模拟环境老化对PE微塑料吸附Zn(II)的影响

探讨了酸处理（1mol/L HCl）、碱处理（1mol/L NaOH）、氧化处理（30% H₂O₂）和高温-冻融处理（70℃和-22℃交替）4种老化方式对聚乙烯（PE）微塑料表面性质和Zn（II）吸附行为的影响.结果表明，4种老化方式均使PE微塑料表面出现大量的粗糙褶皱结构，但未改变表面化学结构.4种老化方式均导致PE微塑料Zn（II）吸附量的增加，其顺序为：碱处理 > 酸处理 > 氧化处理 > 高温-冻融处理 > 原样.PE微塑料吸附Zn（II）的动力学过程符合Lagrange准二级吸附动力学和W-M颗粒扩散模型，说明吸附过程是多个吸附阶段共同作用的结果，吸附等温线符合Langmuir和D-R模型，证实PE微塑料对Zn（II）的吸附属于物理吸附，老化使PE微塑料表面出现的大量褶皱是其Zn（II）吸附量增加的主要原因.

Effects of simulated environmental aging on the adsorption of Zn(II) onto PE microplastics

Effects of acidic treatment (1mol/L HCl), alkaline treatment (1mol/L NaOH), oxidizing treatment (30% H₂O₂) and high temperature-freezing and thawing treatment (repeated 70℃ and -22℃) on the surface properties and Zn(II) adsorption capacity of PE microplastics were studied. Results showed that all four aging treatments induced the presence of wrinkled structures on the surface of PE microplastics, but no chemical change was found. All four aging treatments increased the adsorption of Zn(II) onto PE microplastics, and the adsorption capacity of PE microplastics followed the decreasing tendency:alkali treated PE microplastics > acid treated PE microplastics > oxidition treated PE microplastics > high temperature-freezing and thawing treated PE microplastics > virgin PE microplastics. The adsorption kinetics fitted well with Lagrange pseudo-second-order kinetics and W-M particle diffusion model, implying that multi-processes were involved in the adsorption. The adsorption isotherm consisted with Langmuir and D-R model, suggesting that the adsorption was a physical process. The wrinkled structures present on the surface were the main reasons for the increase of Zn(II) adsorption capacity of aged PE microplastics.