Large-Scale Production of Amphiphilic Magnetic Janus Particle with 3D-Printed Parallelized and Multiplexed Microfluidic Device for Oil Remediation

Oil pollution in water is fatal to the ecosystem and threatens our health. To reduce the oil pollution, remediation materials have been used. However, the conventional remediation materials, such as chemical dispersants and oil absorbents, have limitations and other disadvantages. For instance, chemical dispersants are known to cause toxicity, and their performance relies on oil conditions, and water environments. Moreover, the use of oil absorbents results in a large amount of waste and secondary contamination. To overcome these problems, safer and more effective solid particle-based remediation materials have been developed to replace conventional remediation materials. However, these materials have not been used for industrial applications due to the problems such as labor-intensive device fabrication, complex processes for particle production and functionalization, and slow production rate.<br/>In this study, we presented Amphiphilic Magnetic Janus Particles (AMJPs) as remediation material to resolve these problems. AMJPs are dumbbell-shaped and consist of bio-inert materials: PEGDA hydrogel part and PPGDA polymer part embedded with oleic acid coated Fe₂O₃ nanoparticles. AMJPs were produced in a single step with a 3D-printed microfluidic device and had amphiphilicity and magnetism without any functionalization step. To increase the production rate of AMJPs, we fabricated a parallelized droplet generator consisting of 10 droplet generation junctions connected via flow distributors. This device could produce particles 10 times faster than a single device while maintaining the same level of particle size dispersity. In addition, the device has modular connectors and can be multiplexed. This allowed us to multiplex 4 parallelized devices and boost the production rate by 40 times when compared with a single device while maintaining the single peak particle size distribution. We experimentally verified that AMJPs adsorbed to the oil-water interface for lowering surface energy and made the oil film into stable Pickering emulsions. We conducted experiments to quantify oil removal performance and confirm the versatility of AMJPs. We found that the volume of the remaining film of kerosene and mineral oil decreased by more than 96% at dosage of 750 mg/ml. Also, AMJPs could form o/w Pickering emulsion regardless of oil type, viscosity, water pH, and ion concentration. Especially for the oil, AMJPs could cover a very wide range of viscosity (1~10⁵ cP). Further, we confirmed that AMJPs are recyclable and can capture and separate super heavy non-traditional crude oil in sea water. For industrial and practical applications, large-scale production of AMJPs would be an effective and versatile remediation material for oil adsorption and recovery.<br/><br/><b>Acknowledgment</b><br/>This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2021R1A6A1A03039696), the Ministry of Science, ICT & Future Planning (2020R1A2C3010568) and the Korea government (MIST) (2020R1A5A1019649).