Waste gas containing s2, o2, co2, and n2 is fed to a so2 absorber. The liquid absorbent loaded with so2 is pumped to a reactor containing a solid catalyst, e.g., Al2O3, at 140 deg c. Sufficient h2s is supplied to the reactor to satisfy the following reaction: 2h2s + so2 -> 3s + 2h2o. The liquid s falls to the bottom of the reactor and is removed. Water is removed from the top as steam. The regenerated absorbent is recirculated to the absorber and the process is repeated. At a lower temperature the s is separated from the absorbent liquid as solid particles. The liquid absorbent also separates out nonpolar gases, e.g., O2, n2 and co2, for which the liquid is a nonabsorbent. The organic liquid absorbents are glycols, glycol esters, and glycol ethers.
U.S. Pat. 4,053,575; Oct. 11, 1977; Chem Abstr. 84:P107,839s