Table 3.

FTIR vibration modes of calcined ark clam shell powder and references

Assignments	Vibrational frequencies (cm−1)
	FTIR result	Singh and Purohit (2011)	Rujitanapanich et al. (2014)	Chen et al. (2015)
v C–O	1456	1422	1416	874, 1418, 1462
v O–H	3480	3431	–	–
v O–H	3742	–	3642	3567