Wettability, oil recovery, and interfacial tension with an SDBS-dodecane-kaolin system

The wettability of kaolin with SDBS (sodium dodecyl benzene sulfonate) aque ous solutions was measured by the Washburn equation expressed as contact an gles. The contact angle changes for SDBS aqueous solutions on kaolin surfac e was studied. The interfacial tension between the SDBS solutions and n-dod ecane was measured using both drop volume and spinning drop methods. Then t he oil recovery of n-dodecane on the kaolin surface was tested. It was foun d that the minimum contact angle (the most hydrophilic condition) and the m aximum oil recovery occurred near the critical micelle concentration (CMC) of SDBS while the interfacial tension between the SDES solution and n-dodec ane was far from ultra-low. (C) 1999 Academic Press.