Kinetic parameters for lead removal onto G–CdO, CdO and G.

Adsorbents	Kinetics models
	Pseudo-first-order	Pseudo-second-order	Elovich	Intraparticle diffusion
G–CdO	q e = 69.2	q e = 403.4	α = 1.3 × 103	K int = 5.48
	K 1 = 0.0039	K 2 = 0.00023	β = 0.025	C = 248
	R 2 = 0.6851	R 2 = 0.9999	R 2 = 0.9199	R 2 = 0.6266
CdO	q e = 82.9	q e = 374.3	α = 0.62 × 103	K int = 5.58
	K 1 = 0.0035	K 2 = 0.00018	β = 0.025	C = 210.5
	R 2 = 0.7652	R 2 = 0.9998	R 2 = 0.9295	R 2 = 0.7029
G	q e = 8.6	q e = 67.3	α = 9.5 × 103	K int = 0.57
	K 1 = 0.0021	K 2 = 0.0021	β = 0.208	C = 50
	R 2 = 0.5491	R 2 = 0.9999	R 2 = 0.9076	R 2 = 0.5089