1. Introduction Mesoporous materials with ordered arrays of uniform nanochannels of a controllable size have wide-ranging applications, one of which is membrane separation. In order to be used as a membrane for size-exclusive separation of molecules, it is necessary to synthesize a defect-free structure with continuous nanoporosity. Mesoporous silica and porous anodic alumina have been extensiv...

In the present study, the effect of alumina on the pore structure and hydrothermal stability of nanostructured silica was investigated. SiO2 and SiO2-15wt%Al2O3 membranes were prepared by dip coating on mesoporous γ-Al2O3 coated macroporous α-alumina support. The particle sizes of sol were increased by adding of alumina to silica...

Hierarchically structured membranes composed of mesoporous silica embedded inside the channels of anodic alumina (MS-AAM) were synthesized using the aspiration method. Ethanol is shown to have a significant effect on the type and organization of the mesoporous silica phase. Detailed textural analysis revealed that the pore size distribution of the mesoporous silica narrows and the degree of ord...

Palladium doped silica membranes were synthesized by the sol-gel method using two different procedures. The first palladium-doped silica membrane (M1) was synthesized with a coating of four layers of silica-palladium sol. The second membrane (M2) was synthesized with a coating of two silica layers followed by a coating of two silica-palladium layers. Scanning electron microscopy (SEM) proved th...

in the present investigation surface modification of silica nanoparticles by alumina was carried out by sol-gel process. fourier transform infrared (ftir) and x-ray fluorescence (xrf) confirmed the synthesis of silica and the surface modification as alumina is anchored to silica surface. field emission scanning electron microscopy (fesem) and transmission electron microscopy (tem) investigation...

The apparent diffusion coefficients of tris(2,2'-bipyridyl)ruthenium ([Ru(bpy(3))](2+)) are estimated in silica-nanochannels which are assembled inside columnar alumina pores in an anodic alumina membrane, and are modified with alkylsilanes such as trimethylchlorosilane (C1), butyldimethylchlorosilane (C4), and dodecyldimethylchlorosilane (C12). The estimation is performed by observing the lag-...

In the present investigation surface modification of silica nanoparticles by alumina was carried out by sol-gel process. Fourier transform infrared (FTIR) and X-ray fluorescence (XRF) confirmed the synthesis of silica and the surface modification as alumina is anchored to silica surface. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) investigation...

In the present investigation surface modification of silica nanoparticles by alumina was carried out by sol-gel process. Fourier transform infrared (FTIR) and X-ray fluorescence (XRF) confirmed the synthesis of silica and the surface modification as alumina is anchored to silica surface. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) investigation...

In previous chapters, the synthesis of a highly hydrogen selective membrane formed by the deposition of a silica layer on top of a Vycor glass substrate was discussed. In this chapter, the preparation of a composite membrane using a porous alumina support is described. This membrane showed a high hydrogen permeance of the order of 10 mol m s Pa at 873 K with selectivity of hydrogen over CH4, CO...

1. Introduction Porous solids with bimodal pore structures are widely used as catalyst supports. Examples are formed bodies, such as tablets, beads, extrudates, and monoliths, of molecular sieves, silica and alumina. The formed bodies are prepared usually by compacting fine micro-or mesoporous particles [1]. As a result, macropores are formed between the agglomerated particles. Recently, cataly...