Sonochemical reactions with mesoporous alumina

作者：Chave Tony; Nikitenko Sergei I^*; Granier Dominique; Zemb Thomas

来源：Ultrasonics Sonochemistry, 2009, 16(4): 481-487.

DOI：10.1016/j.ultsonch.2008.12.015

• Ultrasound
• Sonochemistry
• Nanoparticles
• Mesoporous alumina
• Boehmite
• Bayerite
• Dissolution

Herein, we report the sonochemical reactions with MSU-X mesoporous alumina (m-Al(2)O(3)) in aqueous solutions. Sonication (f = 20 kHz, I = 30 W cm(-2), W(aq) = 0.67 W mL(-1), T = 36-38 degrees C, Ar) causes significant acceleration of m-Al(2)O(3) dissolution in the pH range of 4-11. Moreover, power ultrasound has a dramatic effect on the textural properties and phase composition of m-Al(2)O(3). Short-time sonication at pH = 4 leads to the formation of nanorods and nanofibers; of boehmite, AIO(OH). Prolonged ultrasonic treatment causes high aspect morphology transformation to aggregated nanosheets in weakly acid solutions or plated nanocrystals in alkaline solutions. Sonochemical products in alkaline medium are composed principally from boehmite and small amounts of bayerite, AI(OH)(3). Silent hydrolysis of m-Al(2)O(3) yields boehmite at pH = 4 and bayerite at pH = 11. The effect of ultrasound on the textural properties of mesoporous alumina as well as on the transformation of nanosized bayerite to boehmite can be consistently attributed to the transient strong heating of the liquid shell surrounding the cavitation bubble which caused the chemical processes similar to those occurred during hydrothermal treatment.

• 出版日期2009-4