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Removal of arsenite via microbial oxidation coupled with sequestration by ZVI and negative ion-exchange resin
1  School of Chemical Engineering and Energy Zhengzhou University


 The oxidation of arsenite (AsIII) to arsenate (AsV) as an effective pre-treatment step was usually considered in order to ultimatly remove arsenic (As) from reducing aquatic environment such as groundwater. The present work selected quartz sand and pozzolan as two support materials filled into the parallel up-flow fixed-bed reactors. Concentrated AsIII was completly oxidized with two support materials after inoculation of acclimatized arsenite-oxidzing bacteria (AsOB) with various HRT of 6 h, 3 h and 1 h. Moreover, pozzolan was more efficient than quartz sand for AsIII oxidation even at a HRT of 40 min. Batch tests demonstrated that AsIII oxidation rate was negatively correlated with the axial length of reactors, which was closely related with the AsOB distribution in the fixed-bed reactor. Finally, high efficient removal of As realized through the microbial AsIII oxidation followed with the fixed-bed reactors filled with zero valent iron (ZVI) or negative ion-exhange resin.