Inorganic Microporous Membranes for Gas Separation in Fossil Fuel ...

3 Experimental
vacuum sample holder of the spin-coater (Delta+80 7 equipment SÜSS Microtec).
Evaporation between zero and 60 seconds was performed before rotating at 500-5000
RPM.
After the membranes were dip or spin-coated, they were dried at 40ºC in a relative
humidity of 60% (climate chamber) and fired in air at temperatures of 600°C for 3 h with
a heating/cooling rate of 1°C/min to obtain the γ-phase of Al2O3. Unsupported γ-Al2O3
bulk membrane material was obtained for gas physisorption and XRD characterisation by
drying the dip-coating solutions and subsequently firing the dried gels at the abovementioned
conditions.
Figure 17 A) Nima technology rotational dip coater and B) SÜSS Microtec spin coater
3.2 Synthesis of zeolite material and membrane preparation
The synthesis of the selected zeolite materials of deca-dodecasil-3R (DDR) and
dodecasil-1H (DOH) are outlined in this section. The synthesis of DDR zeolite is
described as well as the synthesis and post-treatments of pure DOH zeolite. Finally, the
formation of DOH layers is presented.
3.2.1 Hydrothermal zeolite syntheses
A B
Deca dodecasil-3R synthesis
DDR small crystals were synthesised according to the published recipes. 44,60 The recipe
of Gies 60 was reproduced by dissolving the structure directing agent (SDA)
1-adamantaneamine (ADA, Aldrich) in a basic solution of ethylenediamine (EN, Aldrich)
in water. The tetramethyloxysilane (TMOS, Aldrich) was slowly hydrolysed by drop
wise addition into the aqueous solution. Another approach, described by Tomita et al. 62
and den Exter et al., 44 was used. Namely, dissolving ADA in EN followed by rapid
addition of deionised water. This mixture was heated for 1 hour at 95ºC after being
shaken for 1 hour at RT to dissolve the ADA completely. TMOS at 0ºC was added in the
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