Precipitation of Nanoscale Aluminum Hydroxide Particles

Rasmussen, Don H.; Brancewicz, Chris; Das, Biman; Graeffe, Mats; Rosenholm, Jarl B.; Toscano, Alicia

doi:10.1081/dis-100107858

Cited by 7 publications

(3 citation statements)

References 7 publications

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“…Industrially, gibbsite is extracted and purified by the Bayer process, a large-scale technique for the production of aluminum and alumina. , The gibbsite particles thus produced adopt nonregular morphologies with sizes ranging from several and up to hundreds of micrometers − which restricts their applicability. In the laboratory, several methods have been developed to synthesize nanosized gibbsite particles. − Among them, only few can achieve regularly shaped pure gibbsite nanoparticles. ,,, Moreover, they all suffer from slow course which requires several days to weeks until gibbsite is completely crystallized.…”

Section: Introductionmentioning

confidence: 99%

Fast Synthesis and Size Control of Gibbsite Nanoplatelets, Their Pseudomorphic Dehydroxylation, and Efficient Dye Adsorption

Louaer

Wang

Guo

2013

ACS Appl. Mater. Interfaces

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In this paper, a simple and fast (4 days) procedure to synthesize colloidal gibbsite nanoplatelets (NPTs) from a single aluminum alkoxide (aluminum sec-butoxide) as precursor is presented. The introduction of a preheating step accelerated the precursor's hydrolysis/peptization and considerably shortened the overall reaction time while the acid concentration affected the uniformity of the platelets shape. This procedure was successfully exploited to rapidly produce gibbsite platelets of controllable sizes by combination with the seeded growth method. The use of a single alkoxide precursor induced high growth rates and allowed a fast control of the platelets size over a wide range (nano- to microscale after only three growth steps). No signs for size limitation were observed. The dehydroxylation sequence of the as-synthesized NPTs was systematically investigated. Thermally stable chi-alumina NPTs, pseudomorphs of the parent gibbsite platelets, with a micro/mesoporous structure and high specific surface area, were obtained. The synthesized gibbsite NPTs can efficiently adsorb Methyl Orange dye in wastewater treatment with removal efficiency up to 94.8%.

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Section: Introductionmentioning

confidence: 99%

Fast Synthesis and Size Control of Gibbsite Nanoplatelets, Their Pseudomorphic Dehydroxylation, and Efficient Dye Adsorption

Louaer

Wang

Guo

2013

ACS Appl. Mater. Interfaces

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“…Nanosized gibbsite particles are synthesized according to a few different methods [9,[12][13][14][15][16][17]. These methods have in common that gibbsite is formed at moderate pH (4.5-9), in contrast to the Bayer process, where the crystallization takes place at very high pH.…”

Section: Introductionmentioning

confidence: 99%

Seeded growth of monodisperse gibbsite platelets to adjustable sizes

Wijnhoven

2005

Journal of Colloid and Interface Science

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Nanosized hexagonal gibbsite seeds are grown from a mixture of dissolved alumina alkoxides at 85 • C. Centrifugation reduces the polydispersity by 30%. The seeds can be grown further by adding them to a fresh alkoxide mixture and heating it. This procedure was repeated several times to obtain particles of 570 nm ± 11% diameter and a thickness of 47 ± 23%. No indications of a size limit were observed. The thus obtained particles may form easily a columnar phase. Individual gibbsite particles in solution can be seen by confocal microscope.  2005 Elsevier Inc. All rights reserved.

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“…These particles are meant to be used in phase-separation experiments. Several methods to produce colloidal gibbsite particles exist. − We chose a method with a relative low polydispersity. This method was developed by Wierenga et al and produces gibbsite platelets with an average diameter of 150−200 nm.…”

Section: Introductionmentioning

confidence: 99%

Coating of Gibbsite Platelets with Silica

Wijnhoven

2004

Chem. Mater.

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In this work, gibbsite particles are synthesized from aluminum alkoxides in an acidic environment at 85°C. After centrifugation, coating with silica is investigated following two different methods. Practical aspects and the feasibility to produce significant amounts of material are studied. The first method, analogous to a procedure used for boehmite, is a three-step procedure that starts from the addition of water glass and ends with Stöber growth of silica. In the second method, poly(vinylpyrrolidone) is used to stabilize gibbsite in the Stöber-like mixture for silica growth. Both methods lead to silica-coated particles. The first method is elaborate, but can be used to make very thin (<4 nm) silica layers. The second method is quick and produces smooth layers. The particles are characterized by scanning and transmission electron microscopy and energy-dispersive X-ray analysis and show a smooth silica layer of 10-25 nm thick. These particles can be used for confocal microscopy and in mixtures with different shaped particles to study phase behavior. By acid leaching the gibbsite can be removed and hollow silica platelets remain.

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Precipitation of Nanoscale Aluminum Hydroxide Particles

Cited by 7 publications

References 7 publications

Fast Synthesis and Size Control of Gibbsite Nanoplatelets, Their Pseudomorphic Dehydroxylation, and Efficient Dye Adsorption

Fast Synthesis and Size Control of Gibbsite Nanoplatelets, Their Pseudomorphic Dehydroxylation, and Efficient Dye Adsorption

Seeded growth of monodisperse gibbsite platelets to adjustable sizes

Coating of Gibbsite Platelets with Silica

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