杂原子共掺杂石墨烯基磁性微球的可控构建及活化过硫酸盐的界面作用机制

The antibiotic micro-pollutants in water could be efficiently removed by the graphene-based catalyst/persulfate system. The kinds of doped atoms and the doping types could significantly affect the surface structure of graphene. Therefore, it will be of great importance to study the activation behavior of S2O82- on the different graphene surface for deeply understanding the catalytic mechanism of graphene-based catalyst. Based on the optimization of microscopic structure and macroscopic configuration of graphene-based catalysts, aiming to improve its catalytic performance and structure stability, and focusing on clarifying the surface active sites of heteroatoms doped graphene and elucidating the interface interaction mechanism of activating S2O82-: ①The double-coated graphene-based magnetic microsphere with co-doping non-metal and metal atoms, will be prepared via microfluidic droplet fabrication, and the influencing factors for the controllable synthesis will be discussed; ②Taking the typical antibiotics in the recycle water as the targets, the degradation performance of which will be explored by the graphene-based microspheres/S2O82- system, further to elucidate the degradation pathways and key transformation processes of the micro-pollutants; ③The effects of doping atoms and types on the electron centers for the graphene surface, and the activation behavior of S2O82- on the different surface, will be studied using a variety of characterization and density functional theory (DFT) calculation, to further clarify the key active sites and reveal the detail activation mechanism. The project will provide theoretical basis and technical support for the application of graphene-based catalysts in the removal of micro-pollutants in water.

石墨烯基催化剂/过硫酸盐体系可有效降解水中抗生素微污染物，不同掺杂类型对石墨烯界面结构有显著影响，研究过硫酸盐在不同界面的活化行为，对深入理解石墨烯基催化剂的催化机理具有重要意义。本项目从优化调控石墨烯基催化剂的微观构型和宏观结构出发，以提高其催化性能和结构稳定性为目标，围绕杂原子共掺杂石墨烯表面活性位点解析和活化S2O82-的界面作用机制为关键问题，①采用微流控技术可控合成杂原子掺杂石墨烯基复合微球，明确可控合成的关键因素；②以回用水中典型抗生素为目标物，研究石墨烯基微球/S2O82-体系对目标物的降解效能，明确降解路径及关键转化过程；③采用多种表征手段结合密度泛函理论计算研究不同掺杂类型对石墨烯表面电子中心的影响和S2O82-在不同界面的活化行为，阐明不同界面的关键活性位点，揭示不同界面活化S2O82-的具体作用机制。为石墨烯基催化剂实际应用于水中微污染物的去除提供理论基础和技术支撑。

药物及个人护理品（PPCPs）是我国水环境中普遍存在的一类新兴难降解有机污染物，已对我国水生态安全构成威胁。常规水处理工艺对PPCPs去除效率低，而基于过硫酸盐的高级氧化技术，以其高效、经济等优势被视为是去除PPCPs的良好选择。结构稳定、高效环保的新型催化剂的研发以及催化剂活化过硫酸盐的具体机制是过硫酸盐高级氧化技术的研究难点和重点。本项目从调控催化剂微观构型和宏观结构出发，以醋酸纤维素（CA）为载体，通过调控原料配比、相流速、固化时间等因素，采用微流控技术成功制备了结构稳定、高效、绿色环保的CA-Fe复合微球；CA-Fe微球/过硫酸盐体系对抗生素盐酸四环素表现出良好的降解效果，采用电子顺磁共振（EPR）测试和自由基猝灭实验揭示了CA-Fe微球/过硫酸盐体系中存在的活性自由基为·OH和SO4-·，且SO4-·在盐酸四环素降解中起主要作用。为揭示不同掺杂类型石墨烯基催化剂活化过硫酸的具体机制，本项目制备了金属和非金属元素掺杂的石墨烯基催化剂，并应用于活化过硫酸盐降解盐酸四环素，结果表明与单元素掺杂（Fe掺杂或N掺杂）石墨烯基催化材料相比，Fe和N共掺杂的石墨烯基催化材料能够抑制Fe在石墨烯表面的聚集，使其分布更加均匀，同时表现出更强的电子转移能力，且Fe和N共掺杂石墨烯结构通过活性自由基与非自由基物种（单线态氧）共同介导活化过硫酸盐，而N掺杂石墨烯结构活化过硫酸盐倾向于自由基机制。基于反应过程中Fe/N共掺杂石墨烯界面电荷的动态平衡，该催化剂在活化过硫酸盐过程中表现出良好的稳定性和循环利用性。另外，研究考察了反应条件、腐殖酸和多种阴离子存在条件下该体系对盐酸四环素的降解效能，优化了工艺参数。研究结果能为高效稳定、绿色环保碳基催化材料的合成及其耦合过硫酸盐体系对水体中PPCPs类有机污染物的去除提供理论基础和技术支撑。