Adsorption of Triphenyl Phosphine Oxide at the Dropping Mercury Electrode in Methanolic Solutions

Abstract

Triphenyl Phosphine Oxide (TPO) which is known as a strong inhibitor of electrode processes in aqueous solutions is progressively adsorbed at the dme from methanol in the potential range -0.5 to -1.3 volts as compared with water, -0.15 to -1.6 volts (Ag/AgCl), for the concentrations studied. Adsorption activity as well as the sharpness of the desorption peak of TPO decrease in the order: water > 50% methanol > methanol and the adsorption region contracts as the solvent is changed from water to methanol. Adsorption isotherms in methanol and 50% methanol follow Langmuir's equation with adsorption coefficients equal to 1.58 x 102 l/mole and 1.62 x 104 l/mole respectively.