Evaluation of cellulose-derived carbon molecular sieve membranes for hydrogen separation from light hydrocarbons

Carbon molecular sieve membranes derived from cellulose–hemicellulose have been evaluated for hydrogen separation from light hydrocarbons. Copper(II) nitrate was added to the precursor in the range of 0–6 wt%, resulting in increased hydrogen/methane permselectivity at the expense of permeability. Carbonization temperature was varied from 400 to 700 °C, with the best performance for membranes produced between 550 and 650 °C. Mixed gas tests with H2, CO2, C1–C4 and N2 showed that these membranes tolerate light hydrocarbons and separated hydrogen with a permeability of about 480 Barrer and hydrogen/methane permselectivity >1000. Hydrogen/carbon dioxide permselectivity was found to be approximately 23 at 25 °C. Transport was activated and an increase of 65 °C doubled the mixed gas hydrogen permeability. Performance was strongly influenced by exposure to air.