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The Properties of Asphaltenes and Their Interaction with Amphiphiles

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journal contribution
posted on 2015-12-16, 15:46 authored by Jiqian Wang, Chuan Li, Longli Zhang, Guohe Que, Zhaomin Li
The functional groups on asphaltene surfaces of two kinds of Chinese residue oil were analyzed by X-ray photoelectron spectroscopy (XPS). The ζ potential and electrophoretic mobility of asphaltene solutions and residue solutions were measured through phase analysis light scattering (PALS) technique. The ability to stabilize asphaltenes of two typical ionic amphiphiles, dodecyl benzene sulfonic acid (DBSA) and dodecyl trimethyl ammonium bromide (DTAB), were investigated. Karamay asphaltenes contain large amount of carboxyl and calcium and are negatively charged; whereas Lungu asphaltenes are rich in nickel, vanadium, and pyrrolic structures and are positively charged. DBSA has good ability to stabilize Lungu asphaltenes but has no effect on Karamay asphaltenes. Differently, DTAB has good ability to disperse Karamay asphaltenes but has no obvious effect on Lungu asphaltenes. It is concluded from these results that the charges might derive from the dissociation of metal ions and the deprotonation of acid groups (such as COOH, OH, and SH) or basic groups (such as pyridinic groups) on asphaltene surface. The electric property of asphaltenes plays an important role in the interaction between asphaltenes and amphiphiles. The negatively charged asphaltenes tend to be dispersed by cationic amphiphiles, whereas the positively charged asphaltenes tend to be dispersed by anionic amphiphiles.