Reduction and immobilization of Cr(Ⅵ) in aqueous solutions by blast furnace slag supported sulfidized nanoscale zerovalent iron

摘要

In this study, an industrial waste-blast furnace slag (BFS) supported sulfidized nanoscale zerovalent iron (S-nZVI@BFS) was prepared and used for synergistic reduction and adsorptive removal of Cr(Ⅵ) from aqueous solutions. The characterization analysis showed that Fe° and FeS were well dispersed on the surface of BFS, and the specific surface area of S-nZVI@BFS was 141.986 m~2 g~(-1). Batch experiments demonstrated that the removal capacity of Cr(Ⅵ) was as high as 184 mg/g for S-nZVI@BFS. The pseudo-second-order kinetic model fitted the Cr (Ⅵ) removal kinetics well. Cr(Ⅵ) removal on the S-nZVI@BFS relied highly on pH values. The reduced Cr(Ⅵ) precipitated on S-nZVI@BFS mainly as Cr_xFe_((1-x))(OH)_3, Cr_xFe_((1_x)) OOH and Cr_2S_3, and the alkaline capacity of the BFS could efficiently prevent the release of Cr(Ill) from the precipitations in acid condition. Thus, supporting S-nZVl on BFS was an effective and safe method for Cr(Ⅵ) removal from aqueous solutions.