Adsorption behavior of imidacloprid pesticide on polar microplastics under environmental conditions:critical role of photo-aging  

作　　者：Weiyi Liu Ting Pan Hang Liu Mengyun Jiang Tingting Zhang 

机构地区：[1]Department of Environmental Science and Engineering,Research Centre for Resource and Environment,Beijing University of Chemical Technology,Beijing 100029,China

出　　处：《Frontiers of Environmental Science & Engineering》2023年第4期13-26,共14页环境科学与工程前沿（英文）

基　　金：This work was supported by the National Natural Science Foundation of China(No.41977142);Major Science and Technology Program for Water Pollution Control and Treatment(No.2018ZX07111003).

摘　　要：The photo-aging behavior of microplastics(MPs)in natural environment has become a global concern.The ultraviolet radiation has enough energy to change the polymer structure and physicalchemical properties of MPs.Less attention has focused on the interactions of the photo-aged polar and biodegradable MPs with organic pollutants.This work investigated the structural properties of aged polar polyamide(PA)MPs and biodegradable polylactic acid(PLA)MPs exposed to ultraviolet irradiation and their adsorption behavior and mechanism for neonicotinoid insecticide imidacloprid(IMI).The results showed that the MPs had extensive changes in surface morphology and chemical properties after photo-aging.The C–N bond of PA MPs was disrupted to form more carbonyl groups.The oxygen-containing functional groups on the surface of aged PLA MPs were broken and generated relatively smaller molecules.The adsorption capacity of IMI on PA MPs decreased by 19.2%,while the adsorption capacity of IMI on PLA MPs increased by 41.2%after photo-aging.This depended on the natural structure of the MPs and their ability to absorb ultraviolet light.The electrostatic interactions,hydrogen bonds,van der Waals interactions,and polar-polar interactions were the main adsorption mechanisms of IMI on MPs.High initial solution pH and low ionic strength favored the adsorption of IMI by altering charge distribution on the MPs surface.The formation of the humic acid-IMI complexes decreased the concentration of IMI in the water phase and further decreased the adsorption on MPs.These results are enlightening for a scientific comprehension of the environmental behavior of the polar MPs.

关 键 词：Microplastics Neonicotinoid insecticide Photo-aging adsorption Environmental conditions 

分 类 号：O64[理学—物理化学]