地表水所含微塑料(MPs)的老化破碎过程可导致溶解性有机物(DOM)释放,进而对水环境及水处理过程造成潜在风险.为探索MPs在典型水处理氧化过程中的老化和有机物释放特性,本研究选取聚酰胺 66(PA66)和聚对苯二甲酸乙二醇酯(PET)为研究对象,探究了典型工业级MPs在模拟水处理氧化(UV、UV/H2O2、O3)过程中的DOM析出规律.结果表明:①3 种典型氧化过程均加速了MPs-DOM的溶出,PA66 的DOM生成量[以溶解性有机碳(DOC)计]相对于PET更高.②在对照组、UV氧化、O3 氧化下,PA66-DOM和PET-DOM的DOC值均随反应时间及氧化剂浓度的增加呈上涨趋势,而在UV/H2O2 氧化下呈先增加后减小的规律,且 3 类氧化中O3 技术对 2 类MPs的氧化效果相对更好.③MPs表层的官能团在氧化处理前后未有较大差异,其羰基指数(CI)均有一定程度的升高.④PA66 与PET所产生的DOM在官能团构成及荧光组分上较为相似,主要由类色氨酸、类络氨酸、可溶性微生物代谢产物组成.研究显示,以PA66 和PET为代表的工业级MPs在高级氧化水处理过程中会析出DOM,对后端消毒等工艺产生潜在影响.
Microplastics(MPs)in surface water can pose potential risks to the aquatic environment and water treatment processes by releasing dissolved organic matter(DOM)as they age and degrade.In order to investigate the ageing characteristics and organic matter release of MPs in typical oxidation processes of water treatment,polyamide 66(PA66)and polyethylene terephthalate(PET)were used to analyze the DOM release of typical industrial MPs in the simulated water treatment oxidation process(UV,UV/H2O2,O3).The results showed that:(1)All three oxidation processes accelerated the leaching of MPs-DOM,and the DOM leaching rate(calculated as dissolved organic carbon[DOC]values)of PA66 was higher than that of PET.(2)In the control group,UV oxidation system and O3 oxidation system,the DOC values of PA66-DOM and PET-DOM showed an increasing trend with the increase of reaction time and oxidizer concentration,while in the UV/H2O2 system,DOC values showed a first increasing trend and then decreasing trend.Among the three types of oxidation systems,O3 technology had a relatively good oxidation effect on type 2 MPs.(3)The fragmentation effect of O3 oxidation on MPs was relatively high.There was no significant difference in the functional groups of MPs surface before and after oxidation treatment,and the carbonyl index(CI)of MPS increased to a certain extent.(4)The DOM produced by PA66 and PET was similar in the composition of functional groups and fluorescence components,and was mainly composed of tryptophan,thyrotoxin and soluble microbial metabolites.Therefore,industrial grade MPs represented by PA66 and PET will precipitate DOM during the advanced oxidation water treatment process,which has a potential impact on the disinfection and other processes of the backend.