View in EDS

Seed-assisted hydrothermally synthesized AACH as the alumina precursors.

Saved in:
Bibliographic Details
Title: Seed-assisted hydrothermally synthesized AACH as the alumina precursors.
Authors: Alizadeh, Masoud1, Rahimipour, Mohammad-Reza1, Mirzajany, Roghayeh1,2, Saremi, Mohsen1,2
Source: Materials Chemistry & Physics. Jan2019, Vol. 221, p188-196. 9p.
Subjects: Aluminum oxide, Sorbents, Hydrothermal deposits, Surface area, Elastic modulus
Abstract: Abstract Ammonium Aluminum Carbonate Hydroxide (AACH) is one of the nanostructure materials with a high surface area, which is mostly produced by the hydrothermal method. In this study, kinetics of the hydrothermal reaction has been accelerated with the addition of seed. Nucleation and growth steps have been studied by characterizing the obtained precipitate at different reaction times by FTIR, XRD, FE-SEM, and BET. Different amounts of seeds were added, and the optimum amount in reducing AACH crystallization time has been determined. By seed addition the time required for AACH formation has been reduced from 24h to around 10h, also the specific surface area of the AACH whiskers have been increased about 2.8 times. Mechanism of the reaction and the effect of seed addition have been discussed. Synthesized AACH was calcined at different temperatures to obtain different phases of alumina fibers. The surface area of the obtained Aluminas was investigated by BET; results showed that the highest surface area is achieved when the alumina is in the form of gamma structure. Highlights • AACH have been synthesized hydrothermally with and without seed addition. • Kinetic of the AACH formation has been improved. • AACH crystallization time has been reduced from 24h to around 10h. • Surface area of the AACH has been increased about 2.8 times. • Alumina fibers with high surface area were obtained by AACH calcination (125.53 m 2 / g). [ABSTRACT FROM AUTHOR]
Copyright of Materials Chemistry & Physics is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
Description
Abstract:Abstract Ammonium Aluminum Carbonate Hydroxide (AACH) is one of the nanostructure materials with a high surface area, which is mostly produced by the hydrothermal method. In this study, kinetics of the hydrothermal reaction has been accelerated with the addition of seed. Nucleation and growth steps have been studied by characterizing the obtained precipitate at different reaction times by FTIR, XRD, FE-SEM, and BET. Different amounts of seeds were added, and the optimum amount in reducing AACH crystallization time has been determined. By seed addition the time required for AACH formation has been reduced from 24h to around 10h, also the specific surface area of the AACH whiskers have been increased about 2.8 times. Mechanism of the reaction and the effect of seed addition have been discussed. Synthesized AACH was calcined at different temperatures to obtain different phases of alumina fibers. The surface area of the obtained Aluminas was investigated by BET; results showed that the highest surface area is achieved when the alumina is in the form of gamma structure. Highlights • AACH have been synthesized hydrothermally with and without seed addition. • Kinetic of the AACH formation has been improved. • AACH crystallization time has been reduced from 24h to around 10h. • Surface area of the AACH has been increased about 2.8 times. • Alumina fibers with high surface area were obtained by AACH calcination (125.53 m 2 / g). [ABSTRACT FROM AUTHOR]
ISSN:02540584
DOI:10.1016/j.matchemphys.2018.08.083