6种重金属螯合捕集剂与氧化铝相互作用的分子动力学模拟

Molecular dynamics simulation of interactions between six kinds of heavy metal chelating agents and alumina crystal

采用分子动力学(MD),对三硫代三嗪酸(Trimercaptotriazine,TMT)、N,N-双(2-巯基乙基)间苯二甲酰胺N,N'-bis(2-memaptoethyl)isophthalamide,NBMIPA)、N^1,N^2,N^4,N^5-(1,2,4,5-四巯基乙基)苯甲四酰胺(N^1,N^2,N^4,N^5-tetrakis(2-mercaptoethyl)benzene-1,2,4,5-tetracarboxamide,TMBTCA)、四硫代联氨基甲酸(Tetrathio Bicarbamic Acid,TBA)、二甲基二硫代氨基甲酸(Dimethyl dithio carbamate,DDC)、六硫代胍基甲酸(Sixthio guanidine acid,SGA)等6种重金属螯合捕集剂分子与氧化铝(Al_2O_3)(012)晶面在真空状态下的相互作用进行了模拟,并对不同模拟体系的结合能、重金属螯合捕集剂分子的形变能及其分子中N、S、O原子与Al_2O_3(012)晶面Al原子间的对关联函数(RDF)进行了分析。研究结果表明,6种重金属螯合捕集剂分子均可与Al_2O_3(012)晶面产生明显的相互作用,结合能由大到小依次为:NBMIPA>TMBTCA>TMT>TBA>DDC>SGA,分子形变能依次为:TMBTCA>NBMIPA>SGA>TMT>TBA>DDC,且NBMIPA、TMBTCA 2种分子中N、S、O原子与Al_2O_3(012)晶面Al原子间作用力明显强于其它重金属螯合捕集剂分子。研究结果有利于明晰重金属螯合捕集剂与土壤中氧化铝的相互作用,从而为更好地理解重金属螯合捕集剂的作用机制、提高其作用效能提供一定的理论参考。

Molecular dynamics were used to simulate the interactions between different heavy metal chelating agents, such as Trimercaptotriazine （TMT）, N, N＇-bis（2-mercaptoethyl）isophthalamide （NBMIPA）, N1, N2, N4, N5-tetrakis（2-mercaptoethyl） benzene-l, 2,4,5-tetracarboxamide （TMBTCA）, Tetrathio Bicarbamic Acid （TBA）, Dimethyl dithio carbamate （DDC）, Sixthio guanidine acid （SGA）, and the （012） face of alumina crystal under vacuum condition. The binding energy, molecular deformation energy and the radial distribution functions （RDF） between N, S, O atoms in heavy metal chelating agent molecules and A1 atoms in A1203（012） surface were analyzed and compared. The results showed that all six kinds of heavy metal chelating agent molecules could interact with A1203（012） surface obviously, the binding energies had the order of NBMIPA 〉 TMBTCA 〉 TMT 〉 TBA 〉 DDC 〉 SGA, and the molecular deformation energies had the order of TMBTCA 〉 NBMIPA 〉 SGA 〉 TMT 〉 TBA 〉 DDC. The interactions between N, S, O atoms in NBMIPA and TMBTCA and AI atoms in A1203（012） surface appeared relatively stronger than others. The study will be helpful to understand the interaction mechanism between heavy metal chelating agents and A1203 in soil, and provide theoretical references to improve the efficient utilization in the removal of heavy metals from soil.