Fabrication Of Humidity-controlling Ceramic And Modification By Photocatalyst Under Visible Light

The quality of indoor environment is closely related to people's comfort and health.In recent years,the optimization of indoor environment quality has become the focus of research in many fields such as architecture,environment,biology and public health.Maintaining a reasonable humidity in room is helpful to get health for people.Make the air clean is also urgent to avoid the problemsinduced by indoor environment pollution.Sepiolite has rich micro-pore structure and it is a good material for moisture regulation and adsorption.Based on sepiolite,the present thesisfabricatedan interior decoration material-porous humidity-controllingceramic,and modified it with catalyst to obtain good hygroscopic and visible catalytic properties.The specific contents are as follows.In present experiment,the porous ceramic were fabricated using sepiolite,bentonite,gypsum,aluminum hydroxide and frits as raw materials.The results showed that the density of ceramics was 1.48 g/cm³ sintered at 750 degree,the water absorption rate was 0.29,and the apparent porosity was 43%.The BET isothermal adsorption curve showed that the BJH pore surface area of the sample was 57 m²/g,the BJH average pore diameter was 13.7 nm,and the porosity of BJH was 0.20 cm³/g.Ceramics also have very rich holes between 1.7 and 10 nanometers.At this sintering temperature,the average bending strength of porous ceramic samples is 6.33 MPa,meeting the application requirements of customers.According to the test report of the national building materials testing center,the large-size ceramic samples fully meet the requirements of indoor building decoration materials for humidification function,and the 24-hour moisture absorption?171g/m²?is much higher than the national standard between 50% and 75% of humidity,and the moisture release?124g/m²?also meets the requirements.Due to the large number of micro-pores under 5 nanometers,the porous ceramic in present thesis has strong hygroscopic characteristics in the medium humidity?75%?environment,and the pores over 10 nanometers,which has the largest contribution of pore volume,provide a good inlet and outlet channel for moisture.The optimized pore size distribution is the guarantee of a good hygroscopic response.In present thesis,TiO₂ sol filling method is used to obtain smaller nano TiO₂ using the spatial limiting effect of holes,and the surface oxygen vacancy is also obtained through vacuum heat treatment.The modified moisture-adjusting ceramic has anobvious degradation effect on rhodamine B under visible light,and its related mechanism is also discussed.The experimental results show that the present sepiolite based porous ceramic with visible light catalyst can not only adjust the humidity,but also be used for indoor formaldehyde degradation and purifying the air.