Hydrophilicity of Nonanoic Acid and Its Conjugate Base at the Air/Water Interface
Year: 2017
Journal: ACS Omega, Volume 2, SEP, page 5565–5573
Authors: Badban, Shiva; Hyde, Anita E.; Phan, Chi M.
A general adsorption model based on partial dissociation was developed for carboxylic acids. The model was applied to the adsorption of nonanoic acid at the air/water interface. Two cases were selected for experimental verification: acid-only and acid with a constant Na+ OH- concentration. The model was applied simultaneously at both conditions, and the hydrophilicity of the ionic states was quantified by the adsorption constants, K-A and KAH. It was found that the adsorption constant for the acidic group is significantly higher than that for the carboxylate group, K-AH/K-A similar to 272. The model lays important groundwork for modeling and predicting carboxylic/carboxylate adsorption.
