Synthesis, Characterization and Application of Polymer Based Membranes by Using Modified Zeolite Particles

Abstract

Membrane technology has been extensively explored as fascinating separation technique due to its energy efficient nature. This work concerns with the synthesis of five series of polymer membranes namely Polysulfone/Polyimide/Modified Zeolite mixed matrix membrane (MMM), Polysulfone/Polyimide/Silica nanocomposite membranes (NCM), Polysulfone/Polyimide-Silica- Modified Zeolite NCM, PIM-1/Modified Zeolite MMM and PIM-1/Modified zeolite thin-film composite membranes by solution casting method. Modified zeolite (MZ) filler was added to polymer matrix for tight packing of polymer layers. By adding silica (SiO2) and MZ filler to polymer matrix, the membranes exhibit properties of both organic and inorganic membranes. Polyimide and Polymer of intrinsic microporosity-1 (PIM-1) were synthesized by condensation reactions. Morphology and structure of fabricated samples were investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction analysis (XRD). Mechanical and thermal properties of nanocomposite membranes were also investigated. Polysulfone based membranes were investigated for antibacterial properties while PIM-1/Modified Zeolite MMMs were investigated for CO2/N2 separation. Thermal and mechanical properties of fabricated membranes were enhanced by filler addition due to fine compatibility and strong interaction of polymer and filler. Diffrential scanning calorimetry analysis (DSC) indicated increase in glass transition temperature (Tg) with increasing filler concentration. Better DSC specifications were evaluated for 10 wt% MZ content. Thermogravimetric analysis (TGA) complimented DSC results. Combining effects of Polysulfone (PSf), Polyimide (PI), SiO2 and MZ enhanced the antibacterial properties however, better antibacterial results were observed for 10 wt% nanocomposite in all cases. Integration of MZ filler in PIM-1 improved the CO2 permeability. Moreover, considerable increase in CO2 permeability was evaluated for alcohol treated PIM-1/MZ MMM as alcohol wash opens up the free volume. Effect of membrane’s thickness on gaseous flux was evaluated by fabrication of thin-film composite membrane (TFC) which improved the aging properties for TFC membranes as significant arrest was observed in permeability loss for TFC membranes. In all cases, CO2 permeability was observed to increase with increasing MZ concentration. Thus, we speculate that the permeation properties are adequately enhanced due to strong interaction and fine compatibility of MZ filler in PIM-1 matrix.