Facile Fabrication of Cyclodextrin-Modified Magnetic Particles for Effective Demulsification from Various Types of Emulsions

Effective oil water phase separation from various emulsions,, especially those stabilized by surfactant, is of great importance. Although superhydrophobic and superoleophilic materials have attracted considerable attention in recent years, they are incapable of directly separating all types of oil water mixtures. To separate various types of emulsions, one of the most important features of particles is that they can be dispersed in the continuous phase for delivery and target dispersed phases. In this study, cyclodextrin-modified magnetic composite particles (M CDs) have been fabricated fOr this goal, based on their special interfacial activity and response to an external magnetic field. Though M-CDs are hydrophilic, the intelligent M-CDs can switch from hydrophilicity to hydrophobicity spontaneously, due to the formation Of CD oil inclusion complexes (ICs) at the oil water interface. Physicochemical characteriation reveals that M-CDs can adsorb at the oil water interface arid locate at the droplet surface as an effective Pickering emulsifier. By applying an external magnetic field, M-CDs are removed from the droplet surface and a rapid oilwater phase separation occurs. Our M-CDs can demulsify, for the first time, surfactant-free or surfactant stabilized :oil-in-water (O/W) and-water-in-oil (W/O) emulsions directly, with high separation,efficiency. FurtherrnOre, the recycled MNPs still show high demiilsification efficiency. In view of the sustainability of cydodextrin and effective recycling ability of MNPs, M-CDs provides a new opportunity to develop an environmentally friendly interfacial material for practical applications in wastewater treatment.