Process for the conversion of H.sub.2 S and adjustment of the H.sub.2 /CO ratio in gaseous streams containing hydrogen sulfide, hydrogen, and carbon monoxide

A process comprising

• (a) contacting a gaseous stream containing H.sub.2, CO, and H.sub.2 S with an H.sub.2 S-selective absorbent in an absorption zone and absorbing the bulk of the H.sub.2 S in said stream, producing a partially purified gas stream with water and;
• (b) contacting at least a portion of the purified gas stream with a water shift catalyst under conditions to react CO and water in a conversion zone and converting CO and water to H.sub.2 and CO.sub.2, and producing a modified gas stream having increased ratio of H.sub.2 to CO and a minor portion of H.sub.2 S;
• (c) passing modified gas stream to a contacting zone, and contacting modified gas stream in the contacting zone with an aqueous reactant solution, the solution containing an effective amount of an oxidizing polyvalent metal chelate of nitrilotriacetic acid, and mixtures thereof, and converting H.sub.2 S in the modified gas stream in the contacting zone to sulfur and recovering a substantially sulfur-free gas modified stream having an increased ratio of H.sub.2 to CO.