Adsorption of benzotriazole on mercury from different base electrolytes

Abstract

Electrocapillary curves for 1<i>M </i> solutions of NaCl, NaNO₃ and Na₂SO₄ in the presence of different concentrations of benzotriazole show that the organic compound adsorbs both on positively and negatively charged metal surfaces. The extent of adsorption from these base electrolytes follows the order Na₂SO₄ > NaNO₃ > NaCl. Thermodynamic parameters like charge on the metal surface (q_M), the surface excess of organic molecule adsorbed (<img src='http://www.niscair.res.in/jinfo/gamma1.gif' border=0>_org), surface coverage (<i>q</i>) and free energy of adsorption (-<img src='/image/spc_char/delta.gif' border=0> <i>G</i>) are evaluated and presented. The adsorption of benzotriazole on mercury obeys Langmuir’s adsorption isotherm in all the cases, irrespective of the nature of the base electrolyte used.