900℃.At 700℃,the volume concentrations of CO,H_(2) and CH_(4) peak at 8.91%,8.90% and 4.91%,*** the suspension magnetization roasting process,an optimal iron concentrate with an iron grade of 70.86%,a recovery of 98.66% and a magnetic conversion of 45.70% is obtained at 700℃.Therefore,the magnetization reduction could react greatly in the temperature range of 600 to 700℃ owing to the suitable reducing *** study shows a detail gaseous evolution of roasting temperature and provides a new insight for studying the reduction process of hematite using biomass waste.

关键词： suspension magnetization roasting biomass pyrolysis gases evolution reduction behavior

Precise regulation of the phase transformation for pyrolusite during the reduction roasting process

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 81-90页

作者： Ruofeng Wang Peng Gao Shuai Yuan Yanjun Li Yingzhi Liu Cheng Huang School of resources and Civil engineering Northeastern UniversityShenyang 110819China National-Local Joint engineering research center of High-efficient Exploitation Technology for Refractory Iron Ore resources Shenyang 110819China

The mechanism involved in the phase transformation process of pyrolusite (MnO_(2)) during roasting in a reducing atmosphere was systematically elucidated in this study,with the aim of effectively using low-grade complex manganese ore *** to single-factor experiment results,the roasted product with a divalent manganese (Mn^(2+)) distribution rate of 95.30% was obtained at a roasting time of 25 min,a roasting temperature of 700℃,a CO concentration of 20at%,and a total gas volume of 500 mL·min^(-1),in which the manganese was mainly in the form of manganosite (MnO).Scanning electron microscopy and Brunauer–Emmett–Teller theory demonstrated the microstructural evolution of the roasted product and the gradual reduction in the pyrolusite ore from the surface to the core Thermodynamic calculations,X-ray photoelectron spectroscopy,and X-ray diffractometry analyses determined that the phase transformation of pyrolusite followed the order of MnO_(2)→Mn_(2)O_(3)→Mn_(3)O_(4)→MnO phase by phase,and the reduction of manganese oxides in each valence state proceeded simultaneously.

关键词： pyrolusite phase transformation reduction roasting microstructural evolution reaction mechanism

Optimized the vanadium electrolyte with sulfate-phosphoric mixed acids to enhance the stable operation at high-temperature

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Frontiers of Chemical Science and engineering 2024年第2期18卷 13-26页

作者： Ling Ge Tao Liu Yimin Zhang Hong Liu School of Resource and Environmental engineering Wuhan University of Science and TechnologyWuhan 430081China State Environmental Protection Key Laboratory of Mineral Metallurgical resources utilization and Pollution Control Wuhan University of Science and TechnologyWuhan 430081China Hubei Collaborative Innovation center for High efficient utilization of Vanadium resources Wuhan University of Science and TechnologyWuhan 430081China Hubei Provincial engineering Technology research center of High efficient Cleaning utilization for Shale Vanadium Resource Wuhan University of Science and TechnologyWuhan 430081China School of Resource and Environmental engineering Wuhan University of TechnologyWuhan 430070China

Herein, the influence of the concentration design and comprehensive performance of the sulfate-phosphoric mixed acid system electrolyte is investigated to realize an electrolyte that maintains high energy density and stable operation at high temperatures. Static stability tests have shown that VOPO4 precipitation occurs only with vanadium(V) electrolyte. The concentration of vanadium ion of 2.0–2.2 mol·L^(–1), phosphoric acid of 0.10–0.15 mol·L^(–1), and sulfuric acid of 2.5–3.0 mol·L^(–1) are suitable for a vanadium redox flow battery in the temperature range from –20 to 50 ℃. The equations for predicting the viscosity and conductivity of electrolytes are obtained by the response surface method. The optimized electrolyte overcomes precipitation generation. It has 2.8 times higher energy density than the non-phosphate electrolyte, and a coulomb efficiency of 94.0% at 50 ℃. The sulfate-phosphoric mixed acid system electrolyte promotes the electrode reaction process, increases the current density, and reduces the resistance. This work systematically optimizes the concentrations of composition of positive and negative vanadium electrolytes with mixed sulfate-phosphoric acid. It provides a basis for the different valence states and comprehensive properties of sulfate-phosphoric mixed acid system vanadium electrolytes under extreme environments, guiding engineering applications.

关键词： all vanadium redox flow battery mixed-acid vanadium electrolyte concentration optimization response surface methodology high-temperature stability

Reshaping Li–Mg hybrid batteries:Epitaxial electrodeposition and spatial confinement on MgMOF substrates via the lattice‐matching strategy

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Carbon Energy 2024年第8期6卷 248-261页

作者： Yongqin Wang Fulin Cheng Jiawen Ji Chenyang Cai Yu Fu School of Materials Science and engineering Co‐Innovation Center of Efficient Processing and Utilization of Forest ResourceNanjing Forestry UniversityNanjingJiangsuChina

The emergence of Li–Mg hybrid batteries has been receiving attention,owing to their enhanced electrochemical kinetics and reduced ***,the persistent challenge of uneven Mg electrodeposition remains a significant impediment to their practical ***,we developed an ingenious approach that centered around epitaxial electrocrystallization and meticulously controlled growth of magnesium crystals on a specialized MgMOF *** chosen MgMOF substrate demonstrated a robust affinity for magnesium and showed minimal lattice misfit with Mg,establishing the crucial prerequisites for successful heteroepitaxial ***,the incorporation of periodic electric fields and successive nanochannels within the MgMOF structure created a spatially confined environment that considerably promoted uniform magnesium nucleation at the molecular *** inspiration from the“blockchain”concept prevalent in the realm of big data,we seamlessly integrated a conductive polypyrrole framework,acting as a connecting“chain,”to interlink the“blocks”comprising the MgMOF *** innovative design significantly amplified charge‐transfer efficiency,thereby increasing overall electrochemical *** resulting architecture(MgMOF@PPy@CC)served as an exceptional host for heteroepitaxial Mg electrodeposition,showcasing remarkable electrostripping/plating kinetics and excellent cycling ***,a symmetrical cell incorporating the MgMOF@PPy@CC electrode demonstrated impressive stability even under ultrahigh current density conditions(10mAcm–2),maintaining operation for an extended 1200 h,surpassing previously reported ***,on coupling the MgMOF@PPy@CC anode with a Mo_(6)S_(8) cathode,the assembled battery showed an extended lifespan of 10,000 cycles at 70 C,with an outstanding capacity retention of 96.23%.This study provides a fresh perspective on the rational design of epitaxial electrocrystallizat

关键词： epitaxial electrodeposition lattice‐matching strategy Li-Mg hybrid batteries MOF substrate spatial confinement