功能化介孔吸附剂的制备及其对银离子吸附性能的研究

Study on Preparation and Adsorption Capacity of a Functionalized Mesoporous Absorbent for Ag(Ⅰ)

以F127和CTMABr为模板剂,采用一步法经水热合成了巯基(-SH)修饰的新型介孔吸附剂,并将其应用于水溶液中Ag^+的去除研究。分别考察了初始pH值、振荡时间、Ag^+初始浓度和金属离子竞争对介孔吸附剂性能的影响。结果表明,在pH 5～6的范围内该吸附剂Ag^+吸附量最大(Q=2.998mmol/g),其吸附机理是巯基(-SH)与Ag^+的离子交换和配位化学吸附反应。在Cu^(2+)、Ni^(2+)、Co^(2+)和Pb^(2+)等竞争性金属阳离子存在的情况下,Ag^+去除率仍然高达90%以上。该介孔吸附剂对Ag^+具有较高的吸附效率,其吸附符合Langmuir模型。

A new kind of ordered mesoporous silica material with mercapto group is synthesized by using F127 and CTMABr as co-templates through one-step pathway and employed as an absorbent of Ag＋ in aqueous solution. It is showed that the mercapto group can be introduced into the mesoporous channel under controlled reaction conditions. The effects of initial pH, adsorbent time, Ag＋ concentration and competing cations on the adsorption affinity are studied. The functionalized mesoporous material exhibits high adsorption capacity of 2. 998mmol/g for Ag＋ at pH 5-6 and fast adsorption rate of less than 30min in aqueous solution. The Ag＋ removal rate is still above 90% even if in the presence of other competing cations such as Cu2＋ , Ni2＋ , Co2＋ and Pb2＋. Equilibrium data are well fitted to the Langmiur adsorption isotherm（ r2 = 0. 9994）. The adsorption mechanism might be a ligand exchange process of-SH group on the surface of the mesoporous silica with Ag＋ in aqueous solution.