Cr(VI) removal by biogenic schwertmannite in continuous flow column

Abstract

Adsorption of Cr(VI) by biogenic schwertmannite in a continuous flow column was studied. The effects of flow rates, initial pH values, dosages of schwertmannite, and accompanying anions on Cr(VI) adsorption were investigated. The results demonstrated that the optimal flow rate and pH for Cr(VI) removal were 1 mL/min and 6, respectively. The maximum adsorption amount obtained in this study was 35.30 mg/g, demonstrating that the biogenic schwertmannite held a high adsorption capacity for Cr(VI). Removal of Cr(VI) by adsorption was hardly affected by common anions, except for H2PO4−. Based on the results obtained in this study, a mechanism for Cr(VI) adsorption by biogenic schwertmannite was proposed using the anion exchange processes between various Cr(VI) species and SO42−, a constituent of schwertmannite.