ADSORPTION OF BENZOTRIAZOLE ON MERCURY FROM DIFFERENT BASE ELECTROLYTES

Electrocapillary curves for 1M solutions of NaCl, NaNO3 and Na2SO4 in the presence of different concentrations of benzotriazole show that th e organic compound adsorbs both on positively and negatively charged m etal surfaces. The extent of adsorption from these base electrolytes f ollows the order Na2SO4> NaNO3 > NaCl. Thermodynamic parameters like c harge on the metal surface (q(M)), the surface excess of organic molec ule adsorbed (Gamma(org)), surface coverage (theta) and free energy of adsorption (-Delta G) are evaluated and presented. The adsorption of benzotriazole on mercury obeys Langmuir's adsorption isotherm in all t he cases, irrespective of the nature of the base electrolyte used.