Influence of monovalent and divalent electrolytes on sorption of neomycin sulfate to attapulgite and montmorillonite clays.

Langmuir isotherms for the adsorption of neomycin sulfate to clays such as attapulgite, bentonite, and magnesium aluminum silicate were constructed. Monovalent and divalent cations were investigated for their influence on the formation of neomycin-clay adsorbates and the resulting equilibrium concentration in a neomycin solution. Divalent magnesium ions were more effective in displacing the antibiotic from each clay than were monovalent sodium ions. Ions present in the GI fluid might increase the bioavailability of neomycin from such neomycin-clay adsorbates.