Asahi Glass Company, Limited

Toshikatsu Hamano

Yoshiharu Aoki

Manabu Suhara

Yoshio Oda

Yukio Matsumura

Koji Miura

Shoziro Goto

Takashi Hukushima

A method of making water having a low salt content by desalination comprising the steps of alternately arranging pluralities of cation exchange membranes and monovalent anion selective anion exchange membranes or pluralities of anion exchange membranes and monovalent cation selective cation membranes between electrodes thereby alternately forming pluralities of the diluting cells and concentrating cells of an electrodialysis tank; feeding a salt containing water including hardly soluble salts to the plurality of diluting cells of the electrodialysis tank; feeding electricity to the electrodes; maintaining the salt concentration of the concentrated solution in the plurality of concentrating cells to a value of not less than 700 ppm; and retaining as much as possible the polyvalent anions forming the hardly soluble salts in the salt containing water.

Method of producing water having a reduced salt content

An apparatus for recovering an acid from an acid-containing waste liquor, which is a diffusion dialytic cell having a plurality of anion exchange membranes disposed to alternately form feed liquor compartments to which the acid-containing waste liquor is supplied and recovery compartments to which water is supplied, wherein a cooling compartment defined by a water-impermeable membrane is provided adjacent to such feed liquor compartments or recovery compartments.

Method and apparatus for recovering an acid from an acid-containing

A method for recovering sulfuric acid from a titanium sulfate waste liquor by diffusion dialysis in a diffusion dialytic cell provided with anion exchange membranes, which comprises subjecting the titanium sulfate waste liquor to precision filtration to remove a solid content having a particle size of at least 0.1 .mu.m to a level of not more than 100 .mu.g/l, and placing the filtered liquor to face water with an anion exchange membrane interposed therebetween so that sulfuric acid in the titanium sulfate waste liquor is recovered by diffusion dialysis.

Method and apparatus for recovering sulfuric acid from a titanium

A method for treating a plating solution in an electrolytic cell having a cathode compartment and an anode compartment partitioned by an ion-exchange membrane, which comprises supplying a plating solution containing not more than 10 g/liter of Fe.sup.3+ ions to the cathode compartment and an electrically conductive solution to the anode compartment, and electrolytically reducing the Fe.sup.3+ ions in the plating solution to Fe.sup.2+ ions, wherein an electrode having a hydrogen overvoltage of not higher than 350 mV, preferably made of a carbon material, is used as a cathode.

Method for treating a plating solution

A process for producing an ion exchange membrane comprising impregnating a base material with a polymerizable monomer material and polymerizing the monomer material, if necessary, followed by a reaction for introducing ion exchange groups, wherein said base material is made of an olefin polymer and/or a fluorinated olefin polymer, said polymerizable monomer material is a mixture comprising styrene, chloromethylstyrene and divinylbenzene as three essential components, and the polymerizable monomer material impregnated in the base material is firstly partially polymerized by irradiation of ionizing radiation, and subsequently completely polymerized by heating in the presence of a polymerization initiator.

Process for producing an ion exchange membrane using irradiation by

An electrolysis of an aqueous solution of sodium chloride is carried out by employing a fluorinated cation exchange membrane having an ion-exchange capacity of 0.8 to 2.0 meq/g dry polymer and having carboxylic acid groups as functional groups and maintaining a concentration of an aqueous solution of sodium hydroxide in a cathode compartment in a range of 20 to 45 wt. % and maintaining a calcium concentration in the aqueous solution of sodium chloride to lower than 0.08 mg/liter. The purification of the aqueous solution of sodium chloride to reduce the calcium concentration is carried out in a system comprising the first and second chelate ion-exchange towers which are connected through a detector for detecting impurities in the aqueous solution.

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Chiba, Japan

Toshikatsu Hamano