Insight into the crystal facet-dependent Cr(VI)reduction:A comparative study of pyrite{100}and{111}facets  

作　　者：Binlin Tang Jinye Liang Zhilin Wen Yueqiang Zhou Zhiqiang Yan Yihao Zhou Peng He Chunyao Gu Min Gan Jianyu Zhu 

机构地区：[1]School of Minerals Processing and Bioengineering,Key Laboratory of Biohydrometallurgy of Ministry of Education,Central South University,Changsha 410083,China [2]Hunan Province Geological Disaster Survey and Monitoring Institute,Changsha 410029,China

出　　处：《Journal of Environmental Sciences》2025年第4期78-90,共13页环境科学学报(英文版)

基　　金：supported by the National Natural Science Foundation of China(No.42277256);the Natural Science Foundation of Hunan Province(No.2022JJ30710);Hunan Province Environmental Protection Research Program(No.HBKT-2021014);Guangdong Province Dabaoshan Mining Co.Ltd Technology Program(Semi-industrial test of 200T/time low-grade copper ore bio-heap leaching).

摘　　要：The migration and transformation of hexavalent chromium(Cr(VI))in the environment are regulated by pyrite(FeS2).However,variations in pyrite crystal facets influence the adsorption behavior and electron transfer between pyrite and Cr(VI),thereby impacting the Cr(VI)reduction performance.Herein,two naturally common facets of pyritewere synthesized hydrothermally to investigate the facet-dependent mechanisms of Cr(VI)reduction.The experimental results revealed that the{111}facet exhibited approximately 1.30–1.50 times higher efficiency in Cr(VI)reduction compared to the{100}facet.Surface analyses and electrochemical results indicated that{111}facet displayed a higher iron-sulfur oxidation level,which was affected by its superior electrochemical properties during the reaction with Cr(VI).Density functional theory(DFT)calculations demonstrated that the narrower band gap and lower work function on{111}facet were more favorable for the electron transfer between Fe(II)and Cr(VI).Furthermore,different adsorption configurations were observed on{100}and{111}surfaces due to the unique arrangements of Fe and S atoms.Specifically,O atoms in Cr_(2)O_(7)^(2−)directly bound with the S sites on{100}but the Fe sites on{111}.According to the density of states(DOS),the Fe site had better reactivity than the S site in the reaction,which appeared to be related to the fracture of S-S bonds.Additionally,the adsorption configuration of Cr_(2)O_(7)^(2−)on{111}surface showed a stronger adsorption energy and a more stable coordination mode,favoring subsequent Cr(VI)reduction process.These findings provide an in-depth analysis of facet-dependent mechanisms underlying Cr(VI)reduction behavior,offering new insights into studying environmental interactions between heavy metals and natural minerals.

关 键 词：PYRITE Cr(VI)reduction Facet-dependent Fe/S arrangement DFT calculation 

分 类 号：X703[环境科学与工程—环境工程]