The present invention is to provide a novel adsorbent which is low in cost, has versatility and has high adsorption ability. Specifically, the present invention is to provide an adsorbent containing a metal salt of a cyanometallic acid obtained by a reaction of a salt of a cyanometallic acid and a compound containing a metal element, wherein the reaction is carried out using the compound containing a metal element in an amount of less than 100 mol % of the theoretical amount relative to 1 mol of the salt of a cyanometallic acid, a method of producing the same, and a method for removing harmful ions from water using such an adsorbent.

The invention relates to a technique for handling liquid radioactive waste from a nuclear fuel-energy cycle, and may be used in a process for processing liquid radioactive waste for maximally reducing the volume thereof and removing radionuclides by concentrating same in a solid phase. The aim is achieved by means of a method for processing liquid radioactive waste and for the recovery thereof, including waste oxidation, separating sludge, colloids and suspended particles from a liquid phase, and removing, from the liquid phase, radionuclides to be subsequently recovered using selective sorbents and filters; the method is characterized in that, prior to the stage for separating sludge, colloids and suspended particles from the liquid phase of the radioactive waste, selective sorbents in the form of powders are added and mixed into the liquid waste.

A purification method that uses ion-selective ceramics to electrochemically filter waste products from a molten salt. The electrochemical method uses ion-conducting ceramics that are selective for the molten salt cations desired in the final purified melt, and selective against any contaminant ions. The method can be integrated into a slightly modified version of the electrochemical framework currently used in pyroprocessing of nuclear wastes.

A purification method that uses ion-selective ceramics to electrochemically filter waste products from a molten salt. The electrochemical method uses ion-conducting ceramics that are selective for the molten salt cations desired in the final purified melt, and selective against any contaminant ions. The method can be integrated into a slightly modified version of the electrochemical framework currently used in pyroprocessing of nuclear wastes.

Proposed are a regenerating agent for a radionuclide adsorbent containing aqueous ammonia and organic acid, a regenerating method for a radionuclide adsorbent after using the regenerating agent for the radionuclide adsorbent, a method for treating of a spent regenerating agent obtained by the regenerating method of the spent radionuclide adsorbent, and a method of improving ion exchange capability of the regenerated radionuclide adsorbent obtained by the regenerating method of the spent radionuclide adsorbent.

The present invention relates to a radionuclide adsorbent, which includes a hollow space (specifically, an area which is entirely empty or in which transition metal oxide particles are present); and a transition metal-ferrocyanide shell (specifically, a transition metal-ferrocyanide shell having a structure in which a plurality of two-dimensional nano flakes overlap or a transition metal-ferrocyanide shell having a structure in which a plurality of three-dimensional nano polyhedrons agglomerate) formed on the space surface, a preparation method thereof, and a method of removing a radionuclide using the same.

The present invention relates to a radionuclide adsorbent, which includes a hollow space (specifically, an area which is entirely empty or in which transition metal oxide particles are present); and a transition metal-ferrocyanide shell (specifically, a transition metal-ferrocyanide shell having a structure in which a plurality of two-dimensional nano flakes overlap or a transition metal-ferrocyanide shell having a structure in which a plurality of three-dimensional nano polyhedrons agglomerate) formed on the space surface, a preparation method thereof, and a method of removing a radionuclide using the same.

The present invention provides compositions for removal of arsenic or heavy metal contaminants in the process of fluid filtration comprising an organically modified inorganic adsorbent, wherein the composition is produced by reaction with 1,3-dipolar compounds prior to filtration. Also provided are systems for fluid filtration, comprising compositions as provided herein, in a column or column-like format, wherein a fluid is provided to the column such that the fluid flows through the organically modified inorganic adsorbent, and wherein contaminants present in the fluid are bound to the composition. Additionally provided are methods for fluid filtration, comprising contacting a fluid sample with the composition of claim 1 and collecting the filtered fluid sample after filtration.

The present invention provides compositions for removal of arsenic or heavy metal contaminants in the process of fluid filtration comprising an organically modified inorganic adsorbent, wherein the composition is produced by reaction with 1,3-dipolar compounds prior to filtration. Also provided are systems for fluid filtration, comprising compositions as provided herein, in a column or column-like format, wherein a fluid is provided to the column such that the fluid flows through the organically modified inorganic adsorbent, and wherein contaminants present in the fluid are bound to the composition. Additionally provided are methods for fluid filtration, comprising contacting a fluid sample with the composition of claim 1 and collecting the filtered fluid sample after filtration.

Solid nanocomposite material comprising nanoparticles of a hexacyanometallate or octacyanometallate of an alkali metal and of a transition metal, of formula [Alk.sup.+.sub.x]M.sup.n+[M′(CN).sub.m].sup.z− in which 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, z is 3 or 4, attached to at least one surface of a porous inorganic solid support, in which the nanoparticles are attached by adsorption to the at least one surface of the solid support, and in which the surface is a basic surface. Method for preparing this material. Method for extracting at least one metal cation from a liquid medium containing it, wherein the liquid medium is brought into contact with the material.