Kinetic parameters for the adsorption of Pb(ii) and Cd(ii).

Metal	C 0 (mg g−1)	Experimental	Pseudo-first-order			Pseudo-second-order
		q e (mg g−1)	q e (mg g−1)	k 1 (min−1)	R 2	q e (mg g−1)	k 2 (mg g−1 min−1)	R 2
Pb	50	39.737	38.369	0.314	0.925	39.533	1.109	0.991
	100	73.846	71.382	0.017	0.974	80.399	0.052	0.990
	200	80.392	77.004	0.039	0.991	83.121	0.130	0.992
Cd	50	32.000	27.520	0.403	0.907	28.677	1.093	0.997
	100	55.024	54.125	0.025	0.996	59.539	0.080	0.992
	150	76.800	76.028	0.015	0.993	76.937	0.044	0.998