微米级聚苯乙烯对铜的吸附特性

以铜为目标污染物，系统地研究了微米级聚苯乙烯（PS）微塑料对溶液中铜离子的吸附能力.测定了吸附时间、铜离子浓度、PS浓度、粒径以及共存离子对吸附量的影响.结果表明：0.5μm PS比6.0μm PS吸附能力强，饱和吸附量分别达到（0.1638±0.0204）和（0.1091±0.0133）mg/mg；吸附在720min后达到平衡，吸附动力学可用伪二级动力学模型和Elovich模型较好地拟合（R²分别为0.929、0.904和0.866、0.885）；吸附等温线可用Freundlich模型和Langmuir模型很好地拟合（R²分别为0.974、0.976和0.966、0.977）.此外，随铜离子浓度的增加，PS吸附量增加，但吸附速率减小；而随PS浓度的增加，吸附量减小，吸附速率增加；当溶液中存在其他离子时，PS对铜的吸附量增加.本文中微米级PS对铜的吸附行为研究结果，可为深入探究海洋中微塑料吸附铜的环境行为及其对污染物迁移的影响提供理论基础.

Adsorption characteristics of copper ions on polystyrene microplastics

This study systematically investigated the adsorption capacity of polystyrene (PS) plastic micro-spheres (0.5 and 6μm diameter) toward copper ions under the action of factors such as adsorption time, copper ion concentration, PS concentration, particle size and coexisting ions. Copper showed higher adsorbance on 0.5μm PS compared with 6.0μm PS, and the saturated adsorption capacity reached (0.1638±0.0204) and (0.1091±0.0133) mg/mg, respectively. The adsorption equilibrium was reached by 720min, both Pseudo-second-order kinetic model and Elovich model most suitably described the adsorption kinetics of copper, with R² of 0.929、0.904 and 0.866、0.885, respectively. The adsorption isotherms can be well fitted by Freundlich model and Langmuir model, with R² of 0.974、0.976 and 0.966、0.977, respectively. Our study also found that the copper adsorbance on PS increased with copper concentration but accompanying with a decrease of adsorption rate, while it decreased with PS concentration but adsorption rate increased. The coexisting ions promoted the copper adsorbance on PS. The findings could provide a theoretical basis for further research regarding heavy metals adsorbance on microplastics, their environmental behavior in marine environment, and influences on pollutants transport as well.