Studies on the Adsorption and Desorption of Methylene Blue and Crystal Violet on and from Feldspar

Adsorption and desorption studies of methylene blue and crystal violet have been carried out on and from feldspar. Of the two dyes the sorption data of methylene blue alone indicate the obedience to the Langmuir equation. According to the distribution and selectivity coefficients calculated from the desorption data of the two dyes from their respective clay complexes, the cations are preferred in the sequence: Na<NH₄<K<H<Mg<Ca<Ba<CTA<CP for the mineral surface. The order of affinity of the dyes for the feldspar surface, which is in the reverse order of their desorption is: CV>MB.