Table 1.

Kinetic model parameters for the sorption of Cu (II) and Pb (II) on NFAD.

Model	Parameter	NFAD
		Pb	Cu
Pseudo-first-order	qe (mg/g)	24.604	1.9011
	K1 (min−1)	0.010	0.004
	r2	0.976	0.965
Pseudo-second-order	qe (mg/g)	52.632	7.042
	K2 (g/mg/min)	2.542E−03	2.656E−02
	r2	0.986	0.982
	h (mg/g min)	7.042	1.317
Elovich	qe (mg/g)	20.40	3.908
	β (g/mg)	0.167	1.689
	α (mg/g/min)	0.149	2.533
	r2	0.847	0.852
Intra-particle diffusion	Kid (mg/g/min1/2)	2.723	0.136
	C (mg/g)	23.91	5.040
	r2	0.935	0.955
Liquid film diffusion	Kfd	2.358	0.012
	r2	0.940	0819
Experiment	qe (mg/g)	51.883	7.005