选取典型工业微塑料聚甲基丙烯酸甲酯和聚苯乙烯的混合物(PMMA/PS)为研究对象,研究了溶液pH、微塑料的投加量与粒径、盐度和共存离子对PMMA/PS微塑料吸附典型放射性重金属U(Ⅵ)的影响,并采用傅里叶红外光谱和X射线光电子能谱等手段分析PMMA/PS与U(Ⅵ)的互作机理。结果表明,PMMA/PS对U(Ⅵ)的吸附容量随溶液pH的升高呈先增大后减小的趋势,并于pH 7达到峰值(4.00 mg/g)。此外,高盐度和共存金属离子可以强化PMMA/PS对U(Ⅵ)的吸附作用。PMMA/PS对U(Ⅵ)的吸附由化学吸附控制,且是多层、自发进行的吸热过程。PMMA/PS与U(Ⅵ)的作用机制主要包括静电作用、孔隙填充和表面络合作用。

The mixture of polymethylmethacrylate (PMMA) and polystyrene (PS),a typical industrial microplastics,is selected as the research object to study the influences of solution pH,the dosage and particle size of micro plastics,salinity and coexisting ions on the adsorption of PMMA/PS microplastics to typical radioactive heavy metal (i.e.,U(Ⅵ)).The action mechanism between PMMA/PS and U(Ⅵ) is analyzed be means of Fourier infrared spectroscopy,X-ray photoelectron spectroscopy,etc.Results show that the adsorption capacity of PMMA/PS for U(Ⅵ) increases first and decreases then with the increase of pH value,and reaches the highest (4.00 mg·g^-1) at pH=7.In addition,both high salinity and co-existing metal ions enhance the adsorption of U(Ⅵ) by PMMA/PS.The adsorption of U(Ⅵ) by PMMA/PS is controlled by chemical adsorption,which is a multi-layer and spontaneous endothermic process.The adsorption mechanism between PMMA/PS and U(Ⅵ) includes electrostatic interaction,pore filling and surface complexation.

唐振平(1962-),男,硕士,博士生导师,研究方向为环境勘探与污染控制、环境管理,zptang01@126.com