Piezoelectric catalytic performance of BaTiO3 for sulfamethoxazole degradation

Antibiotics, as emerging trace organic pollutants in water sources, pose a potential threat to drinking water safety. Piezoelectric catalysis is an innovative and green advanced oxidation technology in which mechanical energy can be converted into electrical energy or chemical energy, even without the addition of chemical reagents. Thus, piezoelectric catalysis can be used to degrade trace organic pollutants in water. However, such studies have seldom been reported. In this work, the performance of a typical piezoelectric catalyst, i.e., BaTiO3 (BTO), with mechanical energy from ultrasound (US) for the piezoelectric degradation of sulfamethoxazole (SMX) in water was studied systematically. The results showed that the BTO/US piezoelectric catalytic system exhibited the efficient degradation of SMX. The operating parameters in the BTO/US system were optimized for the effective degradation of SMX, and the influencing factors (initial concentration of SMX, pH, and the coexisting constituents in water) affecting the degradation of SMX by BTO/US were investigated. In addition, the reaction mechanism of the piezoelectric system was investigated via identifying the active species generated in BTO/US through quenching tests and electron paramagnetic resonance analysis. It was found that US could activate BTO to generate hydroxyl radicals (OH), superoxide radicals (O-2(-)), and singlet oxygen (O-1(2)), thus greatly enhancing the SMX degradation efficiency. Overall, the present study demonstrates that the BTO/US system is a promising form of technology for the green degradation of trace organic pollutants in water.