Natural pyrite improved steel slag towards environmentally sustainable chromium reclamation from hexavalent chromium-containing wastewater

Currently, varied processes adopted to remove hexavalent chromium from aqueous solution have been realized to cause secondary pollution. As such, this study explored a green method for aqueous hexavalent chromium (Cr (VI)) reclamation by waste steel slag (SS) enhanced by natural pyrite (NP). Compared with the sole SS or NP, more efficient Cr(VI) removal was achieved by NP-SS at an initial pH value ranging from 1 to 8, resulting in a final pH value of 7-8. Cr(VI) in the solution could be initially reduced to Cr(III) by Fe2+ provided by NP, which was then bound with the OH- in the solution and the supersaturated calcium silicate hydrate on the surface of SS. In addition, the stearic acid anions existing on the surface of SS could promote the adsorption of Cr(III) to form chromium stearate. The used adsorbent could be potentially used for chromium smelting. Overall, this study provides a feasible and environmental sustainable solution to chromium reclamation from hexavalent chromiumcontaining wastewater.

Automated summary

This study proposed a green method for efficient removal of hexavalent chromium from aqueous solution using waste steel slag and natural pyrite. The method provides a feasible and environmentally sustainable solution for chromium reclamation.