γ-Zirconium phosphate phosphite (γ-ZrPP) was prepared by refluxing γ-zirconium phosphate in 0.1mol⋅dm^-3 phosphorous acid according to Alberti's method. Nine n-alkylamines (C₃-C₁₄) were employed as guest molecules to intercalate into γ-ZrPP at 25°C. The interlayer distances (d) were plotted vs. the number of carbon atoms (N_c) in each amine molecule, giving a straight line with an equation d=1.32N_c+12.2 (Å) . It is suggested that the guest molecules are taken up in a monolayer, and each molecule is arranged almost perpendicular to the layer plane of γ-ZrPP.

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New anion exchangeable layered basic salts were prepared and their ion-exchange properties were studied. Basic copper acetate, Cu₂ (OH) ₃ (OCOCH₃) ⋅ H₂O has a layer structure of the botallackite type. The acetate ions are located between the positively charged copper hydroxide layers and exchangeable with various anions. The exchanged product, Cu₂ (OH) ₃ (MnO₄), was thermally decomposed to an amorphous mixture of CuO and CuMn₂O₄, which showed a high catalytic activity towards the oxidation of carbon monoxide. Another basic salt with a composition of Ni_1-xZn_2x (OH) ₂ (OCOCH₃) _2x⋅ nH₂O (0.15<x<0.25) was prepared by hydrothermal hydrolysis of Ni-Zn mixed acetate solutions. The structure is of zinc basic salts such as Zn₅ (OH) ₈Cl₂⋅ nH₂O and Zn₅ (OH) ₈ (NO₃) ₂⋅2H₂O; nickel ions form brucite-type hydroxide layers with vacancies, Ni_1-x (OH) ₂, and zinc ions occupy the tetrahedral sites above and below the vacant sites outside the hydroxide layers. Acetate ions are weakly bound to the Zn²⁺ ions, completing the tetrahedra, and easily exchanged with most of inorganic as well as organic anions. The reactions are reversible. Exchange with [Si₈O₂₀] ^8- ions resulted in the formation of two-dimensional silicate layers analogous to those of 2: 1 type clay minerals.

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Principle of electrodialysis, electrolysis and their actual condition have been mainly introduced for applications of ion exchange membrane. Electrodialysis used to concentrate sea water for producing table salt and product dinking water. Electolysis mainly used chloro-alkali. Progress of membrane reduced energy consumption for electrodialysis and electrolysis. On the other hand, water splitting using bipolar membrane and fuel cell using perfluorinated ion exchange membrane have been studied. The noble kind of membrane will be developed in a variety of fields.

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Removal of organic pollutants from wastewater is an important subject in protection of the environment from pollution. Organic pollutants are scarcely the object of ion exchange adsorption, but they are effectively removed from water by ion exchange adsorption when they contain sulfonic acid group or other strongly acidic group, carboxyl group or other weakly acidic group, quaternary ammonium group or other strongly basic group, or amino group or other weakly basic group. Organic materials containing phenolic hydroxyl group or other very weakly acidic group, or pyridyl group or other very weakly basic group, are not useful for ion exchange adsorption, but they are effectively removed from water through acid-base interaction. These adsorptions are comprehensively discused here based on the viewpoint of molecular design.

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The development of inorganic ion exchangers as aluminum corrosion inhibitor was outlined. We have found a unique Bismuth oxide hydroxide nitrate by controlling synthetic conditions. It has high anion-exchangability even in neutral pH region and high stability in hot water. Adding Antimonic acid (cation exchanger) to it, the mixture showed accelerated anion exchange rate. The epoxy resin as an encapsulant, blended by this mixture, inhibit Al wiring corrosion effectively. Lead hydroxyapatite was found to be effective for halide ion exchange even in a solution containing phosphate ion. It was mixed into electrolyte of an Al electrolytic capacitor and inhibited Al corrosion with effect.

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Ion-exchange materials and ion-exchange membranes have be investigated to the application on water disinfection. Electorodialysis with ion-exchange membrane was the most feasible way from our research. In this system, neutrality disturbance phenomenon caused by high electrical current density have been utilized to water disinfection and deactivation of Endotoxin, although this phenomenon occurred when operational electric current was larger than limiting current density in electrodialysis and it have to be avoid in practical operation.
This paper was involved on the fundamentals of water disinfection and production of medical water (Endotoxin-Free Water), investigation results according to basic experiments, pilot tests and mechanical analysis, dedution of mechanism on disinfection and Endotoxin deactivation by electrodialysis system with ion-exchange membrane.

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The nature of ion-exchanger phase as a special type of solution has been extensively investigated by spectroscopic and distribution methods. The anion exchange mechanism for metal elements has been interpreted in terms of coordination chemistry. Some new complexes of extremely high ligand number or polynuclear complexes, which can not be formed in ordinary solutions, have been found in anion-exchange resin phases, and their compositions have been determined, as well as their characteristic absorption spectra.
A Donnan exclusion chromatography has been developed and applied to the separation for differently charged anions.
The stability constants of metal complexes present in ion-exchanger phases have been evaluated by solid-phase spectrophotometry and ³¹P NMR spectrometry and compared with those in the corresponding solutions. An intrinsic complexation-enhancing effect of ion-exchangers has been observed and explained.
An ion-exchanger phase spectrophotometry as a new ultra-sensitive method has been developed for a number of reagent systems and successfully applied to analyses of environmental samples.
Some new polyphosphate compounds and new binding-isomers have been found by means of ion-exchange distribution analysis, absorption spectrophotometry and NMR spectrometry.

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