Recovery of trivalent and hexavalent chromium from chromium slag using a bipolar membrane system combined with oxidation

Yaoxing Liu; Jianguo Ding; Hanquan Zhu; Xiaoyun Wu; Liping Dai; Riyao Chen; Bart Van der Bruggen

doi:10.1016/j.jcis.2022.03.140

Recovery of trivalent and hexavalent chromium from chromium slag using a bipolar membrane system combined with oxidation

J Colloid Interface Sci. 2022 Aug:619:280-288. doi: 10.1016/j.jcis.2022.03.140. Epub 2022 Apr 1.

Authors

Yaoxing Liu¹, Jianguo Ding², Hanquan Zhu², Xiaoyun Wu³, Liping Dai², Riyao Chen⁴, Bart Van der Bruggen⁵

Affiliations

¹ College of Environmental Science and Engineering, Fujian Key Laboratory of Pollution Control & Resource Reuse, Fujian Normal University, Fujian Province, Fuzhou 350007, China. Electronic address: yxliu19830218@fjnu.edu.cn.
² College of Environmental Science and Engineering, Fujian Key Laboratory of Pollution Control & Resource Reuse, Fujian Normal University, Fujian Province, Fuzhou 350007, China.
³ School of Safety and Environment, Fujian Chuanzheng Communications College, Fujian Province, Fuzhou 350007, China.
⁴ College of Environmental Science and Engineering, Fujian Key Laboratory of Pollution Control & Resource Reuse, Fujian Normal University, Fujian Province, Fuzhou 350007, China. Electronic address: rychen409@sina.com.
⁵ Department of Chemical Engineering, ProcESS-Process Engineering for Sustainable System, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium; Faculty of Engineering and the Built Environment, Tshwane University of Technology, Private Bag X680, Pretoria 0001, South Africa.

PMID: 35397461
DOI: 10.1016/j.jcis.2022.03.140

Abstract

Chromium slag (CS) with large quantities of multivalent Cr species (III and VI) generated during chromium salt production is hazardous to nature and living organisms. Furthermore, CS discharge leads to considerable resource wastage. Herein, a bipolar membrane electrodialysis (BMED) system was employed along with hydrogen peroxide (H₂O₂) oxidation for simultaneously recovering Cr(III) and Cr(VI) from CS in the form of Na₂CrO₄. A bipolar membrane was used to produce OH^- under a direct electric field, providing an alkaline environment for the oxidative conversion of Cr(III) to Cr(VI) in the presence of H₂O₂, followed by the recovery of Cr(III) and Cr(VI) as Na₂CrO₄. The effect of H₂O₂content on Cr(III) oxidation and that of the current density on chromium recovery, current efficiency and specific energy consumption were investigated. Moreover, the morphology of chromium in CS before and after the BMED treatment was analysed. The H₂O₂ content affected the Cr oxidation rate from Cr(III) to Cr(VI). The current density affected chromium removal, current efficiency and specific energy consumption. At a current density of 2 mA/cm², the total chromium recovery exceeded 67% and the remaining chromium was mainly in the residual state (RES). When the number of CS compartments increased, the current efficiency was enhanced and the specific energy consumption decreased. Binding state analysis show that Cr(III) and different species of Cr(VI) could be transformed into exchangeable Cr(VI) after H₂O₂ oxidation and BMED treatment. After the treatment, 92% of the remaining chromium in CS was in the RES. Thus, the employed method can effectively recover chromium from CS and other chromium-contaminated solid waste.

Keywords: Bipolar membrane; Chromium slag; Electrodialysis; Hydrogen peroxide; Solid waste.

MeSH terms

Chromium* / chemistry
Hydrogen Peroxide*
Oxidation-Reduction

Substances

Chromium
chromium hexavalent ion
Hydrogen Peroxide