Kinetic parameters for the pseudo-first-order and pseudo-second-order models for Cu(ii), Zn(ii) and Pb(ii) adsorption onto the prepared adsorbent PEI-RCSA in single system.

Metal ion	q e,exp (mg g−1)	Pseudo-first-order			Pseudo-second-order
		k 1 (min−1)	q e,cal (mg g−1)	R 2	k 2 × 104 (g mg−1 min−1)	q e,cal (mg g−1)	R 2
Cu(ii)	120.0	0.0209	133.5	0.9708	2.4417	130.6	0.9985
Zn(ii)	90.3	0.0192	86.5	0.9786	2.7678	100.1	0.9923
Pb(ii)	146.6	0.0155	102.8	0.9785	2.8786	154.7	0.9990