Green synthesis and sonocatalytic performance of CdO nanoparticles for efficient degradation of direct red 31 dye

This work presents the green synthesis, characterization, and sonocatalytic activity of CdO nanoparticles. The CdO NPs were characterized by XRD, FESEM, EDX-Mapping, BET, DRS, and TEM. The TEM image revealed that nanoparticles were spherical and approximately 30 nm. BET analysis showed a surface area of 28.28 m 2 /g, and DRS indicated a band gap of 1.98 eV. The CdO nanoparticles exhibited 97 % sonocatalytic degradation efficiency for DR31 and 74 % TOC removal in 20 min. Radical scavenger experiments demonstrated that •OH played a dominant role in the degradation mechanism. The degradation by-products and the proposed mechanism were confirmed through LC–MS analysis.