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Table 3 Major adsorption bands appeared and/or disappeared after NaOH treatments

From: Alkali delignification and Bacillus sp. BMP01 hydrolysis of rice straw for enhancing biofuel yields

Assignment of bands

Related structure

Adsorption band of raw RS

Adsorption band appeared or disappeared due to NaOH pretreatment of rice straw

1%

3%

5%

7%

10%

O–H stretching

Lignin

3409.26

3409.97

3410.31

3429.48

3425.09

3407.36

C–H stretching

Lignin

2854.95

2852.00

 

2854.95

2849.06

 

C≡C stretching

aromatic rings

2360.43

2360.43

 

2363.37

 

2366.31

C≡C stretching

aromatic rings

2330.99

2336.88

 

2339.82

 

2333.93

Carbonyl stretching conjugate with aromatic rings

Cellulose

  

1639.25

1621.59

1636.30

1648.08

Aromatic C–O stretch

Lignin

 

1505.84

    

C–O stretching

Cellulose

1405.19

 

1406.11

1405.18

1405.50

1406.34

C–H symmetric and asymmetric deformation

Cellulose

1380.21

 

1383.16

1383.16

1380.21

1380.21

C–O stretching

Cellulose

1333.12

1333.12

1330.17

1336.06

1336.06

 

Acetylated hemicellulos

Hemicellulose

1256.58

1262.47

1268.16

1265.41

1265.41

 

Weak C–O stretching

Cellulose

 

1206.54

 

1200.65

1203.06

 

Glycosidic linkage

Hemicellulose

  

1197.71

  

1197.71

C–O stretching

Cellulose hemicellulose

 

832.71

 

835.65

835.65

841.54

C–H bending

Hemicellulose

770.89

 

709.08

712.02

  

C–C stretching

Hemicellulose

467.70

470.65

   

520.69