Preparation And Adsorption Properties Of Silica Aerogel Microspheres

Si O₂ aerogel microspheres are porous network structures derived from nanoparticles,with porosity of up to 85%-95%and mesh structure filled with solid materials with gaseous disperse medium.Aerogels have the advantages of high specific surface area,low thermal conductivity and low density due to their unique structure,and are widely used in catalytic science,acoustics and other related fields.In this paper,four ethyl orthosilicate was chosen as precursor,and ethanol was selected as the solvent.The Si O₂ hydrogel microspheres were prepared by emulsion ball forming technology and effective control of sol-gel process,and then aerogel microspheres were prepared by atmospheric drying,we prepared magnetic silicon aerogel microspheres through adding ferroferric oxide.Their structural features were characterized by SEM?FTIR?XRD?TGA and BET technique.Firstly,by controlling variables method,it analyze that the single factors such as hydrolyzing time,hydrolyzing temperature,acetic acidquantity effect Silicon aerogel microspheres.At the same time,we optimize factor through orthogonal e xperiment.The experimental results show that the optimum conditions is that it is prparaed under the condition of temperature 40?and ordinary pressure.Si O₂ silicon aerogel microspheres as raw material volume ratio TEOS:ethyl alcohol:acetic acid solution=11:22.5:3.6,polycondensation p H value at about 8-9.TEOS/ethyl alcohol volume ratio of 1:2.The modified time was 24h.Silicon aerogel microspheres were prepared is white spherical particle,uniform size,whose grain size is 0.15-0.3mm,specific surface area is819.5237m²/g,pore size distrabution is 2-10nm.Next,we analyse adsorption property of silicon aerogel microspheres to chromium ions and discuss the influence of factors such as adsorption time,adsorption temperature and microspheres amount to removal rate of chromium ions.We conclusion through adsorption isotherm and adsorption kinetics:silicon aerogel microspheres belong to Freundlich described physics adsorption and pseudo-second order kinetic.