Table 2.

Constants and correlation coefficients obtained by pseudo-first-order andpseudo-second-order kinetics models.

Metal ions	Pseudo-first order		Pseudo-second order
	K1 (min−1)	R12	Qe (mg·g−1)	K2 (g·mg−1·min)	R22
Pb2+	0.00139	0.66	2.50	0.25	1.00
Cu2+	0.00147	0.68	0.79	0.77	1.00
Cd2+	0.00010	0.83	1.24	0.01	0.99
Pb2+ (Pb2+–Cu2+–Cd2+)	0.00047	0.48	2.61	0.075	1.00
Cu2+ (Cu2+–Pb2+–Cd2+)	0.0012	0.71	0.86	0.055	0.99
Cd2+ (Cd2+–Pb2+–Cu2+)	0.00073	0.91	1.58	0.002	0.94