高盐环境下催化臭氧氧化去除反渗透浓水中的土霉素的行为研究

Study on Catalytic Ozonation for Removing Oxytetracycline from Reverse Osmosis Concentrate under High-Salinity Conditions

中文关键词: 高盐环境  反渗透浓水  催化臭氧氧化  土霉素  降解机理  降解途径

英文关键词: high-salinity conditions  reverse-osmosis concentrate  catalytic ozonation  oxytetracycline  degradation mechanism  degradation pathway

中文摘要:

      臭氧传质、自由基生成路径、催化剂稳定性等因素对高盐环境下催化臭氧氧化降解反渗透浓水中的土霉素过程中有复杂影响，土霉素若未得到妥善处理直接排入水体，会导致水域产生抗性基因，破坏生态平衡，威胁人类健康。基于此，本文研究了高Cl-和 高SO42-环境下，以负载Mn-Co氧化物的γ-Al2O3（Mn–Co/γ-Al?O?）为催化剂，模拟反渗透浓水中土霉素（oxytetracycline, OTC）的催化臭氧氧化降解行为。实验结果表明，高Cl-体系中OTC的催化臭氧氧化降解速率比SO42-体系更快，10 min内土霉素去除率均可达98%以上，60 min时总有机碳(TOC)去除率均超过55%。淬灭试验和电子顺磁共振分析结果表明：高Cl-体系以Cl2?-和HO?协同作用为主；高SO42-体系以SO??-和HO?自由基为主。液相色谱–质谱结果推测OTC的降解途径均是发生侧链脱除、芳环开裂进而转化成小分子有机酸，最后完全矿化，只是在各个分支路径的侧重上存在差异。Ecosar软件进行毒性分析发现：在两种体系下，OTC的降解产物毒性均是先增大后减小，最终产物无毒。另外，在两种高盐环境下，Mn-Co/γ-Al?O?催化剂均保持了良好的稳定性和可重复利用性。此研究可以深化对高盐环境下催化臭氧氧化降解行为的科学理解，为反渗透浓水处理提供关键技术方案，具有重要的工程指导价值。

英文摘要:

      Factors such as ozone mass transfer, radical-generation pathways, and catalyst stability exert complex influences on the degradation of oxytetracycline (OTC) in reverse osmosis (RO) concentrate via catalytic ozonation under high-salinity conditions. Discharging untreated OTC into receiving waters may promote the emergence and dissemination of antibiotic resistance genes, disrupt ecological balance, and pose risks to human health. Herein, the catalytic ozonation of OTC in simulated RO concentrate was investigated under high-Cl? and high-SO?2? conditions using γ-Al?O?-supported Mn–Co oxides (Mn–Co/γ-Al?O?) as the catalyst. The results showed that OTC degradation proceeded faster in the high-Cl? system than in the high-SO?2? system. OTC removal exceeded 98% within 10 min, and total organic carbon (TOC) removal was over 55% at 60 min in both systems. Quenching experiments and electron paramagnetic resonance (EPR) spectra indicated that degradation in the high-Cl? system was dominated by the synergistic action of Cl??- and HO?, whereas SO??- and HO? played the dominant roles in the high-SO?2? system. Liquid chromatography–mass spectrometry (LC–MS) suggested that OTC degradation in both systems involved side-chain elimination and aromatic-ring cleavage, yielding small-molecule organic acids and ultimately leading to mineralization, although the contributions of specific branching routes differed. Toxicity assessment using the ECOSAR program showed that the toxicity of transformation products initially increased and then decreased in both systems, and the final products were non-toxic. Furthermore, Mn–Co/γ-Al?O? exhibited good stability and reusability under both high-salinity conditions. This study advances the scientific understanding of catalytic ozonation in high-salinity matrices and provides a promising technical strategy for RO concentrate treatment with practical engineering implications.