Decomplexation of electroplating wastewater by ozone-based advanced oxidation process

Heavy metal contamination from electroplating wastewater is a serious risk to terrestrial life and public health. The complexed metal cannot be effectively removed by traditional precipitation without decomplexing. In this work, four ozone-based advanced oxidation processes, O-3, O-3/H2O2, O-3/UV and O-3/H2O2/UV to decomplex electroplating wastewater were investigated and their performance compared. Ethylenediaminetetraacetic acid (EDTA) and citric acid are the most common components of electroplating wastewater. They were used as representatives to study the decomplexation and mineralization of complexes in the ozone-based advanced oxidation processes. Among all, the highest degradation and mineralization efficiency of EDTA occurred in O-3/UV and was 65% and 53% in 60 min, respectively. For citric acid, the highest degradation (77%) and mineralization (56%) efficiency was observed in the O-3/H2O2/UV process. This indicates that selection of the advanced oxidation process is determined by the target contaminant.