CO2-responsive surfactants for greener extraction of heavy oil: A bench-scale demonstration

Control of the Colloidal and Adsorption Behaviors of Chitin Nanocrystals and an Oppositely Charged Surfactant at Solid, Liquid, and Gas Interfaces

“…The adsorption and self-assembly of surfactant molecules on solid surfaces are essential to mineral flotation, corrosion inhibition, surface coating, and lubrication. − In order to translate our knowledge of ChNC/SDS interactions in liquid systems to a solid surface, we used QCM-D to in situ monitor SDS adsorption onto ChNC-coated surfaces (Figure ). As SDS reached the solid surface from the solution, a significant shift in both frequency and dissipation took place, reflecting the ChNC/SDS interactions.…”

Novel Strategy of Polymers in Combination with Silica Particles for Reversible Control of Oil–Water Interface

“…As an example of complex oil/water systems (basic properties of crude oil shown in Table S3), the applications of the pH-responsive polymer PA in combination with silica particles to emulsify heavy oil and then demulsify on demand are shown below. After the heavy oil with high viscosity (50 °C, 4980 mPa·s) is emulsified into O/W emulsions, the apparent viscosity of heavy oil can show a remarkable reduction due to the aqueous solution acting as the continuous phase. , As shown in Figure a, the solution without polymers cannot reduce the viscosity of heavy oil by emulsification, but the polymer solutions without silica particles can emulsify heavy oil to significantly reduce the apparent viscosity as the concentration is more than 0.1 wt %. This suggests that the polymer enables the formation of stable heavy oil/water emulsions and silica particles alone fail to emulsify the heavy oil owing to the lack of surface activity, consistent with the results in dodecane/water systems.…”

“…The switchable molecules can have different physical and chemical properties controlled by a well-defined stimulus to offer the intelligent feature for solutions. Such a process is typically triggered by temperature, , pH, , light irradiation, − CO 2 /N 2 injection, , magnetic field, − etc., so they are also known as the responsive molecules named after the triggers. For example, the poly­(N-isopropylacrylamide)-modified nylon membrane and the wax-based Janus particles can circularly separate various stable emulsions through the wettability adjustment of the designated temperature. , The multi-responsive molecules with some specific units, such as spiropyran, N-isopropylacrylamide, and acrylic acid, could at the same time exhibit a desirable adjustability of surface properties. , Lowering the pH or exchanging imine deprived the amphiphilic properties of materials, allowing the wetting manipulation of the interfaces for drug release and emulsion separation. − The magnetic iron oxide nanoparticles grafted with hydrophobic and hydrophilic monomers also showed excellent responsive performance in Pickering emulsification and various phase separations. − The analogous strategies have been extensively reported and applied in various emulsions, broadening the scope of applications.…”

Ecofriendly Natural Surfactants in the Oil and Gas Industry: A Comprehensive Review

“…Enhanced oil recovery has become a critical technique for maximizing hydrocarbon production, particularly in mature oil fields where natural pressure declines. In this context, natural surfactants serve as indispensable agents in enhanced oil recovery (EOR) processes. − Surfactants injected into the reservoir act as emulsifiers, breaking down the oil–water interface and facilitating the mobilization and extraction of trapped oil. , This results in improved sweep efficiency and a more comprehensive recovery of oil reserves, making natural surfactants a valuable tool in extending the life of oil fields and increasing overall production. , …”