MoS2/SrTiO3 composite for piezocatalysis and piezocatalytic activation of peroxymonosulfate for efficient degradation of sulfamethoxazole

The piezocatalysis, in which piezoelectric polarization charges on the surface of piezocatalyst can initiate the generation of highly active species, has emerged as one of the effective strategies for organic pollutant removal in water and wastewater treatment. In this work, the composite piezoelectric material MoS2/SrTiO3 (MS/STO) was prepared and characterized. The synergistically piezoelectric effect between SrTiO3 and MoS2 was proven by electrochemical tests. Using ultrasound (US) as inputting mechanical energy, MS/STO exhibited effective degradation (∼ 70.2 % in 20 min) towards target antibiotic (sulfamethoxazole, SMX) in water. Further improving effect of peroxymonosulfate (PMS) on US/(MS/STO) for the degradation of SMX was also investigated. The results revealed that SMX was completely degraded within 20 min. Influencing factors including operation parameters and water composition for SMX degradation in US/(MS/STO)/PMS were studied, which demonstrated the good environmental adaptability of the system. The active species generated in the reaction system were identified via quenching experiments and electron paramagnetic resonance analysis, revealing the presence of O2•−, 1O2, •OH, and SO4•−. The possible reaction mechanism in US/(MS/STO)/PMS and the degrading pathway of SMX were proposed.