Biosorption Studies of Cd²⁺ and Cr⁶⁺ from Aqueous Solution Using Cola-Nut Leaves as Low-Cost Biosorbent

Table 1

FTIR analysis of cola nut leaves before and after adsorption with their corresponding functional groups [16].

S/N	Vibration peaks of cola nut leaves before adsorption (cm^−1)	Functional groups	Vibration peaks of cola nut leaves after adsorption (cm^−1)	Change in wavelength (Δ cm^−1)
1	3384.4	O-H	3276.3	108.1
2	2922.2	C-H2 stretching	2918.5	3.7
3	2855.1	CH3	28561.4	3.7
4	1733.2	C-O-O-CO- saturated acid anhydride	1729.5	3.7
5	1449.2	N-N=O	1438.8	7.4
6	1375.4	CH3 symmetrical deformation	1315.8	59.6
7	1162.9	S group of C=S	1148.0	14.9
8	1066.0	C-O stretch	1032.5	33.5