During thewater treatment process,chlorination and ultraviolet(UV)sterilization can modify microplastics(MPs)and alter their physicochemical properties,causing various changes between MPs and other pollutants.In this ...During thewater treatment process,chlorination and ultraviolet(UV)sterilization can modify microplastics(MPs)and alter their physicochemical properties,causing various changes between MPs and other pollutants.In this study,the impact of chlorination and UV modification on the physicochemical properties of polystyrene(PS)and polyvinyl chloride(PVC)were investigated,and the adsorption behavior of pefloxacin(PEF)before and after modificationwas examined.The effect of pH,ionic strength,dissolved organicmatter,heavymetal ions and other water environmental conditions on adsorption behavior was revealed.The results showed that PS had a higher adsorption capacity of PEF than PVC,and the modification increased the presence of O-containing functional groups in the MPs,thereby enhancing the adsorption capacity of both materials.Chlorination had a more significant impact on the physicochemical properties of MPs compared to UV irradiation within the same time period,leading to better adsorption performance of chlorination.The optimal pH for adsorption was found to be 6,and NaCl,sodium alginate and Cu2+would inhibit adsorption to varying degrees,among which the inhibition caused by pH was the strongest.Chlorination and UV modification would weaken the inhibitory effect of environmental factors on the adsorption of PEF by MPs.The main mechanisms of adsorption involved electrostatic interaction and hydrogen bonding.The study clarified the effects of modification on the physicochemical properties of MPs,providing reference for subsequent biotoxicity analysis and environmental protection studies.展开更多
With the continuous increase in the disposal volume of spent lithium-ion batteries(LIBs),properly recycling spent LIBs has become essential for the advancement of the circular economy.This study presents a systematic ...With the continuous increase in the disposal volume of spent lithium-ion batteries(LIBs),properly recycling spent LIBs has become essential for the advancement of the circular economy.This study presents a systematic analysis of the chlorination roasting kinetics and proposes a new two-step chlorination roasting process that integrates thermodynamics for the recycling of LIB cathode materials.The activation energy for the chloride reaction was 88.41 kJ/mol according to thermogravimetric analysis–derivative thermogravimetry data obtained by using model-free,model-fitting,and Z(α)function(αis conversion rate).Results indicated that the reaction was dominated by the first-order(F1)model when the conversion rate was less than or equal to 0.5 and shifted to the second-order(F2)model when the conversion rate exceeded 0.5.Optimal conditions were determined by thoroughly investigating the effects of roasting temperature,roasting time,and the mass ratio of NH_(4)Cl to LiCoO_(2).Under the optimal conditions,namely 400℃,20 min,and NH_(4)Cl/LiCoO_(2)mass ratio of 3:1,the leaching efficiency of Li and Co reached 99.43% and 99.05%,respectively.Analysis of the roasted products revealed that valuable metals in LiCoO_(2)transformed into CoCl_(2) and LiCl.Furthermore,the reaction mechanism was elucidated,providing insights for the establishment of a novel low-temperature chlorination roasting technology based on a crystal structure perspective.This technology can guide the development of LIB recycling processes with low energy consumption,low secondary pollution,high recovery efficiency,and high added value.展开更多
Recovery of rare earth elements(REEs)from bulk Nd-Fe-B scrap by chlorination with NH_(4)Cl as a chlorinating agent has been reported to be an energy efficient and environmentally friendly method.However,the reaction m...Recovery of rare earth elements(REEs)from bulk Nd-Fe-B scrap by chlorination with NH_(4)Cl as a chlorinating agent has been reported to be an energy efficient and environmentally friendly method.However,the reaction mechanism and phase evolution of the low-temperature selective chlorination process of Nd-Fe-B sludge are not clear.In this paper,we systematically investigated the lowtemperature selective chlorination process of Nd-Fe-B sludge with NH4Cl by combining thermokinetic theoretical calculations and experiments,and revealed its reaction mechanism.The phase evolution during chlorination was determined by X-ray diffraction(XRD),scanning electron microscopy(SEM)and ene rgy-dispersive X-ray spectroscopy(EDS)characterization as well as co mputational analysis of the phase stability diagram of the M-O-Cl system.To determine the optimum chlorination conditions,the effects of chlorinating agent dosage,reaction temperature and reaction time on the reaction were investigated.The results show that the rare earth components in Nd-Fe-B sludge are selectively chlorinated to RECl3and the formation of REOCl is avoided in the temperature range of 300-420℃,while the iron components are preferentially oxidized to Fe2O3.The selective chlorination reaction is consistent with the unreacted shrinking core model,and the rate-controlling step of the reaction is the internal diffusion process of NH4Cl through the transition layer of the reactant product to the surface of the Nd-Fe-B sludge.The complete chlorination of REEs is successfully achieved and 99.8%of REEs are selectively extracted into the leaching solution under optimal chlorination conditions(300℃,2.5 times of stoichiometric amount,4 h).展开更多
Benzotriazole(BTA)-based A_(2)-A_1-D-A_1-A_(2)type wide-bandgap(WBG)non-fullerene acceptors(NFAs)have shown promising potential in indoor photovoltaic,and in-depth investigation of their structure-property relationshi...Benzotriazole(BTA)-based A_(2)-A_1-D-A_1-A_(2)type wide-bandgap(WBG)non-fullerene acceptors(NFAs)have shown promising potential in indoor photovoltaic,and in-depth investigation of their structure-property relationship is of great significance.Herein,we explored the chlorination effect of the side chain on the terminals.We introduced Cl atoms into the benzyl side chains in parent BTA5 to synthesize two NFAs,BTA5-Cl with mono-chlorinated benzyl groups and BTA5-2Cl containing bi-chlorinated benzyl groups.We chose D18-Cl with deep-energy levels and strong crystallinity to pair with these three acceptors,affording high photovoltage and photocurrent.With the stepwise chlorination,the open-circuit voltage(V_(OC))values decrease from 1.28,1.22,to 1.20 V,while the corresponding power conversion efficiencies(PCEs)improve from 5.07%,9.15%,to 10.96%.Compared with BTA5-based OSCs,introducing Cl atoms downshifts the energy levels and slightly increases the non-radiative energy loss(0.14<0.17<0.19 e V),resulting in a sequential decrease in VO C.However,more chlorine atom replacements produce more effective exciton dissociation,higher charge transfer,and balanced carrier mobility in the blend films,ultimately achieving better PCEs.This work indicates that chlorination of the benzyl group on the terminals can improve the device's performance,implying good application potential in indoor photovoltaics.展开更多
Due to the lack of effective screening systems in the rare earth waste recycling industry,the composition of rare earth elements in rare earth waste is complex and difficult to separate.In response to such problems,by...Due to the lack of effective screening systems in the rare earth waste recycling industry,the composition of rare earth elements in rare earth waste is complex and difficult to separate.In response to such problems,by studying the reaction behavior between various elements in rare earth waste and cobalt chloride,we propose a process path for the separation and recovery of iron,cerium and other rare earth elements using cobalt chloride roasting.The experiments on simulated wastes show that the leaching rates of the Nd,Sm,Gd,Pr can reach 98.31%,94.5%,93.87%and 72.05%under the optimal process conditions,respectively.Ce and iron remain in the leaching residue in the form of CeO_(2)and CoFe_(2)O_(4),respectively.And through a simple magnetic separation process,CeO_(2)and CoFe_(2)O_(4)can be enriched in non-magnetic leaching residue and magnetic leaching residue,respectively.The cerium content in the leaching residue composed of cobalt ferrite is only 1.95%.Therefore,this method is beneficial to the separation and high-value utilization of iron,cerium,and other rare earth elements in the waste system.The research results can provide theoretical reference for the low-cost and high-value recovery of rare earth secondary resources.展开更多
Chlorination roasting followed by water leaching process was used to extract lithium from lepidolite.The microstructure of the lepidolite and roasted materials were characterized by X-ray diffraction（XRD）.Various pa...Chlorination roasting followed by water leaching process was used to extract lithium from lepidolite.The microstructure of the lepidolite and roasted materials were characterized by X-ray diffraction（XRD）.Various parameters including chlorination roasting temperature,time,type and amount of chlorinating agents were optimized.The conditional experiments indicate that the best mass ratio of lepidolite to NaCl to CaCl2 is 1：0.6：0.4 during the roasting process.The extraction of lithium reaches peak value of 92.86% at 880 °C,potassium,rubidium,and cesium 88.49%,93.60% and 93.01%,respectively.The XRD result indicates that the major phases of the product after roasting lepidolite with mixture of chlorinating agents（CaCl2 and NaCl） are SiO2,CaF2,KCl,CaSiO3,CaAl2Si2O8,NaCl and NaAlSi3O8.展开更多
Behaviors of TiO2 in the alumina carbothermic reduction and chlorination process in vacuum at different temperatures were investigated experimentally by means of XRD,SEM and EDS.In the preparation of materials,the mol...Behaviors of TiO2 in the alumina carbothermic reduction and chlorination process in vacuum at different temperatures were investigated experimentally by means of XRD,SEM and EDS.In the preparation of materials,the molar ratio of Al2O3 to C was 1：4,and 10% TiO2 and excess AlCl3 were added.The results show that TiC is produced by C and TiO2 after TiO2 transforms from anatase into rutile gradually.In the temperature range of 1 763？1 783 K,the compounds of Ti and Al are not found in slags and condensate.The purity of aluminum reaches 98.35%,and TiO2 does not participate in alumina carbothermic reduction process and chlorination process in vacuum.展开更多
This study utilizes wet/dry cyclic corrosion testing combined with corrosion big data technology to investigate the mechanism by which chloride ions(Cl^(-))influence the corrosion behavior of 650 MPa high-strength low...This study utilizes wet/dry cyclic corrosion testing combined with corrosion big data technology to investigate the mechanism by which chloride ions(Cl^(-))influence the corrosion behavior of 650 MPa high-strength low-alloy(HSLA)steel in industrially polluted environments.The corrosion process of 650 MPa HSLA steel occurred in two distinct stages:an initial corrosion stage and a stable corrosion stage.During the initial phase,the weight loss rate increased rapidly owing to the instability of the rust layer.Notably,this study demonstrated that 650 MPa HSLA steel exhibited superior corrosion resistance in Cl-containing environments.The formation of a corrosion-product film eventually reduced the weight-loss rate.However,the intrusion of Cl^(-)at increasing concentrations gradually destabilized theα/γ^(*)phases of the rust layer,leading to a looser structure and lower polarization resistance(R_(p)).The application of corrosion big data technology in this study facilitated the validation and analysis of the experimental results,offering new insights into the corrosion mechanisms of HSLA steel in chloride-rich environments.展开更多
采用文献计量学方法,系统梳理了2014—2024年收录于Web of Science核心合集的808篇相关文献,并运用VOSviewer和CiteSpace软件进行共现网络与聚类分析,同时结合文献报道的消毒副产物种类、生成量及前体物特性等实验数据深入剖析其生成机...采用文献计量学方法,系统梳理了2014—2024年收录于Web of Science核心合集的808篇相关文献,并运用VOSviewer和CiteSpace软件进行共现网络与聚类分析,同时结合文献报道的消毒副产物种类、生成量及前体物特性等实验数据深入剖析其生成机制。结果显示,全球该领域年发文量呈波动增长趋势,国家、作者以及机构间的合作网络日益全球化。在研究热点层面,低分子质量(m<1 ku)溶解性有机质因活性位点可及性显著提升碳质消毒副产物,如三卤甲烷等的生成,而疏水性组分与含氮官能团(羧基、羰基)则通过亲核取代反应主导氮质消毒副产物生成路径。消毒工艺参数研究表明,pH值从6.0升至8.0时,三氯硝基甲烷生成量增加1.6倍,且氯剂量与三卤甲烷生成量呈强正相关(R^(2)=0.980)。当前该领域研究面临前体物-消毒副产物定量构效模型缺失、多因子耦合机制不明等瓶颈问题。未来应融合高分辨率质谱与机器学习技术,构建动态预测模型,以优化消毒工艺。展开更多
Traditional culture methods may underestimate the tolerance of microorganisms to disinfectants because of the existence of viable but nonculturable or sublethally injured cells after disinfection.The selection of a st...Traditional culture methods may underestimate the tolerance of microorganisms to disinfectants because of the existence of viable but nonculturable or sublethally injured cells after disinfection.The selection of a strict method is crucial for the evaluation of disinfection performance.The actions of 2 typical disinfectants–ultraviolet（UV）and chlorine–on the fecal indicator Escherichia coli were investigated by the detection of culturability,membrane permeability,metabolic activity,deoxyribonucleic acid（DNA）,and messenger ribonucleic acid（m RNA）.During UV disinfection,the irreversible damages in the cell membrane and cellular adenosine triphosphate（ATP）were negligible at low UV doses（80 m J/cm^2）.However,membrane permeability was damaged at low doses of chlorine（5 mg/L）,leading to leakage of cellular ATP.Our study showed that a slight lesion in DNA was detected even at high doses of UV（400 m J/cm^2）and chlorine（5 mg/L）treatments.The decay of m RNA was more rapid than that of DNA.The degradation level of m RNA depended on the choice of target genes.After exposure to 50 m J/cm^2UV dose or 5 mg/L chlorine for30 min,the DNA damage repair function（Rec A m RNA）was inhibited.The m RNA involved in the DNA damage repair function can be a potential indicator of bacterial viability.展开更多
Chlorination has been recognized as an efficient and economically favorable method for treating clogging in drip emitters caused by biological growth during sewage application. Further important criteria for determini...Chlorination has been recognized as an efficient and economically favorable method for treating clogging in drip emitters caused by biological growth during sewage application. Further important criteria for determining an optimal chlorination scheme are the different responses of crops to the chloride added into the soil through chlorination. During two seasons in 2008 and 2009, field experiments were conducted in a solar-heated greenhouse with drip irrigation systems applying secondary sewage effluent to tomato plants to investigate the influences of chlorine injection intervals and levels on plant growth, yield, fruit quality, and emitter clogging. Injection intervals ranging from 2 to 8 wk and injection concentrations ranging 2-50 mg L-1 of free chlorine residual at the end of the laterals were used. For the 2008 experiments, the yield from the treatments of sewage application with chlorination was 7.5% lower than the yield from the treatment of sewage application without chlorination, while the yields for the treatments with and without chlorination were similar for the 2009 experiments. The statistical tests indicated that neither the chlorine injection intervals and concentrations nor the interactions between the two significantly influenced plant height, leaf area, or tomato yield for both years. The qualities of the fruit in response to chlorination were parameter-dependent. Chlorination did not significantly influence the quality of ascorbic acid, soluble sugar, or soluble acids, but the interaction between the chlorine injection interval and the chlorine concentration significantly influenced the levels of soluble solids. It was also confirmed that chlorination was an effective method for reducing biological clogging. These results suggested that chlorination is safe for a crop that has a moderate sensitivity to chlorine, like tomato, and can maintain a high level of performance in drip irrigation systems applying sewage effluent.展开更多
A novel process based on chlorination roasting was proposed to simultaneously recover gold and zinc from refractory carbonaceous gold ore by using NaCl as chlorination agent.The effects of roasting temperature,roastin...A novel process based on chlorination roasting was proposed to simultaneously recover gold and zinc from refractory carbonaceous gold ore by using NaCl as chlorination agent.The effects of roasting temperature,roasting time and NaCl content on the volatilization rates of gold and zinc were investigated.The reaction mechanism and the phase transition process were also analyzed by means of SEM,EDS and XRD.The results demonstrated that under the optimal conditions of NaCl content of 10%,roasting temperature of 800℃,roasting time of 4 h and gas flow rate of 1 L/min,the rates of gold and zinc were 92%and 92.56%,respectively.During low-temperature chlorination roasting stage,a certain content of sulfur was beneficial to the chlorination reactions of gold and zinc;and during high-temperature chlorination roasting stage,the crystal structure of vanadium-bearing mica was destroyed,and the vanadium-containing oxides were beneficial to the chlorinating volatilization of gold and zinc.Eventually,the chlorinated volatiles of gold and zinc could be recovered by alkaline solution.展开更多
Bormate （BrO3^-） is a carcinogenic chemical produced in ozonation or chlorination of bromide-containing water. Although its formation in seawater with or without sunlight has been previously investigated, the format...Bormate （BrO3^-） is a carcinogenic chemical produced in ozonation or chlorination of bromide-containing water. Although its formation in seawater with or without sunlight has been previously investigated, the formation of bromate in dilute solutions, particularly raw water for water treatment plant, is unknown. In this article, the results of bench scale tests to measure the formation rates of bromate formation in dilute solutions, including de-ionized water and raw water from Yangtze River, were presented in dark chlorination and ultraviolet （UV）/chlorination processes. And the effects of initial pH, initial concentration of NaOCl, and UV light intensity on bromate formation in UV/chlorination of the diluted solutions were investigated. Detectable bromate was formed in dark chlorination of the two water samples with a relatively slow production rate. Under routine disinfecting conditions, the amount of formed bromate is not likely to exceed the national standards （10 μg/L）. UV irradiation enhanced the decay of free chlorine, and, simultaneously, 6.6%-32% of Br^- was oxidized to BrO3^-. And the formation of bromate exhibited three stages： rapid stage, slow stage and plateau. Under the experimental conditions （pH = 4.41-11.07, CCl2= 1.23-4.50 mg/L）, low pH and high chlorine concentration favored the generation of bromate. High light intensity promoted the production rate of bromate, but decreased its total generation amount due to acceleration of chlorine decomposition.展开更多
基金supported by the Shanxi Scholarship Council of China(No.2023-054)the Applied Basic Research Project of Shanxi Province,China(No.20210302123121)the National Natural Science Foundation of China(No.52170045).
文摘During thewater treatment process,chlorination and ultraviolet(UV)sterilization can modify microplastics(MPs)and alter their physicochemical properties,causing various changes between MPs and other pollutants.In this study,the impact of chlorination and UV modification on the physicochemical properties of polystyrene(PS)and polyvinyl chloride(PVC)were investigated,and the adsorption behavior of pefloxacin(PEF)before and after modificationwas examined.The effect of pH,ionic strength,dissolved organicmatter,heavymetal ions and other water environmental conditions on adsorption behavior was revealed.The results showed that PS had a higher adsorption capacity of PEF than PVC,and the modification increased the presence of O-containing functional groups in the MPs,thereby enhancing the adsorption capacity of both materials.Chlorination had a more significant impact on the physicochemical properties of MPs compared to UV irradiation within the same time period,leading to better adsorption performance of chlorination.The optimal pH for adsorption was found to be 6,and NaCl,sodium alginate and Cu2+would inhibit adsorption to varying degrees,among which the inhibition caused by pH was the strongest.Chlorination and UV modification would weaken the inhibitory effect of environmental factors on the adsorption of PEF by MPs.The main mechanisms of adsorption involved electrostatic interaction and hydrogen bonding.The study clarified the effects of modification on the physicochemical properties of MPs,providing reference for subsequent biotoxicity analysis and environmental protection studies.
基金financially supported by the National Natural Science Foundation of China(No.52204310)the Guizhou Provincial Key Laboratory of Coal Clean Utilization(No.[2020]2001)+5 种基金the China Postdoctoral Science Foundation(Nos.2020TQ0059 and 2020M570967)the Natural Science Foundation of Liaoning Province(No.2021–MS–083)the Fundamental Research Funds for the Central Universities,China(No.N2125010)the Open Project Program of Key Laboratory of Metallurgical Emission Reduction&Resources Recycling(Anhui University of Technology),Ministry of Education(No.JKF22–02)the Foundation of Liupanshui Normal University(No.LPSSYZDZK202205)the Key Laboratory for Anisotropy and Texture of Materials,Ministry of Education,China。
文摘With the continuous increase in the disposal volume of spent lithium-ion batteries(LIBs),properly recycling spent LIBs has become essential for the advancement of the circular economy.This study presents a systematic analysis of the chlorination roasting kinetics and proposes a new two-step chlorination roasting process that integrates thermodynamics for the recycling of LIB cathode materials.The activation energy for the chloride reaction was 88.41 kJ/mol according to thermogravimetric analysis–derivative thermogravimetry data obtained by using model-free,model-fitting,and Z(α)function(αis conversion rate).Results indicated that the reaction was dominated by the first-order(F1)model when the conversion rate was less than or equal to 0.5 and shifted to the second-order(F2)model when the conversion rate exceeded 0.5.Optimal conditions were determined by thoroughly investigating the effects of roasting temperature,roasting time,and the mass ratio of NH_(4)Cl to LiCoO_(2).Under the optimal conditions,namely 400℃,20 min,and NH_(4)Cl/LiCoO_(2)mass ratio of 3:1,the leaching efficiency of Li and Co reached 99.43% and 99.05%,respectively.Analysis of the roasted products revealed that valuable metals in LiCoO_(2)transformed into CoCl_(2) and LiCl.Furthermore,the reaction mechanism was elucidated,providing insights for the establishment of a novel low-temperature chlorination roasting technology based on a crystal structure perspective.This technology can guide the development of LIB recycling processes with low energy consumption,low secondary pollution,high recovery efficiency,and high added value.
基金Project supported by the National Natural Science Foundation of China(52261037,52401251)Key Research Project of Jiangxi Province(20203ABC28W006)+2 种基金the Research Fund of Key Laboratory of Rare Earths,Chinese Academy of SciencesKey Laboratory of Ionic Rare Earth Re sources and Environment,Ministry of Natural Resources of the People's Republic of China(2022IRERE302)the Ganzhou Science and Technology Innovation Empowerment Youth"Jie bang Gua shuai"Project。
文摘Recovery of rare earth elements(REEs)from bulk Nd-Fe-B scrap by chlorination with NH_(4)Cl as a chlorinating agent has been reported to be an energy efficient and environmentally friendly method.However,the reaction mechanism and phase evolution of the low-temperature selective chlorination process of Nd-Fe-B sludge are not clear.In this paper,we systematically investigated the lowtemperature selective chlorination process of Nd-Fe-B sludge with NH4Cl by combining thermokinetic theoretical calculations and experiments,and revealed its reaction mechanism.The phase evolution during chlorination was determined by X-ray diffraction(XRD),scanning electron microscopy(SEM)and ene rgy-dispersive X-ray spectroscopy(EDS)characterization as well as co mputational analysis of the phase stability diagram of the M-O-Cl system.To determine the optimum chlorination conditions,the effects of chlorinating agent dosage,reaction temperature and reaction time on the reaction were investigated.The results show that the rare earth components in Nd-Fe-B sludge are selectively chlorinated to RECl3and the formation of REOCl is avoided in the temperature range of 300-420℃,while the iron components are preferentially oxidized to Fe2O3.The selective chlorination reaction is consistent with the unreacted shrinking core model,and the rate-controlling step of the reaction is the internal diffusion process of NH4Cl through the transition layer of the reactant product to the surface of the Nd-Fe-B sludge.The complete chlorination of REEs is successfully achieved and 99.8%of REEs are selectively extracted into the leaching solution under optimal chlorination conditions(300℃,2.5 times of stoichiometric amount,4 h).
基金support from the National Natural Science Foundation of China(Nos.52373176,52073067)。
文摘Benzotriazole(BTA)-based A_(2)-A_1-D-A_1-A_(2)type wide-bandgap(WBG)non-fullerene acceptors(NFAs)have shown promising potential in indoor photovoltaic,and in-depth investigation of their structure-property relationship is of great significance.Herein,we explored the chlorination effect of the side chain on the terminals.We introduced Cl atoms into the benzyl side chains in parent BTA5 to synthesize two NFAs,BTA5-Cl with mono-chlorinated benzyl groups and BTA5-2Cl containing bi-chlorinated benzyl groups.We chose D18-Cl with deep-energy levels and strong crystallinity to pair with these three acceptors,affording high photovoltage and photocurrent.With the stepwise chlorination,the open-circuit voltage(V_(OC))values decrease from 1.28,1.22,to 1.20 V,while the corresponding power conversion efficiencies(PCEs)improve from 5.07%,9.15%,to 10.96%.Compared with BTA5-based OSCs,introducing Cl atoms downshifts the energy levels and slightly increases the non-radiative energy loss(0.14<0.17<0.19 e V),resulting in a sequential decrease in VO C.However,more chlorine atom replacements produce more effective exciton dissociation,higher charge transfer,and balanced carrier mobility in the blend films,ultimately achieving better PCEs.This work indicates that chlorination of the benzyl group on the terminals can improve the device's performance,implying good application potential in indoor photovoltaics.
基金Project supported by China Baowu Low Carbon Metallurgy Innovation Foundation(BWLCF202121)Jiangxi Provincial Key Laboratory of Flash Green Development and Recycling(20193BCD40019)+1 种基金Academic and Technical Leaders of Major Disciplines in Jiangxi Province(20213BCJ22003)Yichun Science and Technology Plan Project(2023YBKJGG04)。
文摘Due to the lack of effective screening systems in the rare earth waste recycling industry,the composition of rare earth elements in rare earth waste is complex and difficult to separate.In response to such problems,by studying the reaction behavior between various elements in rare earth waste and cobalt chloride,we propose a process path for the separation and recovery of iron,cerium and other rare earth elements using cobalt chloride roasting.The experiments on simulated wastes show that the leaching rates of the Nd,Sm,Gd,Pr can reach 98.31%,94.5%,93.87%and 72.05%under the optimal process conditions,respectively.Ce and iron remain in the leaching residue in the form of CeO_(2)and CoFe_(2)O_(4),respectively.And through a simple magnetic separation process,CeO_(2)and CoFe_(2)O_(4)can be enriched in non-magnetic leaching residue and magnetic leaching residue,respectively.The cerium content in the leaching residue composed of cobalt ferrite is only 1.95%.Therefore,this method is beneficial to the separation and high-value utilization of iron,cerium,and other rare earth elements in the waste system.The research results can provide theoretical reference for the low-cost and high-value recovery of rare earth secondary resources.
文摘Chlorination roasting followed by water leaching process was used to extract lithium from lepidolite.The microstructure of the lepidolite and roasted materials were characterized by X-ray diffraction（XRD）.Various parameters including chlorination roasting temperature,time,type and amount of chlorinating agents were optimized.The conditional experiments indicate that the best mass ratio of lepidolite to NaCl to CaCl2 is 1：0.6：0.4 during the roasting process.The extraction of lithium reaches peak value of 92.86% at 880 °C,potassium,rubidium,and cesium 88.49%,93.60% and 93.01%,respectively.The XRD result indicates that the major phases of the product after roasting lepidolite with mixture of chlorinating agents（CaCl2 and NaCl） are SiO2,CaF2,KCl,CaSiO3,CaAl2Si2O8,NaCl and NaAlSi3O8.
基金Project (u0837604) supported by the Joint Funds of the National Natural Science Foundation of China and Yunnan ProvinceProject (20095314110003) supported by the Special Research Funds of the Doctor Subject of Higher School,China
文摘Behaviors of TiO2 in the alumina carbothermic reduction and chlorination process in vacuum at different temperatures were investigated experimentally by means of XRD,SEM and EDS.In the preparation of materials,the molar ratio of Al2O3 to C was 1：4,and 10% TiO2 and excess AlCl3 were added.The results show that TiC is produced by C and TiO2 after TiO2 transforms from anatase into rutile gradually.In the temperature range of 1 763？1 783 K,the compounds of Ti and Al are not found in slags and condensate.The purity of aluminum reaches 98.35%,and TiO2 does not participate in alumina carbothermic reduction process and chlorination process in vacuum.
基金financially supported by the National Natural Science Foundation of China(Nos.52104319 and 52374323)。
文摘This study utilizes wet/dry cyclic corrosion testing combined with corrosion big data technology to investigate the mechanism by which chloride ions(Cl^(-))influence the corrosion behavior of 650 MPa high-strength low-alloy(HSLA)steel in industrially polluted environments.The corrosion process of 650 MPa HSLA steel occurred in two distinct stages:an initial corrosion stage and a stable corrosion stage.During the initial phase,the weight loss rate increased rapidly owing to the instability of the rust layer.Notably,this study demonstrated that 650 MPa HSLA steel exhibited superior corrosion resistance in Cl-containing environments.The formation of a corrosion-product film eventually reduced the weight-loss rate.However,the intrusion of Cl^(-)at increasing concentrations gradually destabilized theα/γ^(*)phases of the rust layer,leading to a looser structure and lower polarization resistance(R_(p)).The application of corrosion big data technology in this study facilitated the validation and analysis of the experimental results,offering new insights into the corrosion mechanisms of HSLA steel in chloride-rich environments.
文摘采用文献计量学方法,系统梳理了2014—2024年收录于Web of Science核心合集的808篇相关文献,并运用VOSviewer和CiteSpace软件进行共现网络与聚类分析,同时结合文献报道的消毒副产物种类、生成量及前体物特性等实验数据深入剖析其生成机制。结果显示,全球该领域年发文量呈波动增长趋势,国家、作者以及机构间的合作网络日益全球化。在研究热点层面,低分子质量(m<1 ku)溶解性有机质因活性位点可及性显著提升碳质消毒副产物,如三卤甲烷等的生成,而疏水性组分与含氮官能团(羧基、羰基)则通过亲核取代反应主导氮质消毒副产物生成路径。消毒工艺参数研究表明,pH值从6.0升至8.0时,三氯硝基甲烷生成量增加1.6倍,且氯剂量与三卤甲烷生成量呈强正相关(R^(2)=0.980)。当前该领域研究面临前体物-消毒副产物定量构效模型缺失、多因子耦合机制不明等瓶颈问题。未来应融合高分辨率质谱与机器学习技术,构建动态预测模型,以优化消毒工艺。
基金supported by the National Natural Science Foundation of China (No. 51578441)the National Program of Water Pollution Control (No. 2013ZX07310-001)+2 种基金the Scientific Research Program funded by the Shaanxi Provincial Education Department (No. 15JK1442)the National Key Technology Support Program (No. 2014BAC13B06)the Program for Innovative Research Team in Shaanxi Province (No. 2013KCT-13)
文摘Traditional culture methods may underestimate the tolerance of microorganisms to disinfectants because of the existence of viable but nonculturable or sublethally injured cells after disinfection.The selection of a strict method is crucial for the evaluation of disinfection performance.The actions of 2 typical disinfectants–ultraviolet（UV）and chlorine–on the fecal indicator Escherichia coli were investigated by the detection of culturability,membrane permeability,metabolic activity,deoxyribonucleic acid（DNA）,and messenger ribonucleic acid（m RNA）.During UV disinfection,the irreversible damages in the cell membrane and cellular adenosine triphosphate（ATP）were negligible at low UV doses（80 m J/cm^2）.However,membrane permeability was damaged at low doses of chlorine（5 mg/L）,leading to leakage of cellular ATP.Our study showed that a slight lesion in DNA was detected even at high doses of UV（400 m J/cm^2）and chlorine（5 mg/L）treatments.The decay of m RNA was more rapid than that of DNA.The degradation level of m RNA depended on the choice of target genes.After exposure to 50 m J/cm^2UV dose or 5 mg/L chlorine for30 min,the DNA damage repair function（Rec A m RNA）was inhibited.The m RNA involved in the DNA damage repair function can be a potential indicator of bacterial viability.
基金financially supported by the National Natural Science Foundation of China (50779078)
文摘Chlorination has been recognized as an efficient and economically favorable method for treating clogging in drip emitters caused by biological growth during sewage application. Further important criteria for determining an optimal chlorination scheme are the different responses of crops to the chloride added into the soil through chlorination. During two seasons in 2008 and 2009, field experiments were conducted in a solar-heated greenhouse with drip irrigation systems applying secondary sewage effluent to tomato plants to investigate the influences of chlorine injection intervals and levels on plant growth, yield, fruit quality, and emitter clogging. Injection intervals ranging from 2 to 8 wk and injection concentrations ranging 2-50 mg L-1 of free chlorine residual at the end of the laterals were used. For the 2008 experiments, the yield from the treatments of sewage application with chlorination was 7.5% lower than the yield from the treatment of sewage application without chlorination, while the yields for the treatments with and without chlorination were similar for the 2009 experiments. The statistical tests indicated that neither the chlorine injection intervals and concentrations nor the interactions between the two significantly influenced plant height, leaf area, or tomato yield for both years. The qualities of the fruit in response to chlorination were parameter-dependent. Chlorination did not significantly influence the quality of ascorbic acid, soluble sugar, or soluble acids, but the interaction between the chlorine injection interval and the chlorine concentration significantly influenced the levels of soluble solids. It was also confirmed that chlorination was an effective method for reducing biological clogging. These results suggested that chlorination is safe for a crop that has a moderate sensitivity to chlorine, like tomato, and can maintain a high level of performance in drip irrigation systems applying sewage effluent.
文摘A novel process based on chlorination roasting was proposed to simultaneously recover gold and zinc from refractory carbonaceous gold ore by using NaCl as chlorination agent.The effects of roasting temperature,roasting time and NaCl content on the volatilization rates of gold and zinc were investigated.The reaction mechanism and the phase transition process were also analyzed by means of SEM,EDS and XRD.The results demonstrated that under the optimal conditions of NaCl content of 10%,roasting temperature of 800℃,roasting time of 4 h and gas flow rate of 1 L/min,the rates of gold and zinc were 92%and 92.56%,respectively.During low-temperature chlorination roasting stage,a certain content of sulfur was beneficial to the chlorination reactions of gold and zinc;and during high-temperature chlorination roasting stage,the crystal structure of vanadium-bearing mica was destroyed,and the vanadium-containing oxides were beneficial to the chlorinating volatilization of gold and zinc.Eventually,the chlorinated volatiles of gold and zinc could be recovered by alkaline solution.
文摘Bormate （BrO3^-） is a carcinogenic chemical produced in ozonation or chlorination of bromide-containing water. Although its formation in seawater with or without sunlight has been previously investigated, the formation of bromate in dilute solutions, particularly raw water for water treatment plant, is unknown. In this article, the results of bench scale tests to measure the formation rates of bromate formation in dilute solutions, including de-ionized water and raw water from Yangtze River, were presented in dark chlorination and ultraviolet （UV）/chlorination processes. And the effects of initial pH, initial concentration of NaOCl, and UV light intensity on bromate formation in UV/chlorination of the diluted solutions were investigated. Detectable bromate was formed in dark chlorination of the two water samples with a relatively slow production rate. Under routine disinfecting conditions, the amount of formed bromate is not likely to exceed the national standards （10 μg/L）. UV irradiation enhanced the decay of free chlorine, and, simultaneously, 6.6%-32% of Br^- was oxidized to BrO3^-. And the formation of bromate exhibited three stages： rapid stage, slow stage and plateau. Under the experimental conditions （pH = 4.41-11.07, CCl2= 1.23-4.50 mg/L）, low pH and high chlorine concentration favored the generation of bromate. High light intensity promoted the production rate of bromate, but decreased its total generation amount due to acceleration of chlorine decomposition.
