Preparation and Properties of Porous α‐Al₂O₃ Membrane Supports

Abstract

Strong and permeable macro-porous a-Al 2 O 3 membrane supports are made by colloidal filtration of 20 vol% dispersions of a-Al 2 O 3 with an average particle size of 600 nm. Intact compacts with very good surface quality were obtained at an optimum pH of 9.5 and dosage of 0.2 wt% ammonium aurintricarboxylate (Aluminon), based on dry alumina. The colloidal stability of the aluminon-stabilized slurries is confirmed by n potential measurements. Slight sintering of dense-packed a-Al 2 O 3 compacts was found to result in 467% packing density and a bimodal pore-size distribution as derived from shrinkage behavior and gas adsorption studies. Non-stationary single gas permeation measurements showed improved gas permeability, compared with a-Al 2 O 3 compacts prepared using powder with a smaller particle size (300 nm). The strength of the disk-shaped alumina compacts within the porosity range of 30%-20% increased from 100 to 300 MPa with a standard deviation of 20 and 50 MPa, respectively. J ournal

Permeation porometry: Effect of probe diffusion in the condensate

“…All membranes were deposited on disc-shaped supports, ∼2 mm thick and ∼43 mm in ∅, exhibiting a mechanical flexure strength of ∼210 ± 10 MPa, an appropriate surface morphology (average roughness ∼30 ± 5 nm) and an adequate room temperature gas permeability (f He ≈ 1.30 ± 0.02 × 10 −6 mol/(m 2 s Pa)) [13]. These supports were prepared by vacuum assisted filtration of a stabilized and screened dispersion of ␣-Al 2 O 3 powder (AKP30, Sumitomo Chemical Corporation, Japan), followed by thermal processing.…”

Sol–gel derived mesoporous and microporous alumina membranes

“…The generally used composite asymmetric ceramic membrane structure consists of several layers with a gradual decrease in pore size and thickness on a macroporous support to minimize the resistance to gas transport through the membrane [1]. Although dry pressing and extrusion are conventional techniques for the preparation of ceramic membrane supports, macroporous supports with excellent surface homogeneity and properties have been prepared through colloidal processing (slip casting/filtration) of stable dispersions without strong agglomerates [7,8]. Microporous silica membranes with large surface areas on defect free gamma alumina intermediate layers and tubular alumina supports were prepared by ceramic extrusion method towards the preparation of substrate bundles for H 2 separation recently by Yoshino et al [9].…”

“…The number of comprehensive studies describing the design/characterization/stabilization of mesoporous cAl 2 O 3 membrane pore structures as well as their gas transport properties has increased significantly with the synthesis of stable boehmite sols over the past three decades [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. The pore structure characteristics, molecular properties of gaseous species and their interactions with the pore walls are some of the important factors for gaseous transport through porous membranes.…”

Synthesis of Thin, Oriented Zeolite A Membranes on a Macroporous Support

“…Supports, Zeolite Dispersion, and Adsorption Procedure: For the deposition experiments, we used a-Al 2 O 3 disks with 2 mm thickness and 42 mm Ø, routinely produced in our group by colloidal processing of AKP15 a-Al 2 O 3 powder (Sumitomo Chemical Co. Ltd., Tokyo, Japan) followed by partial sintering [33]. These supports had a surface roughness (root mean square deviation from average) of $25 nm, a surface porosity (fraction of voids) of $33%, and a surface Øp of $40 nm [34].…”