Deposition behaviors and interfacial interaction mechanism between carboxyl-modified polystyrene nanoplastics and magnetite in aquatic environment

Meimei Ran; Xin Nie; Jingxin Wang; Ruiyin Xie; Xiaoping Lin; Hanjun Zhu; Quan Wan; Yuhong Fu

doi:10.1016/j.ecoenv.2024.117608

Deposition behaviors and interfacial interaction mechanism between carboxyl-modified polystyrene nanoplastics and magnetite in aquatic environment

Ecotoxicol Environ Saf. 2024 Dec 28:290:117608. doi: 10.1016/j.ecoenv.2024.117608. Online ahead of print.

Authors

Meimei Ran¹, Xin Nie², Jingxin Wang³, Ruiyin Xie⁴, Xiaoping Lin⁴, Hanjun Zhu², Quan Wan², Yuhong Fu⁵

Affiliations

¹ School of Geography and Environmental Sciences, Guizhou Normal University, Guiyang 550025, China; State Key Laboratory of Ore Deposit Geochemistry, Research Center of Ecological Environment and Resource Utilization, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China.
² State Key Laboratory of Ore Deposit Geochemistry, Research Center of Ecological Environment and Resource Utilization, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China.
³ Guangdong Provincial Engineering Research Center of Public Health Detection and Assessment, School of Public Health, Guangdong Pharmaceutical University, Guangzhou 510310, China.
⁴ State Key Laboratory of Ore Deposit Geochemistry, Research Center of Ecological Environment and Resource Utilization, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; Guangdong Provincial Engineering Research Center of Public Health Detection and Assessment, School of Public Health, Guangdong Pharmaceutical University, Guangzhou 510310, China.
⁵ School of Geography and Environmental Sciences, Guizhou Normal University, Guiyang 550025, China. Electronic address: fuyuhong24@163.com.

PMID: 39733597
DOI: 10.1016/j.ecoenv.2024.117608

Abstract

In aquatic environments, the deposition behaviors of nanoplastics (NPs) are closely associated with interfacial interaction between NPs and iron (hydr)oxides minerals, which are typically coupled with solution chemistry and organic matter. However, the roles of solution chemistry and organic matter in the deposition behavior of NPs with iron (hydr)oxides minerals and related interfacial interaction mechanism are still poorly understood. In this study, the deposition behaviors of carboxyl-modified polystyrene nanoparticles (COOH-PSNPs) with magnetite were systematically investigated. The results showed that electrostatic attraction, hydrogen bond, and charge-assisted hydrogen bond (CAHB) were the main forces for the deposition and interfacial interaction mechanism between COOH-PSNPs and magnetite. Increasing pH could significantly inhibit the deposition of COOH-PSNPs with magnetite. At pH 6.5, phosphate and dichromate significantly inhibited the deposition of COOH-PSNPs since their competitive adsorption for the surface sites on magnetite led to a potential reversal of magnetite, resulting in the strong electrostatic repulsion between COOH-PSNPs and magnetite. Moreover, when the concentration of phosphate exceeded 0.01 mM, the deposition of COOH-PSNPs was completely hindered. Organic macromolecules (OMs) markedly inhibited the interfacial interaction and deposition of COOH-PSNPs with magnetite by enhancing the electrostatic repulsion and steric hindrance between COOH-PSNPs and magnetite due to the formation of magnetite-OM associations. The inhibition abilities followed the order sodium alginate (0.1 mM) > humic acid (0.2 mM) > bovine serum albumin (5 mM). This study may provide insights for better understanding of environmental behaviors of COOH-PSNPs associated with magnetite and organic matter in natural environments at the molecular level.

Keywords: Deposition; Interfacial interaction; Magnetite; Nanoplastics; Organic macromolecules.