Construction of hydrophobic channels on Cu(I)-MOF surface to improve selective adsorption desulfurization performance in presence of water

Abstract

The adsorption desulfurization (ADS) is a promising technology for deep removing thiophene-type sulfurs, yet it remains challenges in maintaining good performance for real applications in the presence of water. Guided by theoretical calculations, we constructed hydrophobic selective channels by crosslinking porous aromatic framework (PAF) of PAF-56 on the surface of adsorbent MOF-199 with Cu nodes reduced. The optimized Cu(I)-BTC@PAF30 shows a high saturated dibenzothiophenes (DBT) adsorption capacity of 61.7 mgS g−1 from the dehydrated model oil. Attributed to the good DBT-affinity (with binding energy (BE) of −90.52 KJ mol−1) and water-repulsion (with BE of −14.72 KJ mol−1), PAF-56 coating layer significantly improves the hydrophobicity, and keeps the DBT adsorption capacity as high as 50.8 mgS g−1 in the presence of 0.5% (v/v) water, the decline of 17.6% was much smaller than the dramatical 70.9% decrease in pristine Cu(I)-BTC. More importantly, it effectively prevents Cu(I) nodes from the oxidation, and exhibits a superior stable cyclic performance with the removal efficiency above 91% after 20 cycles. Therefore, Cu(I)-BTC@PAF30 can be a good representative of this surface modification strategy to achieve promising application in industrial ADS.