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 Technology Research Center of Public Health Detection and Assessment, School of Public Health, Guangdong Pharmaceutical University, Guangzhou 510310, China.
J Hazard Mater. 2023 Mar 15;446:130649. doi: 10.1016/j.jhazmat.2022.130649. Epub 2022 Dec 21.
Nanoplastics (NPs) are emerging contaminants in the environment, where the transport and fate of NPs would be greatly affected by interactions between NPs and minerals. In the present study, the interactions of two types of polystyrene nanoplastics (PSNPs), i.e., bare-PSNPs and carboxylated PSNPs-COOH, with iron (hydr)oxides (hematite, goethite, magnetite, and ferrihydrite), aluminum (hydr)oxides (boehmite and gibbsite), and clay minerals (kaolinite, montmorillonite, and illite) were investigated. The positively charged iron/aluminum (hydr)oxide minerals could form heteroaggregates with negatively charged PSNPs. Electrostatic and hydrophobic interaction dominate for the heteroaggregation of bare-PSNPs with iron/aluminum (hydr)oxide minerals, while ligand exchange and electrostatic interaction are involved in the heteroaggregation of PSNPs-COOH with iron/aluminum (hydr)oxides minerals. However, heteroaggregation between PSNPs and negatively charged clay minerals was negligible. Humic acid markedly suppressed such heteroaggregation between PSNPs and minerals due to enhanced electrostatic repulsion, steric hindrance, and competition of surface attachment sites. The heteroaggregation rates of both bare-PSNPs and PSNPs-COOH with hematite decreased with increasing solution pH. Increased ionic strength enhanced the heteroaggregation of PSNPs-COOH but inhibited that of bare-PSNPs. The results of the present study suggested that the heteroaggregation of PSNPs in environments could be strongly affected by minerals, solution pH, humic acid, and ionic strength.
纳米塑料（NPs）是环境中的新兴污染物，NPs 的迁移和归宿将极大地受到 NPs 与矿物质之间相互作用的影响。本研究考察了两种类型的聚苯乙烯纳米塑料（PSNPs），即裸露 PSNPs 和羧基化 PSNPs-COOH 与铁（氢）氧化物（赤铁矿、针铁矿、磁铁矿和水铁矿）、铝（氢）氧化物（一水软铝石和三水软铝石）和粘土矿物（高岭石、蒙脱石和伊利石）的相互作用。带正电荷的铁/铝（氢）氧化物矿物可以与带负电荷的 PSNPs 形成异质聚集体。静电和疏水相互作用主导裸露 PSNPs 与铁/铝（氢）氧化物矿物的异质聚集，而配体交换和静电相互作用则参与 PSNPs-COOH 与铁/铝（氢）氧化物矿物的异质聚集。然而，PSNPs 与带负电荷的粘土矿物之间的异质聚集可以忽略不计。腐殖酸由于增强的静电排斥、空间位阻和表面附着位点的竞争，显著抑制了 PSNPs 与矿物质之间的这种异质聚集。裸露 PSNPs 和 PSNPs-COOH 与赤铁矿的异质聚集速率随溶液 pH 的增加而降低。增加离子强度增强了 PSNPs-COOH 的异质聚集，但抑制了裸露 PSNPs 的异质聚集。本研究结果表明，环境中 PSNPs 的异质聚集可能受到矿物质、溶液 pH 值、腐殖酸和离子强度的强烈影响。
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