Preparation And Application Of Magnetic Responsive Pickering Emulsions

Pickering emulsion is a stable system which is emulsified with the immiscible two phases by solid emulsifier.Solid particles can effectively reduce the interfacial energy and adsorb stably at the interface of the two phases.The Pickering solid particles possess various compositions and morphologies.The functional solid particles emulsifier can be obtained with the combination and modification of the materials,and then the Pickering emulsion can be functionalized through the emulsification process.The Pickering emulsion based on magnetic response has attracted more and more attention.The magnetic droplets of Pickering emulsion can be directly driven by control of external field,and can broke emulsion droplets by adjusting the magnetic field strength,thus achieving the reusing and recycling of Pickering solid particles and the separation of two phases.Based on the magnetic responsive Pickering emulsion,the functions can be realized by adjusting the composition of Pickering particles.It is more significant that constructing the hybrid Pickering emulsion interface is efficient to replace the complex functional material modification process and achieve a new function superposition,this approach is expected to achieve a simple one-step integration of multi-functional materials and obtain more applications.1.In this investigation,superparamagnetic Fe3O4 nanoparticles were synthesized by thermal solvent method and co-precipitation method.In this paper,the wettability of Fe3O4 nanoparticles synthesized by different methods was compared through the three-phase contact angles.Then The unmodified Fe3O4 nanoparticles were used to emulsify water and hydrophobic[BMIM][PF6]ionic liquids.The emulsification results showed that the Fe3O4 nanoparticles prepared by the thermal solvent method could stabilize the emulsion system and form a magnetic responsive Pickering ionic liquid emulsion,the size of dispersed droplets could be effectively controlled by changing the particle content,and different emulsion structures could be obtained by changing the oil-water ratio at the same time.Based on the above magnetic responsive Pickering emulsion,the resorcinol in aqueous solution was extracted.The extraction rate was as high as 94.6%.After extraction,magnetic field was used to control the directional aggregation of droplets so that ionic liquids were separated and magnetic Fe3O4 particles were recovered.2.In this investigation,CTAB assisted synthesis of TiO2 nanoparticles was successfully prepared by sol-gel within aging solution soaking at room temperature.TiO2 nanoparticles and Fe3O4 nanoparticles can co-emulsify water and decane to form a magnetic responsive Pickering emulsion with photocatalytic properties.Photocatalytic degradation of reactive brilliant blue KN-R in dye wastewater was carried out by using this emulsion system.The results showed that the emulsion system possessed excellent photocatalytic activity and its degradation rate could reach 90.54%.The emulsions can be used to control the separation and aggregation of emulsion droplets by weak magnetic field manipulation,and demulsification by strong magnetic field to separate magnetic Fe3O4 particles and TiO2 photocatalysts.This method based on mixed particles to prepare multifunctional Pickering emulsion breaks through the complex modification process of the original solid emulsifier and makes functional integration very simple.This provides a new way for the preparation and application of complex functional materials.