The modification of the mesoporous carbon CMK-3 with the aqua regia and its adsorption desulfurization mechanism

Ordered mesoporous carbon CMK-3 was synthesized and modified with aqua regia. Dibenzolthiophene (DBT) was employed to evaluate the adsorptive desulfurization performance of the adsorbents. It was found that such modification considerably enhanced the saturated sulfur capacity and breakthrough sulfur capacity toward DBT by 2 times, respectively. The modified CMK-3 possessed good reused performance. In order to make a deep study of main reasons for such increase, some characterizations including XRD, BET, TEM, FTIR, XPS, and Boehm titration were carried out. Based on the characterization results, the increased adsorption performance of modified CMK-3 was mainly attributed to the changes of the surficial acidic oxygen-containing functional groups. On such surface, the phenolic hydroxyl and the carboxyl groups have the chemical interactions with the S and the aromatic rings of DBT. Such interaction concerning the carboxyl groups devoted itself to the desulfurization more than the phenolic hydroxyl, and the cracking of the C-S bond of DBT also happen.