Adsorption and Desorption of Coen3Cl3 on Bentonite

Adsorption and desorption studies of trisethylenediamine cobaltic chloride on and from a bentonite
clay show that adsorption is according to Langmuir's equation, and the desorbing cations arrange themselves according to the Iyotrope series. Quaternary cations such as cetyltrimethylammonium (CTA ⁺) and cetylpyridinium (CP⁺) ions desorb more strongly than the inorganic ions; CP⁺ having a smaller cmc than CTA* is a more efficient desorbing ion. Both adsorption and desorption var y with pH and take place in stages. Thus, adsorption corresponding to maximum (95 me.) of Langmuir's isotherm occurs at pH 3.3; from pH 3.3 to 5.5, 15 me. more are adsorbed and again from 5.5 to 9.8 a further 13 me. are absorbed. 95 me. corresponding to charge due to isomorphous replacement in the lattice and the latter two to what has been termed 'peripheric acidity'. Desorption studies with pH  variation also indicate the existence of cations at the edges.