Adsorption of n-butanol on Pb-Ga in aqueous solutions: Effect of metal on the adsorption of organic compounds in the absence of metal-water chemisorption interaction

摘要

The potential dependence of the differential capacitance is measured by an ac bridge at 420 Hz and 32degreesC at Pb-Ga/H2O interface in 0.05 M Na2SO4 Solutions containing n-butanol in different concentrations. Adsorption parameters for n-butanol are determined using a regression analysis and compared with those for Hg, Tl-Ga, and Bi-Ga. As follows from this comparison, though there is no chemisorption interaction between these metals and water, the energy of n-butanol adsorption at these metals depends on the metal nature. The Pb-Ga data fit a common correlation dependence of the electronic capacitance of different electrodes (CM I)(phys), on the energy of the n-butanol molecules adsorption thereon in the absence of a metal-water chemisorption interaction. This finding evidences that the dependence of the energy parameters for the adsorption of organic compounds on the metals' electronic properties, when characterized by (C-m(-1))(phys), is of general nature.