Influence of Surfactant Concentration and Chain Length on the Absorption of CO₂ by Aqueous Surfactant Solutions in the Presence and Absence of Induced Marangoni Effect

Abstract

We studied the absorption of CO2 at a plane interface by aqueous solutions of anionic surfactants (sodium alkyl sulfates) or of the cationic surfactant cetyltrimethylamonium bromide in the presence and absence of induced Marangoni effect induced by deposition of the liquid of low surface tension on the gas−liquid interface. The surface velocity distributions generated by induced Marangoni effect in the absorption cell were determined for each of the various surfactant solutions by the stroboscopic technique. The resistance to mass transfer induced by the surfactants increased linearly with the logarithm of surfactant concentration, Cs. For the anionic surfactants used, the resistance also depended linearly on their alkyl chain length, n. In the presence of induced Marangoni effect, ≈87% of the total surfactant-induced resistance to absorption of CO2 were due to the effect of the surfactant on interfacial hydrodynamics.