Dual Electroactivation of Peroxymonosulfate for Heavy Metal Complexes Decomplexation and Simultaneous Resource Recovery

The efficient removal of toxic heavy metals chelated with coexisting organic ligands and simultaneous recovery of heavy metals are highly desirable but remains challenging. Herein, we report a strategy of dual electroactivation of peroxymonosulfate (PMS) to efficiently decomplex a metal complex and simultaneously recover heavy metal in simulated wastewater and real electroplating effluents of heavy metal complexes contamination. The synergistic activation of PMS on cathode and anode could achieve 99% dissociation of copper ethylene diamine tetraacetate (Cu(II)-EDTA) and 99% recovery rate of the released Cu ions via in situ deposition on cathode with a record energy efficiency of up to 58.18 g kWh–1. A series of investigations demonstrate that the boosted generation of free radicals such as hydroxyl radicals (·OH), sulfate radicals (SO4•–), superoxide radicals (·O2–), and singlet oxygen (1O2) in the dual electroactivation system play important roles in the Cu(II)-EDTA dissociation process. Furthermore, the dual electroactivation strategy could also achieve excellent dissociation efficiency and metal recovery rates for Ni and Cr complexes, and it is capable of achieving complete treatment of actual wastewater containing copper complexes. This study provides an effective strategy for the removal of heavy metal complexes and the heavy metal recovery.