Table 2.

Kinetic parameters for Pb(II) adsorption by PG.

Concentration (mg/L)	10	20	30
qe, exp (mg/g)	0.64	1.23	1.80
Pseudo-first order model
qe (mg/g)	0.67	1.28	1.9
k1 (min-1)	0.11	0.1	0.11
${\mathrm{R}}_{\mathrm{Adj}}^2$	0.96	0.95	0.93
R2	0.97	0.94	0.94
RSS	0.00	0.02	0.06
Pseudo-second order model
qe (mg/g)	0.81	1.57	2.39
k2 (g/mg min)	0.14	0.07	0.04
${\mathrm{R}}_{\mathrm{Adj}}^2$	0.90	0.88	0.87
R2	0.92	0.90	0.89
RSS	0.00	0.04	0.12
Interparticle diffusion model
k3	0.08	0.16	0.25
C	0.17	0.29	0.33
${\mathrm{R}}_{\mathrm{Adj}}^2$	0.69	0.67	0.67
R2	0.75	0.73	0.73
RSS	0.03	0.12	0.30