Preparation Of Macro-sized Macro-mesoporous TiO₂-based Photocatalyst And Its Application In Organic Pollutants

As a green technology with important application prospects in the field of clean energy and environmental protection,photocatalytic technology has been paid more and more attention by researchers.As an important part of it,TiO₂ photocatalyst can be used to degrade a variety of organic pollutants by using solar energy,which has a series of advantages such as low energy consumption,green and clean,and no secondary pollution.However,nano-TiO₂particles are too small,which are easy to be aggregated and difficult to be separated in the solution,affecting the reuse.Solving this problem is the key to promote TiO₂ photocatalyst to practical application.Therefore,this paper studied several macro-sized macro-mesoporous TiO2-based photocatalysts,characterized by XRD,SEM,FTIR,TEM and N2 adsorption-desorption,and applied them to the photocatalytic degradation of different dyes.The main research work is as follows:?1?The monolithic macro-mesoporous TiO₂ material was prepared by using epoxy resin macroporous polymer as template through impregnation and a subsequent calcination at high temperature.It was found that the epoxy resin macroporous polymer has 3D continuous pass-through macropore structure.After the polymer was removed by roasting,the pore walls of the materials are constructed by dense TiO₂ nanoparticles,and the thickness of TiO₂ thin layer can be controlled by adjusting the mass fraction of tetrabutyl titanate and the times of impregnation.Using azophloxine and methylene blue as simulated pollutants,the photocatalytic activity of the macro-mesoporous TiO₂ was studied under the sunlight irradiation simulated by Xenon lamp under different conditions.The results show that when the mass fraction of tetrabutyl titanate is 40%,calcination temperature is 550?,the concentration of the dye solution for 10 mg·L^-1 and azophloxine solution pH of 2,10 for methylene blue solution pH,macro-mesoporous TiO2 photocatalyst has a good photocatalytic degradation effect on pollutants.?2?A macro-sized macro-mesoporous SiO₂ was prepared by using hard template method and it was used as support to prepare macro-mesoporous TiO₂-nanocrystalline/SiO₂composite through an in situ hydrolysis of tetrabutyl titanate and a subsequent calcination at high temperature.Using azophloxine and methylene blue as simulated pollutants,the photocatalytic activity of the macro-mesoporous TiO₂/SiO₂ was studied under the sunlight irradiation simulated by Xenon lamp under different conditions.The results show that the macro-mesoporous SiO₂ has 3D continuous pass-through macropore structure and its pore wall is silica nano-film.TiO₂-nanocrystallines,in the form of nano-film,in situ grow uniformly on both sides of the nano SiO₂ film,and abundant mesopores are observed on the pore wall of the obtained macro-mesoporous TiO₂/SiO₂ composite.The macro-mesoporous TiO2/SiO2 photocatalyst exhibits the best activity for photocatalytic degradation of pollutant from the macro-mesoporous TiO₂/SiO₂ composite containing 15.7 wt%of TiO₂ calcined at600?,under the conditions of azophloxine concentration 10 mg·L^-1 and azophloxine solution pH of 3,9 for methylene blue solution pH.The macro-mesoporous TiO₂/SiO₂photocatalyst also has good reusability.