利用Fe3O4纳米颗粒磁分离去除水中小粒径微塑料

建立了微塑料（Microplastics，MPs）荧光定量分析方法，系统研究了Fe₃O₄纳米颗粒对水中聚苯乙烯MPs的磁性去除效果.结果表明，MPs浓度在本实验范围内（0.2~10.0mg/L）与荧光强度线性关系良好，相关系数均>0.9990，能准确测定不同粒径（100~1000nm）MPs的浓度.MPs初始浓度与Fe₃O₄纳米颗粒投加量对MPs去除效果具有影响.增加Fe₃O₄纳米颗粒的投加量能够有效提升水中MPs的去除率，当Fe₃O₄投加量为12mg/L时，去除率可达90.8%.在低Fe₃O₄投加量时，MPs去除率随着MPs初始浓度增加而显著增加，显著性水平为0.015；但在中、高Fe₃O₄投加量时，初始浓度对去除效果影响很小，显著性水平分别为0.073和0.060.Fe₃O₄纳米颗粒对MPs的附着过程能够在180min内趋于平衡，整个动力学可通过拟一级或拟二级模型进行拟合.

Removal of small-sized microplastics from aqueous solution with Fe3O4 nanoparticles by magnetic separation

In this study, we developed a fluorescence quantitative analysis method to detect the concentration of Microplastics (MPs), and studied the removal of polystyrene MPs with Fe₃O₄ nanoparticles by magnetic separation in water. Results showed that the concentration of MPs (0.2~10.0mg/L) had a good linear relationship with fluorescence intensity and the correlation coefficients were all greater than 0.9990, indicating its feasibility to accurately determine MPs concentrations with different particle sizes (100~1000nm). The initial concentration of MPs and the dose of Fe₃O₄ nanoparticles had influence on the removal of MPs. Increasing the dose of Fe₃O₄ nanoparticles could obviously improve the removal efficiency of MPs in water. When the dose of Fe₃O₄ was 12mg/L, the removal efficiency could reach 90.8%. When the dose of Fe₃O₄ was low, the removal efficiency of MPs increased significantly with the increase of the initial concentration of MPs and the significance level was 0.015. However, when the dose of Fe₃O₄ was medium or high, the initial concentration had little influence on the removal effect, and the significance level was 0.073 and 0.060, respectively. The adhesion process of Fe₃O₄ nanoparticles to the MPs tended to equilibrium within 180 min, and the dynamics could be fitted using a quasi-first-order or quasi-second-order kinetic model.