Abstract: Silica gel adsorbents with different pore size distributions were prepared by modifying with metal ions and inorganic acids. The separation characteristics of adsorbents for aromatics and alkanes was studied by the static adsorption method and dynamic pulse method. The research results indicated that the selectivity of silica gel adsorbent for bicyclic aromatics was greater than that for monocyclic aromatics. With the increasing of the carbon number of alkylbenzene, the selectivity decreased.When sulfur-containing compounds were present, the selectivity of the adsorbent to aromatics remained almost unchanged. When nitrogen-containing compounds were present, the selectivity of the adsorbent to monocyclic aromatics decreased. Within the range of 60—170 ℃, as the adsorption temperature increased, the retention volume of each component decreased and the adsorption and desorption rate accelerated. The optimal separation temperature was 100—140 ℃. With the increasing of adsorbent pore size, the mass transfer rate of the components increased, but the separation degree decreased. The mass transfer performance of modified adsorbent was improved and the separation degree of aromatics was enhanced. For adsorbent A, with the pore size increasing from 2.2nm to 2.4nm, the selectivity to long-chain alkylbenzene improved.

Key words: silica gel adsorbent, static adsorption method, dynamic pulse method, aromatics-alkane separation, sulfur-containing compound, nitrogen-containing compound