SORPTION PROPERTIES OF INDIUM OXOHYDROXIDES

The influence of the pH of precipitation and of the ionic medium on th e sorption properties (the surface charge and the kinetic characterist ics of sorption) of indium oxohydroxides obtained by alkaline hydrolys is of indium nitrate was investigated. It was found by the method of z ero charge point, by the indicator reactions of heterogeneous hydrolys is, by drop titration, and by thermography that In(OH)(3) . 0.5 H2O (0 .2-0.3) NaOH with a very small degree of crystallinity is formed at pH > 6. The basic properties of the oxohydroxide increase with increasin g pH of precipitation up to 9-10 and then remain constant. The rates o f the indicator reactions depend slightly on the pH of precipitation. The sorption properties of indium oxohydroxides differ markedly from t hose of ferrogels obtained tinder similar conditions. The results obta ined can be explained by the formation of quasistable microstructures during the precipitation of indium oxohydroxide.