Research And Preparation Of TiO₂ Filter Membrane Based On The Sintered Porous Stainless Steel

The United States had achieved the key breakthrough on the preparation of porous metal ceramic membrane. It was rapidly applied in high value-added fluid separation filtration field because it exhibited excellent acid and alkali corrosion resistance, narrow pore size distribution, high strength, long life and other advantages both porous metal and porous ceramic. In this paper TiO2 microfiltration membrane was preparation on the different pore diameter of porous stainless steels by suspend particles sintering method. Those questions included the sintering process of porous stainless steel, the suspension components, the matching of membrane on the different pore size substrate, the influence factors of membrane crack, the influence of particulate suspensions, porous metal support and sintering temperature on the microstructure and properties of TiO2 membrane were examined emphatically. Finally, filtration performance of porous stainless steel TiO2 membrane by homemade filtering equipment was tested. The main results were as follows:It was showed that spherical powder particles became irregular polygon gradually, irregular polygon pore became round gradually and to be the 3D pore network structure when the porous stainless steel sintered. When the 300 mesh powders with 15% pore-forming agent sintered at 1150℃ in 2h, it can be used in the preparation of porous stainless steel membrane with porosity of 33.2%.Long time of ball-mill dispersing and suitable viscosity was the key to improve the coating quality of membranes, the best ratio of TiO2 suspension was 35wt% TiO2 powders,35wt% anhydrous ethanol,15wt% terpineol,8wt% Acetic acid,3wt% PEI and 4wt% PVA. The average pore diameter from 2.0μm to 15.0μm of porous stainless steel substrate was suitable for the preparation of TiO2 membrane by suspension particles sintering. Mould pressing and multiple coating can reduce cracks. The membrane had good comprehensive performance at 950℃, the smooth, uniform aperture distribution mainly concentrates in the 60nm to100nm.Because irregular form porous stainless steel had relatively rough surface, it can provide the "core" for membrane growth and enhanced bonding strength with TiO2 particles.Porous stainless steel membrane was mainly suitable for high pressure ultrafiltration conditions and combined osmotic quantity with energy consumption. It not only filtered out of orange juice, pigment and pectin, but also played a decolorized role of juice solution and had poor filtering effect on the high viscosity of waste oil with through-flow filtration.