Table 4 Kinetic model parameters for removing Cr(VI) and Cu(II) using SA/CMC-ZFN.

Metal ion

Metal ion concentration (mg/L)

\({\text{Q}}_{{\text{e}}}\), exp (mg/g)

Pseudo first order (PFO)

\({\text{Log(Q}}_{{\text{e}}} - {\text{Q}}_{{\text{t}}} {)} = {\text{Log}}\,{\text{qQ}}_{{\text{e}}} - \left( {\frac{{{\text{k}}_{1} }}{2.03}} \right){\text{t}}\)

Pseudo second order (PSO)

\(\frac{{\text{t}}}{{{\text{Q}}_{{\text{t}}} }}{ } = { }\frac{1}{{{\text{k}}_{2} {\text{Q}}_{{\text{e}}}^{2} }}{ } + \left( {\frac{1}{{{\text{Q}}_{{\text{e}}} }}} \right){\text{t}}\)

\({\text{Q}}_{{\text{e}}}\)(mg/g)

k₁ (min⁻¹)

R²

\({\text{Q}}_{{\text{e}}}\)(mg/g)

k₂(g/mg min)

R²