Characterisation and performance of novel TiO2-ZrO2 membranes for gas separation

Felix Hauler 1Tim Van Gestel Wilhelm A. Meulenberg Martin Bram Hans Peter Buchkremer 

1. Forschungszentrum Jülich, Institute of Energy Research IEF (FZJ-IEF), Leo-Brandt-Strasse, Jülich 52425, Germany

Abstract
The rising content of the greenhouse gas CO2 in the atmosphere caused by human activities is presumed to be an important contribution to global warming. At present, fossil fired power plants are one of the main producers of CO2 and an increasing usage of such plants is assumed. A reduction of the CO2 content in the atmosphere could be achieved by separation of CO2 using gas separation membranes having molecular sieving properties. In this paper, the preparation and characterisation of novel TiO2-ZrO2 membranes are presented.

In a first series of experiments, nano-sized TiO2-ZrO2 membrane materials were prepared by a polymeric sol-gel route and their properties were investigated by dynamic light scattering (particle size), N2-adsorption (pore size) and XRD (phase structure). The composition with the TiO2:ZrO2 ratio of 1:1 exhibited the most promising characteristics including a particle size of ~3-6 nm, a microporous structure with a pore size <1 nm and an amorphous phase up to 600 °C.

In a second series of experiments, these membrane materials were coated on an alumina membrane carrier consisting of a macroporous α-Al2O3 substrate and a mesoporous γ-Al2O3 membrane layer with a pore size of 5 nm. Structural examination of the TiO2-ZrO2 membranes by high resolution SEM and TEM showed very homogeneous top layers with a thickness of ~30-50 nm. The gas permeation of the top layer was investigated by standard gas permeation tests with He, H2, CO2 und N2. The results were compared with data obtained for microporous SiO2 membranes which were coated on the same substrate. The SiO2 membranes showed 100 % H2/CO2 separation which indicated the formation of high quality layers by our clean room dip-coating procedure. The novel TiO2-ZrO2 layers were much tighter and showed a H2/CO2 permselectivity of ~10 with very low fluxes. Current investigations are aimed to enhance this performance by synthesis adaption.

 

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Presentation: Oral at E-MRS Fall Meeting 2009, Symposium G, by Felix Hauler
See On-line Journal of E-MRS Fall Meeting 2009

Submitted: 2009-05-14 19:47
Revised:   2009-06-07 00:48