Magneto-Sensitive Adsorbents Modified by Functional Nitrogen-Containing Groups

Table 3 Parameters of copper(II) adsorption calculated from Langmuir and Freundlich isotherm models

Adsorbent	Langmuir isotherm^a C _eq/a _eq = 1/(K _L ∙ a _m) + (1/a _m) ∙ C _eq			Freundlich isotherm^b lg a _eq = lg K _F + (1/n) ∙ lg C _eq
Adsorbent	a _m, mmol/g	K _L, L/mmol	R ²	K _F	R ²
A	0.452	1.358	0.958	0.232	0.966
AM	0.345	1.123	0.989	0.142	0.969
AP	0.487	0.336	0.862	0.149	0.846
DA	0.591	1.111	0.981	0.308	0.924
BA	0.712	4.198	0.997	0.453	0.978

^a a _eq—the amount of solute adsorbed in the same condition (in mmol/g); K _L—the Langmuir’s constant characterizing the adsorption energy; C _eq—the concentration of solute remaining in solution after equilibrium to be reached (in mmol/L); a _m—the maximum adsorption capacity in the monolayer
^b a _eq—the amount of solute adsorbed (in mmol/g); K _F—the Freundlich’s constant, maximum adsorption capacity (in mmol/g); 1/n—the Freundlich’s constant characterizing the intensity of adsorption; C _eq—the concentration of solute remaining in solution after equilibrium (in mol/L)