潮间带表层沉积物中典型抗生素非生物高级氧化行为研究

As one of the most vigorous ecosystems, the intertidal zone is the important natural habitat for various organisms including shellfish, crabs, fish, and birds etc. For the past few years the intertidal zones have been severely polluted and become the important reservoir of a lot of pseudo-persistent antibiotics. As the key process to evaluate the fate and risk of antibiotics in the intertidal zones, the abiotic advanced oxidation process of antibiotics in the subsurface sediments from intertidal zones seems to be thoroughly ignored. The physicochemical properties, elemental components, organic and mineral composition, as well as electron-released capacity of the intertidal subsurface sediments would be investigated in this proposal. The important and key influencing factors on the abiotic advanced oxidation process of antibiotics in the subsurface sediments from intertidal zones would be developed and distinguished. The kinetic processes of abiotic advanced oxidation of selected antibiotics in the simulated sediment minerals would be developed under the certain conditions of pH, temperature, salinity and water content, etc. With the single and multiple influencing factors, the kinetic processes of abiotic advanced oxidation of selected antibiotics in the simulated sediment minerals would be developed respectively. The single factor effect and the multi-factors joint effect upon the abiotic advanced oxidation processes of selected antibiotics in the intertidal subsurface sediments would be elucidated as well. Subsequently the mechanisms of abiotic advanced oxidation processes of antibiotics in the intertidal subsurface sediments would be illuminated, and the quantitatively predictive models would be constituted to assess the abiotic advanced oxidation of antibiotics in the intertidal subsurface sediments based on the descriptors including subsurface sediment physicochemical characteristics and adsorption capacity of antibiotics to subsurface sediments. This project would enrich the methods and theories of environmental chemistry.

潮间带是底栖生物、鱼类和鸟类等多种生物的重要栖息地，然而新兴‘假持久性’污染物抗生素对潮间带生态系统产生的风险几为人们所忽视，而潮间带表层沉积物中抗生素非生物高级氧化过程是污染物归宿和风险评估的关键环节。课题以潮间带表层沉积物为对象，以不同源潮间带表层沉积物理化性质、元素组成、释电能力、矿物特征和有机组成等分析为前提，以天然沉积物中抗生素非生物高级氧化反应影响因素识别基础，开展pH、温度、盐度、含水量等条件下典型沉积矿物质中抗生素非生物氧化反应模拟，以典型沉积矿物为基质开展单要素作用和多要素共存下抗生素非生物高级氧化反应模拟研究，阐释不同源潮间带表层沉积物中抗生素非生物高级氧化反应的单要素作用机理和多要素联合效应，揭示不同源潮间带表层沉积物中抗生素非生物高级氧化的反应机制，进而基于沉积物的理化性质和结构特征以及沉积物抗生素吸附能力等构建潮间带表层沉积物中抗生素非生物高级氧化的定量预测模型。

本项目从2019年到2022年这4年时间里，项目组成员按照计划有序推进项目各项任务，并结合实际研究过程中遇到的问题对研究方法和研究思路进行调整，改进，拓展和优化。课题组以非生物高级氧化为研究对象，探索以氧气作为非生物高级氧化氧化剂的新途径，揭示了不同还原体系介导氧气生成活性氧物质的反应机理，开发了生物炭负载零价铁和还原性胡敏素等高效催化材料，并将其应用于典型抗生素的去除与降解过程中，展现出优异的去除效果。其主要的研究进展如下：. （1）定量评估了生物炭与零价铁复合材料介导氧气生成羟基自由基（·OH）的优异性能，其产量达到了20.19μm/g，并且展现出良好的酸碱耐受性。其优异性能可以归因于良好的理化性质和生物炭与零价铁之间的相互促进，并且生成·OH的路径上也有着H2O2, O2·-等活性氧物质的参与；. （2）探究了生物炭负载零价铁利用氧气高级氧化降解四环素的性能与机理：复合材料去除四环素的能力达到了380mg/g，远远高于生物炭与零价铁，这也与复合材料良好的孔隙结构，较多的反应活性位点有关，并且我们通过检测反应产生的碎片粒子推测出了3条反应路径；. （3）从土壤腐殖质中提取出胡敏素并进行梯度还原，而后将其用于氧气的激活，对生成的羟基自由基进行定量研究。探究了各种环境因素对体系生成羟基自由基的影响，发现弱酸条件较为适宜，共存离子中，Cl-抑制羟基自由基的生成，而SO42-则会促进羟基自由基的生成。反应体系中羟基自由基的生成与各类官能团有关，并且生成过程中有其他活性氧物质的参与；. （4）利用胡敏素去除磺胺二甲嘧啶（SMZ），探究不同pH下还原态胡敏素高级氧化降解SMZ的表现，发现中性条件下降解效果最好；不同淬灭反应显示，中间生成的活性氧物质对羟基自由基的生成以及SMZ的降解有重要意义。降解产物碎片检测显示降解生成了多种中间体，进一步对生成的中间体进行毒性预测，结果显示中间体毒性较小，去除方法非常有效。