新型碳基材料高效活化过硫酸盐及其去除废水中抗生素的机制研究

Sulfate radicals-based oxidation process (SOP) as a new-type advanced oxidation process has recently received extensive attention in the field of wastewater treatment. How to produce sulfate radicals by activating persulfate is the key of SOP. Currently, common activated methods including heat, UV and metal ions have some limitations. In this project, the metal and several nonmetallic heteroatoms co-doping will be adopted to modify the carbon materials, which can simultaneously increase the active sites and electron transfer capacity of carbon materials, further enhancing the catalytic activity and stability of carbon materials. Finally, the as-prepared materials will be used to active persulfate for the degradation of antibiotics in the wastewater. The main research contents include: (1) transition metal (iron and cobalt), sulfur and oxygen will be adopted to modify the graphitic carbon nitride. Then the modified graphite carbon nitride will be used as the precursor to synthesize nano metal-embedded nitrogen, sulfur and oxygen co-doped carbon nanotubes (M@O-S-N-CNTs); (2) based on the results of materials characterization, experimental analysis and density functional theory calculation, the mechanisms of persulfate activation by M@O-S-N-CNTs will be investigated deeply; (3) M@O-S-N-CNTs will be used to activate persulfate for the degradation of antibiotics in the wastewater, and the characteristics and mechanism of antibiotics degradation in the wastewater will be investigated in detail. The results of this project will provide new ideas and methods for activating persulfate to remove antibiotics from the wastewater.

硫酸根自由基氧化技术作为一种新兴的高级氧化技术，在水处理领域中的研究十分活跃。活化过硫酸盐产生硫酸根自由基是该技术的关键。目前常用活化方法，包括热、紫外和金属离子，都存在一定的缺陷。本项目拟利用金属和多种非金属杂原子共修饰碳材料，以增加碳材料的活性位点、增强电子转移能力，进而提高碳材料的催化活性和稳定性。利用新型的碳基材料活化过硫酸盐，并用于去除废水中抗生素。主要研究内容包括：（1）利用过渡金属（铁和钴）、硫和氧共修饰石墨相氮化碳，并以此为前驱体，制备纳米金属嵌入氮氧硫共修饰碳的新型纳米管材料（M@O-S-N-CNTs）；（2）基于材料表征结果、实验分析，并结合密度泛函理论计算，探讨M@O-S-N-CNTs活化过硫酸盐的机理；（3）利用M@O-S-N-CNTs活化过硫酸盐降解废水中的抗生素，探讨抗生素的去除特性及机理。本项目研究成果将为活化过硫酸盐去除废水中的抗生素提供一种新的思路和方法。

本课题制备了系列碳基催化剂，包括非金属杂原子掺杂碳材料、非金属杂原子和金属原子共掺杂碳材料、碳载铁钴双金属材料、碳载铁基双活性位材料、磁性石墨相氮化碳和生物炭复合材料和碳载单原子钴材料。详细研究了上述材料活化PMS降解水中抗生素的特性和机理。探讨了溶液pH和无机阴离子等因素对上述材料活化PMS降解水中抗生素的影响及机制。通过对比分析上述材料的催化活性和活化机理，得出以下主要结论：1）非金属杂原子和金属原子共修饰可以显著改善碳材料的催化活性；2）温度可以调控氮掺杂碳材料活化PMS的机理，氮掺杂碳材料活化PMS降解水中磺胺类抗生素符合两阶段动力学；2）当多种非金属杂原子共掺杂时，掺杂量存在一个最优值；3）硫和钴共掺杂形成的钴硫化物具有优良的催化活性，硫的前驱体调控钴硫化物的类型4）双金属活性位可以增强催化活性和稳定性；5）双活性位的类型及含量可以调控PMS的活化途径；6）PMS活化产生的活性物种类型与催化剂得失电子能力相关；7）碳载单原子钴催化剂的钴原子利用率高，催化活性好，但有限的钴单原子活性位数量影响其催化稳定性；通过增加活性位可以提高碳载钴单原子催化剂的活性。8）基于PMS自身特性，开发了非自由基和自由基耦合工艺，该工艺能增强对水中磺胺类抗生素的矿化效果。本项目成果为开发新型高效、稳定、易回收的非均相催化剂的制备及其活化PMS降解水中抗生素提供理论基础和技术支撑。