TiO2/UV/O3协同老化对微塑料吸附甲基橙的影响

为了探究协同老化后的微塑料与有机污染物的相互作用机制，以PVC作为研究对象，采用TiO₂/UV/O₃协同老化方式，对比考察了老化前后PVC对甲基橙(MO)的吸附性能。结果表明，随着老化的进行，PVC颗粒表面碎片化加深，粒径明显减小，Zeta电位值降低，并出现了新的含氧官能团。原始PVC对MO的吸附符合准一级动力学模型，而老化后的PVC对MO的吸附符合准二级动力学模型，且主要的吸附模式均为液膜扩散和颗粒内扩散。动力学拟合结果表明老化前的PVC对MO的吸附以物理吸附为主，而老化后的PVC对MO的吸附以化学吸附为主。老化前后的PVC对MO的吸附均符合Freundlich等温吸附模型，表明MO与微塑料之间的相互作用是在非均匀表面上的多层吸附。以上研究结果可为微塑料携带有机污染物在环境中的迁移转化的行为提供参考。

Effect of TiO2/UV/O3 collaborative aging on adsorption of methyl orange by microplastics

To explore the interaction mechanism between microplastics and organic pollutants after collaborative aging, PVC was taken as the research object and TiO2/UV/O3 collaborative aging method was adopted to compare the adsorption characteristics of MO on PVC before and after aging. The results showed that with the aging process, the surface fragmentation of PVC particles was deepened, their particle size decreased obviously, their Zeta potential decreased, and new oxygen-containing functional groups appeared. The adsorption of MO on the original PVC conformed to the quasi-first-order kinetic model, while the adsorption of MO on the aging PVC conformed to the quasi-second-order kinetic model, and the main adsorption modes were liquid film diffusion and intra-particle diffusion. The difference of kinetics indicated that the adsorption of MO on PVC before aging was mainly physical adsorption, while the adsorption of MO on PVC after aging was mainly chemical adsorption. The adsorption of MO on PVC before and after aging conformed to Freundlich isothermal adsorption model, indicating that the interaction between MO and microplastics was the multi-layer adsorption on the non-uniform surface. Therefore, this can provide a reference for studying the migration and transformation behavior of organic pollutants carried by microplastics in the environment.