Effect of the calcination temperature of self-ordered mesoporous silicate on its adsorption characteristics for aromatic hydrocarbons

We have studied the changes in the adsorption characteristics of mesoporous silicate (SBA-15) for benzene and toluene that are caused by using different calcination temperatures (T_c = 773 to 1173 K) in the synthesis process. We found that SBA-15 calcined at 773 K shows an extremely high benzene selectivity, especially in the low pressure region, while SBA-15 treated at higher T_c shows lower selectivity. In order to analyze the benzene selective mechanism, we studied the structures of the SBA-15 series, including their meso- and microporosity in detail. We found that the BET surface area (S_BET) and the peak position of the mesopore diameter (2R _p) decreased, the peak position of the micropore diameter (2r _p) increased, and the 2r_p distribution became broader with increasing T_c. Among above factors, we conclude that the size and the distribution of 2r_p are the most important to achieve a high benzene selectivity.