基于形貌调控的钛酸盐纳米材料催化激发过氧乙酸对水体中活性药物的降解机制

Advanced oxidation process (AOP) based on peracetic acid (PAA) has gained great interest in the organic micropollutants wastewater treatment and water disinfection areas in recent years. The advantages of PAA-based AOP techniques include almost no toxic by-product formation, high-efficiency and economical cost when applied in the water treatment facilities. However, developing new PAA activation methods with high efficiency is the bottleneck and key point in this area now. Moreover, there is still a knowledge gap on the mechanism of contaminants attack by formed radicals after PAA activation. Titanate nanomaterials (TNMs) may show great potential on PAA activation due to their specific physiochemical properties. This work aims to develop a class of novel TNMs, and more importantly, achieve fine architecture on the morphology and structure of TNMs. The key parameters of TNMs that dominating PAA activation will be explored, and the radicals (including hydroxyl and alcoxyl radicals) formation during activation will be carefully evaluated. In addition, 16 quinolone antibiotics are selected as the model pharmaceutically active compounds. Mechanism of radicals (especially alcoxyl radicals) attack on these organics will be focused on, and the quinolones degradation pathway will be proposed based on intermediates/products identification. Furthermore, both reactivity of radicals and active sites of organics will be determined through computational chemistry based on density functional theory (DFT) calculation, and a quantitative structure-activity relationship (QSAR) model also will be proposed, by which a standard analysis method or theoretical system for studying organics attacking by alcoxyl radicals will be established. The overall objective of this research is to provide theoretical and technical supports to materials enhanced PAA-involved AOP for organic pollutants removal in water purification area.

以过氧乙酸为核心的高级氧化技术近年来在微污染有机废水处理和水消毒领域受到广泛关注，该工艺具有不产生毒性副产物、高效且经济实用的特点。然而，高效过氧乙酸激发体系的开发又是该领域亟待解决的瓶颈问题，激发后自由基作用于污染物的机制目前也不甚清楚。钛酸盐纳米材料由于其独特的理化性质，在非均相催化激发过氧乙酸方面应用潜力巨大。本项目拟通过水热合成方法实现对钛酸盐纳米材料形貌和组成的精细调控，明确决定过氧乙酸激发效率的该系列材料的主要性质参数，剖析激发过氧乙酸生成自由基（羟基和烷氧自由基）的机理。以16种喹诺酮类抗生素作为活性药物的代表，揭示自由基（尤其是烷氧自由基）作用于有机物的规律，阐明该类有机物的降解途径。构建基于计算化学的烷氧自由基攻击有机物的模式研究方法，并清楚阐述有机物定量结构与反应活性之间的关系。项目研究旨在为材料加成过氧乙酸高级氧化技术在水体有机污染净化中的应用提供理论依据和技术支撑。

项目围绕水中活性药物类新污染物治理的关键问题，研发合成了系列钛酸盐纳米材料，并开发了应用该类材料的非均相过氧乙酸高级氧化技术体系，实现了水中活性药物的高效去除与降解脱毒。首先，通过水热合成条件控制，制备了具不同形貌和晶型的钛酸盐纳米材料，研究表明了材料层间结构（层间距和层间离子）及晶格骨架（三钛酸或六钛酸盐）是影响其催化性能的关键因素，且钛酸盐纳米材料激发过氧乙酸降解污染物是自由基与非自由基过程（直接电子转移和1O2攻击）的综合作用。其次，以两步水热法合成了具树叶枝状形貌的载锰钛酸盐材料，实现了活性金属与钛骨架协同激发过氧乙酸，由此生成了多种烷氧/烷基自由基和羟基自由基，提高了对活性药物磺胺二甲嘧啶的降解效率且实现了其有效脱毒。最后，基于理论计算化学，阐明了过氧乙酸激发体系中重要活性物种（即CH3C(=O)OO·和CH3C(=O)O·两种烷氧自由基）攻击有机物的关键机理，耦合有机物分子轨道分布、静电势和反应活性位点解析，从分子轨道层面深入剖析了两种自由基经单电子转移（SET）、氢提取（HAA）和自由基加成（RAF）三种反应机制与有机物反应的能量演化过程，建成了过氧乙酸高级氧化中有机物降解的模式理论计算方法体系。部分功能钛酸盐材料实现了规模化量产，单机生产能力1050吨/年，并成功应用于含活性药物的养殖尾水处理等多项工程中。.依托项目研究，共发表学术论文37篇（SCI论文31篇），其中第一标注论文14篇（SCI论文13篇，中科院一区论文11篇）；作为共同主编出版纳米技术水处理应用英文专著1部；申请了国家发明专利2项，授权了软件著作权1项；成果获得了2021年国家环境保护科学技术奖二等奖（负责人排名第二）。项目负责人入选了国家高层次人才特殊支持计划（“万人计划”）青年拔尖人才，晋升为国家重点研发计划项目（青年）首席科学家，获得了中国环境科学学会青年科学家奖金奖，入选了2022科睿唯安全球“高被引科学家”榜单、美国斯坦福大学发布的2020-2022年世界排名前2%科学家榜单。