Table 2.

Number of moles sorbed (Nf), parameters of the Langmuir (Ns and b), correlation coefficients (r), and standard errors (SE) for the interaction of divalent metals with modified chitosan CH-AN at 298 ± 1 K using linear method.

Isotherm	Constant	Type I	Type II	Type III	Type IV
Cu2+	Nf (mmol g−1)	2.02	2.02	2.02	2.02
	Ns (mmol g−1)	2.83 ± 0.02	2.82 ± 0.01	2.83 ± 0.02	2.84 ± 0.01
	b (g mmol−1)	0.30 ± 0.01	0.30 ± 0.01	0.30 ± 0.05	0.30 ± 0.01
	R2	0.998	0.999	0.997	0.997
	SE	0.019	0.019	0.019	0.019
	χ2	0.001	0.001	0.001	0.001
Pb2+	Nf (mmol g−1)	2.54	2.54	2.54	2.54
	Ns (mmol g−1)	2.99 ± 0.03	2.99 ± 0.03	2.99 ± 0.03	2.99 ± 0.03
	b (g mmol−1)	0.31 ± 0.01	0.31 ± 0.01	0.31 ± 0.01	0.31 ± 0.01
	R2	0.998	0.998	0.998	0.998
	SE	0.032	0.032	0.032	0.032
	χ2	0.005	0.005	0.005	0.005