College of Sciences, Nanjing Agricultural University, Nanjing, 210095, PR China.
College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, PR China.
Environ Res. 2020 Aug;187:109665. doi: 10.1016/j.envres.2020.109665. Epub 2020 May 15.
CoO-SnO/rice straw biochar (RSBC) was prepared for the first time via calcining oxalate precipitation precursor dispersed on the surface of RSBC and used as a catalyst for activating PMS to degrade sulfisoxazole (SIZ). The results demonstrated that CoO-SnO/RSBC possessed much better catalytic performance than CoO, CoO-SnO, CoO/RSBC, and SnO/RSBC, which is ascribed to the synergy of CoO, SnO and RSBC. Approximately 98% of SIZ (50 mg/L) was decomposed by PMS (1 mmol/L) activated with CoO-SnO/RSBC (0.1 g/L) within 5 min. The optimal degradation efficiency of SIZ was realized at the initial pH 9. CoO-SnO/RSBC also displayed remarkable stability and reusability, and the degradation rate of SIZ maintained over 90% even after the fifth recycle run. The electron paramagnetic resonance (EPR) technique and quenching experiments proved singlet oxygen (O) to be the main reactive oxygen species (ROS) responsible for the SIZ decomposition in the CoO-SnO/RSBC/PMS system. On the basis of the characterization analysis, the identification of the ROS and the SIZ degradation products, the possible mechanism and pathways of the SIZ degradation by a combination of PMS and CoO-SnO/RSBC were further proposed. This study provides not only a new insight into non-radical mechanism for the heterogeneous activating PMS over CoO-SnO/RSBC to degrade organic pollutants but also an eco-friendly synthetic route for exploring novel and efficient catalysts.
草酸共沉淀前驱体分散在稻秆生物炭（RSBC）表面，通过煅烧制备了 CoO-SnO/rice straw biochar（RSBC），并将其用作激活过一硫酸盐（PMS）降解磺胺异恶唑（SIZ）的催化剂。结果表明，CoO-SnO/RSBC 具有比 CoO、CoO-SnO、CoO/RSBC 和 SnO/RSBC 更好的催化性能，这归因于 CoO、SnO 和 RSBC 的协同作用。在 5 min 内，用 CoO-SnO/RSBC（0.1 g/L）激活的 PMS（1 mmol/L）可分解 98%左右的 50 mg/L SIZ。SIZ 的最佳降解效率是在初始 pH 值为 9 时实现的。CoO-SnO/RSBC 还表现出显著的稳定性和可重复使用性，即使经过五次循环运行，SIZ 的降解率仍保持在 90%以上。电子顺磁共振（EPR）技术和猝灭实验证明，单线态氧（O）是 CoO-SnO/RSBC/PMS 体系中导致 SIZ 分解的主要活性氧物质（ROS）。基于特征分析、ROS 和 SIZ 降解产物的鉴定，进一步提出了 CoO-SnO/RSBC 与 PMS 结合降解 SIZ 的可能机制和途径。该研究不仅为 CoO-SnO/RSBC 非均相激活 PMS 降解有机污染物的非自由基机制提供了新的见解，而且为探索新型高效催化剂提供了一种环保的合成途径。
