Cellulose-coated magnetic Janus nanoparticles for dewatering of crude oil emulsions

Abstract

Removing process water from crude oil emulsions is critically required prior to their downstream processing. In this work, cellulose-coated magnetic Janus nanoparticles (MJ NPs) of asymmetric surface wettability were applied to dewatering crude oil emulsions under an applied magnetic field. Despite the emulsified water droplets stabilized by asphaltene film, the MJ NPs showed stronger interfacial activities, making more secure deposition at the interface as compared with interfacially active magnetic nanoparticles (IM NPs) of uniform surface modification. The MJ NPs could remove >90% water from the emulsions of different water contents, showing their robust dewatering ability. The spent MJ NPs were regenerated via standard washing, drying and resuspension process, and reused for at least six cycles while retaining excellent interfacial activities and high dewatering efficiency. Due to the coating of environmentally benign and biodegradable celluloses, the MJ NPs could achieve excellent dewatering without generating secondary hazards to the crude oil.