Elucidation of the effect of ionic liquid pretreatment on rice husk via structural analyses

Table 2 Group frequency of absorption bands of rice husk and regenerated cellulose

Group frequency, wavenumber, cm^-1	Origin	Assignment	Reference
800 – 950	C-H	C-H deformation vibration in cellulose	[34]
~1035	C-O	C-O stretching vibration in cellulose/hemicellulose and aryl-OH group in lignin	[31]
			[33]
			[34]
~1457	C-H	Asymmetric bending of CH₃ and methoxy (-OCH₃) groups present in lignin	[34]
			[33]
			[24]
~1513	C = C-C^a	Aromatic skeletal stretching in lignin	[35]
			[36]
~1637	O-H	O-H bending vibration of adsorbed water molecules	[31]
			[37]
~2919	C-H	C-H stretching in cellulose-rich material	[38]
			[39]
2995 – 4000	O-H	Free and hydrogen-bonded OH stretching	[40]
			[31]
			[38]

ISSN: 2731-3654