This invention is directed to amorphous and crystalline titanosilicate materials that have an unexpected selectivity for cesium and strontium, especially in the presence of high levels of competing ions. The titanosilicates of this invention show very high, unexpected selectivity in the presence of such competing cations such as sodium, calcium, magnesium and potassium, such as present in seawater.

A method of decontaminating a metal surface located on a component within a nuclear plant, in particular within the cooling system of a nuclear power plant, which is covered with a metal oxide layer containing radioactive substances, the method including a decontamination step in which a metal oxide layer pretreated in an oxidation step is contacted with an aqueous solution of an organic acid to dissolve the metal oxide layer, forming a decontamination solution containing the organic acid, metal ions and the radioactive substances, and passing the decontamination solution over an ion exchanger to immobilize metal ions and radioactive substances. An oxidant selected from oxygen, air, hydrogen peroxide and ozone is dosed into the decontamination solution to control the dissolution rate of the metal oxide layer. The method is particularly suitable for large-scale system decontamination and ensures high process stability.

A method of decontaminating a metal surface located on a component within a nuclear plant, in particular within the cooling system of a nuclear power plant, which is covered with a metal oxide layer containing radioactive substances, the method including a decontamination step in which a metal oxide layer pretreated in an oxidation step is contacted with an aqueous solution of an organic acid to dissolve the metal oxide layer, forming a decontamination solution containing the organic acid, metal ions and the radioactive substances, and passing the decontamination solution over an ion exchanger to immobilize metal ions and radioactive substances. An oxidant selected from oxygen, air, hydrogen peroxide and ozone is dosed into the decontamination solution to control the dissolution rate of the metal oxide layer. The method is particularly suitable for large-scale system decontamination and ensures high process stability.

A preparation method of a bacterial cellulose-defective molybdenum disulfide (BC-MoS.sub.2-x) heterojunction material for treating radioactive wastewater is provided, including: preparing bacterial cellulose by the in situ growth technology of Acetobacter xylinum, and freeze-drying to obtain dried bacterial cellulose; carbonizing the dried bacterial cellulose to obtain carbonized bacterial cellulose; dispersing the carbonized bacterial cellulose into deionized water under an ultrasonic treatment; then adding thiourea and Na.sub.2MoO.sub.4.2H.sub.2O, dissolving under an ultrasonic treatment to obtain a reaction mixture, subjecting the reaction mixture to a hydrothermal reaction to obtain a BC-MoS.sub.2 heterojunction; and calcining the BC-MoS.sub.2 heterojunction in a tube furnace with an Ar/H.sub.2 atmosphere to obtain the BC-MoS.sub.2-x heterojunction.

The present invention is directed to a method of removing uranium from a uranium containing aqueous medium. The method comprises a step of contacting the medium with magnetic mesoporous silica nanoparticles. The nanoparticles comprise mesoporous silica and iron oxide. The nanoparticles may also comprise a functionalized surface obtained by grafting or covalently bonding a functional molecule to the nanoparticle.

The present invention is directed to a method of removing uranium from a uranium containing aqueous medium. The method comprises a step of contacting the medium with magnetic mesoporous silica nanoparticles. The nanoparticles comprise mesoporous silica and iron oxide. The nanoparticles may also comprise a functionalized surface obtained by grafting or covalently bonding a functional molecule to the nanoparticle.

This application discloses the method for separating element or isotopes such as protactinium and gallium and isotopes thereof from a corresponding mixture which method comprises contacting the mixture with a carbon-based separation material, wherein the carbon-based separation material selectively associates with the element or isotope thereof.

This application discloses the method for separating element or isotopes such as protactinium and gallium and isotopes thereof from a corresponding mixture which method comprises contacting the mixture with a carbon-based separation material, wherein the carbon-based separation material selectively associates with the element or isotope thereof.

The invention provides an industrially advantageous method for producing a crystalline silicotitanate having high adsorption/removal capabilities for cesium and strontium in seawater. The method includes a first step of mixing a silicic acid source, a sodium compound, titanium tetrachloride, and water to prepare a mixed gel and a second step of hydrothermal reaction of the mixed gel prepared in the first step to produce crystalline silicotitanate of formula: Na.sub.4Ti.sub.4Si.sub.3O.sub.16.nH.sub.2O (wherein n represents 0 to 8). In the first step, the silicic acid source, sodium compound, and titanium tetrachloride are mixed in such a mixing ratio that the resulting mixed gel may have a Ti to Si molar ratio, Ti/Si, of 1.2 to 1.5 and an Na.sub.2O to SiO.sub.2 molar ratio, Na.sub.2O/SiO.sub.2, of 0.7 to 2.5.

The invention relates to a method for producing a solid nanocomposite material comprising nanoparticles of a metal coordination polymer with ligands CN, said nanoparticles satisfying the formula [Alk.sup.+.sub.x]M.sup.n+[M′(CN).sub.m].sup.z− where Alk is an alkali metal, x is 1 or 2, M is a transition metal, n is 2 or 3, M′ is a transition metal, m is 6 or 8, and z is 3 or 4; said M.sup.n+ cations of the coordination polymer being bound by an organometallic bond or a coordination bond to an organic group R2 of an organic graft, and said organic graft furthermore being chemically attached, preferably by a covalent bond, to at least one surface of a solid support, by reaction of a group R1 of said graft with said surface.