Defect creation by benzoic acid in Cu-Based Metal−Organic frameworks for enhancing sulfur capture

The clean and efficient utilization of fossil fuels places increasing demands on desulfurization materials. The metal–organic framework MOF-199, known for its high surface area and easy functionalization, has been shown to be a promising adsorptive material. Strong interaction between the unsaturated copper centers of MOF-199 and sulfides is the main reason for its good desulfurization performance. So-called “defect engineering” is considered to be an efficient modification method for further improving the desulfurization performance of MOF-199. In this study, a defective MOF-199 has been fabricated in the presence of benzoic acid (BA) and characterized by means of experimental and computational methods. The adsorption and regeneration properties of the product towards H2S and CH3SCH3 have been evaluated by breakthrough experiments in a fixed-bed reactor. BA-MOF-199 exhibited superior results for H2S and CH3SCH3 removal compared to those with pristine MOF-199, with higher sulfur capacities of 69.2 and 78.9 mg S/g sorbent, respectively, at 1% breakthrough level, with corresponding partition coefficients of 5.4 and 12.3 mol kg−1 Pa−1. BA modification increased the number of unsaturated copper centers in MOF-199 and formed more mesoporous structures, which served to improve the sulfide adsorption capacity.