硅胶的表面改性及其对水体铜离子的吸附性能研究

Modification of Silica gel and Its Selective Adsorption of Cu2＋ from Aqueous Solution

尝试利用化学性质稳定、机械强度高的硅胶吸附剂，通过定向表面改性，赋予其特定理、化性质，以脱除水体重金属Cu^2＋。研究结果表明，原始硅胶经甲磺酸活化，借助硅胶表面富含的-OH基团，化学共价键联γ-氨丙基三乙氧基硅烷，使硅胶表面借助硅氧基嫁接-NH2基团，进一步地，在偶氮二异丁腈引发下，嫁接丙烯腈，经偕胺肟化聚丙烯腈基团，使改性硅胶吸附剂表面富含-NH2和-OH，显著提升其对水体cu2＋的选择性吸附。利用红外光谱探明了硅胶表面改性的机制，系统探讨了接触时间、Cu^2＋初始浓度、溶液pH值等因素对改性硅胶吸附性能的影响，通过改性硅胶表面Cu^2＋的等温吸附平衡和吸附动力学研究，初步揭示了改性硅胶的化学吸附实质。

In the present work, the silica gel with chemical and mechanical stability were choose as a matrix for further modification, endowed with given specific physical and chemical properties for the removal of Cu2＋ in water. The research suggested that, with the activation by methanesulfonic acid, the amination were achieved by chemical bonding between γ-triethoxysilylpropylamine and hydroxyl groups on the surfaces of silica gel. Furthermore, the acrylonitrile was covalently attached by the eopolymerization between amino silica gel and acrylonitrile with the initiation of azobisisobutyronitrile. Finally, abundant amino and hydroxyl groups were linked onto the surface of modified silica gel through the amidoximation reaction. The surface nature of modified silica gel was illustrated by infrared spectrum measurement. The significant enhancement of the adsorption of aqueous Cu2＋ on modified silica gel were observed and the effects of contact time, initial concentration of Cu2＋, pH value of the solution were investigated. The adsorption isotherm and kinetics were calculated and the adsorption mechanism of Cu2＋ on amidoximed silica gel was proposed.