Influence mechanism of heavy metal removal under microcurrent action

• Published in: Separation and Purification Technology Vol. 263; p. 118351
• Main Authors: Zhang, Jingran, Huang, Shan, Gao, XinTong, Wang, Hui, Cao, Xian, Li, Xianning
• Format: Journal Article
• Language: English; Japanese
• Published: Elsevier B.V 15.05.2021; Elsevier BV
• Subjects: Copper; MFC; Microcurrent; Reduction products; Removal rate; Removal rate; Reduction products; MFC; Copper; Microcurrent
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2021.118351

[Display omitted] •Current was the main determinant of whether Cu2+ reduction occurs.•High current significantly promoted the rate and process of copper reduction.•Cu2+ concentration significantly affected reduction rate and product particle size.•The simultaneous effects of high pH and Cu2+ concentration inhibit copper reduction. Heavy metal pollution is widespread in the environment. Microbial fuel cell (MFC) technology is effective for heavy metal removal; however, the simultaneous variations of multiple parameters in an MFC make it difficult to fully elucidate the mechanism of heavy metal removal under microcurrent conditions. In this study, we used a potentiostat to control the fixed potential in a simulated MFC system. The effects of pH, potential, and heavy metal concentration on current, heavy metal removal rate, product type, and product morphology were studied through orthogonal testing. The mechanism and significance of each parameter in terms of copper reduction removal were analyzed using tests of between-subjects effects and correlation analysis. We found that: (1) potential did not affect the type of electron acceptor, and substances with high redox potentials preferentially received electrons; (2) copper concentration significantly affected the reduction rate and product particle size of copper by controlling the flux of electroactive substances transferred to the electrode surface; (3) the combined effects of higher pH and copper concentration limited the reduction of copper; (4) current was the most important factor controlling copper reduction, as current strength significantly affected the copper reduction rate and mechanism; and (5) pH and copper concentration significantly affected the current level by altering the ionic strength of the solution.