E. Gebrie Ajebe
National Taiwan University of Science and Technology,
Keywords: MXene nanosheets, UiO-66, Pebax, MMM, Gas Separation
Summary:Membrane separation systems have gained a great deal of attention in the gas separation field due to their low cost, high efficiency, and environmental benefits. Poor filler-matrix interactions and agglomeration of highly loaded fillers in mixed matrix membranes limit their advantage in overcoming trade-off limitations between permeability and selectivity. In this work, the hybrids of Mxene (Ti3C2Tx) nanosheets and UIO-66 nanoparticles were prepared and used as dual fillers with Pepax-1657 polymer matrix to synthesize mixed matrix membranes. As-prepared MMMs were used to capture CO2. The morphology, structure and chemistry of synthesized nanofillers and prepared membranes were studied by scanning electron microscopy, X-ray diffraction, differential scanning calorimeter, Fourier transform infrared spectra and thermogravimetric analysis. The controllable surface functionality of UIO-66 and fluidic nanochannels in lamellar mxene not only enhanced selectivity of CO2 from N2 and O2 but also increased the solubility and diffusivity via the carboxylate group of UIO-66 and narrow channels provided by Mxene nanosheets. Pebax-based MMMs incorporated with 10 wt% of Ti3C2Tx nanosheets/UIO-66 hybrid provide CO2 permeability of 248.591 barrers and CO2/N2 selectivity of 141.253. The as-prepared MMMs showed an enhancement of 400% and 500% increment in CO2 permeability and CO2/N2 selectivity respectively, compared to pristine Pebax membrane. The upper limit of Robeson separation has been successfully exceeded, indicating that mixed matrix membranes have potential for CO2 capturing applications. This work provides a roadmap to fabricate highly selective composite gas separation membranes to capture CO2 and reduce environmental pollution.