Asahi Kasei Kogyo Kabushiki Kaisha

Junji Nomura

Yuzuru Ishibashi

Naoya Kominami

Naokuni Yamawaki

Hirokazu Fukumi

Akira Kaneda

Akio Inoue

Kiichiro Sasaguri

Toshio Iwasa

Hideaki Imai

Hiroshi Kayamori

Michio Kato

Toshihiko Amano

Toshiyuki Endo

Tokuzo Konishi

Fluorine or fluorine compounds dissolved at low concentrations in water are efficiently separated by use of hydrated rare earth oxides or insoluble hydrated rare earth salts, particularly hydrous rare earth fluorides or hydrous rare earth phosphates, as the adsorbent. By bringing fluorine dissolved water of pH 2-7 into contact with said adsorbent, fluorine is adsorbed on the adsorbent, and the adsorbed fluorine can be desorbed by contact with an alkali solution of pH 10 to 14 to regenrate said adsorbent. Also, by addition of a precipitating agent for fluorine to the desorbed solution, fluorine compounds can be separated by precipitation and the filtrate can be reused as the regenerating solution for the adsorbent.

Process for adsorption treatment of dissolved fluorine

Borate ions dissolved at low concentration in water are separated efficiently with the use of a hydroxide or hydrous oxide of a rare earth element as the adsorbent. By contacting a borate ion-containing water with the absorbent, borate ions are separated by adsorption, and the adsorbent having adsorbed borate ions is desorbed and the regenerated for reuse with a desorbing solution adjusted to pH about 2 to about 4 or pH about 12 to about 14.

Selective separation of borate ions in water

Borate ions dissolved at low concentration in water are separated efficiently with the use of a hydroxide or hydrous oxide of a rare earth element as the adsorbent. By contacting a borate ion-containing water with the adsorbent, borate ions are separated by adsorption, and the adsorbent having adsorbed borate ions is desorbed and regenerated for reuse with a desorbing solution adjusted to pH about 2 to about 4 or pH about 12 to about 14.

In a process for the separation of elements by chromatography in which a front zone and a rear zone are present in front of and in rear of an adsorption band of elements, a high column efficiency can be attained by developing the adsorption band of elements without causing the entry of a main eluent having a relatively high concentration into the front zone. According to the present invention, elements can be separated into individual species not only in a high state of purity but also in a high state of concentration, so that the productivity of elements may be extremely increased as compared with that of conventional methods. In addition, according to the present invention, the amount of eluent employed is remarkably small as compared with that in conventional methods. Therefore, the present invention is very advantageous for the separation of elements from an industrial standpoint.

Process for the separation of elements by chromatography

Aquatic animals can be kept in a living condition over a long period of time, without feeding them, by placing the aquatic animals, at a large density of more than 200 kg/m.sup.3 in environmental water; maintaining the temperature of the environmental water in a lowest possible range in which it is possible for the aquatic animals to exist; controlling the concentrations of ammonia compounds, water-soluble organic compounds and carbonic acid radical in the environmental water so that their levels do not exceed 20 ppm, 150 ppm and 1,000 ppm, respectively; and regulating the concentration of molecular oxygen dissolved in the environmental water so that it is 3 ppm or more.

Method for keeping aquatic animals alive over long periods of time

Aquatic animals can be kept in living condition over a long period of time by placing the aquatic animals in environmental water in a large density of more than 200 kg/m.sup.3 ; maintaining the temperature of the environmental water at a lowest possible level in which it is possible for the aquatic animals to exist; controlling the concentrations of ammonia compounds, water-soluble organic compounds and carbonic acid radical in the environmental water so that their levels do not exceed 20 ppm, 150 ppm and 1,000 ppm, respectively; and regulating the concentration of molecular oxygen dissolved in the environmental water so that it is 3 ppm or more.

Method for keeping aquatic animals alive over long period of time

Aquatic animals can be kept alive over a long period of time by utilizing the apparatus of the present invention comprising:

Apparatus for keeping aquatic animals alive over long period of time

An acrylonitrile polymer film is produced by the steps of:

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Fuji, Japan

Junji Nomura