Enhanced removal of high-As(Ⅲ)from Cl(-Ⅰ)-diluted SO_(4)(-Ⅱ)-rich wastewater at pH 2.3 via mixed tooeleite and(Cl(-Ⅰ)-free)ferric arsenite hydroxychloride formation  

作　　者：Zidan Yuan Guoqing Zhang Xing Wu Xu Ma Jinru Lin Shaofeng Wang Yongfeng Jia 

机构地区：[1]Key Laboratory of Pollution Ecology and Environmental Engineering,Institute of Applied Ecology,Chinese Academy of Sciences,Shenyang 110016,China [2]Key Laboratory for Yellow River and Huai River Water Environmental and Pollution Control,Ministry of Education,Henan Key Laboratory for Environmental Pollution Control,School of Environment,Henan Normal University,Henan 453007,China [3]Key Laboratory of Industrial Ecology and Environmental Engineering(Ministry of Education,China),School of Environmental Science and Technology,Dalian University of Technology,Dalian 116024,China

出　　处：《Journal of Environmental Sciences》2023年第2期31-41,共11页环境科学学报（英文版）

基　　金：supported by the National Key Research and Development Program of China (No.2019YFC1804400);the National Natural Science Foundation of China (Nos.41877393,41877379,42007364 and 42077309);Youth Innovation Promotion Association CAS (No.2021196);Liao Ning Revitalization Talents Program (Nos.XLYC1807185 and XLYC1807025)

摘　　要：An advanced cost-saving method of removal of high-As(Ⅲ)from SO_(4)(-Ⅱ)-rich metallurgical wastewater has been developed by diluting the SO_(4)(-Ⅱ)content with As(Ⅲ)-Cl(-Ⅰ)-rich metallurgical wastewater and then by the direct precipitation of As(Ⅲ)with Fe(Ⅲ)at pH 2.3.As(Ⅲ)removal at various SO_(4)(-Ⅱ)/Cl(-Ⅰ)molar ratios and temperatures was investigated.The results showed that 65.2–98.2%of As(Ⅲ)immobilization into solids occurred at the SO_(4)(-Ⅱ)/Cl(-I)molar ratios of 1:1–32 and 15–60℃in 3 days,which were far higher than those in aqueous sole SO4(-Ⅱ)or Cl(-Ⅰ)media at the equimolar SO_(4)(-Ⅱ)or Cl(-Ⅰ)and the same temperature.SO_(4)(-Ⅱ)/Cl(-Ⅰ)molar ratio of 1:4 and 25℃were optimal conditions to reach the As removal maximum.Mixed aqueous SO4(-Ⅱ)and Cl(-Ⅰ)played a synergetic role in the main tooeleite formation together with(Cl(-Ⅰ)-free)ferric arsenite hydroxychloride(FAHC)involving the substitution of AsO_(3)^(3−)for Cl(-Ⅰ)for enhanced As fixation.The competitive complexation among FeH_(2)AsO_(3)^(2+),FeSO_(4)^(+)and FeCl^(2+)complexes was the main mechanism for the maximum As(Ⅲ)precipitation at the SO4(-Ⅱ)/Cl(-I)molar ratio of 1:4.Low As(Ⅲ)immobilization at high temperature with increased Fe(Ⅲ)hydrolysis was due to the formation of As(Ⅲ)-bearing ferrihydrite with the relatively high Fe/As molar ratio at acidic pH.

关 键 词：High-As(III) Sulfate Chlorine ion REMOVAL Complex 

分 类 号：X703[环境科学与工程—环境工程]