Process for the continuous removal of hydrogen sulfide from gaseous streams

A process for the continuous removal of hydrogen sulfide from a gaseous stream containing hydrogen sulfide, comprising:

• a) putting a gas containing H2S in contact with an oxidizing acidic aqueous solution of ferric nitrate which further comprises a heteropolyacid having redox properties, as such or partially salified with an alkaline metal or with ammonium, selected from those having general formula (I):
• HnXVyM(12-y)O40, (I)
• wherein n is an integer ranging from 3 to 6;
• X is selected from P, Si, As, B, and Ge;
• y is an integer ranging from 1 to 3;
• and M is selected from Mo and W;
• b) filtering and separating sulfur produced in a) as a result of the oxidizing effect of the ferric nitrate, which is reduced to ferrous nitrate in solution with heteropolyacid;
• c) oxidizing the ferrous nitrate from b) to ferric nitrate with air in an oxidation reactor thereby producing a solution comprising ferric nitrate and heteropolyacid;
• d) recycling the solution comprising ferric nitrate and heteropolyacid from d) to redox (a);
• e) subjecting a gaseous stream comprising one or more nitrogen oxides leaving the oxidation reactor in (c), to washing in a washing apparatus to the head of which is fed from 10 to 100% by weight of the reduced solution coming from sulfur separation (b), before the same is fed to the oxidation (c);
• and
• f) discharging the gaseous stream.