Combustion synthesis and stability of nanocrystalline La_2O_3 via ethanolamine-nitrate process  

作　　者：LONG Yulin YANG Jun LI Xiaoci HUANG Weiya TANG Yu ZHANG Yuanming 龙俞霖;杨骏;李小慈;黄微雅;唐渝;张渊明(Department of Chemistry,Jinan University,Guangzhou 510632,China)

机构地区：[1]Department of Chemistry,Jinan University,Guangzhou 510632,China

出　　处：《Journal of Rare Earths》2012年第1期48-52,共5页稀土学报（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (2008ZX07211-003);Team Project of Natural Science Foundation of Guangdong Province (05200555)

摘　　要：Pure nanocrystalline La2O3 powders were successfully prepared by the combustion method.The effect of ethanolamine-to-nitrate ratio on phase composition and crystallite size of the combustion products was systematically investigated.Pure hexagonal La2O3 powders were almost formed in stoichiometric reaction（ψ=1.15）,while metallic La phase was obtained in fuel-rich conditions（ψ≥3.0）.The as-synthesized hexagonal La2O3 was found to be chemically unstable in ambient air since a complete transformation to hexagonal La（OH）3 was detected after 24 h exposure to air.The resulting hexagonal La（OH）3 showed an excellent ability to remove water pollutant and could nearly remove 100% of the Congo red at room temperature with a removal capacity of 143.5 mg Congo red/g.The phosphate adsorption data on hexagonal La（OH）3 agreed well with the Langmuir model with the estimated maximum adsorption capacity of 57.8 mg/g.Pure nanocrystalline La2O3 powders were successfully prepared by the combustion method.The effect of ethanolamine-to-nitrate ratio on phase composition and crystallite size of the combustion products was systematically investigated.Pure hexagonal La2O3 powders were almost formed in stoichiometric reaction（ψ=1.15）,while metallic La phase was obtained in fuel-rich conditions（ψ≥3.0）.The as-synthesized hexagonal La2O3 was found to be chemically unstable in ambient air since a complete transformation to hexagonal La（OH）3 was detected after 24 h exposure to air.The resulting hexagonal La（OH）3 showed an excellent ability to remove water pollutant and could nearly remove 100% of the Congo red at room temperature with a removal capacity of 143.5 mg Congo red/g.The phosphate adsorption data on hexagonal La（OH）3 agreed well with the Langmuir model with the estimated maximum adsorption capacity of 57.8 mg/g.

关 键 词：OXIDES combustion synthesis X-ray diffraction ETHANOLAMINE rare earths 

分 类 号：TB383.1[一般工业技术—材料科学与工程]