Sewage sludge-derived biochar (SBC) could remove organic contaminants in environment and reuse the sludge effectively. In this study, urea-doped SBC (NSBC) was prepared, characterized, and applied as heterogeneous catalytics to peroxydisulfate (PDS) activation. Sulfadiazine (SD), a widely used antibiotic, was used as a model pollutant to evaluate the efficiency and mechanism of this system. The degradation rate of SD increased to 100% after 4 h when 1 g/L of NSBC was added to the system with a SD concentration of 20 mg/L. In this study, it was confirmed that there were two important pathways in the degradation of SD by NSBC/PDS system: the free radical on the surface of NSBC and the nonradical (¹O₂) in the solution. The doping of N atoms makes neighboring C atoms positively charged, thereby making the direct transfer of electrons with S₂O₈²⁻ and the generation of ¹O₂ via nonradical pathway easy. In addition, the CO functional group formed during the pyrolysis of NSBC can produce ¹O₂ in a similar way. A total of 22 SD degradation products were identified, and 4 possible pathways were proposed. This study provide supplement for the degradation mechanism of organic compounds by carbon-based materials.

污水污泥衍生生物炭（SBC）可以去除环境中的有机污染物并有效地再利用污泥。在这项研究中，尿素掺杂的 SBC (NSBC) 被制备、表征并作为非均相催化剂应用于过二硫酸盐 (PDS) 活化。磺胺嘧啶 (SD) 是一种广泛使用的抗生素，被用作模型污染物来评估该系统的效率和机制。在体系中加入 1 g/L NSBC，SD 浓度为 20 mg/L 时，4 h 后 SD 的降解率提高到 100%。本研究证实NSBC/PDS体系降解SD有两条重要途径：NSBC表面的自由基和非自由基( ¹ O ₂) 在解决方案中。N 原子的掺杂使相邻的 C 原子带正电，从而使电子与 S ₂ O ₈ ^2-的直接转移以及通过非自由基途径产生¹ O ₂变得容易。此外，NSBC 热解过程中形成的 CO 官能团可以以类似的方式产生¹ O ₂。共鉴定出 22 种 SD 降解产物，并提出了 4 条可能的途径。该研究为碳基材料降解有机化合物的机理提供了补充。