Silver-Ion-Functionalized Super Microporous Silica for Enhanced Selective Adsorption Desulfurization of Fuels

Air pollution caused by the conversion of sulfides from fuels to SOx is a significant environmental concern. Adsorbents with favorable selectivity, high sulfur capacity, and satisfactory regeneration performance remain the main constraints and challenges in the field of adsorption desulfurization from fuels. Herein, we developed a high-efficiency desulfurization adsorbent Ag/SMS by using super microporous silica (SMS) as a carrier and functionalizing with silver ions. The unique pore structure and abundant hydroxyl groups of SMS facilitated silver ions uniform dispersion and primary deposition within the pore channels of SMS. The incorporation of silver ions significantly enhanced the desulfurization performance of SMS for removing aromatic sulfides. The saturated sulfur capacities of the optimized adsorbent (0.25-Ag/SMS) derived from 0.25 mol/L AgNO3 toward thiophene (TP), benzothiophene (BT), and dibenzothiophene (DBT), attained 0.148, 0.201, and 0.283 mmol S/g, respectively, demonstrating much higher adsorption capacities compared with previously reported silver-modified adsorbents. Besides, 0.25-Ag/SMS exhibited outstanding adsorptive separation selectivity for TP, BT, and DBT with 1 wt % toluene, achieving 57.3, 49.5, and 51.2%, respectively. Meanwhile, 0.25-Ag/SMS exhibited a remarkable regeneration performance using a microwave-assisted method. Therefore, 0.25-Ag/SMS with excellent desulfurization as well as efficient and eco-friendly regeneration performance might be employed in practical selective adsorption desulfurization of fuels.