Emergent α- corundum nano-Al₂O₃ material for Eriochrome Black T removal

The removal of Eriochrome Black T (EBT) from aqueous solutions by Al₂O₃ nanoparticles has been investigated as a function of contact time, initial EBT concentration, and temperature. The experimental design method generated optimum conditions as t_c = 40 min, 55 mg/L, and T = 298 K. The maximum adsorption yield was 99.43%. The kinetics study was discussed using different kinetic models: Pseudo-first order (PFO) and pseudo-second order (PSO). The adsorption experiments of EBT show a better fit to the model pseudo second order (R² = 0.999). The experimental data were analyzed by different isotherm models: Langmuir and Freundlich. Freundlich’s well-fitted modeling proved that the adsorption of EBT on alumina occurred as multilayers and on a heterogeneous surface. The thermodynamic study for the present process was performed by determining the values of ∆G°, ∆H°, and ∆S° indicate that the adsorption was spontaneous, physisorption and exothermic. The photocatalytic activity of alumina nanoparticles has been evaluated and leads to the degradation of the EBT molecules into small unharmful compounds.