Table 2.

Parameters of nonlinear kinetic models for the adsorption of Pb²⁺ ions onto the pristine and functionalized ECNFs at 298 K.

	ECNFs	o-ECNFs	melam-ECNFs	PmPDA-ECNFs
PFO
qe,exp	81.52	244.28	412.20	309.11
qe, cal	79.57	226.28	378.35	298.19
k1	0.0217	0.1195	0.2065	0.1815
R2	0.9822	0.9705	0.9550	0.9865
χ2	4.18	5.85	14.36	3.31
PSO
qt, cal	88.28	235.55	388.49	305.21
K2 (×10−4)	3.55	8.83	10.90	0.0014
R2	0.9943	0.9941	0.9731	0.9971
χ2	0.5855	1.21	8.77	0.7436
Elovich
α	3.66	40372.04	5.66*E6	2.55*E8
β	0.0075	0.05727	0.0462	0.0735
R2	0.9583	0.99165	0.9954	0.9963
χ2	4.74	1.79000	1.54	0.9294
Intraparticle diffusion
Kid(1)	6.13	11.33	4.55	6.28
I	5.85	130.18	316.26	235.27
R2	0.9711	0.9921	0.9671	0.9633
Kid(2)	0.2368	1.31	0.8774	0.4887
I	75.74	209.46	388.94	295.94
R2	0.4976	0.9734	0.7980	0.9585