Liang Shuai, Cao Shengguang, Liu Changrong, Zeb Shah, Cui Yu, Sun Guoxin
School of Chemistry and Chemical Engineering, University of Jinan Jinan 250022 Shandong P. R. China
Institute for Smart Materials & Engineering, University of Jinan Jinan 250022 Shandong P. R. China.
RSC Adv. 2020 Feb 19;10(12):7259-7264. doi: 10.1039/d0ra00125b. eCollection 2020 Feb 13.
Heavy metal pollution is an essential environmental issue in the world. The current methods present limitations for the removal of low concentration divalent heavy metals from wastewater, such as high cost, unsatisfactory adsorption capacity, and poor reusability. Herein, we designed and prepared a novel chelating adsorbent. The adsorbent was prepared using chloromethyl polystyrene microsphere as a framework material modified by ethylenediaminetetraacetic acid (EDTA) with two types of functional groups and six binding sites in one coordination unit. Each coordination unit of the adsorbent prepared provides two negative charges of two carboxyl groups to balance the two positive charges of the divalent heavy metal ion, and forms coordination bonds through its two nitrogen atoms and two amidic carbonyl groups. This synergistic adsorption effect produced by electrostatic interaction and chelation significantly improves the adsorption capacity. The adsorption of some environmental heavy metals was tested, and high adsorption capacity for Pb(ii) was obtained. The saturated adsorption capacity for Pb(ii) was as high as 352.1 mg g, and the effluent concentration of the column experiment was less than 0.20 ppm. Simultaneously, the presence of the amide group shows good anti-interference to alkali metals and alkali soil metals. The result is of considerable significance to the actual wastewater treatment.
重金属污染是全球一个重要的环境问题。目前的方法在从废水中去除低浓度二价重金属方面存在局限性，如成本高、吸附容量不理想和可重复使用性差等。在此，我们设计并制备了一种新型螯合吸附剂。该吸附剂以氯甲基聚苯乙烯微球为骨架材料，用乙二胺四乙酸（EDTA）进行改性，在一个配位单元中具有两种官能团和六个结合位点。所制备的吸附剂的每个配位单元提供两个羧基的两个负电荷以平衡二价重金属离子的两个正电荷，并通过其两个氮原子和两个酰胺羰基形成配位键。这种由静电相互作用和螯合产生的协同吸附效应显著提高了吸附容量。测试了对一些环境重金属的吸附情况，对Pb(ii)具有高吸附容量。对Pb(ii)的饱和吸附容量高达352.1 mg/g，柱实验的流出液浓度小于0.20 ppm。同时，酰胺基团的存在对碱金属和碱土金属表现出良好的抗干扰性。该结果对实际废水处理具有相当重要的意义。
