Supported fluorocarbon liquid membranes for hydrogen/oxygen separation

Photocatalytic water splitting is an environmentally-friendly method for hydrogen formation, but usually H-2 and O-2, are produced together, so separation is needed. This paper describes the separation of the gases with supported liquid membranes. The permselective liquids were various perfluorocarbon-based fluids, Dimethyl perfluorosebacate ((CF2)(6)(COOCH3)(2)), ethyl perfluorononanoate (CF3(CF2)(7)COOC2H5), perfluoro(perhydrophenanthrene) (C14P24) and 1H,1H,2H,2H-perfluorodecyl acrylate (CF3(CF2)(7)(CH2)(2)OCOCH=CH2). It was found that the perfluorodecyl acrylate-based liquid membrane showed the highest performance with H-2 permeance of 2.4 x 10(-9) mol m(-2) s(-1) Pa-1 (6700 barrers) and a H-2/O-2 selectivity of 10. The permeance properties of H-2 and O-2 were measured by a time-lag technique and respective diffusivities of 1.1 x 10(-9) and 6.7 x 10(-9) m(2) s(-1) and solubilities of 2.7 x 10(-4) and 4.1 x 10(-5) mol m(-3) Pa-1, were obtained. The lifetime of the membrane was over 48 h, which was much longer than that of other perfluorocarbon-based liquid membranes. The membrane was also stable at humid conditions. (C) 2016 Elsevier B.V. All rights reserved.