Effects of clay minerals on the transport of polystyrene nanoplastic in groundwater

Xinyao Ye; Zhou Cheng; Ming Wu; Yanru Hao; Guoping Lu; Bill X Hu; Cehui Mo; Qusheng Li; Jianfeng Wu; Jichun Wu

doi:10.1016/j.watres.2022.118978

Effects of clay minerals on the transport of polystyrene nanoplastic in groundwater

Water Res. 2022 Sep 1:223:118978. doi: 10.1016/j.watres.2022.118978. Epub 2022 Aug 13.

Authors

Xinyao Ye¹, Zhou Cheng², Ming Wu³, Yanru Hao¹, Guoping Lu¹, Bill X Hu⁴, Cehui Mo¹, Qusheng Li⁵, Jianfeng Wu⁶, Jichun Wu⁶

Affiliations

¹ Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, College of Life Science and Technology, Jinan University, Guangzhou 510632, China.
² Guangdong Provincial Academy of Environmental Science, Guangzhou 510045, China.
³ Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, College of Life Science and Technology, Jinan University, Guangzhou 510632, China; Key Laboratory of Surficial Geochemistry, Ministry of Education, Department of Hydrosciences, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China. Electronic address: wumingnj@foxmail.com.
⁴ Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, College of Life Science and Technology, Jinan University, Guangzhou 510632, China; School of Water Conservancy and Environment, University of Jinan, Jinan 250022, China.
⁵ Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 510632, China.
⁶ Key Laboratory of Surficial Geochemistry, Ministry of Education, Department of Hydrosciences, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China.

PMID: 35988332
DOI: 10.1016/j.watres.2022.118978

Abstract

Microplastics are widely detected in the soil-groundwater environment, which has attracted more and more attention. Clay mineral is an important component of the porous media contained in aquifers. The transport experiments of polystyrene nanoparticles (PSNPs) in quartz sand (QS) mixed with three kinds of clay minerals are conducted to investigate the effects of kaolinite (KL), montmorillonite (MT) and illite (IL) on the mobility of PSNPs in groundwater. Two-dimensional (2D) distributions of DLVO interaction energy are calculated to quantify the interactions between PSNPs and three kinds of clay minerals. The critical ionic strengths (CIS) of PSNPs-KL, PSNPs-MT and PSNPs-IL are 17.0 mM, 19.3 mM and 21.0 mM, respectively. Experimental results suggest KL has the strongest inhibition effect on the mobility of PSNPs, followed by MT and IL. Simultaneously, the change of ionic strength can alter the surface charge of PSNPs and clay minerals, thus affecting the interaction energy. Experimental and model results indicate both the deposition rate coefficient (k) and maximum deposition (S_max) linearly decrease with the logarithm of the DLVO energy barrier, while the mass recovery rate of PSNPs (R_m) exponentially increases with the logarithm of the DLVO energy barrier. Therefore, the mobility and associated kinetic parameters of PSNPs in complex porous media containing clay minerals can be predicted by 2D distributions of DLVO interaction energy. These findings could help to gain insight into understanding the environmental behavior and transport mechanism of microplastics in the multicomponent porous media, and provide a scientific basis for the accurate simulation and prediction of microplastic contamination in the groundwater system.

Keywords: Clay minerals; DLVO interaction energy; Groundwater; Nano-plastic; Transport model.

MeSH terms

Bentonite
Clay
Groundwater*
Kaolin
Microplastics*
Minerals
Plastics
Polystyrenes
Quartz
Sand
Soil

Substances

Microplastics
Minerals
Plastics
Polystyrenes
Sand
Soil
illite
Bentonite
Quartz
Kaolin
Clay