微塑料的化学老化过程及吸附有机污染物的研究进展

Research progress on chemical aging microplastics and the adsorption of organic pollutants

微塑料的环境行为和生态影响如今备受瞩目,环境中微塑料受光照、化学物质、机械力和生物等因素而老化,影响其环境行为和归趋.化学老化可以产生具有强氧化能力的活性氧引起自由基链式反应,导致微塑料物理化学性质发生显著改变,进而影响其对污染物的吸附性能.高级氧化过程是常见的化学老化方法,用于模拟和加速微塑料的自然老化.此外,微塑料作为载体吸附环境中的有机污染物是近年来研究的热点.本文阐述了化学老化过程中微塑料的表面形貌、粒径、含氧官能团和亲疏水性等物理化学性质的变化,总结了微塑料化学老化的方法(例如芬顿、过氧化氢、过硫酸盐、臭氧和光复合老化)及机制;同时综述了化学老化微塑料吸附疏水性有机污染物和亲水性有机污染物的研究现状,并结合吸附动力学和吸附热力学模型,进一步明确化学老化对微塑料吸附有机污染物的影响.最后,基于此对微塑料化学老化存在的问题和后续研究方向提供了展望.

The environmental behavior and ecological impact of microplastics have been in the spotlight nowadays.Microplastics are subject to aging by sunlight,chemical substances,mechanical forces,and biofilm,which affect their environmental behaviors and fate in the environment.Chemical aging can generate reactive oxygen species with strong oxidative capacity,which induces free radical chain reactions,resulting in significant changes in the physicochemical properties of microplastics,thereby affecting the absorption performance towards pollutants by microplastics.Advanced oxidation processes are common chemical aging methods used to simulate and accelerate the natural aging of microplastics.Additionally,the adsorption of organic pollutants in the environment by microplastics as carriers has been a hot research topic in recent years.This paper elaborates the variations of physicochemical properties,including surface morphology,particle size,oxygen-containing functional groups,hydrophilicity and hydrophobicity on microplastics chemical aging.We also summarize the methods and mechanisms of chemical aging microplastics(e.g.,Fenton,hydrogen peroxide,persulfate,ozone,and combined technologies based on light irradiation and AOPs).Meanwhile,the current research status on the adsorption of hydrophobic organic pollutants and hydrophilic organic pollutants by chemical aging microplastics are reviewed,combined with adsorption kinetics and adsorption thermodynamics models to further clarify the effects of chemical aging on the adsorption of organic pollutants by microplastics.Finally,the existing problems and potential research directions about microplastics chemical aging in the future are proposed.