College of Chemistry and Chemical Engineering, Neijiang Normal University, Neijiang, 641112, China.
College of Chemistry and Chemical Engineering, Neijiang Normal University, Neijiang, 641112, China.
Carbohydr Res. 2020 Nov;497:108133. doi: 10.1016/j.carres.2020.108133. Epub 2020 Aug 14.
A biodegradable adsorbent, modified konjac glucomannan (MKGM), was prepared by konjac glucomannan (KGM) acylated with phthalic anhydride catalyzed using concentrated sulfuric acid. The modified conditions such as reaction temperature, mass ratio of phthalic anhydride to KGM, catalyst dosage and reaction time were investigated, respectively. MKGM exhibited preferable adsorption performance for the removal of Fe (Ⅲ) ion. The adsorption behavior was discussed using the Langmuir and Freundlich isotherm models. The results showed that the Freundlich linear model was suitable for describing the adsorption process of Fe (Ⅲ). The maximum adsorption capacity of MKGM for Fe (Ⅲ) ion was 31.87 mg g at 298 K. The kinetics studies suggested that adsorption process followed the pseudo-second-order model and the adsorption process was mainly controlled by both surface reactivity and intra-particle diffusion. Together with the evaluation of the thermodynamic parameters such as Gibbs free energy, enthalpy and entropy changes, the results indicated that the adsorption process of Fe (Ⅲ) was endothermic, feasible, and spontaneous in nature. Hence, as a bioadsorbent, the MKGM has a promising potential for the removal of Fe (Ⅲ) ion from aqueous solutions.
一种可生物降解的吸附剂，即用邻苯二甲酸酐对魔芋葡甘聚糖（KGM）进行酰化改性得到的改性魔芋葡甘聚糖（MKGM），是在浓硫酸的催化作用下合成的。分别考察了反应温度、邻苯二甲酸酐与 KGM 的质量比、催化剂用量和反应时间等改性条件。MKGM 对 Fe（Ⅲ）离子的去除表现出较好的吸附性能。采用 Langmuir 和 Freundlich 等温吸附模型对吸附行为进行了讨论。结果表明，Freundlich 线性模型更适合描述 Fe（Ⅲ）的吸附过程。在 298 K 时，MKGM 对 Fe（Ⅲ）离子的最大吸附容量为 31.87 mg·g。动力学研究表明，吸附过程符合准二级动力学模型，吸附过程主要受表面反应和颗粒内扩散控制。结合对吉布斯自由能、焓变和熵变等热力学参数的评价，结果表明 Fe（Ⅲ）的吸附过程是吸热的、可行的，且在本质上是自发的。因此，作为一种生物吸附剂，MKGM 有望用于从水溶液中去除 Fe（Ⅲ）离子。
