No abstract

In this study, two-step methods were used to prepare sulfide nano-zero valent iron and the morphology, elemental composition, surface charge, crystal structure and elemental valence were characterised. The influence factors (S/Fe ratio, initial pH and initial concentration of Cr(VI)) and the mechanism of Cr(VI) removal was determined. The results revealed that the sulphide modification could increase the removal rate of chromium. The maximum removal rate of chromium was 81 mg/g, achieved at an S/Fe ratio of 0.1. The Cr(VI) removal process by S-nZVI0.1 is a multistep process, starting with strong adsorption to the surface of the particles by adsorption, followed by reduction of Cr(VI) to Cr(III), and finally fixing the contaminants on the S-nZVI0.1 surface by co-precipitation. This study has great significance for preparing a remediation material that could be efficiently used for repairing of Cr(VI) contaminated sites.