Poly ether block Amide/Polyvinyl Alcohol/ MgO nanocomposite membranes: Selectivity for CO2 and CH4 gases

Abstract

One of the methods of improving mixed matrix membranes is the use of nanoparticles and compounds containing hydroxyl and carboxyl groups, which can be a suitable choice to help more permeability of gases. In this study, a mixed matrix membrane comprising polyether block amide/polyvinyl alcohol (Pebax/PVA) and magnesium oxide (MgO) nanoparticles was fabricated via solution casting. The Pebax/PVA membrane with MgO loadings of 10–15 % at varying PVA weight ratios (0, 20, 50, 80 %) was evaluated for CH4 and CO2 gas separation performance. Characterization via Fourier transform infrared (FTIR), X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) revealed the nanoparticles well-dispersed within the polymer matrix, with surface roughness increasing with MgO addition. XRD analysis indicated stronger interaction between MgO and PVA chains versus Pebax. Peaks at ∼ 42, 62° suggest nanoparticles lodged between polymer strands. Variables assessed as independents impacting CH4 and CO2 permeability included PVA content, MgO loading, pressure and temperature. ANOVA showed the quadratic model best fitted correlations between variables and responses. Experimental data yielded the formulation with optimum selectivity. Molecular dynamics simulation (MDS) via Materials Studio estimated CH4 and CO2 diffusion through selected membranes. Simulated results matched experimental data well. Relative to prior separation data and outcomes herein, the synthesized nanocomposite membrane proved highly effective, promising potential for diverse gas mixtures. Membrane permeabilities were also evaluated.

Keywords

• Polyether block amide
• Polyvinyl alcohol
• MgO nanoparticles
• Molecular dynamics simulations, Permeability