Agency of Industrial Science and Technology

Director-general of Agency of Industrial Science and Technology

Japan As Directed by Director General of Agency of Industrial Science

Yoshio Onodera

Takashi Iwasaki

Hiromichi Hayashi

Kazuo Torii

Takeo Ebina

Osamu Itabashi

Hitoshi Mimura

The present invention provides an easy-to-handle biopolymer composite ion-exchanger with high cesium selectivity, and method for manufacturing this ion-exchanger with ease and good reproducibility, and relates to a cesium separation/recovery agent comprising a composite ion-exchanger with high cesium selectivity by employing a calcium alginate gel as a matrix and loading this matrix with an inorganic ion-exchanger; and to a manufacturing method therefor.

Biopolymer composite ion-exchanger with high cesium selectivity and its manufacturing method

A novel synthetic mixed-layer silicate consisting of the layers of serpentine and layers of saponite each having a specified chemical composition is proposed, which has excellent dispersibility in water to form a colloidal dispersion capable of being converted into a gel by standing to be useful as a gelating agent exhibiting thixotropy along with unique porosity characteristics which enable the use thereof as an adsorbent. The mixed-layer silicate is prepared by the process comprising the steps of: (a) preparing an acidic aqueous solution containing silicic acid, magnesium salt and aluminum salt; (b) alkalifying the solution by the addition of an alkaline compound to precipitate a hydrous composite oxide containing silicon, magnesium and aluminum; (c) collecting the precipitates of the hydrous composite oxide; (d) admixing the precipitates of the hydrous composite oxide with an aqueous solution of an alkali metal hydroxide to give an aqueous slurry; and (e) subjecting the aqueous slurry of the hydrous composite oxide to a hydrothermal treatment by heating at a temperature up to 500.degree. C.

Synthetic mixed-layer silicate and method for the preparation thereof

Disclosed is a novel hydrous composite oxide of cerium (IV) and phosphorus characterized by the specified chemical composition and the unique X-ray diffractometric pattern, which is useful as an adsorbent or immobilizing agent of strontium ions in an aqueous solution such as radioactive wastes from atomic power plants. The composite oxide prepared by the precipitation reaction of a Ce (IV) salt in an aqueous solution and phosphoric acid can be imparted with an increased adsorption capacity for strontium ions when the precipitates are heat-treated under hydrothermal conditions at up to 300.degree. C. Immobilization of strontium ions adsorbed on the adsorbent can be more complete when the adsorbent bearing strontium ions is dried and subjected to a heat treatment at a temperature of 200.degree. C. or higher.

Hydrous composite cerium-phosphorus oxide for immobilization of

Proposed is a novel synthetic inorganic porous material having a chemical composition of the general formula

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Sendai, Japan

Yoshio Onodera