Parameter

Langmuir Isotherm

Freundlich Isotherm

k_L (L/mg)

Q_m (mg/g)

r²

K_f (L/g) × 10⁷

1/n

r²

Iron Oxide

Co(II)

−0.44

27.40

0.9891

3.9

−2.108

0.9963

Ni(II)

−0.82

21.10

0.9931

212

−2.794

0.9858

Goethite

Co(II)

−0.20

37.59

0.987

0.4

−1.755

0.9957

Ni(II)

−0.36

29.85

0.9961

4.4

−2.124

0.9965