Surfactant Recovery by Foam Fractionation using the Gas-Liquid Contactor,Emulsion Venturi

Sodium dodecylbenzene sulfonate (SDBS), an anionic surfactant, was removed from its aqueous solution by foam fractionation in an emulsion venturi, a gas-liquid contactor functioning in self-aspiration. The performance of the reactor was evaluated by measuring the self-aspired gas flow and the mass transfer coefficient in the presence and the absence of SDBS. Data confirmed that both the gas flow self-aspired and the mass transfer coefficient increased with increasing the recirculated liquid flow. However, the presence of SDBS decreased the mass transfer capacity of the reactor influencing self-aspiration capacity in a positive manner. The percentage removal of SDBS in the emulsion venturi increased with increasing the recirculated liquid flow; at the highest liquid flow value used in this work (1.4 m³/h), 96% of SDBS was removed from the solution after 20 min of foam operating. The process was dependant on initial surfactant concentration. Neutral pH and temperature of 25°C were the optimal conditions for the foam separation of SDBS in the emulsion venturi.