Abstract
Torlon® is a thermally and plasticization-resistant polyamide imide characterized by low gas permeability at room temperature. In this work, we aimed at improving the polymer performance in the thermally-enhanced He/CO2 and H2/CO2 separations, by compounding Torlon® with a highly permeable filler, ZIF-8, to fabricate Mixed Matrix Membranes (MMMs). The effect of filler loading, gas size, and temperature on the MMMs permeability, diffusivity, and selectivity was investigated. The He permeability increased by a factor of 3, while the He/CO2 selectivity decreased by a factor of 2, when adding 25 wt % of ZIF-8 at 65 °C to Torlon®; similar trends were observed for the case of H2. The MMMs permeability and size-selectivity were both enhanced by temperature. The behavior of MMMs is intermediate between the pure polymer and pure filler ones, and can be described with models for composites, indicating that such materials have a good polymer/filler adhesion and their performance could be tailored by acting on the formulation. The behavior observed is in line with previous investigations on MMMs based on glassy polymers and ZIF-8, in similar conditions, and indicates that ZIF-8 can be used as a polymer additive when the permeability is a controlling aspect, with a proper choice of loading and operative temperature.
Highlights
Membrane materials with good size selectivity and thermal resistance are required to remove carbon dioxide from hydrogen or helium; the separation performance is enhanced, both in terms of permeability and selectivity, at high temperatures [1,2,3,4,5]
scanning electron microscopy (SEM) images of the cross section of pure Torlon® membrane and Torlon/ZIF-8 Matrix Membranes (MMMs) are shown in Figure S2, where we can detect the effect of the filler addition on the membrane cross-section
ZIF-8: as it can be from theThe data relative suchperformed membrane,only there a good linear relationship between the seen from the data such diameter, membrane, is a good linear relationship between permeability andrelative the gas to kinetic at there both temperatures inspected, as follows: the permeability and the gas kinetic diameter, at both temperatures inspected, as folP P = −Aσ + B
Summary
Membrane materials with good size selectivity and thermal resistance are required to remove carbon dioxide from hydrogen or helium; the separation performance is enhanced, both in terms of permeability and selectivity, at high temperatures [1,2,3,4,5]. Previous studies have investigated the use of Torlon® in membrane separation (CO2/CH4), as it was believed that this material, due to its tightly packed structure, could resist to the plasticization induced by high pressure CO2 [48,51] Such tight packing is due, as demonstrated via IR spectroscopy, to the fact that almost all the N-H groups of the polymer are connected either through inter-chain or intra-chain hydrogen bonds [48].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
