Synthesis of Wide-Pore Alumina Support from Gibbsite

The syntheses were carried out at 220 °C for 3 to 10 d with distilled water or acidic solutions using a mixture of silica-gel derived from alkoxide and gibbsite with a Si/Al ratio of 1:1 as the starting material.

(1989), Synthesis of wide-pore alumina support from gibbsite

(2006), On the Decomposition of Synthetic Gibbsite Studied by Neutron Thermodiffractometry.
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Synthesis of submicron gibbsite platelets by organic …

Three different responses were observed: a) aluminium toxicity at pH < 5.0 represented joint action with hydrogen ions producing ionoregulatory failure; b) at pH 5.0-6.0 aluminium toxicity required concentrations of inorganic forms that greatly exceeded theoretical gibbsite solubility; c) at acutely lethal levels of pH and ionic strength, aluminium increased the resistance time of eggs, fry and adults.

Novel synthesis of unit-cell thickness ZSM-5 catalyst using gibbsite

Thermodynamic calculations reveal that, at pH values higher than 5, equilibrium with gibbsite or an insoluble trivalent alkaline form of aluminium acts to limit solubility, whereas, at lower pH values, aluminium could be in equilibrium with a hydroxysulfate salt.

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ALUMINIUM SULFATE (Sulfuric acid, aluminum salt)

Single-crystal gibbsite nanorods with a high aspect ratio were synthesized by a facile hydrothermal method. Characterizations by HRTEM, SAED, and XRD revealed that the nanorods prefer to grow along the -axis. The nanorods can be easily transformed to χ-alumina by calcination at 250 °C, while the nanorod morphology is well-maintained. HRTEM indicates that the χ-alumina nanorod possesses a single-crystal-like structure formed by orientated connection of crystalline nanodomains. Altering the synthetic procedure will lead to alumina nanostructures with a different phase structure and morphology, such as alumina nanotubes.

Professor Parisa Arabzadeh Bahri - Murdoch University

Allophane is a naturally occurring aluminosilicate consisting of hollow and spherical particles with diameters of 3.5–5.0 nm. It has poorly crystalline structure and no definite chemical composition with a chemical formula of Al2O3·(SiO2)1.3–2·(2.5–3)H2O. Allophane is fundamentally composed of an outer layer of gibbsite-like sheet with SiO4 tetrahedral attached to its interior and having defects or pores in the wall structure with diameters of around 0.3 nm. Because of its high surface area and porous structure, allophane can be used as adsorbent for pollutants. Some researchers reported that As(V) and boric acid were adsorbed by formation of inner-sphere complex with exposed aluminol groups on the allophane surface while Cr(VI) and Se(VI) were adsorbed by formation of outer-sphere complex.,) In this study, we have developed a synthesis process of allophane utilizing the undissolved residue of BFS by acid treatment. Identification of the synthesized allophane was performed by X-ray diffraction (XRD) for long range order, Fourier transform infrared (FT-IR) spectroscopy for short range order and transmission electron microscopy (TEM) for morphology.

Aluminium (EHC 194, 1997) - INCHEM

Changes in morphology of the parent solid materials, and the texture of kaolin crystals developed during hydrothermal synthesis of kaolin, may be graphically followed by scanning electron micrography (SEM) of the samples drawn during synthesis. Because the chemical conditions prevailing during synthesis are controlled and known, a possiblity arises for correlating the type of kaolin texture that is produced with the various known properties of the genetic environment. In this study, which is a first attempt toward that objective, the texture of kaolin produced by four different variations of hydrothermal synthesis using amorphous silica, allophane, and gibbsite in H2SO4 and H4EDTA solutions are illustrated with SEMs.