ABSTRACT
Hydrogen sulfide (H2S) is a toxic gas found in many industrial environments. As hydrogen sulfide diffuses through the membrane, an oxidation-reduction reaction occurs and the resulting electrons cause a current flow, which is in proportion to the H2S concentration in the air. Gold films absorb hydrogen sulfide and register the concentration by a proportional change in their electrical resistance. For the solid-state sensor, hydrogen, isopropanol, ethyl and methyl mercaptan interfere with the measurement. Hydrogen sulfide reacts with lead acetate to form lead sulfide, causing a brown stain on the paper. The measurement of the ultraviolet (UV) absorption of H2S provides a sensitive and selective technique for monitoring H2S concentrations in gas streams with no other UV absorbing compounds. In special system, H2S is extracted with a dilute ammonium hydroxide solution, and the strong UV absorption of the ammonium sulfide formed in solution is measured and calibrated for H2S concentration in the gas stream.
