Adsorption of theophylline from aqueous solution on organic aerogels and carbon aerogels

A series of organic aerogels (AGs) with different porous structures were prepared by controlling the conditions of sol–gel polymerization, and related carbon aerogles (CAs) were obtained by carbonization at 1,173 K. Their structures were investigated by N₂ adsorption–desorption analysis. The static adsorption of theophylline from aqueous solution on AGs and CAs was studied to explore the influence of micropore areas, mesopore volume and surface chemistry on adsorption capacity. The results show that the adsorption capacities of theophylline on CAs are better than on AGs. The adsorption properties of all samples obey Langmuir model. The values of correlation coefficient are almost over 0.99, indicating a good mathematical fit. The comparison of the adsorptions on AGs and CAs indicated that both micropores and mesopores play important roles in determining the adsorption capacity. But for AGs, besides the pore structure, the surface chemistry also contributes to the adsorption capacities.