Alumina Microsphere Synthesized By Spray Drying And Its Adsorbed Properties

Porous microspheres have been widely used in adsorption,catalysis and separation due to their high surface area and large pore volume.Alumina porous microspheres not only have the advantages of porous microspheres,but also have good mechanical,thermal and chemical stability characteristics.Porous alumina microspheres were synthesized using alumina and pseudo-boehmite as raw material respectively by sol-spray drying method in this paper intends to obtain micro sized and well spherical alumina microspheres,and the adsorption properties were also discussed.Main factors that influenced on the microscopic morphology and structure in the processing were studied systematically by SEM,TEM,XRD,TG,DSC,Zeta potential,FTIR,granularity analysis.Microspheres adsorption performance of methyl violet is mainly studied and their adsorption kinetics and adsorption thermodynamic behavior are also analyzed.The results showed that the optimum conditions for preparing porous microspheres with alumina as raw material and PVA as binder were:solid content of 40 wt%,PVA of 3%and pore-forming agent of 15%.With the increase of solid content,the adsorption capacity and removal rate of methyl violet increased,but the maximum removal rate was only 65.80%,and the obtained microsphere surface collapsed seriously.When using alumina sol as the binder the optimum process conditions is as follows:the solid content of 40 wt%,sol 3%,pore-forming agent 5%,inlet temperature of 180?.The as-synthesized microspheres keep in perfect balls with microporous structure.The maximum removal rate of methyl violet was 79%.The optimal process conditions for preparing alumina porous microspheres using alumina sol as raw materials by spray drying are as follows:pH=3,25%solid content,water bath temperature 95?,the spray drying of the inlet temperature of 180?,the feed speed of 4.The as-produced alumina microspheres morphology has improved,and the particle size of alumina microsphere decreased from dozens of microns to several microns.It's adsorption performance of methyl violet significantly also improved.The removal rate can reach 96.44%.Dynamic adsorption behavior of porous alumina microspheres analyzed results show that it below to pseudo secondary dynamics equation.The thermodynamic behavior meets the Langmuir isothermal adsorption equation,and it is a spontaneous,exothermic,orderly monolayer adsorption behavior.