Volume 1: Energy Innovations: Accelerated Deployment, New Concepts, and Emerging Technologies

Ultra-permeable polymeric membranes containing ZIF-8 nanoparticles for CO2 capture Leiqing Hu, Haiqing Lin, Jun Cheng

Abstract

—Membrane technology is an attractive approach for CO2 capture from flue gas derived from coal-power plants, due to its inherent advantages such as high energy-efficiency, small footprint and potentially low cost. The state-of-theart membranes are based on polar poly(ethylene oxide) (PEO), which exhibit high CO2 permeability and high CO2/N2 selectivity. In this work, these PEO containing materials were doped with zeolitic imidazolate framework (ZIF-8) nanoparticles to improve CO2 permeability. Specifically, ZIF-8 was incorporated into polymers prepared from poly(ethylene glycol) diacrylate (PEGDA). These ZIF-8 nanoparticles had high porosities and average pore aperture of 0.34 nm that was between the molecule size of CO2 (0.33 nm) and N2 (0.364 nm), indicating their potential of achieving high CO2 permeability and CO2/N2 selectivity. The in situ synthesis of ZIF-8 provided uniform nanoparticle size of about 100 nm, enabling a good dispersion in polymers at loadings as high as 50 wt%. Increasing the ZIF-8 loading dramatically increased CO2 permeability. For example, adding 10 wt% ZIF-8 increased the CO2 permeability from 130.8 Barrers in a polymer prepared from PEGDA to 318.3 Barrers without changing the CO2/N2 selectivity. At a loading of 50 wt%, the nanocomposite exhibited a CO2 permeability of 1334.5 Barrers and CO2/N2 selectivity of 33.1 at 35 oC, which was one of the best separation properties reported in the literature.

Keywords —CO2 capture, membrane, ZIF-8, PEGDA