Separation of n-butanol from aqueous mixtures using TiO2 and h-BN functionalized MIL-101(Cr) incorporated PVDF mixed matrix membranes

Abstract

In the present work, polyvinylidenefluroide (PVDF) mixed matrix membranes (MMMs) membranes are synthesized for selective separation of n-butanol from an aqueous mixture through organophilic pervaporation (PV). Hydrophobic MIL-101(Cr) surface-modified with TiO2 and h-BN nanoparticles (NPs) are incorporated into the PVDF membrane. The prepared nanocomposites and MMMs are characterized by various analytical techniques: FESEM, AFM, HRTEM with SAED pattern, PXRD, FTIR, XPS, TGA, porosity and water contact angle measurements. The prepared MMMs are applied to recover the 1.5 wt% n-butanol/water mixture. The hydrophobic nature of MIL-101(Cr) enhances the adsorption selectivity for butanol, resulting in enhanced butanol flux and selectivity. Experimental data show that the total flux and selectivity boost with increased feed composition and temperature. The modified membranes show enhancement in total flux and selectivity by 19.03 % and 63.25 % (A2), 80.03 % and 284.72 % (A3), and 90.99 % and 145.13 % (A4), respectively. Incorporating h-BN NPs into the MIL-101(Cr) increases the affinity for water molecules to pass through membranes, reducing the butanol selectivity of the membranes. From the experimental data, it can be concluded that adding hydrophilic nanoparticles such as TiO2 and h-BN into the MIL-101(Cr) enhances each membranes total flux and separation factor. The significant separation results are found for A3 membrane with total flux of 3139.21 g m−2 h−1 and separation factor of 95.04. Also, the A3 membrane shows good long term performance stability of 160 h. Overall, good physiochemical characteristics and separation performance show the practical applicability of the butanol separation for the prepared membranes.