General adsorption isotherm for polyoxyethylene alkyl ethers CnEOm adsorbed at the water/air surface

•An empirical adsorption isotherm model is presented for a given homologous series of surfactants.•Surface tension, surface pressure, surface coverage, surface-to-solution coefficient and molar surface area are determined.•main driving force for the adsorption at the aqueous solution surface is specified.•The proposed model is compared with the Langmuir model and its quality to estimate the surface properties is superior.