Base Exchange Between Dyes and Soils

Beaumont, Rohland and Wilkinson and Hoff have shown the effect of acidity and alkalinity of solutions on the adsorption of dyes by soils. Ashley found that during the adsorption of basic dyes by soils the dyes exchanged some of their positive ions for the metal ions of the soil thus fixing some of the dye by base-exchange. Wilkinson and Hoff found that a methylene blue solution liberates more calcium and magnesium from a soil than does distilled water alone. Sante Mattson found in the case of two soils that the methylene blue adsorbed was approximately equivalent to the monovalent and divalent bases that were set free. The purpose of this investigation is to determine quantitatively the relationship between the equivalents of dye adsorbed and the negative and metal ions liberated from several soils with two basic dyes and by comparison from this data find the fraction of the dye that is taken up by base-exchange and the fraction held in some other way