Peroxydisulfate activation process on copper oxide: Cu(III) as the predominant selective intermediate oxidant for phenol and waterborne antibiotics removal

In this study, activated peroxydisulfate (PDS) by micrometer copper oxide (CuO) particles effectively degraded phenol and several antibiotics in water. Cupryl ion (Cu(III)) was proposed for the first time to be predominant reactive species accounting contaminants degradation CuO/PDS oxidation system. Singlet oxygen also heavily produced from superoxide radical anion (•O2−) decomposition found but slightly involved since it rapidly quenched Transformation pathways of were elucidated. The mechanism mainly generation •O2− resulting an outer-sphere surface PDS complexation which prompted reduction Cu(II) Cu(I). Cu(I) oxidized Cu(III) or H2O2 reduced a one-electron so that catalytic effect alternate copper. As process did not rely on sulfate hydroxyl radical, chloride bicarbonate ions showed no degradation, while humic acid hindered probably due their sorption CuO. Interestingly, leaching CuO significantly limited < 500 µg/L wastewater. These findings indicated potential applicability system electron-rich compounds including good catalyst stability against time.