“…An absorption band at 2398.06 cm −1 was attributed to the C=O stretching vibrations of carboxylic while the steep peaks observed around 1630.29 to 1398.26 cm −1 corresponded to the C–C stretching, and C–O asymmetric stretch which might be attributed to the presence of an aromatic or olefinic compounds ( Lin et al., 2019 ). The C–Br Stretching vibration and C–O stretching of alcohol or carboxylic acid were recorded at peaks ranging from 1003.01 to 898.34 cm −1 ( Indha et al., 2016 ). Figure 1 (b) shows the FT-IR spectrum of the amine-modified adsorbent, which shows peaks at 3850.13, 3632.07, 3450.53, 2389.63, 2128.13, 956.10, and 602.54 cm −1 , which are attributed to the O–H stretching vibration, C–H asymmetric stretching vibration of the CH 2 group connection, C–H stretching vibration, C=O stretching vibrations, and C–Br stretching vibrations, respectively.…”