H2 PURIFICATION VIA POLYMERIC MEMBRANES SEPARATION

New polymeric membranes are used for purifying H2-rich gas mixtures, in particular thermally treated (at 120 °C) poly-ether-ether-ketone with Cardo group (PEEK-WC) and polylactic-acid (PLA). In this work, dense PLA membranes showed great results overcoming the Robeson's upper-bound (2008) with an ideal selectivity H2/CO2 around 25 and H2 permeability of 25 barrer. PLA membranes have been tested at ambient conditions, constituting a cost-effective solution for recovering hydrogen from gaseous mixtures coming from a reforming stage, meanwhile concentrating in CO2 the retentate stream. PEEK-WC membranes have been experimentally characterized for low/medium temperature operation (80 °C), showing interesting results in terms of H2/CH4 separation, with an ideal selectivity value higher than 40. For PEEK-WC thermally treated membranes, the H2 permeating flux increased with transmembrane pressure from 25 to 80 °C, reaching 20 barrer of H2 permeability at 80 °C.