STUDY OF CHEMICAL REACTION PRECEDING REDUCTION OF CADMIUM NITRILOTRIACETIC ACID COMPLEXES USING STATIONARY ELECTRODE POLAROGRAPHY

The theory of stationary electrode polarography has been considered for the electrochemical system [formula ommited]where A and'O are in chemical equilibrium in the solution. O undergoes a reversible charge transfer reaction at the electrode and A undergoes an irreversible charge transfer reaction. A numerical method was employed to solve the integral equations obtained from the boundary value problem. The electrolysis mechanism of cadmium and its complex with nitrilotriacetic acid (NTA) was selected to test the theoretical calculations and to demonstrate the use of cyclic stationary electrode polarography for this reaction scheme. Extensive correlations were made between the experiment and the theory. The rate constant for the direct dissociation of Cd(NTA)~ was too small to be determined by stationary electrode polarography, but an upper limit of 5 sec1 could be assigned. The value obtained for a parallel acid assisted dissociation was 4.1 ± 0.5 X 105M-1 sec-1 in 0.1M acetate buffer and 1.0M KN03. © 1969, American Chemical Society. All rights reserved.