Abstract
By the determination of the stepwise change of pH in the absorption tube during cation adsorption and the amount of cerresponding anion adsorbed, precipitation of basic salt of metals was assumed, and following tests were carried out. Hydrogen ion concentration at the time of precipitation was determined with glass electrode pH meter and the relationship between pH at the time of absorption and the amount absorbed were examined by static adsorption, and it was found that the precipitation pH range and the order of adsorption were in good agreement and that the adsorption of cation became maximum in the precipitation pH range. From these facts, it was assumed that the adsorption of metallic ions by alumina was chiefly due to the precipitation of their basic salts. It was also found that the influence of anions was rather great in the adsorption of mercury salt, as the adsorption of mercury became extremely small in the presence of a chloride and this was assumed to be due to the formation of mercuric chloride of small degree of dissociation.
