Combination of coordinatively unsaturated metal sites and silver nano-particles in a Ni-based metal-organic framework for adsorptive desulfurization

Abstract The Ag@CPO-27-Ni composites were deliberately synthesized with different loading amounts of silver nano-particles in CPO-27-Ni which features unsaturated metal sites and cylindrical one-dimensional channels having a diameter of ca. 11 A constructed by 2,5-dihydroxybenzene-1,4-dicarboxylate and Ni2+ by a simple one-pot solvothermal method. The well-characterized composites were used as adsorbents to eliminate the aromatic S-compounds of the model oil and fluid catalytic cracking (FCC) oil at room temperature. The experimental results showed that the adsorptive desulfurization followed pseudo-second order reaction kinetics and the adsorptive desulfurization capacity of Ag@CPO-27-Ni (wherein Ag is 1.23 wt%) was notably enhanced as compared with CPO-27-Ni under the same experimental conditions. Impressively, 35 ppmwS dibenzothiophene (DBT) (or benzothiophene (BT))-containing model oil (20 g) was desulfurized to 2.01 ± 0.27 (or 4.05 ± 0.26) ppmwS by using 0.2 (or 0.5) g of the composite, respectively; the composite showed much higher selectivity factor of adsorbing DBT to naphthalene than CPO-27-Ni. The notable enhancement in adsorptive desulfurization performance is thought to be due to the interactions between Ag particles and sulfur or π-system of thiophene moiety in the S-containing compounds that consequently promote selective attraction between S-containing compounds and the composite. Besides, the composite also showed satisfactory recyclability.