Co-impacts of cation type and humic acid on migration of polystyrene microplastics in saturated porous media

Wenxin Gao; Xiaoxia Wang; Yinzhu Diao; Yiqun Gong; Jing Miao; Wenjing Sang; Hui Yuan; Zheng Shen; Mohamed E A El-Sayed; Islam A Abdelhafeez

doi:10.1016/j.jenvman.2024.120918

Co-impacts of cation type and humic acid on migration of polystyrene microplastics in saturated porous media

J Environ Manage. 2024 May:358:120918. doi: 10.1016/j.jenvman.2024.120918. Epub 2024 Apr 20.

Authors

Affiliations

¹ Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China.
² Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China; Institute of New Rural Development, School of Electronics and Information Engineering, Tongji University, Shanghai 201804, China.
³ Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China. Electronic address: wjsang@dhu.edu.cn.
⁴ Tianjin Eco-Environmental Monitoring Center, 19 Fukang Road, Nankai District, Tianjin, 300191, China.
⁵ Institute of New Rural Development, School of Electronics and Information Engineering, Tongji University, Shanghai 201804, China; College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
⁶ Soils, Water and Environment Research Institute, Agricultural Research Center, Giza 12112, Egypt.

PMID: 38643625
DOI: 10.1016/j.jenvman.2024.120918

Abstract

The aging process of microplastics (MPs) could significantly change their physical and chemical characteristics and impact their migration behavior in soil. However, the complex effects of different cations and humic acids (HA) on the migration of aged MPs through saturated media are not clear. In this research, the migration and retention of pristine/aged PSMPs (polystyrene microplastics) under combined effects of cations (Na⁺, Ca²⁺) (ionic strength = 10 mM) and HA (0, 5, 15 mg/L) were investigated and analyzed in conjunction with the two-site kinetic retention model and DLVO theory. The findings showed that the aging process accelerated PSMPs migration under all tested conditions. Aged PSMPs were less susceptible to Ca²⁺ than pristine PSMPs. Under Ca²⁺ conditions, pristine/aged PSMPs showed higher retention than under Na⁺ conditions in the absence of HA. Furthermore, under Na⁺ conditions, the migration of aged PSMPs significantly increased at higher concentrations of HA. However, under Ca²⁺ conditions, the migration of aged PSMPs decreased significantly at higher concentrations of HA. In higher HA conditions, HA, Ca²⁺, and PSMPs interact to cause larger aggregations, resulting in the sedimentation of aged PSMPs. The DLVO calculations and two-site kinetic retention models' results showed the detention of PSMPs was irreversible under higher HA conditions (15 mg/L) with Ca²⁺, and aged PSMPs were more susceptible to clogging. These findings may help to understand the potential risk of migration behavior of PSMPs in the soil-groundwater environment.

Keywords: DLVO; H(2)O(2) aging; Influencing factor; Migration; Two-site kinetic retention model.

MeSH terms

Cations* / chemistry
Humic Substances*
Kinetics
Microplastics* / toxicity
Polystyrenes* / chemistry
Porosity
Soil / chemistry

Substances

Humic Substances
Polystyrenes
Microplastics
Cations
Soil