Adsorption behaviour of quinolin at the mercury-solution interface II: Measurement of differential capacitance and characteristics of the adsorption isotherms

ABSTRACT

The adsorption of quinoline at the mercury electrode was studied by Lovercek and Cipris [1] and by Bordi and Papeschi [2]. Differential capacitance measurements [1] in 0.1 N-HC1 produced curves with two minima at c[a]-400 and -900 mV [sec]. The corresponding capacitance values were about 15 and 4 micro F cm [-2], respectively. Adsorption in the anodic potential side was said to be due to influence of the u-electrons, while adsorption on the cathodic side was attributed to the presence of organic cations. Electrocapillary measurements [2] in N-KNO[3] provided information related to the reorientation of the adsorbed molecules. In the present investigation, an attempt is made to study the various factors affecting the adosrption and reorientation of quinoline at the mercury electrode in different electrolytes, with or without specific anion adsorption. The results of differential capacitance measurements were correlated to those previously reported using electrocapillary measurements [3]. Characterization of the adsorption isotherms was also attempted