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

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 0 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 x Fe (1-x) (OH) 3 , Cr x Fe (1-x) OOH and Cr 2 S 3 , and the alkaline capacity of the BFS could efficiently prevent the release of Cr(III) from the precipitations in acid condition. Thus, supporting S-nZVI on BFS was an effective and safe method for Cr(VI) removal from aqueous solutions.