桥连双亚胺介孔材料对Cr(Ⅵ)的吸附性能

Adsorption Properties of Double Imine Bridged Mesoporous Silica to Chromium(Ⅵ)

以CTAB/PAANa为混合模板剂,正硅酸乙酯为硅源,自制双亚胺基桥连硅烷偶联剂为改性剂,采用共缩聚法制备了双亚胺桥连介孔硅材料PMOS。利用FTIR、XRD、N2吸附-脱附、固体核磁和TEM对PMOS材料的结构和形貌进行了表征,将其应用于对Cr(Ⅵ)的吸附,并系统考察了pH值、吸附剂用量和吸附时间对PMOS吸附Cr(Ⅵ)的影响,且重点探究了PMOS对Cr(Ⅵ)的吸附行为。结果表明,PMOS具有高度有序的介孔结构,其对Cr(Ⅵ)的最佳吸附条件为:pH=6,初始浓度为200mg/L,吸附时间为8h。PMOS对Cr(Ⅵ)的吸附遵循Langmuir模型,在45℃时,其对Cr(Ⅵ)的饱和吸附量为428.61mg/g。此外,PMOS对Cr(Ⅵ)的吸附行为可用准二级动力学模型来描述,且PMOS与Cr(Ⅵ)之间的作用力主要为静电作用力和配位作用力。

The diimine bridged mesoporous silica （PMOS） was synthesized by copolycondensation method with CTAB/PAA- Na as mixed template, tetraethyl orthosilieate as silicon source and homemade silane coupling agent as modifier. The structure and morphology of PMOS materials were characterized by FTIR, XRD, BET, solid-state nuclear magnetic and TEM. The effects of pH value, mass rations of adsorbent and absorption time on adsorption for Cr（gi） were discussed. Besides, the adsorption behavior of PMOS for Cr（Ⅵ） was mainly investigated. The results showed that PMOS was highly ordered mesoporous structure. While pH= 6, the concentration of initial solution was 200 rag/L, adsorption time was 8 h, the PMOS showed excellent adsorption for Cr（ Ⅵ）. The adsorption could be described by Langmuir model and pseudo-second order kinetics model. When the temperature was 45 ℃, the saturated adsorption for Cr（ Ⅵ ） was 428. 61 mg/g. The force between PMOS and Cr（ Ⅵ ） is mainly electrostatic force and coordination force.