Preparation Mechanism And Application Research Of Hierarchically Porous Materials

Hierarchically porous materials are a gradient distribution of porous materials, which have macropores, mesopores and micropores. They have the superior pore surface characteristics as well as the morphology of the monolith. They are expected to overcome the disadvantges of powders and thin films, because of the pore structure of powders and thin film only have single pore size and can not allow fluid or liquid through smoothly. Hierarchically porous materials can be used in separation, adsorbent, and filtration, catalytic and other areas.This thesis introduced the current situation of hierarchically porous materials. Carbonization and activation of bamboo charcoal and loading photocatalytic materials are systemly studied, bamboo charcoal owns macro and meso and micropores, but it shows un-continuous structure and the amount of meso and micropores are not easily controlled. So we studied how to make co-continuous pore structure. Hierarchically porous AIPO4and TiO2monolith via epoxide-mediated sol-gel process accompanied by phase separation are prepared. The influence of phase separation inducers, solvent and gelation to sol gel system are stuied. The mechanisms of sol gel and phase separation are analysised; monoliths with co-continuous macropores and meso and micropores structure are prepared. The size of mcaropores can be controlled by the amount of phase separation inducer. The results of this thesis would be favor to application in adsorbent, catalysis and high performance liquid chromatography area.The innovation of thesis includes three points:(1) Carrying out a kind of method which is bamboo charcoals’secondary activation and photocatalytic materials modified charcoal. Through this we not only to improve the large pore size, but also increase the number of the cell wall of mesopore and micropore. With photocatalytic material to modity macroporous pore, the surface area can get reach to767m2/g;(2) AlPO4monolithic gels with well-defined bicontinuous macropores and mesopores structured skeletons have been prepared via the sol-gel process in the presence of PO and PEO, and the micro-and mesotextures of the gel skeletons have been tailored by utilizing high-temperature hydrothermal aging treatment as a post-gelation process. AlPO4monolith with Φ1.5cm×1cm,the size of macropores are about2～5μm, the size of mesopores are about10～12nm, the surface are can get reach to282m/g;(3) Monolithic macroporous titanium dioxide (TiO2) derived from ionic precursors has been successfully prepared via the sol-gel route accompanied by phase separation in the presence of formamide (FA) and ethylene glycol (EG). The addition of FA promotes the gelation, whereas PVP enhances the polymerization-induced phase separation, EG acts as a chleating agent. Appropriate choice of the starting compositions allows the production of cocontinuous macroporous TiO2monoliths in large dimensions, and controls the size of macropores. TiO2monolith with01.5cm×0.8cm, the size of macropores are about1～5μm, the size of mesopores are about3～4nm, the surface are can get reach to228m2/g. the sources of metal are inexpensive and this would be a low cost method for largely application...