Study On The Preparation And Property Of Silicalite-1 Based Photocatalyst

In today's world,organic dyestuff,pesticide and surfactant are widely used in various fields,which lead to the serious pollution of the environment.Until now,there are many ways to treat these contaminants,such as biodegradation,physical absorption,photocatalytic degradation.Among these methods,some photocatalysts,such as TiO2 and ZnO,can produce electron transition under some light and form light electrons and holes,which can degrade organic pollutants.Study along with photocatalysts development continuously thorough,it can be found that when the photocatalyst is nanosized,its photocatalytic activity can be enhanced obviously.But the nanoparticles are easy to aggregate together and difficult to be recycled.These disadvantages can be overcomed by loading photocatalyst nanoparticles on porous materials.In this paper,we used silicalite-1 and SiO2@silicalite-1 as support to prepare the silicalite-1 based photocatalysts,in which TiO2 nanoparticles and Co/ZnO nanoparticles containing different amounts of Co supported on the surface of silicalite-1 particles.The physicochemical property and photocatalytic performance of silicalite-1 based photocatalysts were analyzed by characterizing its structure,morphology,photoresponse performance and photocatalytic degradation of rhodamine B.The main research results are listed as follow:(1)Silicalite-1 was synthesized by using industrial silica sol as silica source.And SiO2@TiO2@silicalite-1 photocatalyst was prepared through pressing,sintering and immersing methods,in which TiO2(P25)nanoparticles were bonded on the surface of silicalite-1 by industrial silica sol.It can be found that the degradation efficiency of SiO2@TiO2@silicalite-1 photocatalyst for RhB is 99.7%,which is higher than TiO2(P25).And the photocatalytic efficiency of SiO2@TiO2@silicalite-1 photocatalyst keeps 99.2%of the original after four photocatalytic degradation cycles.(2)The SiO2@silicalite-1,coating with a layer of amorphous SiO2 and existing grooves on its surface,were prepared by using industrial silica sol as silica source through optimizing the proportion of template and sodium hydroxide in the precursor solution and adjusting the crystallization time.Then,TiO2@SiO2@silicalite-1 catalyst was prepared by using tetrabutyl titanate as precursor solution,SiO2@silicalite-1 as support through hydrolytic method and hybrid method.It can be found that the content of TiO2 in SiO2@silicalite-1 is 3.48 times higher than that in traditional silicalite-1.The degradation rate of TiO2@SiO2@silicalit-1 is 2.58 times higher than the TiO2 supported in traditional silicalite-1.And TiO2@SiO2@silicalite-1 also has high stability.After four photocatalytic degradation cycles,the photocatalytic efficiency of SiO2@TiO2@silicalite-1 photocatalyst just reduces 2.99%.(3)Silicalite-1 zeolite was used as support to load a layer of Co/ZIF-8 on its surface containing different amount of Co to prepare the Co/ZIF-8@silicalite-1,which was synthesized by controlling the content of Co2+ in the precursor solution of ZIF-8.And the Co/ZnO@silicalite-1 photocatalysts containing different amount of Co were prepared by stirring method.It can be found that doping Co in ZnO@silicalite-1 photocatalyst can extent its response to visible light.When ZnO@silicalite-1 photocatalyst is doped with 5%Co,its degradation rate for RhB is maximized(94.0%).And it keeps the high stability.After four photocatalytic degradation cycles,the photocatalytic efficiency of Co/ZnO@silicalite-1 photocatalyst is 90.4%.