A simplified model to predict the current-voltage relationship of an electro-chlorination cell

A simplified model is described to predict the Current-Voltage (I-V) relationship of a parallel plate electro-chlorination cell containing aqueous NaCl solution as electrolyte. The simplifications allowed obtaining an analytical solution without recourse to computationally intensive numerical solutions like finite element method. The anodic and cathodic exchange current densities and symmetry factors for the model were obtained using linear sweep voltammetry experiments for two different electrodes, viz. graphite and mixed metal oxide coated titanium. Using them, anodic and cathodic overpotential values (for a particular device current I) were predicted using the Butler-Volmer equation. The solution potential drop for the same device current was determined using a modified Nernst-Plank equation. The predicted device voltage (for the device current I), which is the sum of equilibrium electrode potentials, electrode overpotentials and solution potential drop, was compared with experimental (I-V) data for the two electrochemical cells as mentioned above. Results showed that the simplified model could predict the I-V data well, when the electrode surface area was assumed to be twice the superficial area.