N-Rich Algal Sludge Biochar for Peroxymonosulfate Activation toward Sulfadiazine Removal

The fabrication of a green, high activity and low-cost carbon-based catalyst capable of activating new oxidant (peroxymonosulfate, PMS) for contaminants abatement is needed. In this research, we prepared novel N-doped biochars via one-step pyrolysis of algal sludge without external nitrogen sources. The obtained ASBC800 possessed the largest specific surface area (SBET= 145.596 m2g−1) and thus it displayed the best catalytic performance, as revealed by the effective elimination of sulfadiazine (SDZ, >95% within 70 min) with 0.2 g L−1ASBC800 and 0.5 mM PMS. Both radical species (e.g., SO4•−, and•OH), and nonradical regime (1O2and electron-transfer) contributed to SDZ oxidation, in which ASBC800 played essential roles in activating PMS, accumulating SDZ, and regulating electron shuttle from SDZ to ASBC800-PMS*. Overall, this work not only provides a novel strategy for the synthesis of N-rich and cost-effective biochar but also promotes the development and application of carbon-based functional materials in environmental remediation.Keywords:peroxymonosulfate;pre-adsorption;oxidation;electron-transfer;N doping