Table 3 Kinetic parameters for the adsorption of Pb(II) onto HS and HSN Sahara plants derived adsorbents samples.

Kinetic parameter

 q_eexp (mg/g)

37.7

48.9

Pseudo-1st -order kinetic equation

 q_e1(mg/g)

4.27

9.103

 k₁ (1/min)

5.48 × 10^− 3

0.01

 R²

0.125

0.233

 χ²

10315.76

4710.2

 SSE

44048.29

42862.84

 MSE

4894.25

6123.3

PseudoSecond-2nd -order kinetic equation

 q_e2 (mg/g)

37.02

48.23

 k₂ [g/(mg min)]

0.0155

9.90 × 10^− 3

 R²

0.998

0.998

 χ²

492.066

307.06

 SSE

18216.3

14,809

 MSE

2024.032

2115.623

Intraparticle diffusion equation

 k_int [mg/(g min^1/2)]

0.594

1.508

 c (mg/g)

28.69

29.75

R²

0.321

0.394

 Boyd equation

 Intercept

1.702

1.251

 R²

0.125

0.239