Leveraging lewis acid and π-complexation to boost desulfurization efficiency in bimetallic Al/Cu(I)-MOF

The combustion of thiophene sulfides in fuel leads to the release of sulfur oxides (SO_x), which pose significant threats to both ecological systems and human health. Adsorption desulfurization has gained considerable attention from researchers due to its mild operating conditions, low production costs, and minimal impact on octane number. This study investigates the use of Cu-BTC as a platform for developing a novel adsorbent aimed at efficiently removing thiophenic compounds from fuel. Aluminum atoms were incorporated into the framework of Cu-BTC to create micro/mesoporous Al/Cu-BTC. Subsequently, the π-complexation adsorbent Al/Cu(I)-BTC, featuring Lewis acid sites, was synthesized through the in-situ reduction of Al/Cu-BTC using sodium thiosulfate. The adsorption properties of Al/Cu(I)-BTC for thiophene were assessed through both batch and breakthrough experiments. Al/Cu(I)-BTC-0.10(0.28) demonstrated exceptional adsorption performance. The static and dynamic adsorption capacities of thiophene at 500 and 200 ppm were 18.54 mg S/g and 9.49 mg S/g, respectively. Importantly, the adsorption capacity of Al/Cu(I)-BTC-0.10 (0.28) for thiophene in fuel containing 500 ppm sulfur remained at 15.45 mg S/g after six regeneration cycles. In the competitive adsorption of toluene, the adsorption capacity of the adsorbent for thiophene in the fuel containing 200 ppm sulfur was 7.84 mg S/g.