Binary Solvents with Ethanol for Effective Bitumen Displacement at Solvent/Mineral Interfaces

摘要

Displacements of bitumen from silica surfaces were studied using various solvents and binary mixtures of ethanol. It was found that single-component solvents, including water, toluene, cyclohexane, and ethanol, were not able to completely remove bitumen on silica. However, adding 5% ethanol to toluene greatly enhanced its ability to displace bitumen from the silica surface. Surface vibrational spectra obtained by sum frequency,generation vibrational spectroscopy showed that no trace of bitumen could be detected on silica after treatment with the 5%, ethanol-toluene mixture. Similar effects were observed for cyclohexane with 10% ethanol. The results suggested that binary solutions with amphiphilic components, such as ethanol, are effective solvents for release of bitumen from the mineral surface. This expectation was confirmed by batch extraction experiments on Athabasca oil sands samples using cyclohexane-ethanol solutions.