The influence of hydrogen ion concentration on the adsorption of weak electrolytes by pure charcoals

Abstract

Recent progress in enzyme chemistry has been largely due to the use of adsorbents. In vitamin studies also, adsorbents such as Fuller's earth have been introduced with marked success. A prominent feature of such work is the influence of hydrogen ion concentration upon the efficiency of the adsorption. A technique recently introduced by Kinnersley and Peters for concentrating the antineuritic vitamin (B 1) involves at one stage the adsorption of the vitamin by acid-treated Norite charcoal. In this case also it has been found that the hydrogen ion concentration influences considerably the degree of adsorption. Adsorbents which are themselves of acidic or basic character might be expected to be influenced in their behaviour by hydrogen ion concentration, but in the case of charcoal the reason for the change in adsorptive, power is more obscure. Bartell and Miller have stressed the importance of using pure charcoals in the study of adsorption phenomena. It is probable indeed that many of the anomalous results obtained by workers in this subject have been due to the use of various impure charcoals. The acid-treated charcoal used in the vitamin work contained about 1 per cent. of mineral impurity. It was important therefore to discover whether the effect of hydrogen ion concentration on the absorption by pure charcoals was equally marked, and if so whether these effects could by correlated with the recognised chemical properties of various adsorbates.