Interfacial interactions between colloidal polystyrene microplastics and Cu in aqueous solution and saturated porous media: Model fitting and mechanism analysis

• Published in: Journal of environmental management 2024-11, Vol.370, p.122741, Article 122741
• Main Authors: Chu, Xianxian, Tian, Yimei, An, Ruopan, Jiang, Menghan, Zhao, Weigao, Guo, Hao, Zhao, Peng
• Format: Article
• Language: English
• Subjects: Adsorption; aqueous solutions; cations; Colloids - chemistry; Copper - chemistry; density functional theory; endothermy; environmental management; glass; Heavy metal; heavy metals; ionic strength; Microplastics; Microplastics - chemistry; pollution; polystyrenes; Polystyrenes - chemistry; Porosity; Theoretical calculations; Transport; Water Pollutants, Chemical - chemistry
• ISSN: 0301-4797; 1095-8630; 1095-8630
• DOI: 10.1016/j.jenvman.2024.122741

Microplastic (MP) and heavy metal pollution have received much attention. Few researches have been carried out on the influence of the interaction between MPs and heavy metals on their transport in saturated porous media, which concerns their fate. Therefore, the interaction mechanisms between colloidal polystyrene microplastics (PSMPs) and Cu were first carried out by applying batch adsorption experiments. Subsequently, the transport and retention of PSMPs and Cu in saturated porous media was explored through column experiments. The interaction process between PSMPs and Cu was further investigated using density functional theory (DFT) calculations. Findings demonstrated that PSMPs had strong adsorption capacity for Cu ((60.07 ± 2.57) mg g−1 at pH 7 and ionic strength 0 M) and the adsorption process was chemically dominated, non-uniform, and endothermic. The O-containing functional groups on PSMP surfaces showed essential roles in Cu adsorption, and the adsorption process mainly contained electrostatic and complexation interactions. In column experiments, Cu could inhibit PSMP transport by the cation bridging effect and changing the electrical properties of glass beads, while PSMPs may facilitate Cu transport through the carrying effect. These findings confirmed that interfacial interactions between MPs and Cu could influence their transport in saturated porous media directly, providing great environmental significance. [Display omitted] •Electrostatic interaction and complexation were the main mechanisms between PSMPs and Cu.•PSMPs promoted Cu transport through the Trojan horse effect.•Cu inhibited the transport of PSMPs by the cation bridging effect.•O-containing functional groups of PSMPs were vital for Cu fate.