David J. Edlund

Hydrogen-permeable metal membranes for high-temperature gas separations

Abstract In this paper we describe a composite-metal membrane that shows promise for practical large-scale applications including the manufacture of ethylene, recovery of hydrogen from refinery streams, and the environmentally clean decomposition of hydrogen sulfide in sour natural gas and refinery off-gases. Specifically, this composite membrane exhibits improvements over previously developed metal membranes that include (1) stable hydrogen flux at 700°C, (2) low cost and (3) chemical compatibility with many common feed-stream impurities, including hydrogen sulfide.

Thin-film polymeric sensors for detection and quantification of multivalent metal ions

Abstract Chemical sensors that reversibly respond to multivalent metal ions are described. These sensors consist of a thin polymeric sensing element that changes size upon reversibly binding analyte ions, particularly heavy-metal ions. The polymeric sensing elements have been bonded to thin metal-foil strain gauges to form sensors. In laboratory evaluations these sensors exhibit high sensitivity to Ba(II), Cd(II), Pb(II), Cr(III), and Cr(VI). Sensor response time is fast, ranging from several seconds to a few minutes. The selectivity and repsonse characteristics of these sensors depend on the composition of the polymeric sensing element. This paper describes the sensitivity and selectivity demonstrated by sensors containing three chemically different polymeric sensing elements. Potential applications of these sensors include in situ real-time monitoring of the heavy-metal content of ground and surface water, municipal water supplies, and household tap water.