There are few studies on the adsorption of heavy metals by microplastics containing additives in water environment. The present study investigated the adsorption mechanism of Cd(II) on polystyrene microplastics containing hexabromocyclododecane (PS-HBCD MPs). In the experiments, the effects of pH value, salinity, particle size and dissolved organic matter derived from PS-HBCD MPs on the adsorption capacity were analyzed. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to analyze the properties of PS-HBCD MPs and adsorption behavior of Cd(II) onto MPs. The adsorption kinetics and isotherms of Cd(II) onto PS-HBCD MPs can be described well by the pseudo-second-order kinetics model and Langmuir isotherm model, respectively. Solution pH, salinity, dissolved organic matter derived from MPs and particle size have a greater impact on the adsorption behavior of cadmium on microplastics. The results of this study highlight the importance of C-Br bonds of PS-HBCD MPs in controlling the adsorption of Cd(II).

关于水环境中含有添加剂的微塑料对重金属的吸附研究较少。本研究调查了 Cd(II) 在含有六溴环十二烷 (PS-HBCD MPs) 的聚苯乙烯微塑料上的吸附机制。在实验中，分析了来自PS-HBCD MPs的pH值、盐度、粒径和溶解有机物对吸附能力的影响。使用扫描电子显微镜 (SEM)、傅里叶变换红外光谱 (FTIR) 和 X 射线光电子能谱 (XPS) 来分析 PS-HBCD MPs 的性质和 Cd(II) 在 MPs 上的吸附行为。Cd(II) 在 PS-HBCD MP 上的吸附动力学和等温线可以分别用拟二级动力学模型和 Langmuir 等温线模型很好地描述。溶液 pH 值、盐度、来自 MPs 的溶解有机物和粒径对镉在微塑料上的吸附行为有较大影响。本研究的结果强调了 PS-HBCD MPs 的 C-Br 键在控制 Cd(II) 吸附方面的重要性。