A method of removing sulfur compounds from a hydrocarbon fluid. The method includes contacting the hydrocarbon fluid with an adsorbent comprising a carbonaceous material doped with nanoparticles of uranyl oxide (UO.sub.3) to reduce the concentrations of the sulfur compounds. The carbonaceous material is at least one selected from the group consisting of activated carbon and carbon nanotubes, and the adsorbent has a weight ratio of C to U in the range from 9:1 to 17:1, and a weight ratio of C to O in the range from 5:1 to 13:1.

A method to activate U.sub.3O.sub.8 for conversion of this uranium oxide to hydrated UO.sub.4 via reaction with hydrogen peroxide H.sub.2O.sub.2, wherein the following successive steps are performed: a) an aqueous suspension is prepared containing a powder of U.sub.3O.sub.8 and hydrogen peroxide; b) the aqueous suspension containing a powder of U.sub.3O.sub.8 and hydrogen peroxide is contacted with ozone, whereby an aqueous suspension is obtained of a powder of activated U.sub.3O.sub.8; c) optionally the powder of activated U.sub.3O.sub.8 is separated from the aqueous suspension.

A method to convert U.sub.3O.sub.8 to hydrated UO.sub.4 of formula UO.sub.4, nH.sub.2O where n is 2 or 4, comprising at least one step at which hydrogen peroxide H.sub.2O.sub.2 is added to the aqueous suspension of a powder of activated U.sub.3O.sub.8 obtained at the end of step b) of the activation method or to an aqueous suspension prepared by placing in suspension in water the powder of activated U.sub.3O.sub.8 obtained at the end of step c) of the activation method.

A method to activate U.sub.3O.sub.8 for conversion of this uranium oxide to hydrated UO.sub.4 via reaction with hydrogen peroxide H.sub.2O.sub.2, wherein the following successive steps are performed: a) an aqueous suspension is prepared containing a powder of U.sub.3O.sub.8 and hydrogen peroxide; b) the aqueous suspension containing a powder of U.sub.3O.sub.8 and hydrogen peroxide is contacted with ozone, whereby an aqueous suspension is obtained of a powder of activated U.sub.3O.sub.8; c) optionally the powder of activated U.sub.3O.sub.8 is separated from the aqueous suspension.

A method to convert U.sub.3O.sub.8 to hydrated UO.sub.4 of formula UO.sub.4, nH.sub.2O where n is 2 or 4, comprising at least one step at which hydrogen peroxide H.sub.2O.sub.2 is added to the aqueous suspension of a powder of activated U.sub.3O.sub.8 obtained at the end of step b) of the activation method or to an aqueous suspension prepared by placing in suspension in water the powder of activated U.sub.3O.sub.8 obtained at the end of step c) of the activation method.

Methods of producing peroxides of uranium may include preparing an aqueous solution comprising uranyl ions (UO.sub.2.sup.+2) in a vessel, bubbling ozone (O.sub.3) through the aqueous solution comprising the uranyl ions, and recovering the peroxide of uranium. The peroxide of uranium may comprise at least one of studtite (UO.sub.4.Math.4(H.sub.2O) or metastudtite (UO.sub.4.Math.2(H.sub.2O).

A reactor (1) for hydrolysis of uranium hexafluoride comprises a tubular injector (9) comprising first (11), second (13) and third (15) concentric fluid circulation ducts intended to be connected respectively with a source of UF.sub.6, a source of inert gas and a source of water vapor. The tubular injector (9) is obtained by additive manufacturing.