An Investigation on Gas Transport Properties of Cross-Linked Poly(ethylene glycol diacrylate) (XLPEGDA) and XLPEGDA/TiO_2 Membranes with a Focus on CO_2 Separation

摘要

Poly(ethylene oxide) (PEO)-based membranes are known as outstanding candidates for carbon dioxide (CO2) separation as the major greenhouse gas responsible for global warming. In this paper, gas transport properties (solubility, permeability, and diffusivity) of neat and nanocomposite cross-linked poly(ethylene glycol diacrylate) (XLPEGDA) membranes were investigated for CO2 as well as CH4, C2H4, C2H6, C3H8, H-2, and N-2 gases. XLPEGDA as a low-molecular-weight PEO, has not been studied much, compared to other PEO-based membranes such as poly(ether-block-amide) (PEBA) for CO2 capture. To make the conducted research more practical, the operating conditions were selected near to industrial operational conditions, i.e., in the temperature range of 35-75 degrees C and at pressures up to 16 bar. All membranes were synthesized by UV photopolymerization. To prepare nanocomposite membranes, inorganic titanium dioxide (TiO2) nanoparticles were incorporated within the polymeric matrix prior to its cross-linking. Structural properties of the prepared membranes were characterized by scanning electron microscopy energy-dispersive X-ray (SEM-EDX), Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and density analysis. DSC and FTIR results confirmed completeness of the cross-linking reaction. SEM images showed homogeneous structure of the membranes and rather uniform dispersion of the TiO2 nanoparticles. It was found that incorporation of the TiO2 nanoparticles, more specifically at 3 wt % loading, results in enhancement of CO2 permeability and solubility by 39% and 18.5%, respectively. Furthermore, CO2 selectivity values over the investigated light gases including H-2, CH4, and N-2 increased by 16.2%, 15.6%, and 26.6%, respectively.