Micro-arc plasma decomplexation of Cu-EDTA by TC4 liquid-phase discharge: underneath mechanisms

The paper discusses a method to treat wastewater (Cu-EDTA, copper ethylenediamine tetra acetic acid) using micro-arc plasma by combining micro-arc oxidation technology and advanced oxidation technology from the fields of material surface treatment and environmental engineering. The aim is to change copper ions from a complex state to a free state. The decomplexation rate was up to 73.82%, and the mineralization rate was up to 32.7% for the samples after 100 min of treatment with micro-arc plasma. Cu-EDTA decomplexation is divided into the decomposition of EDTA and free copper ion reactions. The active substance reacts with Cu-EDTA to generate intermediates, leading to the mineralization of EDTA through continuous decomposition and synthesis. Meanwhile, copper ions complete the decomplexation and react with other anions in the solution and on the anode surface. This study not only provides a new wastewater treatment technology but also improves the theoretical study of micro-arc plasma on organic matter.