Table 2. Kinetics parameters for the adsorption of Pb(ii) and MB by EC–AB.

Kinetic models	Parameters	Adsorbent
		Pb(ii)	MB
Pseudo-first-order model	q e,exp (mg g−1)	271.80	467.35
	q e,cal (mg g−1)	255.15	434.05
	k 1 (min−1)	0.0046	0.0033
	RMSE	8.86	14.45
	R 2	0.9954	0.9970
Pseudo-second-order model	q e,cal (mg g−1)	279.76	540.08
	k 2 (g mg−1 min−1)	0.000018	0.0000017
	RMSE	6.05	10.26
	R 2	0.9978	0.9975
Intra-particle diffusion model	k i,1 (mg g−1 min−1/2)	12.74	19.24
	k i,2 (mg g−1 min−1/2)	7.83	11.75
	k i,3 (mg g−1 min−1/2)	0.99	3.39
	C i,1 (mg g−1)	−28.18	−57.60
	C i,2 (mg g−1)	46.13	85.57
	C i,3 (mg g−1)	222.42	307.03