Adsorption of Heavy Metals in Contaminated Water Using Zeolite Derived from Agro-Wastes and Clays: A Review

Table 7

Summary of FTIR analysis of zeolites.

Zeolite	Synthesis method	Observations		References
		Wavelength (cm^−1)	Group or Reason
Needle-like nanozeolite	Hydrothermal synthesis	3400	O-H stretch	[171]
		1640	Zeolitic water influence
Hydroxy-sodalite/cancrinite	Hydrothermal alkali activation	1400–400 (disappear)	Si-O, Si-O-Al vibrations	[226]
		4000–3500 (disappear)	-OH vibrations
ZIF-8	Solvothermal synthesis	421	Zn-N	[227]
		692	Co-N
		755	CN
		1100–1310	C = N
		1577	C = C
NaP zeolite	One step hydrothermal synthesis	1008 and 735	Si-O or Al-O assymetric stretching	[228]
		690	Symmetric stretching of Si-O or Al-O symmetric stretching
		600	Double ring in NaP
		435	Si-O or Al-O bending
Phillipsite zeolite	Hydrothermal synthesis	439.19	O-Si-O	[229]
		607.47	Si-C
		693.06	Mn-O
		1026.96	Assymetric Si-O-Al
		1638.92	H-O-H or C = C
		3435.81	Si-OH