A ceria nanoparticles preparation method is provided. The method includes preparing a mixed solution containing a cerium precursor and an imidazole derivative and preparing ceria nanoparticles by stirring the mixed solution.

A ceria nanoparticles preparation method is provided. The method includes preparing a mixed solution containing a cerium precursor and an imidazole derivative and preparing ceria nanoparticles by stirring the mixed solution.

A method of processing a purified rare earth sulphate solution, the method including the steps of: contacting the purified rare earth sulphate solution with sodium hydroxide to precipitate rare earths as rare earth hydroxide, including the addition of an oxidant to oxidise cerium contained in the rare earth hydroxide precipitate; and selectively leaching the rare earth hydroxide precipitate with hydrochloric acid to form a rare earth chloride solution and a residue.

A method of processing a purified rare earth sulphate solution, the method including the steps of: contacting the purified rare earth sulphate solution with sodium hydroxide to precipitate rare earths as rare earth hydroxide, including the addition of an oxidant to oxidise cerium contained in the rare earth hydroxide precipitate; and selectively leaching the rare earth hydroxide precipitate with hydrochloric acid to form a rare earth chloride solution and a residue.

A porous formed article includes an organic polymer resin and an inorganic ion adsorbent and having the most frequent pore size of 0.08 to 0.70 μm measured with a mercury porosimeter. Such a porous formed article can be prepared by crushing and mixing a good solvent for the organic polymer resin and the inorganic ion adsorbent to obtain slurry; dissolving the organic polymer resin and a water-soluble polymer in the slurry; shape-forming the slurry; promoting coagulation of the shape-formed product by controlling the temperature and humidity of a spatial portion coming into contact with the shape-formed product, until the shape-formed product is coagulated in a poor solvent; and coagulating the coagulation-promoted shape-formed product in a poor solvent. A production apparatus can be used to prepare such a porous formed article.

A porous formed article includes an organic polymer resin and an inorganic ion adsorbent and having the most frequent pore size of 0.08 to 0.70 μm measured with a mercury porosimeter. Such a porous formed article can be prepared by crushing and mixing a good solvent for the organic polymer resin and the inorganic ion adsorbent to obtain slurry; dissolving the organic polymer resin and a water-soluble polymer in the slurry; shape-forming the slurry; promoting coagulation of the shape-formed product by controlling the temperature and humidity of a spatial portion coming into contact with the shape-formed product, until the shape-formed product is coagulated in a poor solvent; and coagulating the coagulation-promoted shape-formed product in a poor solvent. A production apparatus can be used to prepare such a porous formed article.

The present invention relates to a composite having the ability to stably and reliably detect a target gas even in a moist environment. The composite of the present invention includes: a nanostructure of an oxide semiconductor selected from the group consisting of SnO.sub.2, ZnO, WO.sub.3, NiO, and In.sub.2O.sub.3; and a CeO.sub.2 additive loaded on the nanostructure. The oxide semiconductor nanostructure is uniformly loaded with CeO.sub.2. The composite of the present invention can rapidly detect an analyte gas with high gas response irrespective of the presence and concentration of moisture. The present invention also relates to methods for preparing the composite, a gas sensor including the composite as a material for a gas sensing layer, and a method for fabricating the gas sensor.

The present invention relates to a composite having the ability to stably and reliably detect a target gas even in a moist environment. The composite of the present invention includes: a nanostructure of an oxide semiconductor selected from the group consisting of SnO.sub.2, ZnO, WO.sub.3, NiO, and In.sub.2O.sub.3; and a CeO.sub.2 additive loaded on the nanostructure. The oxide semiconductor nanostructure is uniformly loaded with CeO.sub.2. The composite of the present invention can rapidly detect an analyte gas with high gas response irrespective of the presence and concentration of moisture. The present invention also relates to methods for preparing the composite, a gas sensor including the composite as a material for a gas sensing layer, and a method for fabricating the gas sensor.

An adsorbent capable of adsorbing radioactive antimony, radioactive iodine and radioactive ruthenium, the adsorbent containing cerium(IV) hydroxide in a particle or granular form having a particle size of 250 μm or more and 1200 μm or less; and a treatment method of radioactive waste water containing radioactive antimony, radioactive iodine and radioactive ruthenium, the treatment method comprising passing the radioactive waste water containing radioactive antimony, radioactive iodine and radioactive ruthenium through an adsorption column packed with the adsorbent, to adsorb the radioactive antimony, radioactive iodine and radioactive ruthenium on the adsorbent, wherein the absorbent is packed to a height of 10 cm or more and 300 cm or less of the adsorption column, and wherein the radioactive waste water is passed through the adsorption column at a linear velocity (LV) of 1 m/h or more and 40 m/h or less and a space velocity (SV) of 200 h.sup.−1 or less.

An adsorbent capable of adsorbing radioactive antimony, radioactive iodine and radioactive ruthenium, the adsorbent containing cerium(IV) hydroxide in a particle or granular form having a particle size of 250 μm or more and 1200 μm or less; and a treatment method of radioactive waste water containing radioactive antimony, radioactive iodine and radioactive ruthenium, the treatment method comprising passing the radioactive waste water containing radioactive antimony, radioactive iodine and radioactive ruthenium through an adsorption column packed with the adsorbent, to adsorb the radioactive antimony, radioactive iodine and radioactive ruthenium on the adsorbent, wherein the absorbent is packed to a height of 10 cm or more and 300 cm or less of the adsorption column, and wherein the radioactive waste water is passed through the adsorption column at a linear velocity (LV) of 1 m/h or more and 40 m/h or less and a space velocity (SV) of 200 h.sup.−1 or less.