Absorption of Pyrimidines, Purines, and Nucleosides by Co-, Ni-, Cu-, and Fe(III)-Montmorillonite (Clay-Organic Studies XIII)

G. E. Lailach, T. D. Thompson and G. W. Brindley
Department of Geochemistry and Mineralogy, The Pennsylvania State University, University Park, Pennsylvania
Materials Research Laboratory, The Pennsylvania State University, University Park, Pennsylvania

Abstract: Absorptions of purine and pyrimidine derivatives by Co- and Ni-montmorillonite at pH < 6 and by Cu-montmorillonite at pH < 3 are similar to their absorption by Ca-montmorillonite and take place primarily by a cation exchange process. In the weakly acidic to weakly alkaline range, absorption is due to complex formation with the inorganic cations, and decrease in the order Cu ≫ Ni > Co ≫ Ca. Adenine, 7-methyladenine, hypoxanthine, and purine are strongly absorbed, 9-methyladenine, 6-chloropurine, and cytosine are weakly absorbed, and thymine and uracil are not absorbed. At pH < 5, the nucleosides are absorbed by Co-, Ni-, and Cu-montmorillonite in approximately the same manner as by Ca-montmorillonite, but at pH > 6 their absorptions decrease in the order Cu ≫ Ni > Co > Ca. Fe(III)-montmorillonite behaves quite differently from the other montmorillonites studied. With purines and pyrimidines, there is strong absorption from pH 3 to pH 7–8; with the nucleosides, the absorption varies considerably with the compounds considered decreasing in the order adenosine > cytidine ≫ guanosine ≫ inosine.

Clays and Clay Minerals; 1968 v. 16; no. 4; p. 295-301; DOI: 10.1346/CCMN.1968.0160406
© 1968, The Clay Minerals Society
Clay Minerals Society (www.clays.org)