Ultrasonic deposition of high-selectivity nanoporous carbon membranes

Ultrasonic deposition creates a thin film of polymer on a tubular, macropor ous, stainless steel support. Using polyfurfuryl alcohol as the nanoporous carbon precursor and a pyrolysis temperature of 723 kelvin, a membrane was prepared with the following permeances, measured in moles per square meter per Pascal per second: nitrogen, 1.8 X 10(-12); oxygen, 5.6 X 10(-11); heli um, 3.3 X 10(-10); and hydrogen, 6.1 X 10(-10). The ideal separation factor s as compared to that for nitrogen are 30:1, 178:1, and 331:1 for oxygen, h elium, and hydrogen, respectively.