Date of Graduation

1982

Document Type

Dissertation/Thesis

Abstract

Organic compounds capable of ion-exchange were adsorbed on granular graphite. The ion-exchange capacity of the graphite modified in this manner was found to be limited to (DBLTURN) 10('-6) eq/g of graphite by the available surface area of the graphite. Acidic surface oxides on the graphite interfered with the determination of the contribution of the adsorbed organic compounds to ion-exchange. An electrically conductive ion-exchange medium was developed by partially oxidizing granular graphite with strong oxidizing agents. The reaction of graphite with K(,2)Cr(,2)O(,7) in concentrated H(,2)SO(,4) was extensively studied. The ion-exchange capacity of the oxidized graphite for H('+) and divalent metal ions was shown to be a function of the reaction temperature and duration and the amount of oxidant. Exchange capacities of 10('-4) eq/g of modified graphite were easily obtained. Three types of graphite structures were inferred from the ion-exchange capacity of the modified graphite at various stages of oxidation. These structures are the surface oxides already present on the graphite and unorganized and well organized graphite-type structures. The ion-exchange capacity of the oxidized graphite was shown to be pH dependent. An anodic potential applied to the oxidized graphite was shown to be effective in increasing the apparent rate of exchange of Na('+) for adsorbed Cu('+2).

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