典型抗生素在催化臭氧化/活性炭联用工艺中的去除机制研究

Concerns about antibiotics in drinking water are greatly increasing worldwide; the removal mechanisms of trace antibiotics in the advanced treatment of drinking water have become an urgent and challenging problem. The main research subjects of this project are the catalytic ozonation mechanism and pathway, the activated carbon biological cometabolic degradation process and the removal mechanisms of these two coupled processes in the treatment of typical antibiotics in drinking water by combined catalytic ozonation/activated carbon treatment process. Through research of catalytic oxidation pathway and morphological transformation in the catalytic ozonation of trace typical antibiotics of different structure and morphology in drinking water, highly efficient catalytic approach to improve the removal efficiency of antibiotic in micro-polluted source water are investigated, and the environmental factors and mechanisms affecting the catalytic pathway are also studied. The mechanism and affecting factors of the removal of antibiotics and their oxidation products in oligotrophic water conditions by activated carbon layer biological cometabolism are studied, and the distribution of biofilm bacteria and antibiotic resistance genes in activated carbon layer are investigated. The response mechanisms of activated carbon layer biological cometabolism to the catalytic ozonation in the catalytic ozonation/activated carbon combined process are researched; the induction effect and impact mechanism of catalytic ozonation on the biofilm bacteria antibiotic resistance genes are investigated; and the coupling effect and mechanism of the combined process of catalytic ozonation/biological activated carbon on the treatment of antibiotics are studied. The mechanisms and parameters of antibiotics removal in drinking water by combined catalytic ozonation/biological activated carbon process are further investigated and discussed based on the above studies.

饮用水中抗生素的问题已引起高度重视，微量抗生素在饮用水深度处理中的去除机制成为急需研究的课题。本课题主要研究饮用水臭氧/活性炭催化氧化-生物活性炭工艺中典型抗生素的催化氧化途径与机理、活性炭生物共代谢降解及联合工艺的耦合去除机制。通过对不同结构抗生素在催化臭氧氧化过程中的形态转化和活性炭表面结构性质的构效关系研究，探索该催化体系下抗生素的催化氧化途径和机理；研究贫营养水质因素下活性炭生物膜生物共代谢作用对抗生素及其氧化产物的去除机制和影响效应、活性炭炭层生物膜细菌抗生素抗性基因与共代谢效能的关联性；研究催化臭氧氧化与活性炭联合工艺中炭层生物共代谢及抗性基因对催化臭氧化的感应效应及影响机制，揭示臭氧/活性炭催化臭氧化与生物炭联合工艺去除抗生素的耦合效应与机制，为提高抗生素在催化臭氧化-活性炭工艺中的协同去除效率提供科学依据。

环境水体中普遍存在痕量抗生素，饮用水深度处理工艺能否将其有效去除影响到饮用水的安全性。本课题首先分析了本地几种水体中典型抗生素的污染来源及污染水平，检测出了多种痕量抗生素；以常用的磺胺甲恶唑和红霉素为典型目标物质，研究了水中微量典型抗生素的臭氧氧化效果以及环境因素pH、臭氧量等对其氧化去除的影响，研究了臭氧、臭氧/双氧水及臭氧/活性炭等催化氧化工艺对典型抗生素的降解特征，揭示了臭氧催化氧化对抗生素去除主要是强化了羟基自由基氧化的机制；探讨了磺胺甲恶唑的臭氧氧化的可能降解途径和中间产物，磺胺甲噁唑在臭氧氧化过程中可形成3—氨基—5—甲基异噁唑（C4H6N2O）、对苯二酚（C6H6O2）、4-硝基苯磺酰胺（C6H6N2O4S）、对硝基苯胺（C6H6N2O2）和4—氨基苯磺酰胺（C6H8N2O2S）等中间产物，其结构中的S元素最终转化为SO42-，N元素最终转化为NH4+、游离氨和NO3-等；解析了痕量抗生素在水厂“混凝沉淀-臭氧氧化-活性炭滤池”工艺中的去除规律和去除效率，其中臭氧工艺是去除抗生素的关键技术；利用斑马鱼微核率实验，研究了药物诺氟沙星及其臭氧化中间产物的生理生物毒性，分析了臭氧氧化对该药物生物毒性的影响，臭氧氧化可以有效降低诺氟沙星对斑马鱼的生理毒性。通过费氏弧菌的发光抑制性研究表明，pH对水中诺氟沙星、左氧氟沙星及磺胺甲恶唑等药物臭氧化产物的生物毒性有较大影响，中性pH条件下臭氧氧化形成的中间产物毒性最低。研究了活性炭特性与抗生素吸附的关系，通过利用KOH和NH4Cl对活性炭改性均提高了对抗生素的饱和吸附容量和吸附速率；分析了生物活性炭中微生物菌群、抗性基因对微生物抗氯能力的影响，不同高度生物活性炭层中的生物膜细菌主要类群基本相同，其生物量沿水流方向减少，水中抗生素可诱导细菌产生抗性基因，并使细菌对抗生素的耐受性和抗氯性均增强，当进水抗生素浓度为500ng/L，运行5个月后生物膜对抗生素的耐受强度能达10mg/L,抗氯强度可达5mg Cl2/L。项目研究对提高饮用水安全性具有较重要的科学和实际意义。