IR peak frequency (cm−1)

Assignment

H-C-H symmetric

and asymmetric stretching (alkane)

C=N stretching (oxime)

N=O

stretching (nitro group)

C-H in plane bending (alkane)

N=O bending (nitro group)

C-O stretching (ester or ether)

Okra leaves loaded with Cr(VI)

2913.05

2843.59

1593.19

-

1405.22

-

1229.51

1004.77

Plain okra leaves for the sorption of Cr(VI)

2921.23

2855.85

1621.79

1527.18

-

1388.44

1233.60

1025.20

Assignment

O-H stretching

C-H stretching (alkane)

C=N stretching (oxime)

O-H bending (carboxylic acid)

N=O bending (nitro group)

C-O stretching (carboxylic acid)

-

Okra leaves loaded with Cr(III)

3280.82

2917.14

2851.76

1605.45

1421.57

1315.32

1229.51

-

Plain okra leaves for sorption of Cr(III)

3260.39

2933.48

2839.50

1613.62

1417.48

1311.24

1233.60

-