新污染物在含溶解有机物水体中光降解行为研究进展

Research progress on photodegradation behavior of emerging pollutants in water containing dissolved organic matter

新污染物(emerging contaminants,ECs)是一类稳定性高、亲水性强的环境污染物,其中大部分物质最终会进入并滞留在自然水域,因其对生态和人类健康的危害而受到广泛关注.光化学降解是ECs在水体中的主要转化过程之一,包括直接光解、间接光解和自敏化光解.溶解有机物(dissolved organic matter,DOM)作为水体中具有优异光化学性质的光敏剂,吸光后产生·OH、1O2、3DOM*等活性反应中间体,对ECs的间接光降解过程有着重要影响.为探究ECs在水体中的迁移转化并评估其生态环境风险,有必要提高对其降解过程的认识.鉴于此,文章在论述DOM环境光化学特性和过程的基础上,重点阐述了DOM类型、来源、荧光组分及环境因素对ECs光降解过程的影响.DOM对ECs间接光降解过程的影响主要包括促进作用和抑制作用.促进作用主要表现在DOM产生的活性反应中间体与ECs反应,抑制作用主要包括光屏蔽作用和猝灭效应.DOM的作用效果与其类型、来源、组分及环境因素密切相关.同时,文章就DOM对ECs光降解影响的研究工作进行展望,这将有助于更全面地了解ECs的光化学行为,对于评估ECs在自然水体中的环境归趋和生态风险具有重要意义.

Emerging contaminants(ECs)are a class of environmental pollutants with high stability and hydrophilicity,most of which eventually enter and remain in natural waters.They have received increasing attention for its harm to ecological and human health.Photochemical degradation is one of the main transformation processes of ECs in water,including direct photodegradation,indirect photodegradation and self-sensitized photodegradation.As a photosensitizer with excellent photochemical properties,dissolved organic matter(DOM)produces active reaction intermediates such as·OH,1O2,and 3DOM*after light absorption,which has an important influence on the indirect photodegradation process of ECs.In order to explore the migration and transformation of ECs in water and assess their ecological risks,it is necessary to improve the understanding of their degradation process.In view of this,on the basis of discussing the environmental photochemical characteristics and processes of DOM,this paper focused on the effects of types,sources,fluorescent components of DOM and environmental factors on the photodegradation process of ECs.Influence of DOM on the photodegradation process of ECs mainly includes promoting effect and inhibiting effect.The promoting effect is mainly manifested in the reaction of active reaction intermediates generated by DOM with ECs.However,the inhibition effect mainly includes light shielding effect and quenching effect.The effect of DOM on the photodegradation of ECs was closely related to type,source,composition and environmental factors of DOM.Meanwhile,the future research work on the effect of DOM on the photodegradation of ECs was prospected.This will contribute to a more comprehensive understanding of the photochemical behaviour of ECs,which is of importance for assessing the environmental fate and ecological risk of ECs in natural waters.