H2O2沉淀铝酸钠溶液法制备大孔容纳米γ-Al2O3纤维粒子

采用H₂O₂沉淀铝酸钠溶液和乙醇分散并洗涤沉淀相结合的方式成功地制备出了大孔容纳米γ-Al₂O₃纤维.运用XRD、FT-IR、TG-DSC、TEM、BET和压汞法对比研究了水洗和乙醇分散并洗涤两种沉淀处理方式对产物结构、形貌和织构性质的影响.结果表明，乙醇洗涤产物γ-Al₂O₃纤维的直径约为10 nm，长度约在100 nm以上，孔容和比表面分别为2.23 ml•g^-1和222.0 m²•g^-1，而水洗γ-Al₂O₃的二次粒子无固定形状，孔容和比表面仅为0.37 ml•g^-1和162.3 m²•g^-1.乙醇洗涤时形成的CH₃CH₂O—基不仅使γ-Al₂O₃前驱物拟薄水铝石晶粒定向生长成纤维，还阻止了相邻颗粒表面之间因Al—O—Al键形成而产生的硬团聚.

PREPARATION OF NANOFIBROUS γ-Al2O3 PARTICLES WITH LARGE PORE VOLUME FROM H2O2 AND SODIUM ALUMINATE SOLUTIONS

Nanofibrous γ-Al₂O₃ with very large pore volume was successfully prepared by precipitation from H₂O₂ and sodium aluminate solutions combined with dispersing and washing the precipitate with ethanol.The effects of ethanol washing and water washing on structure, morphology and texture properties of pseudoboehmite-calcined γ-Al₂O₃ were comparatively studied with XRD, FT-IR,TG-DSC,TEM,BET and mercury porosimeter.The ethanol-processed γ-Al₂O₃ presented fibrous-like texture about 10 nm thick and over 100 nm long whose pore volume and BET surface area could reach about 2.23 ml•g^-1 and 222.0 m²•g^-1, respectively.However,the secondary particles of the water-processed γ-Al₂O₃ had no regular shape and its as-mentioned texture properties of pore volume and BET surface were only 0.37 ml•g^-1 and 162.3 m²•g^-1,respectively. CH3CH2O— groups on the surface of ethanol-processed pseudoboehmite particles could not only induce fiber formation through hydrogen bonding between the oxide groups and the surface OH—groups, but also inhibit chemical Al—O—Al bonds formation among the adjacent particles and thus hard agglomerate could be prevented.