Nanosized Spinel Ferrites Synthesized by Sol-Gel Autocombustion for Optimized Removal of Azo Dye from Aqueous Solution

Table 4

Isotherm parameters for Congo-Red adsorption onto spinel ferrites.

Isotherm	Adsorbent: CoFe2O4		Adsorbent: NiFe2O4
	= 293 K	= 333 K	= 293 K	= 333 K
Freundlich
	ARE = 3.21	ARE = 4.71	ARE = 2.79	ARE = 3.30
Langmuir
(L/mg)
(mg/g)	ARE = 11.72	ARE = 10.43	ARE = 12.10	ARE = 9.97
D-R
(g/g)
(mol^2 kJ^−2)
(kJ mol^−1)	ARE = 4.78	ARE = 5.51	ARE = 4.05	ARE = 3.69