Removal of chromate from tannery wastewater: the applicability of sulfate-green rust in real coprecipitation processes

Abstract

Ferrihydrite and green rust (GR) have been identified as promising removing agents for chromate. However, while ferrihydrite efficiency is the still too low for practical applications, it is not known whether GR is stable in real wastewater systems. In this work, we investigated the removal of chromate from a real tannery wastewater by using sulfate-GR and ferrihydrite. We studied the effect of pH and Cr/Fe molar ratios on removal performances and elucidated the removal mechanism by XRD analysis. We performed removal experiments from simple chromate-bearing solutions under non-oxidizing Ar atmosphere, and from complex solution under open air atmosphere.