Ethylbenzene Removal by Froth Flotation Under Conditions of Middle‐Phase Microemulsion Formation I: Interfacial Tension, Foamability, and Foam Stability

Abstract

The objective of this study was to investigate the relationship of the froth flotation performance in removal of emulsified ethylbenzene in water with microemulsion formation and with foam formation characteristics. The surfactant used was dihexyl sulfosuccinate (Aerosol MA or AMA) which can form microemulsions with ethylbenzene. The systems studied were designed to form Winsor Type III microemulsions with ethylbenzene, which generally correspond to ultra‐low interfacial tensions between oil and water phases. By varying the surfactant concentration, NaCl concentration, and oil‐to‐water ratio, it was found that the lowest interfacial tension was obtained at 1 wt% AMA and 3 wt% NaCl, while the interfacial tension was not substantially influenced by the oil‐to‐water ratio. The highest oil removal was achieved in froth flotation with 0.3 wt% AMA and 3 wt% NaCl. No separation was experienced when the NaCl concentration exceeded 4 wt% due to the poor foamability of the froth formed under these conditions. Therefore, these results demonstrate that both interfacial tension and foam characteristics influence the efficiency of oil removal in the froth flotation process.

Keywords:

• Froth flotation
• microemulsion
• interfacial tension
• foamability
• foam stability

Acknowledgments

The Thailand Research Fund is acknowledged for providing a Royal Golden Jubilee Ph.D. grant to Ms. Ummarawadee Yanatatsaneejit as well as providing a research grant under TRF Advanced Research Scholar. The Research Unit of Applied Surfactants for Separation and Pollution Control supported by the Ratchadapiseksompoch Fund from Chulalongkorn University and the Petroleum and Petrochemical Technology Consortium under the Minister of Education are also acknowledged for providing financial support and facilities, respectively. Financial support for this research was also received from the industrial sponsors of the Institute for Applied Surfactant Research including Akzo Nobel, Clorox, Conoco/Phillips, Church and Dwight, Dial, Ecolab, Halliburton, Kerr‐McGee, Huntsman, Procter & Gamble, Shell, and Unilever.