Geoscience Reference
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(a)
(f)
376
249
229
112
116
(b)
(g)
240
234
110
114
+
(c)
(h)
355
229
234
-
114
118
(d)
(i)
450
359
398
205
117
117
(e)
(j)
454
358
452
374
115
106
0
200
400
600
0
200
400
600
T (°C)
Figure 6.13 DTG curves of different gels (a) 24 h of aging at room temperature and
(b) 1 day, (c) 3 days, (d) 5 days and (e) 7 days of heating at 115
C, and gel B after (f) 24 h
of aging at room temperature and (9) 1 day, (h) 3 days, (i) 5 days and (j) 7 days of heating
at 115
C
[82]
.
500
C. The first
endotherm is mainly due to the desorption of water, while the second and the third
result from the exothermic decomposition of organics in faujasite zeolites.
Similarly, Bell
[83]
and Gilson
[84]
have attempted to identify the nature and
relative amounts of the silicate and aluminosilicate species present in the mother
liquor using
29
Si and
27
Al NMR spectroscopy. However,
200
C, 200
300
C, and 300
weight loss on the faujasites, 25
29
Si NMR technique has
an important limitation, i.e., silicate species containing more than 12 Si atoms have
