Adsorbed copper on urea modified activated biochar catalyzed H 2 O 2 for oxidative degradation of sulfadiazine：Degradation mechanism and toxicity assessment

The combined pollution of heavy metals and organic compounds usually occurs simultaneously and induces high toxicity. The technology of simultaneous removal of combined pollution is lacking and the removal mechanism is not clear. Sulfadiazine (SD), a widely used antibiotic, was used as a model contaminant. Urea modified sludge-based biochar (USBC) was prepared and used to catalyze H O to remove the combined pollution of Cu and sulfadiazine (SD) without causing secondary pollution. After 2 h, the removal rates of SD and Cu were 100 and 64.8%, respectively. Cu adsorbed on the surface of USBC accelerated the activation of H O by the USBC catalyzed by CO bond to produce hydroxyl radical ( OH) and single oxygen ( O ) to degrade SD. Twenty-three intermediate products were detected, most of which were completely decomposed into CO and H O. The toxicity was significantly reduced in the combined polluted system. This study highlights the potential of the low-cost technology based on sludge reuse and its inherent significance in reducing the toxic risk of combined pollution in the environment.