硫掺杂纳米四氧化三铁/生物炭复合材料活化过硫酸盐降解磺胺类抗生素研究

Sulfonamide antibiotics in water pose a serious threat to human’s health and ecological safety. Advanced oxidation processes have been proved to be effective ways for the degradation and removal of sulfonamide antibiotics from water, wherein activated persulfate oxidation technology exhibits good stability and strong oxidizing ability and has good prospects for development. As a typical heterogeneous catalyst, nano-Fe3O4 has been widely used in advanced oxidation processes, however, its capacity of activated persulfate is not satisfactory. In the study, sulfur will be doped into nano-Fe3O4 to improve its electronic conductivity and the nanoparticles will be dispersed onto biochar, thus, S-doped nano-Fe3O4/biochar composites will be synthesized. Then the preferred composites will be employed as activators of persulfate for the degradation of sulfonamide antibiotics in water. The effects of external conditions on the degradation process will be analyzed and the reuse performance of the composites will be evaluated. The degradation mechanisms of sulfonamide antibiotics by persulfate activated with S-doped nano-Fe3O4/biochar composites will be clarified through the identification of active species, analysis of triggering mechanisms and inference of degradation pathways. The study will provide theoretical guidance and technological support for the development of novel persulfate activators and efficient removal of sulfonamide antibiotics.

磺胺类抗生素带来的水污染问题严重威胁着人类健康和生态安全。高级氧化技术可以有效实现水中磺胺类抗生素的降解去除，其中活化过硫酸盐技术稳定性好，氧化能力强，具有良好的发展前景。纳米四氧化三铁是一种典型的非均相催化剂，在高级氧化技术领域应用广泛，但其对过硫酸盐活化效能却不高。针对上述问题，本研究拟通过硫掺杂的方式提高纳米四氧化三铁的电子传导能力，通过生物炭负载进一步提高纳米粒子的分散性，优化制备硫掺杂纳米四氧化三铁/生物炭复合材料。在此基础上，开展复合材料活化过硫酸盐降解磺胺类抗生素研究，分析外界条件对降解过程的影响，评价材料的重复利用性能，通过活性物种鉴定、引发机制研究和降解路径推断，阐明复合材料活化过硫酸盐降解磺胺类抗生素的机理。本研究将为新型过硫酸盐活化剂的开发和磺胺类抗生素的高效降解去除提供理论指导和技术支持。

针对纳米四氧化三铁活化过硫酸盐效能不高的问题，本研究通过硫掺杂的方式提高纳米四氧化三铁的电子传导能力，通过生物炭负载进一步提高纳米粒子的分散性，优化制备了硫掺杂纳米四氧化三铁/生物炭复合材料。构建复合材料/过硫酸盐高级氧化体系，用于磺胺类抗生素的降解去除，分析外界条件对降解过程的影响，评价材料的重复利用性能，阐明复合材料活化过硫酸盐降解磺胺类抗生素的机理。主要得出以下结论：①复合材料与过硫酸盐之间存在协同作用，表面官能团及铁的存在形态与复合材料活化过硫酸盐的效能密切相关。②初始溶液pH对磺胺嘧啶的去除效果影响不大，一定范围内的高温有利于抗生素的去除。③在一定浓度范围内，Na+、K+、Ca2+ 和Mg2+四种阳离子和SO42-对磺胺嘧啶的去除影响很小，高浓度CO32-、HCO3-和HPO42-会对体系产生显著的抑制作用。天然水环境中的背景物质对体系的影响不大，该体系可用于实际水体中磺胺类抗生素的去除。④多次使用后体系对磺胺嘧啶仍然具有较好的去除效果，自由基在磺胺嘧啶降解过程中发挥了重要作用。