Fe(Ⅱ)-mediated transformation of schwertmannite associated with calcium from acid mine drainage treatment  

作　　者：Cong Fan Chuling Guo Wei Chen Guining Lu Yu Shen Zhi Dang 

机构地区：[1]National Research Base of Intelligent Manufacturing Service,Chongqing Technology and Business University,Chongqing 400067,China [2]School of Environment and Energy,South China University of Technology,Guangzhou 510006,China [3]The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters,Ministry of Education,South China University of Technology,Guangzhou 510006,China [4]Chongqing Key Laboratory of Environmental Materials and Remediation Technologies,Chongqing University of Arts and Sciences,Chongqing 402160,China

出　　处：《Journal of Environmental Sciences》2023年第4期612-620,共9页环境科学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (Nos.42007363,41977277);Scientific Research Project of Chongqing Technology and Business University (No.KFJJ2019051);Science and Technology Research Projects of Chongqing Education Commission (No.KJQN202000814);Chongqing Science and Technology Commission of China (No.cstc2019jcyj-msxmX0647);Foundation for High-level Talents of Chongqing University of Arts and Sciences (No.R2018CH11);Innovation Group of New Technologies for Industrial Pollution Control of Chongqing Education Commission (No.CXQT19023)。

摘　　要：Schwertmannite is an important Fe(Ⅲ)-oxyhydroxysulfate in acid mine drainage (AMD) polluted areas and its stability depends on surrounding environmental factors and previously bound elements.The treatment and neutralization of AMD normally involve the use of lime,which leads to the discharge of abundant Ca in the mining area.Such an environmental disturbance brings up an important and less considered problem of how the reductive transformation of schwertmannite associated with coexisting Ca occurred.Here,the Fe(Ⅱ)-mediated transformation of Ca-adsorbed schwertmannite and subsequent Ca repartitioning behaviors were investigated.Results showed that adsorbed Ca had a weak inhibitory effect on Fe(Ⅱ)-mediated schwertmannite transformation.Release of SO_(4)2-and SEM images both indicated that transformation rates of schwertmannite decreased under the influence of adsorbed Ca.XRD patterns indicated that adsorbed Ca altered schwertmannite transformation pathways and product compositions upon treatment with 0.4 mmol/L Fe(Ⅱ).The end products of Sch notably contained both goethite and lepidocrocite;however,transformation products of SchCa only contained goethite all along.Approximately 33.5%of the surface adsorbed-Ca was released into solution within 6 hr after Fe(Ⅱ) injection.Aqueous Ca behaved in a“first release and then im-mobilization”manner,which indicated dissolution and secondary mineralization drove Ca migration during the Fe(Ⅱ)-mediated transformation of SchCa.Adsorbed Ca blocked the surface sites for subsequent Fe(Ⅱ) adsorption,limited the Fe(Ⅱ)-Fe(Ⅲ) ETAE,and decreased the transformation rates.This work sheds light on the complex geochemical behavior of schwertmannite under the influences of environmental perturbations in AMD environments.

关 键 词：Acid mine drainage SCHWERTMANNITE CALCIUM FE(II) TRANSFORMATION 

分 类 号：X753[环境科学与工程—环境工程]