改性介孔无机凝胶的制备及其在溶液中的吸附机理

未改性的介孔无机凝胶虽然具有较大的孔径,原则上可以吸附较大的分子或离子,但由于吸附剂的表面性质简单,与吸附质之间的作用力弱,因而吸附容量低,选择性不理想.采用表面修饰或杂化的方法在介孔凝胶中引入各种官能团或改变介孔凝胶的表面电荷之后,吸附剂的表面性质得到了很大的改善,吸附剂可以靠静电作用、离子交换、疏水作用、氢键、络合作用、基于分子阀门的开关效应和基于分子印迹的分子识别等机制对吸附质进行选择吸附.

Synthesis of Modified Mesoporous Inorganic Gels and Their Adsorption Mechanism in Solution

Although unmodified mesoporous inorganic gels may adsorb relatively big molecules and ions because of their large pore diameter, however, their simple surface properties and the weak interactions between adsorbents and adsorbates result in low adsorption capacity and poor selectivity. The surface properties of the adsorbents can be improved greatly by modification or hybridization, which can graft functional groups to the pore walls of the mesoporous gels or change the surface charges of the mesoporous gels. The absorbents may adsorb the adsorbates by some mechanisms, such as electrostatic interaction, ionic exchange, hydrophobic interaction, hydrogen bonding, complexation, on-off effect based on molecular gates, molecular recognition based on molecular imprinting, etc.