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Migration and distribution characteristics of soil heavy metal(loid)s at a lead smelting site

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Journal of Environmental Sciences 2024年第1期135卷 600-609页

作者： Chuxuan Li Mu Li Jiaqing Zeng Shanxin Yuan Xinghua Luo Chuan Wu Shengguo Xue School of metallurgy and Environment Central South UniversityChangsha 410083China chinese national engineering research center for control and treatment of heavy metal pollution Central South UniversityChangsha 410083China

heavy metal(loid)s contamination is a constant issue at smelting *** is essential to investigate the spatial distribution and migration characteristics of heavy metal(loid)s in the soil for environmental management and remediation strategies of non-ferrous smelting *** this study,203 soil samples from 57 sites were collected in a typical lead smelting *** findings demonstrated that there were significant Pb,Zn,Cd,and As contamination in soil *** spatial distribution of heavy metal(loid)s showed strong spatial heterogeneity,the contaminated soil areas of Pb,As,Cd,and Zn were 99.5%,98.9%,85.3%,and 72.4%,***,Cd,and As contamination of the soil reached a depth of 5 m,which migrated from the surface to deep soil *** leaching contents of Zn,Pb,and As decreased obviously in 3-4 m soil layer,but the leaching content of Cd was still high,which indicated the high migration of *** the increase of depth,the proportion of acid soluble fraction of heavy metal(loid)s decreased,and the residual fraction *** acid soluble fraction of Cd accounted for a higher proportion,and As mainly existed in reducible and residual fractions in *** to the calculation of the migration factor,the migration of heavy metal(loid)s in soils were ordered as Cd>Zn>Pb>*** outcomes are advantageous for risk reduction and site remediation for non-ferrous metal smelting sites.

关键词： Smelting sites heavy metal(loid)s Spatial distribution Chemical speciation Migration characteristics

Factors hindering the degradation of pharmaceuticals from human urine in an iron-activated persulfate system

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Journal of Environmental Sciences 2024年第1期135卷 130-148页

作者： Yiruiwen Xie Dao Guan Yangfan Deng Yugo Sato Yu Luo Guanghao Chen Department of Civil and Environmental engineering Water Technology LabHong Kong Branch of Chinese National Engineering Research Center for Control&Treatment of Heavy Metal PollutionThe Hong Kong University of Science&TechnologyHong Kong 999077China

This study investigated the degradation of clofibric acid(CFA),bezafibrate(BZF),and sulfamethoxazole(SMX)in synthetic human urine using a novel mesoporous iron powderactivated persulfate system(mFe-PS system),and identified the factors limiting their degradation in synthetic human urine.A kinetic model was established to expose the radical production in various reaction conditions,and experiments were conducted to verify the modeling *** the phosphate-containing mFe-PS system,the 120 min removal efficiency of CFA decreased from 95.1%to 76.6%as the phosphate concentration increased from 0.32 to 6.45 mmol/L,but recovered to 90.5%when phosphate concentration increased to 16.10 mmol/***,the increased concentration of phosphate from 0.32 to 16.10mmol/L reduced the BZF degradation efficacy from 91.5%to 79.0%,whereas SMX removal improved from 37.3%to 62.9%.The m Fe-PS system containing(bi)carbonate,from 4.20 to166.70 mmol/L,reduced CFA and BZF removal efficiencies from 100%to 76.8%and 80.4%,respectively,and SMX from 83.5%to 56.7%within a 120-min reaction *** addition,alkaline conditions(pH≥8.0)inhibited CFA and BZF degradations,while nonacidic pH(pH≥7.0)remarkably inhibited SMX *** of the kinetic model indicated the formation of phosphate(H_(2)PO_(4)^(·)/HPO_(4)^(·-))and/or carbonate radicals(CO_(3)^(·-))could limit pharmaceutical *** transformation products(TPs)of the pharmaceuticals revealed more incompletely oxidized TPs occurred in the phosphate-and(bi)carbonate-containing m Fe-PS systems,and indicated that H_(2)PO_(4)^(·)/HPO_(4)^(·-)mainly degraded pharmaceuticals via a benzene ring-opening reaction while CO_(3)^(·-)preferentially oxidized pharmaceuticals via a hydroxylation reaction.

关键词： Pharmaceutical degradation Human urine Iron-activated persulfate system Phosphate radicals Carbonate radicals Transformation products

Nanosize-effect on the distribution of heavy metals in copper smelting dust:Based on sophisticated dust sorting approach

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Nano research 2024年第1期17卷 312-320页

作者： Ken Li Zuwu Liao Hengdi Ye Qingzhu Li Fenghua Shen Qian Li Hui Liu Qingwei Wang Xu Yan Zhang Lin Liyuan Chai School of metallurgy and Environment Central South UniversityChangsha 410083China chinese national engineering research center for control&treatment of heavy metal pollution Changsha 410083China national engineering research center of Sintering and Pelletizing Equipment System Zhongye Changtian International Engineering Co.LtdChangsha 410205China

Dust particles emitted from smelters can be hazardous to ecosystems and humans,as they are often enriched in metallic ***,we combined multi-method mineralogical analysis with a sophisticated size sorting approach for copper smelting dust to study the nanosize-effect on heavy metal distribution,which has hitherto been *** types of dust were collected from a copper flash smelter and then size-sorted using a Dekati low-pressure *** showed that all three samples could easily sort out nanoscale dust particles(heavy metals(Pb,Zn,Cu,and As)and their mineral species in dust was examined at various particle *** was discovered that different heavy metals are enriched on nanoparticles in specific *** micron-sized particles,heavy metals are generally found in discrete phases(e.g.,CuSO_(4),PbSO_(4),and As_(2)O_(3)).In nanoscale particles,the dominant phase is Fe_(3)O_(4),while heavy metals are mostly found in lattice substitution(e.g.,CuFe_(2)O_(4)and ZnFe_(2)O_(4)).Two distinct nano-dust morphologies were found:One with irregular mesh or chain structures consisting of particles of a few nanometers,and the other with polygonal crystals in larger sizes of hundreds of *** enrichment of heavy metals in the latter morphology is more pronounced,possibly because lattice substitution of heavy metals is more likely to occur when polycrystalline particles are formed.

关键词： copper flue dust size-sorted heavy metal distribution morphology nano-sized effects

Atomically Dispersed Zinc Active Sites Efficiently Promote the Electrochemical Conversion of N2 to NH3

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Energy & Environmental Materials 2024年第03期7卷 179-185页

作者： Yanjiao Wei Xinyu Wang Mengjie Sun Min Ma Jian Tian Minhua Shao School of Materials Science and engineering Shandong University of Science and Technology Department of Chemical and Biological engineering The Hong Kong University of Science and Technology Energy Institute and Chinese National Engineering Research Center for Control & Treatment of Heavy Metal PollutionThe Hong Kong University of Science and Technology

At present,the research on highly active and stable nitrogen reduction reaction catalysts is still challenging work for the electrosynthesis of ammonia （NH3）.Herein,we synthesized atomically dispersed zinc active sites supported on N-doped carbon nanosheets （Zn/NC NSs） as an efficient nitrogen reduction reaction catalyst,which achieves a high ammonia yield of46.62μ***-0.85 V （vs RHE） and Faradaic efficiency of 95.8%at-0.70 V （vs RHE）.In addition,Zn/NC NSs present great stability and selectivity,and there is no significant change in NH3rate and Faradaic efficiencies after multiple *** structural characterization shows that the active center in the nitrogen reduction reaction process is the Zn-N4sites in the *** calculation confirms that Zn/NC with Zn-N4configuration has a lower energy barrier for the formation of*NNH intermediate compared with pure N-doped carbon nanosheets （N-C NSs）,thus promoting the hydrogenation kinetics in the whole nitrogen reduction reaction process.

关键词： electrocatalysis nitrogen reduction single-atom catalyst Zn–N4

Geochemical fractionation and potential release behaviour of heavy metals in lead–zinc smelting soils

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Journal of Environmental Sciences 2024年第5期139卷 1-11页

作者： Xinghua Luo Chao Xiang Chuan Wu Wenyan Gao Wenshun Ke Jiaqing Zeng Waichin Li Shengguo Xue School of metallurgy and Environment Central South UniversityChangsha 410083China chinese national engineering research center for control and treatment of heavy metal pollution Central South UniversityChangsha 410083China Department of Science and Environmental Studies The Education University of Hong KongHong Kong 999077China

The lack of understanding of heavy metal speciation and solubility control mechanisms in smelting soils limits the effective pollution *** this study smelting soils were investigated by an advanced mineralogical analysis(AMICS),leaching tests and thermodynamic *** aims were to identify the partitioning and release behaviour of Pb,Zn,Cd and *** integration of multiple techniques was necessary and displayed coherent *** addition to the residual fraction,Pb and Zn were predominantly associated with reducible fractions,and As primarily existed as the crystalline iron oxide-bound *** quantitative analysis further confirmed that Fe oxyhydroxides were the common dominant phase for As,Cd,Pb and *** addition,a metal arsenate(paulmooreite)was an important mineral host for Pb and *** pH-stat leaching indicted that the release of Pb,Zn and Cd increased towards low pH values while release of As increased towards high p H *** separate leaching schemes were associated with the geochemical behaviour under the control of minerals and were confirmed by thermodynamic *** calculations suggested that the formation of arsenate minerals(schultenite,mimetite and koritnigite)and the binding to Fe oxyhydroxides synchronously controlled the release of Pb,Zn,Cd and *** results emphasized the governing role of Fe oxyhydroxides and secondary insoluble minerals in natural attenuation of heavy metals,which provides a novelty strategy for the stabilization of multi-metals in smelting sites.

关键词： Smelting soils heavy metal Fractionation AMICS Geochemical modelling

Progress of gaseous arsenic removal from flue gas by adsorption:Experimental and theoretical calculations

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Journal of Environmental Sciences 2024年第2期136卷 470-485页

作者： Xuelei Yan Qingzhu Li Xiaowei Huang Bensheng Li Shengtu Li Qingwei Wang School of metallurgy and Environment Central South UniversityChangsha 410083China national engineering research Centre for control and treatment of heavy metal pollution Central South UniversityChangsha 410083China national engineering research center for Rare Earth Materials General Research Institute for Non-Ferrous MetalsBeijing 100088China

Because of its high mobility and difficult capture,gaseous arsenic pollution control has become the focus of arsenic pollution *** mainly exists in the form of highly toxic As_(2)O_(3)in the flue ***,removing gaseous As_(2)O_(3)from flue gas is of great practical significance for arsenic pollution *** gaseous As_(2)O_(3)on the surface of adsorbents by physical or chemical adsorption is an effective way to reduce the content of arsenic in the flue gas and alleviate arsenic *** the past few decades,various adsorbents have been developed to capture gaseous As_(2)O_(3)in the flue gas,and their adsorption mechanisms have been studied in ***,it is necessary to review the strategies of arsenic removal from flue gas by adsorption,which can inspire further *** on summarizing the morphological distribution of gaseous As_(2)O_(3)in the flue gas,this review further summarizes the removal of gaseous As_(2)O_(3)by several adsorbents and the effect of temperature and the main components of the flue gas on arsenic *** addition,the mechanism of arsenic removal based on adsorption in the flue gas is discussed in depth through theoretical calculations,which is the particular focus of this ***,prospects based on the present research state of arsenic removal by adsorption are proposed to provide ideas for developing effective and stable adsorbents for arsenic removal from flue gas.

关键词： Gaseous arsenic Flue gas Adsorption Theoretical calculation Mechanism

Efficient removal of natural organo-chromium(Ⅲ)through selfcirculating decomplex and immobilization with nanoscale zerovalent iron

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Nano research 2024年第1期17卷 364-371页

作者： Zhicheng Dong Yunyun Xu Can Wu Jin Chao Chen Tian Zhang Lin School of metallurgy and Environment Central South UniversityChangsha 410083China chinese national engineering research center for control&treatment of heavy metal pollution Changsha 410083China College of Ecology and Environment Chengdu University of TechnologyChengdu 610059China School of Environment and Energy The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters(Ministry of Education)South China University of TechnologyGuangzhou 510006China

Organo-chromium(III)complex is one of the chromium contaminant species,which would transform to high-toxic Cr(VI)during migrating in the *** natural organo-chromium(III)(NOCr)is difficult to remove by traditional degradation or precipitation methods,due to its high stability and ***,we demonstrated a novel NOCr removing method by transforming it to certain structures similar to Cr-Fe minerals in nature,through a self-circulating decomplex and immobilization mechanism with nano zero-valent iron(nZVI).Taking chromium glycinate(Cr-Gly)as a probe,nZVI showed a high Cr removal efficiency of 99.4%under ambient *** removal process included three stages of adsorption,decomplexation,and ***-Gly was first adsorbed on the surface of nZVI by chemisorption of the oxide ***,the adsorbed Cr-Gly was decomplexed and oxidized to Cr(VI)by·OH and 1O_(2),which were generated from molecular oxygen activated by ***,the released Cr(VI)could be in-situ adsorbed and re-reduced to Cr(III),which was further immobilized in form of Cr-O-Fe *** the Cr-O-Fe complexing structure was similar to that of Cr-Fe minerals(such as chromohercynite)in nature,this work explored a novel and efficient NOCr removing method that was potential to weaken chromium pollution in the environment.

关键词： organo-chromium(III) zero-valent iron adsorption decomplexation Cr immobilization

Preparation of Fe-As alloys by mechanical alloying and vacuum hot-pressed sintering:microstructure evolution,mechanical properties,and mechanisms

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Rare metals 2024年第8期43卷 3876-3892页

作者： Fei Chai Fei-Ping Zhao Zhan Hu Shi-Yi Wen Ben-Hammouda Samia Ze-Lin Fu Xin-Ting Lai Yan-Jie Liang Xiao-Bo Min Li-Yuan Chai School of metallurgy and Environment Central South UniversityChangsha 410083China chinese national engineering research center for control&treatment of heavy metal pollution Institute of Environmental EngineeringCentral South UniversityChangsha 410083HunanChin State Key Laboratory of Powder metallurgy Central South UniversityChangsha 410083China Department of Building Civiland Environmental EngineeringConcordia UniversityMontreal H3G 1M8Canada

Arsenic materials have attracted great attention due to their unique ***,research concerning iron-arsenic(Fe-As) alloys is very scarce due to the volatility of As at low temperature and the high melting point of ***,a new Fe-As alloy was obtained by mechanical alloying(MA) followed by vacuum hot-pressed sintering(VHPS).Moreover,a systematic study was carried out on the microstructural evolution,phase composition,leaching toxicity of As,and physical and mechanical properties of Fe-As alloys with varying weight fractions of As(20%,25%,30%,35%,45%,55%,65%,and 75%).The results showed that pre-alloyed metallic powders(PAMPs) have a fine grain size and specific supersaturated solid solution after MA,which could effectively improve the mechanical properties of Fe-As alloys by VHPS.A high density(> 7.350 g·cm^(-3)),low toxicity,and excellent mechanical properties could be obtained for FeAs alloys sintered via VHPS by adding an appropriate amount of As,which is more valuable than commercial Fe-As *** Fe-25% As alloy with low toxicity and a relatively high density(7.635 g·cm^(-3)) provides an ultra-high compressive strength(1989.19 MPa),while the Fe-65% As alloy owns the maximum Vickers hardness(HVo.5 899.41).After leaching by the toxicity characteristic leaching procedure(TCLP),these alloys could still maintain good mechanical performance,and the strengthening mechanisms of Fe-As alloys before and after leaching were *** in the grain size,micro structure,and phase distribution induced significant differences in the compressive strength and hardness.

关键词： Mechanical alloying Vacuum hot-pressed sintering High-pressure Arsenic-iron alloys Mechanical properties

Highly active and durable core-shell electrocatalysts for proton exchange membrane fuel cells

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Nano research 2024年第10期17卷 8772-8784页

作者： Hsiwen Wu Fei Xiao Jing Wang Meng Gu Minhua Shao Department of Chemical and Biological engineering The Hong Kong University of Science and TechnologyClear Water BayHong KongChina Department of Materials Science and engineering Southern University of Science and TechnologyShenzhen 518055China Fok Ying Tung research Institute The Hong Kong University of Science and TechnologyGuangzhou 511458China Energy Institute and chinese national engineering research center for control&treatment of heavy metal pollution The Hong Kong University of Science and TechnologyClear Water BayHong KongChina

This work presents simple post-treatment methods to selectively and partially remove the Pd core of Pd-Pt core–shell(Pt@Pd/C)*** proton exchange membrane fuel cell with the post-treated Pt@Pd/C cathode(Pt loading:0.10 mg·cm^(-2))delivers an impressive peak power density of 1.2 W·cm^(-2).The partial removal of Pd core endows an ultrahigh oxygen reduction reaction(ORR)mass activity of 0.32 A·g_(PGM)-1 when normalized to the platinum group metal(PGM)mass,or equivalently 0.55 A·mg_(Pt)^(-1) at 0.9 V measured in a fuel *** post-treatment thickens the Pt shells and mitigates the Pd dissolution during potential *** a result,the post-treated core-shell catalyst demonstrates superior durability in ORR mass activity and polarization power density retention than untreated core-shell catalyst and benchmark Pt/***-situ inductively coupled plasmamass spectrometry(ICP-MS)results highlight that the amount of dissolved Pd in post-treated core–shell catalyst is 17-times lower than that of the untreated *** findings highlight the importance of structural tuning of catalysts in enhancing their mass activity and durability.

关键词： core-shell catalyst platinum monolayer proton exchange membrane fuel cell oxygen reduction reaction durability