Towards source reduction and green sustainability of metal-bearing waste streams: The electrochemical processes

Abstract

With the increase in globalization and industrialization, the concomitant heavy metal pollution and scarcity of critical metals have been widely reported around the world. It is highly desirable to develop technologies that minimize pollution during the production and recovery of these metals from end-of-life waste streams. Due to the characteristic redox nature of metals and their oxides, sulfides, alloys, and hydroxides, electrochemical processes that utilize electrons as the oxidant/reductant rather than exogenous chemicals have been successfully employed for the source reduction and sustainable restoration of metal-bearing wastes. The efficient and selective electrochemical treatment of metals-bearing wastes typically involves adsorption, oxidative leaching, reductive deposition, integrated membrane separation, biological and photochemical reactions. In this review, we systematically summarize the recent progress toward the development of electrochemical processes for the environmental remediation of metal-bearing waste and unconventional natural resources. In addition, the current challenges and future perspectives, including the detailed mechanism and practical applications.