Three-component mixed matrix membrane containing [Hmim][PF6] ionic liquid and ZSM-5 nanoparticles based on poly (ether-block-amide) for the pervaporation process

Abstract

Three-component mixed matrix membranes based on poly (ether-block-amide) (PEBA) were prepared by incorporation of ZSM-5 zeolite nanoparticles and [Hmim][PF6] ionic liquid for the separation of ethyl acetate (EAc) from EAc/water mixtures using the pervaporation process. At first, the dual-layer PEBA/polyethersulfone (PES) membranes containing [Hmim][PF6] in the active layer were prepared and employed in the pervaporation process. It was found that the ionic liquid leached out from the membrane during the pervaporation experiments and decreased the membrane selectivity. In order to avoid leaching out of the ionic liquid, triple-layer membranes consisting of a ZSM-5/PEBA as the top layer on a [Hmim][PF6]/PEBA as the intermediate layer and PES as the support layer were developed. The effect of ionic liquid concentration in the intermediate layer on the membrane separation performance was investigated and the results indicated that the membrane containing 2.5%wt. [Hmim][PF6] had the best separation performance in terms of the pervaporation separation index (PSI). Moreover, the ZSM-5 nanoparticles were added to the intermediate layer of the triple-layer membranes to improve the performance of the membranes. It was found that simultaneous loading of the ZSM-5 and [Hmim][PF6] in the PEBA matrix significantly improved the separation performance of the membrane as the PSI of the prepared three-component mixed matrix membrane was 1.5 times the PSI of the neat PEBA membrane.