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.
