Self-catalytic Fenton-like reactions stimulated synergistic Cu-EDTA decomplexation and Cu recovery by glow plasma electrolysis

Heavy metal-organic complexes have potential threats to organisms in water environment and human health, and it is a big challenge to remove them by traditional chemical precipitation. In this study, a glow discharge plasma (GDP) system coupling oxidation and reduction processes was established to decompose heavy metal -organic complex, taking Cu-ethylenediaminetetraacetic acid (Cu-EDTA) as a model. Approximately 87% of CuEDTA decomplexation and 64% of Cu recovery were achieved after 90 min of GDP treatment. Cu-EDTA decomplexation was mainly triggered by oxidation by & BULL;OH in the GDP system, leading to successive breakage of Cu-O > C-O > C-N > OH > C = O based on two-dimensional correlation spectroscopy analysis. Self-catalytic Fenton-like reactions were induced by Cu-based byproducts and H2O2, further promoting Cu-EDTA decomplexation. The released Cu2+ was simultaneously reduced to Cu+/Cu0 by & BULL;H and eaq-on the cathode surface. The technique exhibited great performance for Cu-EDTA decomplexation in water environment, as well as for other heavy metal complexes. This study disclosed the underlying mechanisms of synchronous Cu-EDTA decomplexation and Cu recovery in the GDP system, providing a prospective technique for heavy metal complex control.

Automated summary

In this study, a glow discharge plasma (GDP) system was established to decompose heavy metal-organic complexes. The technique showed great performance in water environment and has potential applications in the removal of other heavy metal complexes.