Table 3.

Summary of isotherm models parameters for metal ions adsorption on NCH.

	Langmuir model			Freundlich model			Dubinin–Kaganer–Radushkevich (DKR)
	K L/mg	qmax (mg/g)	R2	Kf	n	R2	Xm (mol/g)	β (mol2/j2)	E, KJ/mol	R2
As	0.038	20	0.822	0.84	1.23	0.969	0.297	7.74 × 10−8	2.54	0.817
Fe	0.136	48.08	0.958	8.52	1.75	0.99	1.23	2.0 × 10−8	4.08	0.7
Mn	0.033	20.83	0.603	0.2	0.72	0.972	0.48	1.17 × 10−7	1.95	0.838