Table 2.
FT-IR functional group’s analysis of PAA for 4-nitrophenol removal before.
| Vibrational assignment | Observed wave number (cm−1) | Functional groups | Visible intensity |
|---|---|---|---|
| O—H stretching | 3291.33 | Carboxylic acids | Wide peak |
| C—H stretching | 2922.22 | Aldehyde | Small medium peak |
| NO2 asymmetric stretching | 1636.95 | Nitrate | Sharp peak |
| NO2 asymmetric stretching | 1540.45 | Aromatic nitro compound | Small medium peak |
| N N stretching | 1395.81 | Azo compound | Small peak |
| C—O stretching | 1230.97 | Esters | Sharp peak |
| C—O stretch | 1031.94 | Alcohol and phenols | Medium sharp peak |