No abstract

Polymeric membranes are attractive for CO2 separation and concentration from different gas streams because of their versatility and energy efficiency; they can compete with, and they may even replace, traditional absorption processes. Here we describe a simple and powerful method for developing nanostructured and CO2-philic polymer membranes for CO2 separation. A poly(ethylene oxide)−poly(butylene terephthalate) multiblock copolymer is used as membrane material. Smart additives such as polyethylene glycol dibutyl ether are incorporated as spacers or fillers for producing nanostructured materials. The addition of these specific additives produces CO2-philic membranes and increases the CO2 permeability (750 barrer) up to five-fold without the loss of selectivity. The membranes present outstanding performance for CO2 separation, and the measured CO2 flux is extremely high (>2 m3 m−2 h−1 bar−1) with selectivity over H2 and N2 of 10 and 40, respectively, making them attractive for CO2 capture.

This paper reports the design of a tailor made polymeric membrane by using poly(ethylene oxide)–poly(butylene terephthalate) (PEO‐PBT) multi‐block copolymers. Their properties are controlled by the fraction of the PEO phase and its molecular weight. To explain the effect of structural changes in copolymer membranes, transport properties of four gases (CO2, H2, N2, and CH4) are discussed. After characterization, the two best copolymers are selected in order to prepare tailor made blends by adding poly(ethylene glycol) (PEG). The best selected copolymer that contained 55 wt. % of 4000 g mol−1 PEO produced a blend with high CO2 permeability (∼190 barrer), which is twice the permeability of the pure copolymer. At the same time, an enhancement of CO2/H2 selectivity is observed (∼13). These results suggest that the morphology of PEO‐PBT can be well controlled by the addition of low‐molecular‐weight PEG, and consequently the gas transport properties can be tuned.

Miniaturization and manipulation of materials at nanometer scale are key challenges in nanoscience and nanotechnology. In membrane science and technology, the fabrication of ultra-thin polymer films (defect-free) on square meter scale with uniform thickness (<100 nm) is crucial. By using a tailor-made polymer and by controlling the nanofabrication conditions, we developed and manufactured defect-free ultra-thin film membranes with unmatched carbon dioxide permeances, i.e. > 5 m(3) (STP) m(-2) h(-1) bar(-1). The permeances are extremely high, because the membranes are made from a CO(2) philic polymer material and they are only a few tens of nanometers thin. Thus, these thin film membranes have potential application in the treatment of large gas streams under low pressure like, e.g., carbon dioxide separation from flue gas.

The paper describes the performance of Pebax ® /PEG blend thin film composite membranes for CO 2 separation from gas mixtures containing H 2 , N 2 and CH 4. Membranes were tested at different conditions; temperature and pressure dependence of gas flux and selectivity were explored. The temperature dependence was correlated with the Arrhenius equation to determine the activation energy of single gas permeation. Single and mixed gas permeation was measured for different pressures at 293K up to 20 bar. Improved permeabilities and CO 2 /H 2 selectivities were obtained in the newly developed composite membranes