不同金属盐改性对硅胶的水蒸气吸附性能影响

用不同的金属盐溶液对中孔硅胶进行了改性,并进行了吸附水蒸气动力学实验.讨论了改性硅胶的吸湿性与离子半径之间的关系及吸附速率与平均孔径的关系.实验结果表明:(1) CaCl2,LiCl,MgCl2,ZnCl2改性硅胶,可以使硅胶的吸湿性能明显增加.其中用CaCl2改性的硅胶的吸湿量最大,其平衡吸湿量是未改性硅胶的3倍;(2) 用CaCl2溶液改性的中孔硅胶其吸湿量已接近微孔硅胶的吸湿量,但其吸附速率明显大于微孔硅胶的吸附速率;(3) 用CaCl2和ZnCl2的混合溶液改性硅胶对其吸湿量的提高没有明显效果.

THE EFFECT OF SURFACE MODIFICATION BY DIFFERENT METAL SALT SOLUTIONS ON THE HYGROSCOPIC PROPERTY OF SILICA GELS

In this work, mesopore silica gel was modified separately by several kinds of salt solution to prepare a series of dehumification materials, and then kinetic experiments of water vapour adsorption on the modified mesopore silica gels were carried out. The effects of ion radius and average pore diameter on the absorption capacity and velocity were discussed. Results showed that (1) the hygroscopic ability of the silica gel modified respectively by CaCl2, LiCl, MgCl2 and ZnCl2 was improved, of which the adsorption capacity of the silica gel modified by CaCl2 was the highest in the modified mesopore silica gels and was three times of the adsorption capacity the unmodified silica gel; (2) the adsorption capacity of the mesopore silica gel modified by CaCl2 was up to that of the micropore silica gel, and its adsorption velocity was much higher than that of the micropore silica gel; (3) no improvement was observed when the mixed solution of CaCl2 and ZnCl2 was used to modify the mesopore silica gel.