Metal ion

Langmuir isotherm

Freundlich isotherm

r²

q_m (mg/g)

K_l (L/Fmg)

R_L

r²

n

K_f (mg/g)

Pb²⁺

0.9732

1250

0.16

0.167

0.9799

1.922

199.43

Cu²⁺

0.6479

161.29

0.188

0.035

0.4668

3.604

105.58