Abstract:

Efficient and stable CeO₂/CNT composites were prepared by impregnation-calcination method. The structure of the material was characterized by means of X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy, and the degradation performance of sulfisoxazole(SIZ) by activated peroxymonosulfate(PMS) of the composite was studied. The introduction of CeO₂ increases the defects content of carbon nanotubes, and the Ce³⁺/Ce⁴⁺ provides active sites for the reaction, which effectively improves the performance of carbon nanotube when activating PMS. The catalyst performance was studied by investigating the effects of CeO₂ doping amount, catalysts dosage, PMS dosage and initial pH on the degradation system. The results show that when the dosage of catalysts is 75 mg·L^-1, the dosage of PMS is 0.3 mmol·L^-1 and the initial pH is 5.36, the removal rate of SIZ can reach more than 90% in 30 min and 100% in 50 min, and the reaction process conforms to the pseudo first-order reaction kinetic model. After 5 cycles, the catalyst can still maintain 77% degradation. Electron paramagnetic resonance experiments indicated that SO₄?^-, ?OH and ¹O₂ were produced in the degradation of SIZ. The surface defects of carbon nanotubes may be related to the formation of ¹O₂. At the same time, the direct electron transfer mediated by carbon nanotubes was existed in the system. The cycle of Ce³⁺/Ce⁴⁺ in the system promotes the activation of PMS.

Key words: CeO₂, carbon nanotubes, composites, activation, peroxymonosulfate, sulfisoxazole, degradation

摘要：

采用浸渍-煅烧法制备了高效稳定的CeO₂/CNT复合材料。利用X射线衍射、X射线光电子能谱和Raman光谱等手段对材料结构进行表征，并研究了复合材料活化过一硫酸盐（PMS）对磺胺异唑的降解性能。结果表明，在材料投加量为75 mg·L^-1、PMS投加量为0.3 mmol·L^-1、初始pH为5.36时，30 min降解率可达90%以上，50 min内可完全去除，反应过程符合伪一级反应动力学模型，活化剂使用5次后仍有77%的去除率。电子顺磁共振实验表明，SO₄?^-、?OH和¹O₂均参与了反应，碳纳米管表面缺陷可能与¹O₂的形成有关。CeO₂的掺杂提高了碳纳米管中缺陷碳的含量，同时Ce³⁺/Ce⁴⁺为反应提供了更多活性位点，从而有效提升了碳纳米管活化PMS的性能，为铈基碳纳米管复合材料应用于过硫酸盐高级氧化技术提供了借鉴。

关键词: CeO₂, 碳纳米管, 复合材料, 活化, 过一硫酸盐, 磺胺唑, 降解