Abstract: Using template PEG as structure directing agent and urea as the precipitant, alumina microfibers with mesoporous structures were successfully synthesized from a hydrothermal preparation and thermal-decomposition of precursor of ammonium aluminum carbonate hydroxide (denoted as AACH), and its adsorbability was also investigated. The phase state, chemical structure, surface morphology, special surface areas and mesoporous structure of the synthesized alumina microfibers were characterized systemically by means of XRD, SEM, TEM, TG/DTA, and N₂ adsoption-desoption techniques, respectively. The adsorptive property of the obtained mesoporous alumina fibers was examined by using a typical SCR(Selective Catalytic Reduction) denitrification facility. The results show that the AACH microfibers with diameter of about 200-300nm and length up to 8μm or 10μm are prepared by using PEG as template. The mesoporous η-Alumina microfibers with specific surface area 316m²/g and average pore diameter 2.5nm are obtained after calcined at 900℃ for 2h, and the morphology is retained in the calcination process. SCR denitrification tests show that the as-prepared mesoporous alumina microfibers exhibit more favorable adsorptive property and its efficiency of denitrification increases approximately 15% compared with commercial γ-Al2O3 powder.

Key words: alumina, porous microfibers, hydrothermal and thermal-decomposition synthesis, surfactant assisted, adsorbability