Herein, the Cu(III) synthesized from copper plating effluent was developed for the first time to evaluate the onsite degradation performance of heavy metal complexes in the wastewater, thus achieving the purpose of “treating waste with waste”. The results indicated that synthetic Cu(III) presented the excellent decomplexation performance for Cu(II)/Ni(II)-organic complexes. The removal efficiency of Cu(II)/Ni(II)-EDTA significantly increased with increasing Cu(III) dosage, and the degradation of Cu(II)/Ni(II)-EDTA by synthetic Cu(III) system displayed highly pH-dependent reactivity. The radical quencher experiments confirmed that Cu(III) direct oxidation were mainly involved in the degradation of Cu(II)-EDTA. Additionally, the continuous decarboxylation process was proven to be the main degradation pathway of Cu(II)-EDTA in Cu(III) system. The coexisting substances (SO 4 2− , Cl − and fulvic acids) showed little impacts at low level for the removal of Cu(II)/Ni(II)-EDTA, while retarded the degradation of Cu(II)-EDTA slightly at high level, which features high selective oxidation. Encouragingly, it was also effective to remove Cu(II)/Ni(II)-EDTA from in treating actual Cu/Ni-containing wastewater through synthetic Cu(III) treatment.
A novel CuO–CeO 2 –Co 3 O 4 nanocatalyst loaded on Al 2 O 3 ceramic composite membrane (CCM-S) was synthesized through spraying-calcination method, which can be beneficial to the engineering application of scattered granular catalyst. BET and FESEM-EDX testing revealed that CCM-S possessed a porous character with high BET surface area of 22.4 m 2 /g and flat modified surface with extremely fine particle aggregation. The CCM-S calcined above 500 °C presented excellent anti-dissolution effect due to the formation of crystals. XPS indicated that the composite nanocatalyst possessed the variable valence states, which were conducive to exert the catalytic effect of Fenton-like reaction. Subsequently, the effects of experimental parameters including fabricate method, calcination temperature, H 2 O 2 dosage, initial pH value, and CCM-S amount were further investigated considering the removal efficiency of Ni(II)-complex and COD after decomplexation and precipitation (pH = 10.5) treatment within 90 min. Under the optimal reaction condition, the residual Ni(II)-complex and Cu(II)-complex concentration from actual wastewater was all lower than 0.18 mg/L and 0.27 mg/L, respectively; meanwhile, the removal efficiency of COD was all higher than 50% in the mixed electroless plating effluent. Besides, the CCM-S could still maintain high catalytic activity after a six-cycle test, and the removal efficiency was slightly declined from 99.82% to 88.11%. These outcomes indicated that CCM-S/H 2 O 2 system was provided with a potential applicability on treatment of real chelated metal wastewater.