We herein report the preparation of Co3O4,
α-Fe2O3, and CoFe2O4
nanostructures through a hydrothermal
method followed by a subsequent heat treatment.
The as-prepared nanostructures exhibited good adsorption
properties for the removal of Orange G (OG) textile dye.
Various parameters influencing the adsorption process have
been investigated such as contact time, initial dye concentration,
ionic strength, adsorbent dose, and temperature.
The maximum adsorption capacity values were found to
be 33.3, 53.2, and 62.0 mg/g, for Co3O4,
α-Fe2O3 nano-adsorbents, respectively. The adsorption data
fit the pseudo-second-order kinetic and Langmuir isotherm
models well. Based on the calculated thermodynamic
constants: ΔH° (3.660, 14.82, and 0.4710 kJ/mol), ΔG°
(from −0.8090 to −1.109, from −0.6444 to −1.682, and
from −3.665 to −3.943 kJ/mol), and Ea
(9.277, 5.060, and
12.10 kJ/mol), the adsorption of OG dye on the aforementioned
nano-adsorbents, respectively, was found to be endothermic,
spontaneous, and physisorption process. In addition,
because of the relatively high adsorption capacity and
chemical stability, the as-synthesized α-Fe2O3 adsorbent is
suggested as a promising candidate for the removal of OG