Oil detachment from silica surface modified by carboxy groups in aqueous cetyltriethylammonium bromide solution

Using molecular dynamics simulations, we investigated the process of oil detachment from silica surface modified by carboxy groups in aqueous surfactant (cetyltriethylammonium bromide) solution. And it was found that appropriate temperature, surfactant concentration, and calcium ion concentration were vital for higher oil displacement efficiency in oil recovery. •The mechanism of oil detachment is shown in this simulation.•The water channel is vital for the oil detachment from silica surface.•Surfactant molecular disperses on oil/water interface in the final configurations.•The effect of surfactant concentration and calcium ion concentration is interpreted.•Our study provides a simple method to design appropriate oil-displacing agents. Using molecular dynamics simulations, we investigated the process of oil detachment from silica surface modified by carboxy groups in aqueous surfactant (cetyltriethylammonium bromide (CTAB)) solution. It is demonstrated that CTAB molecules promote the formation of water channel between oil molecules and silica surface, which is vital to the detachment of oil drop from silica surface. In this paper, the effects of temperature, surfactant concentration, and calcium ion concentration on the oil detachment from silica surface have been extensively examined. We find that appropriate temperature, surfactant concentration, and calcium ion concentration are crucial for improving oil detachment efficiency. Our study can provide a simple method to design and choose appropriate oil-displacing agents, which is important for its applications in oil recovery, ore floatation, detergency, printing fields, and so on.