▎ 摘　　要

Piezocatalysis, relying on piezopotential and piezoelectric properties of catalysts, is intriguing deep research enthusiasm in water and wastewater treatment for its potential application on organic degradation. In this study, a novel piezocatalytic oxidation system, reduced graphene oxide/graphitic carbon nitride-persulfate-ultrasound (rGO/CN-PDS-US), in which g-C3N4 was proved to be piezoelectric, was constructed to degrade the antibiotics (sulfamethoxazole, SMX) in water. In rGO/CN-US system, 80.0 % of SMX was degraded in 30 min. The degradation efficiency of SMX was further improved to 95.7 % in presence of PDS. Density function theory (DFT) calculation results illustrated that deformation of g-C3N4 caused by ultrasonic vibration would generate dipole moment along the plane, which was the source of piezopotential. The piezoelectrically generated electron-hole pairs could efficiently separate with the assistance of in-built piezoelectric field. In this process, the electrons would effectively transfer from g-C3N4 to rGO. Compared with rGO/CN-US system, the degradation efficiencies of SMX by US alone and rGO/CN without US were only 1.1 % and 48.8 % respectively. After dosing PDS, the degradation efficiency further improved due to the facilitated electron transfer between PDS and piezocatalyst. Analyzed by DFT, -C--O had the highest reaction activity compared with C-O-C, -COOH, -CHO and -OH groups in rGO/CN-PDS-US system. Finally, the radicals and degradation products were analyzed, and possible degradation pathways of SMX under rGO/CN-PDS-US oxidation was proposed. This work provided a green and efficient piezocatalytic technology to remove antibiotic from water, and the mechanism was expected to be mutually beneficial for facilitating electron transfer among g-C3N4, rGO and PDS.