Magnetic Poly(Ionic Liquid) Microcapsules for Oil Capture and Recovery

A new application for the liquid marble's process which consists in developing microcapsules for oil capture and recovery was studied. Empty magnetic microcapsules between 1 and 20 ?L size were prepared by fabricating liquid marbles by rolling a water droplet containing magnetite nanoparticles onto hydrophobic poly(ionic liquid) micropowders, melting the powdery polymeric shell of the liquid marble by a fast solvent treatment, and evaporating the water inside the liquid marble. The optimized exposure to chloroform vapors produced magnetic microcapsules with a good balance between shell porosity and capsule mechanical stability as the further evaporation of the water did not produce the collapse of the capsule. The empty microcapsules showed high selectivity up to 1000% for oil removal when placed in oil/water mixtures, maintaining their magnetic properties. The higher adsorption capacity value obtained in this study was slightly superior to the gold standard of synthetic oil sorbents, polypropylene, which adsorbs 10 g of oil per gram of sorbent. The quantification of the oil absorption showed that most of the oil absorbed filled the capsule inside void, and only a small part of it was swelling the capsule shell.