Microplastic (MP) pollution is an increasing global problem due to the ubiquity of these particles in the environment and the uncertainty surrounding their fate. Most MPs undergo extensive weathering in the environment, which may result in the release of dissolved organic matter (DOM) into the aqueous phase. In this study, for the first time, we examined the adsorptive behavior of MP-derived DOM (MP-DOM) on minerals (kaolinite and goethite) using DOM samples leached from commercial plastics including polyvinylchloride (PVC) and polystyrene (PS) under dark and ultraviolet (UV) irradiation conditions. MP-DOM was characterized by a higher distribution of relatively smaller-sized molecules than natural organic matter (NOM). The PS-derived DOM (PS-DOM) leached under UV treatment exhibited more oxygen-containing groups than their counterparts in the dark. MP-DOM also exhibited net negative charges at neutral pH ranges. Adsorption isotherm experiments revealed that the mineral surfaces had high adsorption affinities for both types of MP-DOM, which is likely associated with both electrostatic attraction and ligand exchange. The extent of adsorption was greater for the UV-irradiated than the dark-treated DOM, and on goethite compared to kaolinite. The Fourier-transform infrared (FTIR) spectra of the residual PS-DOM after adsorption revealed differences in the adsorption affinities between its functional groups. Two-dimensional correlation spectroscopy for the irradiated PS-DOM showed that preferential adsorption occurred on minerals in the sequential order of oxidized structures → (PS monomers) → carboxylates in additives → carbonyl groups. The adsorption isotherm model parameters for MP-DOM were comparable to those obtained from aquatic/terrestrial NOM, which suggests that plastic-derived DOM can interact with minerals as strongly as NOM. This study highlights the overlooked role played by plastic-derived DOM in mineral-enriched environments, opening new opportunities for improving our understanding of the fate and environmental impacts of MPs.

由于这些微粒在环境中的普遍性以及围绕其命运的不确定性，微塑料（MP）污染是一个日益严重的全球性问题。大多数MP在环境中经受广泛的风化，这可能导致溶解的有机物（DOM）释放到水相中。在本研究中，我们首次使用在黑暗条件下从包括聚氯乙烯（PVC）和聚苯乙烯（PS）的商业塑料中浸出的DOM样品，研究了MP衍生DOM（MP-DOM）对矿物（高岭石和针铁矿）的吸附行为。和紫外线（UV）照射条件。MP-DOM的特点是相对较小分子的分布比天然有机物（NOM）高。在紫外线处理下浸出的PS衍生的DOM（PS-DOM）表现出比在黑暗中更多的含氧基团。MP-DOM在中性pH范围内也显示净负电荷。吸附等温线实验表明，矿物表面对两种类型的MP-DOM具有高吸附亲和力，这很可能与静电吸引和配体交换有关。与高岭石相比，紫外线辐射的吸附程度要比暗处理的DOM大，针铁矿的吸附程度也更大。残留PS-DOM吸附后的傅立叶变换红外（FTIR）光谱显示了其官能团之间的吸附亲和力差异。辐照的PS-DOM的二维相关光谱显示，矿物质按氧化结构→（PS单体）→添加剂中的羧酸盐→羰基的顺序优先吸附在矿物上。MP-DOM的吸附等温线模型参数与从水生/陆地NOM获得的等温线模型参数相当，这表明塑料衍生的DOM可以与NOM一样强烈地与矿物相互作用。这项研究强调了塑料衍生的DOM在富含矿物质的环境中所扮演的被忽视的角色，这为增进我们对国会议员的命运和环境影响的理解提供了新的机会。这表明塑料衍生的DOM可以与NOM一样强烈地与矿物质相互作用。这项研究强调了塑料衍生的DOM在富含矿物质的环境中所扮演的被忽视的角色，这为增进我们对国会议员的命运和环境影响的理解提供了新的机会。这表明塑料衍生的DOM可以与NOM一样强烈地与矿物质相互作用。这项研究强调了塑料衍生的DOM在富含矿物质的环境中所扮演的被忽视的角色，这为增进我们对国会议员的命运和环境影响的理解提供了新的机会。