Gas Separation

Polymeric Membranes for H2 and N2 Separation

“…The structure of PSF is characterized by the diphenylene sulfone repeating units which effectively impart the polymer backbones with a certain degree of rigidity owing to their hindrance to the intrasegmental rotations. This bestows PSF with a high Tg of around 186 °C and a satisfactory combination of a H2 permeability of 14 Barrer and H2/N2 and H2/CH4 selectivities of both 56 at 35 °C, which was fairly acceptable during the early stage of development for GS membranes [30]. The iconic structure of PSF, which is also a commercial product under the trade name of Ultrason® S, is shown in Fig.…”

“…Table 2. Common applications of H2 and N2 separation and their corresponding polymer materials [30] Polymeric membranes are generally dense and nonporous such that the gas transport through them follows a well-established solution-diffusion mechanism that comprises three major processes: 1) gas molecules adsorb onto the membrane surface on the highpressure upstream side, 2) then they diffuse into and through the polymer matrix, 3) and eventually desorb away from the low-pressure downstream side [3]. More specifically, from a microscopic point of view, process 2) actually does not occur as a continuous passage.…”

“…Upilex® (Fig. 4), synthesized from BPDA and 4,4'-oxydianiline (ODA) monomers, is one representative member of the Ube polyimide family and it has demonstrated outstanding hydrogen separation performance with a H2 permeability of 50 Barrer and H2/N2 and H2/CH4 selectivities of 83 and 125, respectively [30].…”