Natural pyrite improved steel slag towards environmentally sustainable chromium reclamation from hexavalent chromium-containing wastewater. (November 2021)

• Record Type: Journal Article
• Authors: Shu, Yaorong; Ji, Bin; Li, Yuexin; Zhang, Wei; Zhang, Huining; Zhang, Jun
• Is Part Of: Chemosphere. Volume 282(2021)
• Publication Date: 2021-11
• Subjects: Steel slag -- Hexavalent chromium removal -- Adsorption -- Redox -- Flocculation; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2021.130974
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: 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 Fe 2+ 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 chromium-containing wastewater. Graphical abstract: Image 1 Highlights: Natural pyrite improved steel slag (NP-SS) was used for aqueous Cr(Ⅵ) removal. The aqueous chromium ions could be efficiently fixed onto the solid NP-SS. The mechanisms involved reduction, flocculation, co-precipitation and adsorption. The proposed process could alter the acid raw wastewater to nearly neutral. NP-SS carrying chromium could be potentially used for chromium smelting.