Mechanochemical treatment of Cr(VI) contaminated soil using a sodium sulfide coupled solidification/stabilization process. (December 2018)

• Record Type: Journal Article
• Authors: Yuan, Wenyi; Xu, Weitong; Wu, Zebing; Zhang, Ziwei; Wang, Lincai; Bai, Jianfeng; Wang, Xiaoyan; Zhang, Qiwu; Zhu, Xuefeng; Zhang, Chenglong; Wang, Jingwei
• Is Part Of: Chemosphere. Volume 212(2018)
• Page Start: 540
• Page End: 547
• Publication Date: 2018-12
• Subjects: Cr(VI) contaminated soil -- Mechanochemical treatment -- Redox reaction -- Soil remediation -- Sodium sulfide; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2018.08.121
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: In this research, mechanochemical reduction was carried out to remediate Cr(VI) contaminated soil, and the reduction effectiveness was evaluated by analyzing the corresponding leachable fraction obtained through the toxicity characteristic leaching procedure (TCLP) proposed by the EPA. The results indicated that mechanochemical reduction can efficiently reduce the Cr(VI) concentration in the leachate. Under a milling time of 2 h, milling speed of 500 rpm, ball-to-powder weight ratio of 14 and Na2 S dosage of 5%, the Cr(VI) leaching concentration significantly decreased from 663.98 mg L −1 to 0.84 mg L −1, much lower than the regulatory limit of 5 mg L −1 . In addition, the significant decrease in Cr(VI) was mainly due to the reduction of Cr(VI) to Cr(III), as supported by X-ray photoelectron spectroscopy (XPS). The mechanochemical reduction with mechanism proposed in this experiment may involve two major processes: solidification and reduction (stabilization). Graphical abstract: Highlights: Mechanochemical reduction was applied for the remediation of Cr (Ⅵ) contaminated soil with Na2 S. Mechanochemical reaction between Cr (Ⅵ) in contaminated soil and Na2 S occurred. After treatment, leachable Cr (Ⅵ) concentrations reduced and be lower than 5 mg L −1 . Mechanochemical reduction technique is promising for Cr (Ⅵ) contaminated soil remediation.