Comparative study of malachite green and phenol adsorption on synthetic hematite iron oxide nanoparticles (α-Fe2O3)

This article explored the adsorption of the cationic malachite green (MG) dye and phenol, on hematite iron oxide nanoparticles (α-Fe2O3).The characterization of Fe2O3 was evaluated by specific surface measurements of Brunauer Emmett-Teller (BET) and by Fourier transform infrared spectroscopy (IFTR).The results collected on the kinetics adsorption of malachite green show that the adsorption followed a pseudo-second order kinetics.The percentage of elimination reaches respectively 86.13% and 94% for MG (C=6.10−4mol/L) and phenol (C=5.10−4mol/L).The experimental isotherms were analyzed with Langmuir and Freundlich using nonlinear regression. The results showed respectively that the isotherms of Freundlich and Langmuir best fitted to the equilibrium data for MG and phenol. The thermodynamic study has shown that the adsorption of MG and phenol on α-Fe2O3 is endothermic (ΔH°> 0); it increases with temperature. Negative ΔG° values have shown that the adsorption of MG and phenol on α-Fe2O3is spontaneous. However, the positive values of ΔS° indicate the increase in the disorder of the interface of the α-Fe2O3solution during the fixation of MG and phenol.