This paper considers the problem of the kinetics of adsorption at the electrode/solution interphase, for a substance which does not undergo chemical or electrochemical reactions. The differential system which describes semi-infinite linear diffusion to a plane has been examined, assuming that at the boundary a generic isotherm holds. In this way one arrives at a Volterra integral equation which in general is non-linear. The numerical solution of such an equation has been carried out for the case of a Frumkin isotherm. The coverage of the electrode$ ,u = F/I',,, as a function of the adimensional quantity log z [= log (C*s4Df/I'~% )] depends on the parameters PC* = 'I' and A of the isotherm. The relative graphs allow us to determine the time required to arrive at a fixed coverage. The effects of attractive and repulsive interactions are discussed.
R&mu&On
considere le probleme de la cinetique d'adsorption a l'interphase &ctrodssolution pour une substance qui n'est pas soumise a des reactions chimiques ou &ctrochimiques.
Le systeme differentiel qui d&rit la diffusion Tin&ire semi-intinie, a et& etabli en supposant qu'une isotherme de forme g&t&alis&. soit valable comme condition limite. On arrive ainsi a une equation integrale de Volterra, en g&r&al non lineaire, dont le calcul num6rique nous a dorm6 la solution darts le cas particulier dune isotherme de Frumkin. Le taux de surface occupee p = F/l?, en fonction de la grandeur sans dimensions log z = log (C*'4Dt/r,% ) depend des param&res Y' = PC* et A de l'isotherme. Les diagrammes correspondants permettent de determiner le temps r&essaire pour obtenir un taux d'occupation superhcielle predeterminee.
On discute de l'influence des interactions d'actraction et de repulsion entre le molecules adsorb&s sur la cinetique de l'adsorption.