Manganese modified multifunctional carbon material for desulfurization of transportation fuel and CO2 sequestration

Abstract A comprehensive study on a newly developed multifunctional porous material (Mn@PP) derived from Pongamia pinnata (PP) biomass through surface modification with manganese was investigated for multiple environmental applications: desulfurization of transportation/liquid fuels and CO2 sequestration. Its efficiency was then compared with that of commercial activated carbon (DARCO). Mn@PP was found to have a very high specific surface area of 951 m2.g−1, and the concentration of Mn atom on PP surface was determined to be 1.18 at. percent. Desulfurization studies were performed with model fuel of 50 ppm dibenzothiophene (DBT) in hexane under optimized reaction conditions (12 g.L−1 dosage, and equilibrium time of 2 h) at ambient temperature. Isotherm, kinetic and thermodynamic studies were also investigated to understand the adsorption mechanism. An improved adsorption capacity post-Mn modification was observed where the maximum DBT removal was 22.73 mg.g−1, which was relatively higher than DARCO (9.12 mg.g−1) and PP (12.12 mg.g−1). Desulfurization of commercial gasoline also indicated favorably higher % removal for thiophenic fractions, viz. 84% and ~74% for benzothiophene and dibenzothiophene, respectively. The spent Mn@PP was regenerated with toluene and showed 96.9% removal of DBT within 3 cycles. CO2 adsorption studies at 273 K and 303 K at 760 torrs showed that the maximum CO2 adsorption capacity for DARCO, PP, and Mn@PP was 0.732, 0.832, and 0.856 mmol.g−1 respectively.