College of Chemistry, Chemical Engineering and Environment, Minnan Normal University, Zhangzhou 363000, PR China; School of Biological Science and Biotechnology, Minnan Normal University, Zhangzhou 363000, PR China.
Laixi Food and Drug Administration, Qingdao 266000, PR China.
Int J Biol Macromol. 2022 Mar 31;202:397-406. doi: 10.1016/j.ijbiomac.2021.12.160. Epub 2022 Jan 4.
In this study, pectin (Pe) with different esterification degrees was used as raw materials to prepared hydrogel adsorbents via free radical polymerization. The effect of Pe esterification degree on hydrogel structure and adsorption performance was studied by FTIR, SEM and XPS characterization and copper ion adsorption experiment. The results demonstrated that the carboxyl group in the hydrogels was bonded to Cu through electrostatic force and coordination, which was an important factor in its adsorption capacity. The hydrogels prepared from Pe with low esterification degree had finer pores and higher carboxyl content, so the adsorption capacity on both water and Cu was stronger. The preparation of hydrogels from low-ester Pe was more conducive to the adsorption of copper ions. Besides, the adsorption behavior of the hydrogels on Cu was investigated through the adsorption thermodynamics and kinetics. The results indicated that the adsorption kinetics of the hydrogels was in accordance with the quasi-second-order model. The adsorption of Cu by hydrogels was the result of physical and chemical adsorption, which was endothermic under natural condition, and a higher temperature will result in more favorable spontaneous adsorption.
在这项研究中，使用不同酯化度的果胶（Pe）作为原料，通过自由基聚合制备水凝胶吸附剂。通过傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）和 X 射线光电子能谱（XPS）表征以及铜离子吸附实验研究了 Pe 酯化度对水凝胶结构和吸附性能的影响。结果表明，水凝胶中的羧基通过静电力和配位作用与 Cu 结合，这是其吸附能力的重要因素。低酯化度 Pe 制备的水凝胶具有更细的孔和更高的羧基含量，因此对水和 Cu 的吸附能力更强。低酯 Pe 制备水凝胶更有利于铜离子的吸附。此外，还通过吸附热力学和动力学研究了水凝胶对 Cu 的吸附行为。结果表明，水凝胶的吸附动力学符合准二级模型。水凝胶对 Cu 的吸附是物理和化学吸附的结果，在自然条件下是吸热的，较高的温度会导致更有利于自发吸附。
