Study On The Preparation Of Porous/hollow Microspheres By Foam Phase Separation And Their Adsorption Of Phenol

Recently,porous polymer particles have attracted considerable interest because of their special structure and morphology,low density,and high specific surface area as a new functional polymer material.Their application in many fields such as biomedicine,catalytic carrier and sewage reatment because of porous polymer microspheres obtained by different preparation methods have sundry hierarchical porous structure or adjustable pores size and range.Due to the different pore size,morphology,particle size,composition and so determines the application of porous microspheres.Therefore,to find an efficient and versatile preparation methods,simple and effective regulation of micro-structure and particle size of the internal structure of the researchers became the important content.Nowadays,methods such as suspension polymerization,emulsion polymerization and seed swelling combined with membrane emulsification and microfluidics can effectively control particle size and porous structure.However,these methods are also faced with complicated steps,or need technical support to achieve effective control and other issues.Solvent evaporation-induced phase separation is a simple and effective method for preparing porous polymer microspheres.However,the traditional methods mostly evaporate the solvent in the aqueous phase,which takes a long time,is difficult to be continuous,or industrially produced.In this paper,a new simple,efficient and versatile method for preparing porous polymer microspheres is proposed: Preparation of porous polymer microspheres by using foam phase solvent evaporation induced phase separation method.The method was compared with water phase to verify the efficiency of the method and the formation of particles process by changing the ratio of polymer and porogen,protective colloid concentration,stirring speed and other conditions on the particles surface morphology,pore structure,and regulation of particle size and distribution.At the same time,the P(MMA-BA)porous microspheres prepared by this method were used to study the adsorption of phenol on aqueous solution by the rapid swelling adsorption of phenol.The primary contents of this paper include:1.Foam phase separation method can be easily and efficiently prepared porous polymer microspheres.By comparing the solvent evaporation method of water phase and foam phase,the microspheres were found to be able to volatilize good solvents quickly in 3min in the foam,phase separated into pores,and the porous microspheres were prepared efficiently.In the meantime,the ratio of oil to water in the reactor during bubbling is constantly changing,and the foam has an important influence on the stability and dispersion of the microspheres.Therefore,the complete porous microspheres can still be obtained when the ratio of oil to water is 3,and the yield is47%.2.The ratio of polymer to porogen or polymer concentration decreases and the microsphere can be made to evolve from a solid-porous(non-through)-porous(through)hollow structure.When the concentration of protective colloid or rotational speed is increased,the particle size of microspheres decreases,but the migration rate of volatile solvents is different,so the microstructure of porous microspheres is different.Increasing the concentration of PVA results in fewer microspheres surface pores and the pore size larger,while increasing the speed of the microspheres obtained more holes.The properties of the polymer and the type of porogen were changed,affect the time and extent of separation of the porogen from the polymer,resulting in different microsphere pore structures.3.When the heating rate is decreased,the solvent evaporation rate is also affected,resulting in different phase separation effects.The resulting microspheres have a reduced surface pore size and an increased number of pores.By changing the initial temperature of the experiment,the heating rate,the volatilization rate of solvent migration and the degree of gasification inside the oil droplet,different microstructures were obtained.Addition of absolute ethyl alcohol or ethyl acetate in the aqueous phase changes the polarity of the aqueous phase,ie,changes the "path" of migration of the solvent in the oil phase to obtain hollow polymer microspheres.By reducing the amount of polymer,the thickness of the hollow microsphere shell and the diameter of the microspheres can be reduced.4.Under static adsorption conditions,P(MMA-BA)porous microspheres in the high concentration of phenol aqueous solution has obvious swelling adsorptioneffect.Through different phenol concentration,changing the amount of microspheres,adsorption time,temperature and other conditions,found in 10000 ppm phenol aqueous solution:(1)When the amount of microspheres accounted for 4% of phenol aqueous solution,the adsorption capacity Q reached the maximum adsorption of119.64mg/g.The greater the amount of microspheres,the less obvious the swelling adsorption effect;(2)The adsorption capacity of the microspheres in the aqueous solution of 10000 ppm phenol after 60 min has gradually become gentle,however,the lower the phenol concentration,the longer the adsorption equilibrium will be reached.(3)With the increase of temperature,the adsorption capacity of microspheres decreased,but the adsorption rate increased.At 60?,adsorption of microspheres could reach the equilibrium within 10 min,and the adsorption capacity Q was 69.32mg/g.Adsorption thermodynamic equation(Fredunlich and Langmuir adsorption isotherm equation)further proved that the adsorption capacity of the microspheres.In addition,the design of multi-stage adsorption,so that 10000 PPm phenol aqueous solution quickly reduced to 100~200 ppm.