溶胶-凝胶法制备纳米氢氧化铝溶胶

[Article]

物理化学学报(Wuli Huaxue Xuebao )

Acta Phys.鄄Chim.Sin .,2007,23(5)：728-732

May

Received:October 9,2006;Revised:November 13,2006;Published on Web:March 12,2007.∗

Corresponding author.Email:wclu@;Tel:+8621⁃66133513.

国家自然科学基金(20373040)和上海市纳米专项(0452nm019)资助项目

ⒸEditorial office of Acta Physico ⁃Chimica Sinica

溶胶⁃凝胶法制备纳米氢氧化铝溶胶

张良苗1,2

冯永利2

陆文聪2,∗

2

(1上海大学材料科学与工程学院,上海

200072;

2

上海大学化学系,上海

200444)

摘要：研究了利用铝酸钠溶液碳酸化产生的沉淀,经胶溶作用制备出纳米氢氧化铝溶胶的过程

.分析了铝酸钠溶液滴加到大量碳酸氢钠溶液中时发生的反应.X 射线衍射研究结果表明,在纳米氢氧化铝溶胶制备过程中,从无定形氢氧化铝沉淀到拟薄水铝石的晶型转变过程是氢氧化铝沉淀胶溶时溶解再析出的过程.将碳酸氢钠加入到苛性比为1.7的铝酸钠溶液中,中和至苛性比为1.3后,溶液诱导期中的紫外光谱显示270nm 处的Al(OH)3-6吸收增强.经与含铝原子六配位的晶体紫外光谱对比后表明,在铝酸钠分解生成氢氧化铝的过程中,其铝的配位结构从四配位转化为六配位.拟薄水铝石溶胶粒子的形貌与胶溶所用的酸和分散剂有关.关键词：纳米氧化铝;铝酸钠溶液;

无定形氢氧化铝;拟薄水铝石;

溶胶⁃凝胶法

中图分类号：O648

Synthesis of Nano ⁃Alumina Hydroxide Sol Using Sol ⁃gel Method

ZHANG Liang ⁃Miao 1,2

FENG Yong ⁃Li 2LU Wen ⁃Cong 2,∗(1School of Material Science and Engineering,Shanghai University,Shanghai 2

Department of Chemistry,Shanghai University,Shanghai 200444,P.R.China )

Abstract ：The preparation process of nano ⁃aluminum hydroxide sol by peptizing aluminum hydroxide precipitate produced via carbonation of sodium aluminate was investigated.The reaction,in which the sodium aluminate solution was dropwise added into abundant sodium bicarbonate solution,was analyzed.The XRD results indicated that the amorphous aluminum hydroxide precipitates transformed into pseudo ⁃boehmite because the precipitates dissolved and recrystallized into pseudo ⁃boehmite crystals during the sol preparation.Furthermore,the increase of absorption at 270nm in the UV spectra indicated the presence of Al(OH)3-6ion during the sodium aluminate solution with caustic ratio of

1.7was neutralized to paring with the absorption spectrum of the structure of six hydroxyl groups around Al atom,it could be concluded that the coordination numbers of Al atom with hydroxyl groups changed from four to six during the decomposition of sodium aluminate solution.Besides,the morphology of particles in the sol was also influenced by surfactants and acids used.Key Words ：Nano ⁃alumina;

Sodium aluminate solution;

Amorphous Al(OH)3;

Pseudo ⁃boehmite;

Sol ⁃gel

process

纳米氧化铝陶瓷和纳米氧化铝薄膜具有优越的性能和广泛的用途.目前其制备主要是以价格较高的醇盐或无机盐为原料[1-4].近年来我们[5]试行研究以廉价的冶金氧化铝工业生产中的循环液铝酸钠溶液为原料来制取纳米氧化铝的方法,已制得纳米氧化铝薄膜(见图1)和高纯纳米氧化铝粉体(见图2).

所得纳米孔氧化铝薄膜粒子大小约10nm,孔大小约10nm.1200℃高温处理所得纳米氧化铝粉体粒子大小约50nm,纯度可达99.9%.该制法除需用少量酸做胶溶介质外,不需耗用大量的酸和碱,是一种制取纳米氧化铝材料的廉价方法.在研制过程中,我们对若干关键步骤的反应过程作了研究.本文报道

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