WAXRD

The SAXRD pattern of the studied samples are shoAvn in Figure 1. It can be seen three reflection peaks for SBA-15 and for samples W5, WIO, W15 and W30. These reflections can be indexed in a pseudohexagonal symmetry as it is expected for mesoporous SBA-15. On the other hand the SAXRD patterns of samples WO and W40 show only one peak (marked by an arrow) indicating a distorted hexagonal mesoporous structure. No peaks were observed in the WAXRD patterns (Figure 2) of samples WO to W15, while those of samples W30 and W40 reveal the formation of microporous ZSM-5. 

A. For samples W5, WIO and W15, recrystallized in the presence of water, a broadening of the pore radius distribution and a shift of the mean pore radius to lower values is observed. For these samples, an increase of the dV/dr values with decreasing pore radius for pore radii below 15 A indicates that the irregular micropores of the parent SBA-15 are still preserved. With the increase of the water content, such irregular micropores are not observed for samples W30 and W40, which contains mesopores with a relatively narrow radius distribution centered at 19 A. The sharp peaks at 8 A observed in the pore radius distribution of samples W30 and W40 are probably artifacts caused by a phase transition ( solidification ) of the nitrogen adsorbed in the ZSM-5 micropores [10] and therefore confirming the formation of crystalline ZSM-5 in these samples, already proved by their WAXRD patterns (Figure 2). 

The WAXRD patterns (Figure 2) demonstrate that crystalline ZSM-5 is only formed when glycerol contains at least 30 weight % of water. Although the absence of reflections caimot exclude the presence of small ZSM-5 crystallites or precursors, such precursora were not identified by FTIR in the samples recrystallized in glycerol with water contents lower than 30 weight % (Figure... 

Figure 3. (A) UV-Vis spectra, (B) SAXRD patterns, and (C) WAXRD patterns of 0.1 Sn02-MSM samples synthesized with varied periods of hydrothermal treatment. (As as-made (in grey color) Ca calcined (in black color) period of HT inh)...

Trimukhe, K. D. and Varma, A. J. A morphological study of heavy metal complexes of chitosan and crosslinked chitosans by SEM and WAXRD. Carbohydr. Polym. 71 (2008) 698-702. 

Figure 4.10 Magnified TEM image of an AU55 microcrystal and crystallographic data from SAXRD and WAXRD studies. The hid values 111 and 110 are reduced by 5% due to the size-determined contraction of Au—Au distances in small particles.

From Table 11.1 and Fig. 11.6, it is clear that the treated fibres show an overall initial increase in the crystallinty index, with maximum for alkali treated fibres which is an indication of the improvement in the order of crystallites as the cell wall thickens upon chemical treatment. The use of wide angle X-ray diffractiOTi studies (WAXRD) counts offers a simple and quick method of determining the crystallinty index, and the minimum between 101 and 002 peaks (Fig. 11.8) is an indication of the reflection intensity of the amorphous material. Alkalisation and silane treatment increases the crystallite packing order. Crystallinty index is a measure of the order of the crystallites rather than the crystallinty of the crystallites. 

Fig. 11.8 WAXRD spectra of untreated, alkali treated, and silane treated fibres...

WAXRD studies indicate an increase in the crystallinity index after chemical treatment. 

Chitosan/kaohn/nanosized Y-Fe Oj composites were prepared by a micro emulsion process and characterized by TEM, SEM, and WAXRD. Many pores and pleats were visible on the surface of the composites and provided a good condition for dye adsorption. Methyl orange was selected as a model anionic azo dye to examine the adsorption behavior of the composites. About 71% of methyl orange was adsorbed within 180 min, from 20 mg/1 at ph 6 by 1.0 g/1 adsorbent dosage. The composites can... 

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