Reduction of asphaltenes adsorbed on kaolinite by polymers based on cardanol

Oil sands are suspended fine solids in bitumen in which asphaltenes become adsorbed on the surfaces of these particles, reducing the quality of the oil and hence generating higher costs for the oil industry. Since some polymers containing specific functional groups are able to interact with asphaltenes, it can be expected that these kinds of polymers are able to reduce the amount of asphaltene adsorbed. In this work, the performance of three (co)polymers, with different molar ratios of cardanol and styrene was evaluated in the adsorption process of a model system (pentane insoluble asphaltenes- C5I in kaolinite) monitored by ultraviolet–visible spectrometry. Kaolinite and asphaltene were characterized by scanning electron microscopy with energy dispersive X-ray spectroscopy and the wettability of these samples was measured with a goniometer, before and after the adsorption process. The increase in polymer concentration (from 0.025 to 0.2%w/v) reduced the amount of adsorbed asphaltenes on kaolinite. Polycardanol homopolymer presented the best performance, indicating the important role of the hydroxyl group and pendent hydrocarbon chain on the adsorption of asphaltenes on kaolinite. The results evidence the potential of polycardanol, obtained from a renewable source, in the extraction process of bitumen from oil sand.(author)