Table 1. Comparison of Kinetic Parameters of Various Models for Pb(II) and Cd(II) Adsorption.

kinetic model	parameters	Pb(II)	Cd(II)
pseudo-first-order	K1 (min–1)	0.0025	0.0009
	R2	0.7878	0.4893
pseudo-second-order	K2 (g/(mg·min))	0.000736	0.00159
	R2	1.00	0.9762
	qe	97.09	18.62
intra-particle diffusion	Kd,1 (min–1)	9.813	−36.97
	R21	0.9919	0.7971
	C1	13.93	206.1
	Kd,2 (min–1)	2.308	–0.092
	R22	0.9793	0.9227
	C2	60.13	16.90
	Kd,3 (min–1)	0.1513	0.2518
	R23	0.9953	0.7717
	C3	90.79	9.274