改性氧化石墨烯去除重金属离子的分子动力学模拟

发布时间：2018-10-30 12:39

【摘要】：通过硅烷化反应在氧化石墨烯(Graphene oxide,GO)表面嫁接螯合官能团N-(三甲氧基硅丙烷)乙二胺三酸(EDTA-Si),得到改性氧化石墨烯(GO-EDTA),采用分子动力学模拟在分子水平上研究了Pb~(2+)在GO-EDTA表面的动态吸附分布、构象及动力学性质,比较了Pb~(2+)和单价Na~+离子在氧化石墨烯上的吸附行为,模拟了GO-EDTA与Ca~(2+)相互作用,与Pb~(2+)的吸附行为进行了对比.模拟结果表明,Pb~(2+)和Na~+的吸附位点是GO-EDTA体系中的羧基,而非氧化石墨烯表面的羟基;Pb~(2+)和Na~+与羧基的吸附构象不同,前者吸附构象以摩尔比2∶1为主,即两个羧基对一个Pb~(2+)离子,而后者更多倾向于摩尔比1∶1的吸附模式,即一个羧基对一个Na~+离子;Pb~(2+)离子相对于Ca~(2+)和Na~+离子,形成的COO--Pb~(2+)离子对构象越过的能垒最低,但是破坏该离子对构象时能垒较高,表明Pb~(2+)离子在氧化石墨烯膜上表现出良好的吸附性.
[Abstract]:The modified graphene oxide (GO-EDTA) was prepared by grafting the functional group N- (trimethoxysilyl) ethylenediamine triacid (EDTA-Si) onto the surface of graphene oxide (Graphene oxide,GO). The dynamic adsorption distribution, conformation and kinetic properties of Pb~ (2) on the surface of GO-EDTA were studied by molecular dynamics simulation. The adsorption behavior of Pb~ (2) and monovalent Na~ on graphene oxide was compared. The interaction between GO-EDTA and Ca~ (2) was simulated and the adsorption behavior of Pb~ (2) was compared. The results show that the adsorption sites of Pb~ (2) and Na~ are carboxyl groups in GO-EDTA system, not hydroxyl groups on the surface of graphene oxide. The adsorption conformation of Pb~ (2) and Na~ is different from that of carboxyl group. In the former, the molar ratio is 2:1, that is, two carboxyl groups have a Pb~ (2) ion, while the latter is more inclined to the adsorption mode of molar ratio 1:1. That is, one carboxyl group to one Na~ ion; Compared with Ca~ (2) and Na~ ions, Pb~ (2) ion has the lowest barrier over the conformation of COO--Pb~ (2) ion, but the barrier is higher when the ion pair conformation is destroyed. It is shown that Pb~ (2) ions exhibit good adsorption on graphene oxide film.
【作者单位】：山东大学化学与化工学院;山东大学国家胶体材料工程技术研究中心;
【基金】：国家自然科学基金(批准号:21475076) 科技部国际合作专项基金(批准号:2015DFA50060)资助~~
【分类号】：O647.3

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