Nanoplastics (NPs) inevitably interact with iron minerals (IMs) after being released into aquatic environments, changing their transport and fate. In this study, batch heteroaggregation kinetics of four types of NPs, i.e., polymethyl methacrylate (PMMA), polystyrene (PS-Bare), amino-polystyrene (PS-NH), and carboxyl-polystyrene (PS-COOH), with two different IMs (hematite and magnetite) were conducted. We found that the heteroaggregation of NPs and IMs and the associated interfacial interaction mechanisms are both NPs-dependent and IMs-dependent. Specifically, the NPs had stronger heteroaggregation with hematite than magnetite; the heteroaggregation order of two IMs with NPs was PMMA > PS-NH > PS-Bare > PS-COOH. Moreover, hydrogen bond, complexation, hydrophobic, cation-π, and electrostatic interaction were involved in the interfacial reaction between NPs and hematite, and electrons were transferred from the NPs to the hematite, causing the reduction of Fe into Fe. Furthermore, we first revealed that both pre-homoaggregation of NPs and IMs could affect their subsequent heteroaggregation, and the homoaggregates of IMs could be interrupted by PMMA or PS-COOH NPs introduction. Therefore, the emerging NPs pollution is likely to generate an ecological effect in terms of elemental cycles such as iron cycle. This work provides new insights into assessing the environmental transfer and ecological effects of NPs in aquatic environments.

中文翻译：

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纳米塑料和铁矿物类型都决定了它们的异聚集：聚集动力学和界面过程

纳米塑料（NP）在释放到水生环境中后不可避免地会与铁矿物质（IM）相互作用，改变它们的运输和命运。在这项研究中，四种类型的纳米粒子，即聚甲基丙烯酸甲酯（PMMA），聚苯乙烯（PS-Bare），氨基聚苯乙烯（PS-NH）和羧基聚苯乙烯（PS-COOH）的批量异聚集动力学，具有两种不同的进行了 IM（赤铁矿和磁铁矿）。我们发现 NP 和 IM 的异质聚集以及相关的界面相互作用机制均依赖于 NP 和 IM 。具体而言，纳米粒子与赤铁矿的异聚集性强于与磁铁矿的异聚集性；两种带有NP的IM的杂聚顺序为PMMA>PS-NH>PS-Bare>PS-COOH。此外，氢键、络合、疏水、阳离子π和静电相互作用参与了纳米粒子与赤铁矿之间的界面反应，电子从纳米粒子转移到赤铁矿，导致Fe还原成Fe。此外，我们首先发现，NPs和IMs的预均聚可能会影响其随后的杂聚，并且IMs的均聚可能会被PMMA或PS-COOH NPs的引入打断。因此，新出现的纳米颗粒污染很可能在铁循环等元素循环方面产生生态效应。这项工作为评估水生环境中纳米粒子的环境转移和生态影响提供了新的见解。