Adsorption desulfurization of model gasoline by metal-organic framework Ni3(BTC)2

摘要

This work presented the synthesis of Ni-based metal-organic framework material with a paddle-wheel structure Ni3(BTC)2 (Ni-BTC) and its application in thiophene (TP) adsorption from gasoline distillate by batch method. Adsorption isotherms of TP, cyclohexene, and toluene in cyclohexane onto Ni-BTC were conducted at 298-308 K to interpret the different effect of cyclohexene and toluene on TP adsorption. The results showed that, compared w让h cyclohexene, toluene addition in model gasoline led to a more evident decline in sulfur capacity of Ni-BTC, which is opposite to isostructural HKUST-1. The adsorption isotherms of TP, cyclohexene and toluene fit Langmuir model, S-type model and Temkin model well, respectively, indicating that the adsorption mechanisms of TP and the two competitors are different from one another The adsorption capacities on Ni-BTC followed the order of cyclohexene < toluene < TP at the same equilibrium concentrations, implying the order of the adsorption affinities, which is in good agreement with the different extent of influence by the two competitors. The enthalpy of TP adsorption on Ni-BTC was estimated to be -80.01 kj/mol, almost twice that on HKUST-1. The poor reusability of Ni-BTC in batch experiment, which is owing to its sensitivity to the air, can be prevented from regenerating used Ni-BTC in fixed-bed reactor by N2 flow. The difference between Ni-BTC and HKUST-1 in maximum adsorption capacity (q0),△H of TP adsorption, and stability demonstrates that the central metal in isostructural MOFs plays a key role in adjusting the desulfurization performance, which may open up a potential avenue for the development of MOF-based adsorbents with superior desulfurization performance.