Preparation, characterization and permeation property of Al₂O₃, Al₂O₃–SiO₂ and Al₂O₃–kaolin hollow fiber membranes

• Published in: Journal of membrane science Vol. 372; no. 1-2; pp. 154 - 164
• Main Authors: Han, Ling-Feng, Xu, Zhen-Liang, Cao, Yue, Wei, Yong-Ming, Xu, Hai-Tao
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.04.2011; Elsevier
• Subjects: aluminum oxide; ambient temperature; artificial membranes; Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; kaolin; mechanical properties; Membranes; porosity; Porous materials; scanning electron microscopy; silica; X-ray diffraction; Binary compound; Density; Precursor; Silica; Characterization; Particle; Pore size; Hollow fiber membrane; Hollow fiber; Membrane; Mullite; Structure; Aluminium oxide; Clay; Scanning electron microscopy; Permeation; Mechanical properties; X ray diffraction; Dispersion; Silicon oxides; Sintering; Morphology; Preparation; Solid state reaction; Distribution; Porosity; Alumina; Kaolin; Inorganic membrane
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2011.01.065

Al₂O₃, Al₂O₃–SiO₂ and Al₂O₃–kaolin hollow fiber precursors were prepared by a wet-spinning method using polyethersulfone (PES), Al₂O₃, SiO₂ and kaolin. The hollow fiber membranes were obtained after a preheating and sintering combining process. These inorganic hollow fiber membranes had been characterized by SEM, XRD, porosity, density, mechanical property, permeation property and the mean/maximum pore size as well as pore size distribution, to investigate the effects of SiO₂ and kaolin on α-Al₂O₃ hollow fiber membranes. The morphology of precursors depended on the particle contents and PES concentrations in the dispersion, and the final structure of sintered membranes were controlled by the precursors. XRD results showed that Al₂O₃ remained as α-Al₂O₃ before and after being sintered while SiO₂ changed from tridymite to cristobalite from ambient temperature to 1450°C, and at higher temperature it would react with Al₂O₃ to produce the stoichiometric 3:2 mullite (3Al₂O₃·2SiO₂, or Al₆Si₂O₁₃) by solid state reaction. The effect of SiO₂ and kaolin on the membrane properties depended on both the ratio of Al₂O₃:SiO₂/kaolin and the sintering temperature. Moreover, when sintering temperature was 1600°C, Al₂O₃–kaolin-5 (Al₂O₃:kaolin=1:1) achieved a mean pore size of about 0.5μm.