Study on the effect of surfactant on the liquid diffusion process based on the liquid-core cylindrical lenses

Abstract

The liquid diffusion coefficient, reflecting the diffusion rate is an important basic parameter for studying the liquid mass transfer process. Speeding up liquid diffusion rates is of great significance for improving efficiency and reducing costs. However, at present, the commonly used methods mostly require increasing the temperature of the diffusion system, which is not usually applicable to active molecules. This paper proposes a new method to enhance the diffusion rate at room temperature by adding a small amount of an appropriate surfactant to a liquid diffusion system. To verify this method, the diffusion coefficients of ethylene glycol, glycerol, and triethylene glycol diffused in water with and without a surfactant (sodium dodecyl benzene sulfonate), at five different temperatures were accurately measured using the equal-refractive-index thin-layer method based on a liquid-core cylindrical lens. In addition, the diffusion activation energies of alcohols with and without surfactants were calculated using the Arrhenius formula. Results showed that the addition of a surfactant effectively reduced the diffusion activation energy and increased the liquid diffusion coefficient at room temperature. This method of enhancing the diffusion rate without temperature changes can be widely applied in the chemical, medicinal, and biological fields, among others.