Preparation Of TiO₂ Ceramic Membranes

Titanium dioxide is a kind of ceramic material with excellent performance,which has the characteristics of high temperature and alkali resistance.It has a wide application in inorganic ceramic separation film.In this paper,a narrow-dispersion TiO₂ nanoparticles were prepared by an improved sol-gel method.Then,using?-Al₂O₃ as a support,a stable membrane tube was obtained by sol-gel method after high-temperature calcination.An improved sol-gel method was used to prepare raw-dispersion TiO₂ nanoparticles,including the preparation of particles in larger size and the preparation of titanium sol.Monodisperse TiO₂ particles was successful synthesized with a particle size of 110³00 nm with KCl as the stabilizer.In the process,the effects of water-titanium molar ratio,rotation speed,KCl concentration and reaction temperature on the particle size and monodispersity were investigated.The results showed that with the increase of molar ratio of water to titanium,the particle size increased first and then decreased;with the increase of KCl concentration,the particle size decreased and the size was more uniform;as the temperature increased,the particle size increased and the monodispersity became worse.In the preparation of titanium sol,with the nitric acid as the stabilizer,the narrow dispersion of sol particles with particle size in the range of 1.75¹0nm were successfully synthesized.The effects of H⁺concentration and water-titanium ratio on the particle size of sol were investigated.The results showed that the water-titanium ratio had a significant effect on the particle size.With the increase of water-titanium ratio,the particle size increased gradually,and a gel formed at a ratio of 9.TiO₂ submicron particles obtained in the laboratory were used as the raw materials in the dip coating progress.During the process,the effects of the addition amount of TiO₂ particles,the number of coating films,the calcination temperature,the pore size of the support,and the addition amount of SiO₂ particles on the separation performance of the membrane tube were investigated.The results showed that with the increase of addition,membrane permeation flux decreased gradually,retention rate in short time increased significantly;when the size of support was 200nm,membrane has a better performance;the film can keep good retention rate at higher permeation flux when the coating times was 2;SiO₂ particles can improve the hydrophilicity of the membrane tube,and the flux and the rejection rate of the membrane tube were the best when the addition amount was 3%..The TiO₂ separation membrane with small pore size was prepared by the sol-gel method,in which,the raw material was TiO₂ nanoparticles prepared by the laboratory.The film was applied in two different ways,and the different coating methods were analyzed,discussed and optimized to determine the better coating process.The effects of filming time,baking temperature and coating times on the separation performance of the membrane tube were investigated.The results showed that with the extension of coating time,the pure water flux of the membrane tube gradually decreased;with the increase of the number of coating membranes,the pure water flux of the separation membrane gradually decreased.When the coating times were three,the highest retention rate of the separation membrane was achieved,reaching 100%.