Hristov J.2024-07-102024-07-102024-07-102024-07-102016-01-011018-364710.1016/j.jksus.2015.03.008SCOPUS_ID:84955212975https://rlib.uctm.edu/handle/123456789/364The article addresses a reappraisal of the famous Ward-Tordai equation describing the equilibrium of surfactants at air/liquid interfaces under diffusion control. The new derivation is entirely developed in the light of fractional calculus. The unified approach demonstrates that this equation can be clearly reformulated as a nonlinear ordinary time-fractional equation of order 1/2. The work formulates versions with different isotherms. A simple solution of the case with the Henry's isotherm and a discussion of a Cauchy problem involving the Freundlich isotherm are provided.enArticle