Modification And Sintering Research Of Diatomite-Based Materials For Environmental Application

Diatomite is a natural porous material which is mainly consist of amorphous silica. Diatomite possess a series of advantages, like chemical stability, high specific surface area and so on. In our country, diatomite is of high quality and abundant, but most of them are used as heat insulting material and low-grade filter aid. Developing the applications of diatomite in environmental treatment can not only broaden the application area of diatomite, but also be of great importance in environmental remediation, living-quality improvement of human life, and reducing energy comsumption.Surface morphology of diatomite from different mining are labored. Based on the application features, we choose the one who’s specific area is relatively higher as the basic material. It is mainly researched in developing diatomite-based functional materials for environmental applications. We fabricated diatomite-based composite for hexavalent chromium[Cr(VI)] removal by depositing Fe3O4nanoparticals, which is fabricated by chemical method, on diatomite. Sintering technics of diatomite-based porous ceramics are researched by adding different pore-forming agent. The influence of technical parameters of fabrication to the specific area, pore structure, surface morphology, density and water vapor Adsorption/Desorption property are discussed by using several material characterization method for structure and performance. Results are as follows:1. The surface morphology, specific area and pore size distribution features of diatomite from different regions showed quite a diversity because of different mineralization species. The more the percentage of cylindric diatomite the big the specific area.2. Fe3O4nanoparticals can be deposited in pores of porous structure diatomite by simple chemical co-precipitation method. The deposition percentage of can be adjusted by varing the amount of diatomite used. The fabricated composite showed a strong adsorption of hexavalent chromium[Cr(VI)].3. A sintering technic of diatomite-based porous ceramic is proposed. With the sintering temperature raising from700℃to1000℃, the water vapor adsorption/desorption capacity decreased as the specific area of diatomite-based ceramic descend.4. The results of multicycle test of water vapor adsorption/desorption indicate that the porous ceramic fabricated in this thesis can be used in continual adsorption/desorption process.