EFFECT OF ELECTRICAL DOUBLE-LAYER ON THE KINETICS OF METAL-OXIDE DISSOLUTION

Experimental data are reported on the kinetics of dissolving oxides of titanium, manganese, iron, nickel, and copper in hydrochloric, sulfur ic, phosphoric, and nitric acids. The effects of the solution pH, the anion nature, and complexones (ethylenediaminetetraacetic acid, oxyeth ylidenediphosphonous and diethylenetriaminepentaacetic acids) on the d issolution process have been studied. Based on the principles of forma l kinetics, we have determined the constants of the dissolution rate a nd the reaction order for various ions. The structure concepts of die ionic part of die electrical double layer at the oxide/solution interf ace were used to explain the principles of the dissolution process. Me chanisms have been proposed to account for the influence of pH and the concentration of complexones and complexonates upon the dissolution p rocess.