Determination of Cobalt in Seawater Using Neutron Activation Analysis after Preconcentration by Adsorption onto γ-MnO₂ Nanomaterial

Table 1

Isotherm equilibrium parameters calculated from different models.

Models

Equations

Parameters

RMSE

χ^2

Langmuir

(mg/g): 90.91

(L/mg): 0.5430

1.999

0.2918

Freundlich

(Log/g): 63.82

1/n: 0.0769

2.233

0.3418

Sips

(mg/g): 95.00

(L/mg): 0.9810

: 0.5694

1.593

0.1751

Notations.  : adsorption capacity at equilibrium (mg/g); : equilibrium concentration (mg/L); : monolayer maximum adsorption capacity (mg/g); : Langmuir constant; : Freundlich constant; : adsorption intensity; : the maximum adsorption capacity (mg/g); : Sips isotherm model constant (L/mg); : Sips isotherm model exponent; RMSE: root-mean-square error ; χ²: nonlinear chi-square test .