In order to solve the water solubility and difficult re-use of plant polyphenol (PP) in Cd(II) adsorption, PP was immobilized on the surface of magnetic material in this study. A core-shell nanocomposite Fe₃O₄/SiO₂/PP (∼18 nm) was synthesized with 3–8 nm SiO₂ and 2–5 nm PP. TGA analysis revealed the PP coating amount was 2.39%. VSM detection suggested that saturation magnetization of Fe₃O₄/SiO₂/PP was 45.94 emu/g. The adsorption equilibrium was reached in 2 h and the adsorption kinetics followed a pseudo-second-order model. The adsorption data fitted well to a Langmuir isotherm, achieving a 98.6% of Cd(II) removal at 0.6 g, pH 7.0, 298 K and 160 rpm. The adsorption capacity of Cd(II) on Fe₃O₄/SiO₂/PP highly depended on the pH. The adsorption capacity increased as the initial solution pH was increased in the range of 3.0–8.0. The adsorbed Cd(II) on Fe₃O₄/SiO₂/PP could be effectively desorbed by 0.1 mol/L of HNO₃ and the Fe₃O₄/SiO₂/PP still maintained a stable adsorption capacity after five cycles. The adsorption mechanism of Cd(II) on Fe₃O₄/SiO₂/PP is mainly dependent on complexation and electrostatic adsorption from the FTIR and XPS analyses. This study provided a new way for PP to remove Cd(II) from aqueous solution.

为了解决水溶性问题和植物多酚（PP）在Cd（II）吸附中的重用问题，本研究将PP固定在磁性材料表面。用3–8 nm SiO ₂和2–5 nm PP合成了核-壳纳米复合材料Fe ₃ O ₄ / SiO ₂ / PP（〜18 nm）。TGA分析表明PP的涂覆量为2.39％。VSM检测表明Fe ₃ O ₄ / SiO _2的饱和磁化强度/ PP为45.94 emu / g。在2 h内达到吸附平衡，吸附动力学遵循伪二级模型。吸附数据非常适合Langmuir等温线，在0.6 g，pH 7.0、298 K和160 rpm的条件下，去除了98.6％的Cd（II）。Cd（II）在Fe ₃ O ₄ / SiO ₂ / PP上的吸附能力高度依赖于pH值。随着初始溶液pH值在3.0-8.0范围内增加，吸附能力增加。0.1 mol / L的HNO ₃和Fe ₃ O ₄ / SiO ₂可有效地解吸Fe ₃ O ₄ / SiO ₂ / PP上吸附的Cd（II）/ PP在五个循环后仍保持稳定的吸附能力。Cd（II）在Fe ₃ O ₄ / SiO ₂ / PP上的吸附机理主要取决于FTIR和XPS分析的络合和静电吸附。该研究为PP从水溶液中去除Cd（II）提供了新途径。