老化前后聚乙烯微塑料在多孔介质中的迁移特性研究

Transport Characteristics of Polyethylene Microplastics in Porous Media Before and After Aging

土壤是微塑料(microplastics,MPs)重要的长期储存库,每年排放到土壤中的MPs数量远超于海洋。进入土壤中的MPs,在物理、化学和生物因素共同作用下逐渐老化,其环境行为从而受到影响。本文以饱和石英砂作为多孔介质,研究不同环境因素对聚乙烯微塑料(PE-MPs)迁移行为的影响。结果表明,阻塞效应导致PE的迁移能力随着PE浓度升高而降低,而水流剪切作用导致PE的迁移能力随着流速升高而升高。pH和离子强度对老化PE的迁移能力影响较小,这主要是由于老化作用导致PE表面粗糙度增加,从而影响其迁移过程。富里酸(FA)的存在显著提高PE的迁移能力,这与其表面负电荷增加有关,从而增加了土壤MPs污染地下水的风险。

Soil is a significant long-term reservoir for microplastics(MPs),with the annual amount of MPs released into soil far exceeding that released into the ocean.MPs entering the soil gradually undergo aging under the combined influence of physical,chemical,and biological factors,thereby affecting their environmental behavior.In this study,saturated quartz sand was used as a porous medium to investigate the effects of different environmental factors on the transport behavior of polyethylene microplastics(PE-MPs).The results show that the blocking effect caused a decrease in the transport ability of PE as its concentration increased,while flow shear stress led to an increase in transport ability as flow velocity increased.pH and ionic strength had little effect on the transport ability of aged PE,primarily due to the increase in surface roughness caused by aging,which affected the migration process.The presence of fulvic acid(FA)significantly enhanced the transport ability of PE,which was related to the increase in surface negative charge,thereby raising the risk of soil MPs contaminating groundwater.