Another band pertaining to the functional group (-COOH) is found at 3362 [cm.sup.-1] and refers to the stretching bond
Asymmetric O-H stretching bond
shifted upfield from 3319 [cm.sup.-1] of pure water to 3394 [cm.sup.-1].
In curves (d) and (e), the broad band in the range of 1050-1250 cm-1 is related to asymmetrical stretching bond
of Si-O-Si bridges, which can be supportive to the being of a silica structure of Si-MCM-41 and an apparent signal in 965 cm-1 that is ascribed to stretching bond
of Si-OH .
Distinct absorption peak around 468.9 [cm.sup.-1] for all the samples represents stretching bond
for Zn-O mode .
From Figure 3, the spectrum for NiO, ZnO, and NiO/ZnO shows a common broad peak in the range of 2800 to 3500 [cm.sup.-1], attributed to the O-H stretching bond
. An asymmetric and symmetric C-H stretching bond
for NiO, ZnO, and NiO/ZnO are observed at around 2975 [cm.sup.-1].
As C6H5-COOH structure has only one-COOH group in the benzenering, the intensity of the C=O stretching bond
is considered to be a measure of -COOH content in the solution.
Absorption band between (1081 [cm.sup.-1] - 1156 [cm.sup.-1]) derived from C-O-H stretching bond
. Reduction 1070 - 1200 [cm.sup.-1] belongs to alcohol absorption band and indicated of fast degradation rate of Carbon chain .
C=O stretching vibrations of 1701-1704 [cm.sup.-1] the ester carbonyl group C=O stretching vibrations of 1643-1652 [cm.sup.-1] the carboxylic acid C=O groups Copolymers The N-H stretching bonds
3170-3389 [cm.sup.-1] of U/SA/EG The C-H stretching bonds
2930 [cm.sup.-1] Presence of NH-CO groups 1579-1582 [cm.sup.-1] The C-N stretching bonds
1356 and 1410 [cm.sup.-1] C-O-C stretching vibrations 1150-1187 [cm.sup.-1] of the repeated--O [H.sub.2]C[H.sub.2] units TABLE 4.