Facile construction of hierarchically porous CPO-27-Ni by mixed ligand strategy towards enhanced adsorption desulfurization from fuels

High-efficiency removal of macromolecular aromatic sulfide from fuel via adsorption technology remains a challenge due to the limited mass-transfer efficiency in traditional microporous materials. Constructing hierarchically porous structure might be an alternative route to overcome the problem. Herein, we propose an approach to prepare rationally defective Nickel(II) 2,5-dihydroxyterephthalate (CPO-27-Ni) using benzoic acid (BA) and 2, 5-dihydroxyterephthalic acid (DHTA) as mixed ligands, aiming at reducing the diffusion resistance of molecules in adsorbents through introducing mesopores and thus enhancing the performance of aromatic sulfide removal. By adjusting the ratio of BA and DHTA (x), CPO-27-Ni (BA-C-x) with rational defects was successfully synthesized. Compared with the single-channel CPO-27-Ni, the penetrating sulfur capacity in the dynamic adsorption experiment was increased by 9.97 times for thiophene (TP), 7.25 times for benzothiophene (BT) and 2.81 times for dibenzothiophene (DBT). After the addition of organic ligand B, additional mesoporous pores were formed in the microporous CPO-27-Ni. The obtained hierarchical structure possessed better textural properties and ensured structural constancy, which improved the utilization rate of high active sites and mass transfer rate of adsorbent, leading to promoted desulfurization performance. The reported method of introducing mesopores into MOFs to construct hierarchically porous structures would provide a meaningful reference for facile preparation of high-efficiency desulfurization adsorbents.