Effect of calcination temperature on the properties of Ti/SnO2-Sb anode and its performance in Ni-EDTA electrochemical degradation.

Pd-doped Ti/SnO2-Sb anode was prepared at different calcination temperatures by a wet-impregnation method and employed in simultaneous electrochemical catalytic degradation of Ni-EDTA and recovery of nickel. The results showed that Ti/SnO2-Sb-Pd-500 could achieve the highest electrochemical activity (87.5% of Ni-EDTA removal efficiency), superior durability (50.7 h of accelerated lifetime), and higher Ni recovery (19.8%) on cathode. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) analysis suggested that Ni-EDTA degradation on anode was mainly indirect oxidation-controlled reaction, attributing to the high oxide state of MOX + 1 and MOX(·OH), rather than direct oxidation. Scanning electron microscope (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses indicated that calcination temperature could modify the morphology of electrode surface and affect the incorporation and valence state transformation of metal species (Sb and Pd) in SnO2 lattice. Ti/SnO2-Sb-Pd-500 achieved the highest electrochemical capacity with the highest levels of adsorbed oxygen Oads/ET (27.11%) and lattice oxygen Olat/ET (29.69%). Moreover, the operation conditions for Ni-EDTA electrochemical degradation were optimized. These findings were valuable for developing a high-performance electrode for Ni-EDTA electrochemical degradation.