Magneto-Sensitive Adsorbents Modified by Functional Nitrogen-Containing Groups

Table 2 Kinetic adsorption parameters obtained by using pseudo-first- and pseudo-second-order models for Cu(II) adsorption

Adsorbent	Pseudo-first order ln (a _eq − a _t) = ln a _eq − k ₁ t		Pseudo-second order t/a _t = 1/(k ₂ ∙ a _eq ²) + t/a _eq
Adsorbent	k ₁	R ²	a _eq	k ₂	R ²
A	0.039 ± 0.01	0.954	0.381 ± 0.038	0.122 ± 0.039	0.957
AM	0.045 ± 0.001	0.844	0.268 ± 0.009	0.122 ± 0.048	0.949
AP	0.026 ± 0.005	0.993	0.476 ± 0.047	0.307 ± 0.047	0.988
DA	0.014 ± 0.001	0.969	0.54 ± 0.003	1.996 ± 0.599	0.999
BA	0.006 ± 0.001	0.846	0.73 ± 0.114	0.061 ± 0.031	0.915

a _t and a _eq—the amounts of adsorbed Cu(II) ions, at time (t) and (a _t) equilibrium (in mmol/g); k ₁ and k ₂—the rate constants of pseudo-first-order (in min⁻¹) and pseudo-second-order adsorption process (in g/mmol/min)