High removal of thiophene from model gasoline by porous MIL-101(Cr)/SA hybrid membrane

Abstract

Membrane separation technologies have great promising potential for applications in several industries. Metal–organic frameworks (MOFs), for their large surface areas, low framework densities, transition-metal ions in the skeleton and high pore volumes relative to other porous matrices, have great potential for the removal of sulfur from gasoline with high efficiency. In the present study, a novel porous membrane adsorbent MIL-101(Cr)/SA was prepared by immobilizing MIL-101(Cr) onto sodium alginate (SA) matrix, which can combine the size/shape selectivity of MIL-101(Cr) with the processability and mechanical stability of SA polymer. The physico-chemical properties of MIL-101(Cr)/SA were investigated by FT-IR, SEM, BET, XRD and EDX methods. To investigate the effects of some important factors on the adsorption behavior for thiophene, a batch of experiments were performed by changing the concentration of porogen polyethylene glycol in the MIL-101(Cr)/SA, solution temperature, initial thiophene concentration and contact time. Meanwhile, benzothiophene, thiophene and 3-methyl thiophene were used to test the selectivity of MIL-101(Cr)/SA. The MIL-101(Cr)/SA showed an excellent uptake capacity of 671 mg g⁻¹ under the optimal adsorption conditions. Selectivity testing indicated that the uptake capacity of MIL-101(Cr)/SA follows the order of benzothiophene > thiophene > 3-methyl thiophene. Kinetics experiments indicated the pseudo-second-order model displayed good correlation with adsorption kinetics data. The Crank model showed that the intraparticle solute diffusion is the rate-controlling adsorption step. Regeneration experiment result shows that the prepared MIL-101(Cr)/SA has excellent adsorption and desorption efficiencies.