An Investigation on Gas Transport Properties of Cross-Linked Poly(ethylene glycol diacrylate) (XLPEGDA) and XLPEGDA/TiO₂ Membranes with a Focus on CO₂ Separation

Abstract

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, H2, and N2 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 °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 H2, CH4, and N2 increased by 16.2%, 15.6%, and 26.6%, respectively.

Toward the Recycling of Low-GWP Hydrofluorocarbon/Hydrofluoroolefin Refrigerant Mixtures Using Composite Ionic Liquid–Polymer Membranes

“…In this regard, several works have previously reported the adequacy of using the Flory–Huggins model to fit convex-shaped sorption isotherms of different solvent vapors, such as methanol, ethanol, or butanol, in membranes made of the family of Pebax copolymers or the sorption of water vapor through the Pebax 1074 grade . Besides, good correlations were found for the sorption of CO 2 in similar polymers to Pebax, such as crosslinked PEO or crosslinked PEO diacrylate membranes . However, to the best of our knowledge, this model has not been widely applied to describe gas solubility in CILPMs. …”

“…52 Besides, good correlations were found for the sorption of CO 2 in similar polymers to Pebax, such as crosslinked PEO 38 or crosslinked PEO diacrylate membranes. 53 However, to the best of our knowledge, this model has not been widely applied to describe gas solubility in CILPMs.…”

The State-of-the-Art Functionalized Nanomaterials for Carbon Dioxide Separation Membrane

“…The introduction of CO 2 -affinitive functional groups can lead to the creation of 'reverse selective' membrane whereby the permeation of CO 2 (3.3 Å) is more favorable than that of smaller/lighter gases especially H 2 (2.9 Å) [244][245][246]. Compared to H 2 -selective membrane, reverse selective membrane is deemed more practical for separation of H 2 -CO 2 pair because CO 2 is directly removed from the system while purified H 2 which is still pressurized is retained and passed down the production line [36,247]. This could contribute to a substantial cost saving for the purification process as recompression of H 2 stream is omitted.…”

“…The application of a membrane for gas separation is closely associated with the energy sector, in which the removal of contaminant gases such carbon dioxide (CO 2 ) and hydrogen sulfide (H 2 S) is critical for improving the calorific values of the gaseous feedstock to maximize power generation [33][34][35]. Since CO 2 and H 2 S are corrosive, the elimination of both gases can also prevent damage to system instruments and pipelines [36,37]. Contemporarily, CO 2 separation via a polymeric-based membrane is widely explored in applications such as natural gas sweetening [30,38,39], hydrogen purification [40,41] and biogas upgrading [31,42,43].…”

UV Cross-Linked Poly(ethylene glycol)-Based Membranes with Different Fractional Free Volumes for CO2 Capture: Synthesis, Characterization, and Thiol-ene Modification Evaluation

“…Nevertheless, the well-known trade-off between permeability and selectivity values of polymeric membranes is a predominant challenge encountered for their industrial application. − Therefore, development of advanced materials with high affinity for CO 2 can extend their capability for developing membrane technology for CO 2 removal. , Lin and Freeman , found that poly­(ethylene oxide) (PEO)-based membranes are promising candidates for CO 2 separation from light nonpolar gases such as N 2 , CH 4 , and H 2 , providing high CO 2 solubility selectivity. Indeed, the presence of the polar electron-rich ether oxygen (EO) units in these polymers backbones results in high affinity to CO 2 molecules due to dipole–quadrupole interactions. − However, development of PEO-based membranes with high EO content is rather challenging owing to strong crystallization tendency, caused by their high chain packing, resulting in drastic CO 2 permeation decline . Moreover, PEO-based membranes mostly suffer from lack of mechanical strength …”