果胶-PDA微球的功能化制备及对Th4 的吸附性能的研究

Functional preparation of Pectin-PDA Microsphere and Its Adsorption Properties for Th4

摘要:

利用溶胶-凝胶法，以Ca2+为交联剂制备出果胶-Ca微球，再用多巴胺修饰果胶微球生成功能化的果胶-PDA微球吸附剂，探讨了该吸附剂去除Th4+的吸附性能，并利用SEM、FTIR和XPS分析了其功能化制备和吸附机理。结果表明：果胶-PDA微球在pH=3.5时效果最好，在25 ℃、pH=3.5、初始Th4+质量浓度为20 mg/L、吸附剂质量为0.03 g的条件下，接触时间为1200 min，吸附容量可达到37.172 mg/g；共存离子Cs+、Sr2+、Mn2+和Mg2+对Th4+的吸附影响较小，说明该吸附剂对Th4+的吸附选择性较好；热力学和动力学研究结果表明：此吸附过程符合线性Langmuir等温吸附模型和准二级动力学模型，拟合的最大吸附量为99.010 mg/g；热力学数据表明果胶-PDA吸附Th4+是一个自发吸热的过程；通过TG分析知果胶-PDA的热稳定性较改性前有所提高；果胶-PDA上的N、O与溶液中Th4+的发生螯合作用是果胶-PDA微球吸附Th4+的主要吸附机理。

Abstract:

Pectin-Ca microsphere was prepared by sol-gel method with Ca2 as cross-linking agent, and Functional pectin-PDA microsphere adsorbent was modified with dopamine-modified pectin microsphere. The adsorption performance of this adsorbent for removing Th4 was discussed. SEM, FTIR and XPS were used to analyze the preparation and adsorption mechanism.The results showed that the pectin-PDA microsphere had the best effect at pH=3.5. The adsorption capacity of adsorbent reached 37.172 mg/g under the conditions of 25℃, 20 mg/L mass concentration of Th4 , 0.03 g adsorbent, and 1200 min contact time. Co-existing ions Cs , Sr2 , Mn2 and Mg2 had little effect on the adsorption of Th4 . indicating that the adsorbent had better adsorption selectivity;The results of thermodynamics and kinetics showed that the adsorption process conformed to the Langmuir linearisotherm model and the pseudo-second-order kinetics model. The maximum adsorption capacity was 99.010 mg/g. The thermodynamic data showed that the adsorption of Th4 by pectin-PDA was a spontaneous absorption.The thermal stability of pectin-PDA was improved by TG analysis compared to that before modification. The mechanism of adsorption of Th4 by pectin-PDA microsphere was due to the sequestration of N and O on pectin-PDA and Th4 in solution.