Impact of Iron(Ⅱ)Concentration and Sequential Addition of Metal(loids)on the Removal of Aqueous Antimony and Arsenic Through Microbial Sulfate Reduction
Different Fe2+concentrations(10,20,50,100,200 and 500 mg/L),antimony(Sb),and arsenic(As)species(i.e.Sb(V)+As(V)and Sb(Ⅲ)+As(Ⅲ),5 mg/L)were introduced to batch experiments of microbial sulfate reduction at different intervals.The changes in physicochemical parameters such as pH,redox potential(Eh),total alkalinity,SO42-,sulfides,and variations in Fe,Sb,or As concentrations were analyzed at 0.5 h and on the 7th day after Sb and As addition to elucidate the effects of Fe2+concentrations and the adding sequence of Fe2+,Sb and As on the efficiency and mechanisms of microbial sulfate reduction to remove aqueous Sb and As.Results indicated that compared to the adding sequence,Fe2+concentration had a more significant impact on the removal efficiency.Lower Fe2+concentrations(≤20 mg/L)did not promote As removal.In comparison,higher Fe2+concentrations(≥50 mg/L)significantly improved As removal efficiency.Antimony removal exceeded 95％for all treatments,so the effects of adding sequences and Fe2+concentrations on Sb removal were challenging to delineate.When treating Sb and As containing wastewater through microbial sulfate reduction,the addition of Fe2+should be considered to enhance removal efficiency.Similarly,the environmental behavior of Fe-bearing minerals needs to be better considered when treating Sb-and As-contaminated sediments or soils by enhanced microbial sulfur reduction to achieve more significant remediation results.
sulfate-reducing bacteriaantimonyarsenicferrous iron
万方数据
维普
