Evaluation of anode materials in sonoelectrochemistry processes: Kinetic, mechanism, and cost estimation

Eco-friendly pollutant treatment technology has a developing tendency in future. The combination of ultrasound (US) and electrochemical (EC) is a promising technology, because they are efficient, clean and environmentally friendly. In this study, the impacts of anode material have been investigated in US (300 kHz) and EC (10V) system. The results of all systems revealed that the kinetic constant decreased with increasing pH. The results are also shown that ΔG^# > 0 and ΔH^# > 0 during PCP degradation in EC or US-EC systems are non-spontaneous and endothermic reactions. Meanwhile, in the US-EC system, TiO₂, Ti₄O₇, PbO₂, SnSb, RuIr, and BDD, except for TiO₂, all the anode materials showed a synergistic index (SI) of 106-197%, and the activation energies were 19.32, 33.4, 33.74, 32.84, 10.41, 36.44 kJ mol^-1, respectively. In EC and US-EC systems, PCP can be completely mineralized by BDD anode within 30 min. TBA scavenger experiments verified that hydroxyl radicals were the main oxidant in each system using BDD and PbO₂ anode. As a result of estimating the cost according to the anode material when removing PCP using the EC or US-EC system, BDD was the smallest in the two systems, 1.58 and 1.12 $ m^-3, respectively. Finally, this study may serve as a reference for implementation of US-EC system in wastewater treatment.