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

3 Experimental
3.4 Characterisation for microporous materials and membranes
3.4.1 Microporous material characterisation
Particle size analysis of the sols was performed by using dynamic light scattering (DLS)
equipment (Horiba Nanoparticle Size Analyzer LB-550) and small angle X-ray
scattering. Prior to analysis, the sols were filtered with a Schleicher & Schuell 800 nm
membrane sieve.
Small angle X-ray scattering
SAXS studies 126 were performed using a NANOSTAR camera (Bruker AXS), fitted with
a rotating anode source, run at 40 kV and 40 mA and filtered to yield only CuKα with
wavelength λ=1.540 Å. The collimation path consisted of 3 pinholes and the primary
beam stop at about 1.05 m from the sample position was chosen at 2 mm in diameter to
allow the smallest scattering vector q~0.006 Å -1 to be obtained. Scattering patterns in
2-dimensionals were collected on a Hi-Star Xenon-filled 1000·1000 wired grid area
detector. Typical acquisition times for the dilute solutions, which were kept for 10 hours,
for statistical reasons, in sealed quartz capillaries of 1.5 mm diameter in the evacuated
sample chamber. Transmissions of the solutions were in the order of 40-50% from
absorbance measurements using a glassy carbon standard which was inserted in the
optical path between the sample and the detector. The spot size of the beam on the
sample was 500 µm. All data was corrected for background scattering of the quartz after
a radially averaging process of the raw data to yield a usable scattering vector range
0.008