Table 5.
Assignment of principal IR absorption bands in the spectra of unprocessed FSS and its chars
| Location of wave numbers (cm-1) | Vibrations | Band assignment of functional group/component | |
|---|---|---|---|
| Unprocessed FSS | FSS chars | ||
| 3331 | 3336 | O-H stretch | Hydroxy and carbonyl groups characteristic of cellulose-based substrate |
| 3292 | 3286 | ||
| 3005 | 3005 | C-H stretch | Aliphatic methylene group |
| 2922 | 2922 | ||
| 2852 | 2852 | ||
| 1743 | 1743 | C=O stretch | Vibrations of carbonyl, esters or carboxyl |
| 1626 | 1651 | C=C C=O | Presence of aromatic rings, ketones/quinones |
| 1535 | D | N-H in plane | Secondary amides |
| 1454 | 1452 | C-H bend | Aliphatic methylene group |
| 1367 | |||
| 1359 | O-H bend | Aromatic bend | |
| 1315 | 1315 | ||
| 1278 | O-H bend | Primary or secondary OH in plane bend | |
| 1244 | 1242 | N-H bend Stretches of C-O H-O | Secondary amide |
| 1203 | 1199 | ||
| 1159 | 1159 | Hydroxyl, ester or ether vibrations | |
| 1059 | 1103 | ||
| 1051 | 1055 | C-O stretch | Polysaccharide bands |
| 1031 | 1030 | ||
| 893 | 896 | Bends due to N-H C-O | Skeletal vibrations due to secondary amine, carbonate, inorganic sulphates |
| 804 | |||
| 696 | |||
| 659 | 663 | ||