Synthesis and characterization of PVA-co-acrylic acid incorporating magnesium nanoparticles and their application in sweetening of natural gas.

Natural gas sweetening, involving removal of CO2 and H2S from CH4, is conventionally carried out by amine scrubbing, which is highly energy intensive. In the present study, we report the synthesis of poly(vinyl alcohol-co-acrylic acid) (PVA-co-AAc) based nanocomposite membranes incorporated with surface-stabilized magnesium nanoparticles (MgNPs) through a simple aqueous route. The MgNPs act as Lewis basic sites providing reversible chemisorption for CO2/H2S, while the polymer matrix ensures hydrophilic pathways for solution-diffusion along with mechanical robustness. The prepared membranes were characterized by FTIR, XRD, SEM, TEM, AFM, TGA/DSC, DMA and tensile strength. Gas permeation studies at 25-60 °C and 1-10 bar revealed improved CO2/CH4 and H2S/CH4 selectivity, with CO2/CH4 selectivity reaching 20.8, without loss in permeance. The synergistic effect of polymer-nanoparticle interaction enhanced both stability and separation performance. Process analysis indicates potential energy savings compared to conventional amine processes, showing promise for industrial scale natural gas sweetening.