Effects of Sol-Gel Synthesis on 5Fe-15Mn-40Zn-40Ti-O Mixed Oxide Structure and its H_2S Removal Efficiency from Industrial Gas Streams

摘要

A novel Fe-Mn-Zn-Ti-O mixed metal oxide has been developed for efficient low-temperature (25-50 ℃) removal of H_2S from a gas mixture containing 600 ppm H_2S, 25 vol% H_2, 7.5 vol % CO_2, and 1-3 vol% H_20 that simulates typical conditions experienced at the outlet of a bioreactor loaded with sulfate metal reducing bacteria (SMRB) that converts toxic Cr~(6+) and As~(5+) present in ground and surface waters and soils into nontoxic elements. During the latter conversion H_2S gas is produced and has to be treated. In the present work it is demonstrated for the first time that by using the sol-gel synthesis route at given experimental conditions (e.g., metal precursor salts, solvent system, and solution pH), optimum structural properties for the Fe-Mn-Zn-Ti-O solid can be obtained for maximization of H_2S uptake. In particular, at 25 ℃ an H_2S uptake (0.085 g H_2S/g solid) larger by at least a factor of 3 compared to a commercial Ni-based H_2S absorbent material was obtained.