With rapid urbanization, microplastics and natural organic matters (NOMs) are ubiquitous in aquatic environment, and microplastics could act as carriers for organic matters in the aqueous solution and may pose a potential risk. In this study, the adsorption behaviors and mechanism of typical NOM, humic acid (HA), on polyvinyl chloride (PVC) and polystyrene (PS) microplastics were investigated. Various influence factors such as solution pH, ions species and concentrations, particle size, and coexisting surfactants were studied. The results suggested that HA adsorption onto PVC and PS was low pH-dependent, and ion species and concentrations have a significant impact on the adsorption capacity. In addition, the particle size of PVC and PS microplastics exhibited a significant correlation with HA adsorption, and the adsorption process was influenced by the surfactant species and concentrations. Moreover, the adsorption behaviors of HA in different real water environments were tested, and UV aging exhibited the opposite effects on adsorption capacity of PVC and PS. Furthermore, the adsorption mechanisms of HA onto PVC and PS were explored, indicating halogen bonding, hydrogen bonding, and π–π interaction play important roles in the adsorption process.

随着城市化进程的加快，微塑料和天然有机物（NOMs）在水生环境中无处不在，微塑料可以作为水溶液中有机物的载体，可能带来潜在的风险。在本研究中，研究了典型 NOM、腐植酸 (HA) 在聚氯乙烯 (PVC) 和聚苯乙烯 (PS) 微塑料上的吸附行为和机理。研究了各种影响因素，例如溶液 pH 值、离子种类和浓度、粒径以及共存的表面活性剂。结果表明，HA 对 PVC 和 PS 的吸附具有低 pH 依赖性，离子种类和浓度对吸附容量有显着影响。此外，PVC和PS微塑料的粒径与HA吸附呈显着相关性，吸附过程受表面活性剂种类和浓度的影响。此外，测试了HA在不同真实水环境中的吸附行为，UV老化对PVC和PS的吸附能力表现出相反的影响。此外，探索了 HA 在 PVC 和 PS 上的吸附机制，表明卤键、氢键和 π-π 相互作用在吸附过程中起着重要作用。