Asahi Glass Company, Limited

Mitsubishi Jukogyo Kabushiki Kaisha

Chubu Electric Power Company, Inc.

Yoshiharu Aoki

Toshikatsu Hamano

Yoshio Sugaya

Shinichiro Kotake

Tsumoru Nakamura

Motoo Fukui

Tatunori Miwata

The present invention provides a cation exchange membrane which has excellent durability, a high limiting current density, a low direct current membrane resistance and excellent selectivity to monovalent cations. In the present invention, a cation exchange membrane excellent in selective permeability to monovalent cations is produced by bringing high molecular cations into contact with a surface of a cation exchange membrane in the presence of anions of an oxyacid or anions of an organic sulfonic acid.

Cation exchange membrane selectively permeable to monovalent cations and method for its production

A process for treating effluent from a flue-gas desulfurization system wherein the resulting gypsum is removed, comprises filtering the gypsum and fly ash free effluent by a filter, transferring the filtrate to an electrodialyzer wherein cation-exchange membranes and univalent anion-exchange membranes are alternately set up, concentrating chlorine ions in the solution therein by dialysis, further concentrating the solution by evaporation in an evaporator, kneading the concentrated solution with cement or a mixture of cement and coal ash to a solid matter with no harm, and thereafter abandoning for landfill; and an apparatus for treating effluent from a flue-gas desulfurization system, comprising a filter for filtering the effluent to a turbidity low enough for treatment by an electrodialyzer wherein the effluent is to be separated into concentrated and dilute solutions, the electrodialyzer equipped with an alternate arrangement of cation- and anion-exchange membranes, with concentration and dilution compartments alternately provided between the both ion-exchange membranes, means for conducting the concentrated solution to a step for final disposal, and means for recycling the dilute solution as makeup water to the desulfurization system.

Process for treating effluent from flue-gas desulfurization system and

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.

Growing community of inventors

Ichihara, Japan

Yoshiharu Aoki