The invention is directed to a process to prepare elemental sulphur by (i) contacting an aqueous solution comprising bisulphide with oxidised sulphide-oxidising bacteria under anaerobic conditions wherein elemental sulphur is produced and a reduced sulphide-oxidising bacteria is obtained and (ii) wherein the reduced sulphide-oxidising bacteria are oxidised by transfer of electrons to an anode of an electrochemical cell to obtain the oxidised sulphide-oxidising bacteria.

The present invention discloses a method and system of recovering elemental sulfur and regenerating the catalyst for a sulfur-deposited catalyst, including immersing the sulfur-deposited catalyst in the ammonium sulfide solution, the leaching reaction under normal pressure and temperature, replacing the ammonium sulfide solution and immersing again for extraction for the same time; collecting the leachate of the two steps, conducting gas stripping of the elemental sulfur by adopting the high-temperature nitrogen gas, condensing the tail gas of gas stripping, subjecting to a purification treatment and then discharging, with the liquor condensate being the ammonium sulfide solution. Finally, the solid in the leachate is filtered, washed and dried after the gas stripping to obtain the elemental sulfur; and the washing and drying of catalysts that has been subjected to the two times of immersion and extraction obtain the regenerated catalysts.

The present invention discloses a method and system of recovering elemental sulfur and regenerating the catalyst for a sulfur-deposited catalyst, including immersing the sulfur-deposited catalyst in the ammonium sulfide solution, the leaching reaction under normal pressure and temperature, replacing the ammonium sulfide solution and immersing again for extraction for the same time; collecting the leachate of the two steps, conducting gas stripping of the elemental sulfur by adopting the high-temperature nitrogen gas, condensing the tail gas of gas stripping, subjecting to a purification treatment and then discharging, with the liquor condensate being the ammonium sulfide solution. Finally, the solid in the leachate is filtered, washed and dried after the gas stripping to obtain the elemental sulfur; and the washing and drying of catalysts that has been subjected to the two times of immersion and extraction obtain the regenerated catalysts.

The invention is directed to a process to prepare elemental sulphur by (i) contacting an aqueous solution comprising bisulphide with oxidised sulphide-oxidising bacteria under anaerobic conditions wherein elemental sulphur is produced and a reduced sulphide-oxidising bacteria is obtained and (ii) wherein the reduced sulphide-oxidising bacteria are oxidised by transfer of electrons to an anode of an electrochemical cell to obtain the oxidised sulphide-oxidising bacteria.

The invention is directed to a process to continuously treat a hydrogen sulphide comprising gas, said process comprising the following steps: (a) contacting the hydrogen sulphide comprising gas with an aqueous alkaline liquid comprising sulphide-oxidising bacteria and elemental sulphur particles thereby producing a loaded aqueous liquid comprising dissolved sulphide, polysulphide compounds, sulphide-oxidising bacteria and elemental sulphur particles and a gas having a lower content of hydrogen sulphide, and passing the loaded aqueous liquid through a polysulphide reactor zone comprising one or more plug flow reactor zones, (b) contacting the loaded aqueous liquid with an oxidant to enable the sulphide-oxidising bacteria to oxidise sulphide to elemental sulphur, thereby producing an enriched aqueous liquid comprising an increased amount of elemental sulphur particles and (c) separating elemental sulphur particles from the enriched aqueous liquid, wherein the residence time of the loaded aqueous liquid between its preparation in step (a) and its supply to step (b) is between 3 and 45 minutes, and wherein the content of elemental sulphur as part of the polysulphide compounds in the loaded aqueous liquid [S.sup.0 in S.sub.x.sup.2?] as supplied to step (b) is above 0.7 mM.