Preparation And Application Of Fine Structure Silicon Adsorbents

A new kind of fine structure silicon adsorbents based on silica microspheres and magnesium silicates and there ability to adsorb organic compounds and metal ions has been studied.The particle size of the silica microspheres is 100-300 mesh(about 149-48 ? m)and the magnesium silicates are prepared by Na2SiO3/MgCl2·6H2O or silica sol(30%)/MgCl2·6H2O.The Chemical properties were studied.We also researched the sorption behaviours of the adsorbents respectively towards on Ni2+ and methylene blue(MB).In the preparation of organic-modified silica microspheres,we researched the preparation methods of modified silica microspheres.This paper attempts to modify silica microspheres with silane coupling agent ?-aminopropyl triethoxysilane with an amino(KH550),silane coupling agent ?-(2,3-epoxypropoxy)propyl trimethoxysilane with an epoxy(KH560),silane coupling agent methacryloxy propyl trimethoxy silane with an vinyl(KH570).Then benzaldehyde,benzyl chloride,organic amine,stearic acid,lauric acid,styrene,acrylonitrile,and other organic matters are further bonded to modified silica microspheres,to get the desired products.Or one of the silane coupling agents(KH550,KH560,KH570)could be reacted with benzaldehyde,benzyl chloride,organic amine,stearic acid,styrene-based organic reactions,and then the resulting product is reacted with silica microspheres,to get the desired product.Among the products,styrene-coated silica microspheres were conducted experimental conditions.Styrene-coated silica microspheres and acrylonitrile-coated silica microspheres were conducted by sulfonation reaction and amidoxime,respectively.Characterizations of Fourier transform infrared(FTIR)spectroscopy and scanning electron microscope(SEM)for the products show that in the reaction of styrene-modified silica microspheres,weight ratio of silica gel:styrene=5:8 is best,the polymerization is preferably coated with the silica microspheres.In the preparation of magnesium silicate,magnesium silicate were used to study the preparation.Different materials(nSi:n Mg = 3:1,2:1,1:1)between raw materials,different dropping order,different activation temperature were changed to study the sample structure and adsorption properties.By changing the above three conditions,the 24 samples were prepared.SEM(scanning electron microscope)results showed that magnesium silicate of raw material ratio n si:n Mg = 1:1,anti-drip prepared and activated at 450?(450-10)had a more abundant pore structure.We selected silica microspheres(550-1)modified by benzaldehyde,silica microspheres(560-2)modified by benzyl chloride,silica microspheres(570-4)coated by acrylonitrile-amidoxime,and all magnesium silicate samples to conduct adsorption experiment.The adsorption tests were carried by water solution of Ni2+dimethylglyoxime spectrophotometric measurement by UV absorbance after adsorption solution.The results show,550-1,560-2,570-4 to Ni2+ adsorption.We found 550-1 had the largest adsorption capacity for Ni2+(10.67mg/g),three adsorbents reached equilibrium in 12 hours.In the adsorption test of magnesium silicate to methylene blue,UV spectrophotometry was used to test adsorption solution absorbance,and a commercial magnesium silicate was used for conparation.The results showed that adsorption equilibrium time of methylene blue was 48 hours.No.450-10 and No.650-6 had nearly same maximum adsorption capacity,both were 108.5mg/g.Adsorption amount of commercial magnesium silicate for methylene blue was 69mg/g.This showed synthetic magnesium silicate had a better adsorption capacity for methylene blue.