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Preparation of Porous Mullite Fibers for Support of Environmental Catalyst

环境催化剂载体多孔莫来石纤维的制备

基本信息

批准号：
08555152
负责人：
OKADA Kiyoshi
金额：
$ 12.74万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08555152/
关键词：
Porous materials Fiber Mullite Catalyst support Selective leaching

项目摘要

Porous materials made of glass fibers and ceramic fibers have high porosity and good permeability for fluid, and were applicable as filters and porous ceramics with high thermal stability and chemical durability. The functions are further expected to improve by increasing specific surface area of the fibers. Therefore, porous mullite fibers were prepared by crystallization and selective leaching of glass fibers because mullite has good thermal stability, oxidation resistance and high chemical durability. First, three kinds of etchent solutions, i.e.NaOH,HF-H_2SO_4 and HF-NH_4F were used in the selective leaching treatment and examined their selectivity by changing the concentration, temperature, solid/solution ratio and soaking time. As the results, HF-NH_4F solution was decided to be the best etchent solution among them. The porous properties of mullite fibers were examined by changing the crystallizing temperatures from 1100 to 1300ﾟC.Corresponded to these crystallizing temperatures, the surface areas obtained ranged from 12 to 32 m^2/g and the pore sizes ranged from 5 to 36 nm. In this way, porous properties of mullite fibers were found to be tunable by controlling the crystallizing temperature and soaking time. Since the pores prepared in the mullite fibers maintained up to firing temperature 1200ﾟC,the thermal stability of the porous mullite fibers thus obtained was very high level compared with those of the other porous materials.

由玻璃纤维和陶瓷纤维制成的多孔材料具有高的孔隙率和良好的流体渗透性，是一种具有高热稳定性和化学耐久性的过滤器和多孔陶瓷材料。通过增加纤维的比表面积，有望进一步改善纤维的性能。因此，由于莫来石具有良好的热稳定性、抗氧化性和较高的化学耐久性能，采用玻璃纤维晶化和选择性浸出的方法制备了多孔莫来石纤维。首先，采用NaOH、HF-H_2SO_4和HF-NH_4F三种腐蚀液，通过改变溶液浓度、温度、固液比和浸泡时间，考察了三种腐蚀液的选择性。结果表明，HF-NH_4F溶液是其中最好的蚀刻液。通过改变晶化温度1100~1300ﾟC考察了莫来石纤维的多孔性。与此相对应，莫来石纤维的比表面积为12~32m^2/g，孔径为5~36 nm。这样，通过控制晶化温度和浸泡时间，可以调节莫来石纤维的多孔性。由于莫来石纤维中的气孔一直保持到1200ﾟC的烧成温度，因此与其他多孔材料相比，所获得的多孔莫来石纤维具有很高的热稳定性。