One-step Treatment of Cr(III) Complexes Wastewater Using a P-doped Ti4O7 Anode in a Compact Flow Electrolysis Device

Inefficient OH productivity of anode materials and its uncontrolled oxidation behavior in the traditional electrochemical H2O oxidation system question the practicability of this technology in heavy metal complexes wastewater treatment. Herein, we construct an electrochemical oxidation system integrating a P-doped Ti4O7 anode and a compact flow electrolysis device that enables one-step disposal of Cr(III) complexes. Compared to the P-free counterpart, P at shallow lattices of Ti4O7 motivates surface Ti sites to efficiently oxidize H2O to OH for Cr(III)-EDTA decomplexation at the anode. Meanwhile, the combined compact flow electrolysis device enables the immediate transfer of released Cr(III) to the carbon felt cathode with almost 100% electrodeposition. Impressively, this integrated system realizes one-step removal of Cu, Ni, and Cr complexes in real electroplating effluents. This study sheds light on the importance of rational design of electrode materials and associated electrolysis devices to controllably utilize OH for heavy metal complexes wastewater treatment.