Adsorption Ability for Toxic Chromium (VI) Ions in Aqueous Solution of Some Modified Oyster Shell Types

Table 2

List of crystal parameters of OS samples obtained from XRD patterns.

Sample	Type of crystal	2θ (degree)	d-spacing (Å)	Crystallite size (Å)
QNOS-	CaCO3	29.4	3.037	2.87
PP	Ca(OH)2	34.0	2.630	1.79
QNOS-PP-800	CaCO3	29.4	3.037	3.58
	CaO	37.2	2.405	3.66
	Ca(OH)2	34.0	2.624	1.43
QNOS-PP-800-EDTA	CaCO3	29.4	3.039	4.78
	CaO	37.4	2.426	2.44
	Ca(OH)2	34.0	2.628	1.79
PYOS-PP	CaCO3	29.4	3.039	4.78
PYOS-PP-Na	CaCO3	29.4	3.039	7.17
PYOS-PP-Na-800	CaCO3	29.4	3.042	2.87
	Ca(OH)2	34.0	2.629	1.79
PYOS-PP-Na-750	CaCO3	29.4	3.040	14.33
	Ca(OH)2	34.0	2.629	2.87
PYOS-PP-Na-900	CaCO3	29.4	3.031	14.3
	Ca(OH)2	34.1	2.622	2.07
PYOS-PP-Na-800-EDTA	CaCO3	29.4	3.040	7.17