Liu Changkun, Bai Renbi, Hong Liang
Department of Chemical and Biomolecular Engineering, Faculty of Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260.
J Colloid Interface Sci. 2006 Nov 1;303(1):99-108. doi: 10.1016/j.jcis.2006.07.057. Epub 2006 Jul 27.
Amine-functionalized adsorbents have attracted increasing interest in recent years for heavy metal removal. In this study, diethylenetriamine (DETA) was successfully grafted (through a relatively simple solution reaction) onto poly(glycidyl methacrylate) (PGMA) microgranules to obtain an adsorbent (PGMA-DETA) with a very high content of amine groups and the PGMA-DETA adsorbent was examined for copper ion removal in a series of batch adsorption experiments. It was found that the PGMA-DETA adsorbent achieved excellent adsorption performance in copper ion removal and the adsorption was most effective at pH>3 in the pH range of 1-5 examined. X-ray photoelectron spectroscopy (XPS) revealed that there were different types of amine sites on the surfaces of the PGMA-DETA adsorbent but copper ion adsorption was mainly through forming surface complexes with the neutral amine groups on the adsorbent, resulting in better adsorption performance at a higher solution pH value. The adsorption isotherm data best obeyed the Langmuir-Freundlich model and the adsorption capacity reached 1.5 mmol/g in the case of pH 5 studied. The adsorption process was fast (with adsorption equilibrium time less than 1-4 h) and closely followed the pseudo-second-order kinetic model. Desorption of copper ions from the PGMA-DETA adsorbent was most effectively achieved in a 0.1 M dilute nitric acid solution, with 80% of the desorption being completed within the first 1 min. Consecutive adsorption-desorption experiments showed that the PGMA-DETA adsorbent can be reused almost without any loss in the adsorption capacity.
近年来，胺功能化吸附剂在去除重金属方面越来越受到关注。在本研究中，二乙烯三胺（DETA）通过相对简单的溶液反应成功接枝到聚甲基丙烯酸缩水甘油酯（PGMA）微粒上，以获得具有非常高胺基含量的吸附剂（PGMA-DETA），并在一系列间歇吸附实验中考察了PGMA-DETA吸附剂对铜离子的去除性能。结果发现，PGMA-DETA吸附剂在去除铜离子方面具有优异的吸附性能，在所考察的1-5的pH范围内，pH>3时吸附效果最佳。X射线光电子能谱（XPS）显示，PGMA-DETA吸附剂表面存在不同类型的胺位点，但铜离子吸附主要是通过与吸附剂上的中性胺基形成表面络合物，从而在较高的溶液pH值下具有更好的吸附性能。吸附等温线数据最符合Langmuir-Freundlich模型，在所研究的pH 5的情况下，吸附容量达到1.5 mmol/g。吸附过程很快（吸附平衡时间小于1-4 h），并紧密遵循准二级动力学模型。在0.1 M稀硝酸溶液中，PGMA-DETA吸附剂上的铜离子最有效地解吸，80%的解吸在最初1分钟内完成。连续的吸附-解吸实验表明，PGMA-DETA吸附剂几乎可以无吸附容量损失地重复使用。
