Abstract:
Iron-Aluminum mixed oxide (HIAMO) and various proportions of Graphene oxide (GO)-incorporated iron-aluminium mixed oxide (GIAMO-1 to GIAMO-6) composite materials were prepared and characterized by several modern instrumental techniques such as FTIR, XRD, TGA/DTA, SEM, TEM, and Raman spectroscopy. The prepared materials particularly GIAMO-1 and GIAMO-3 were employed for adsorption of the arsenic and fluoride from aqueous solutions respectively.
GIAMO-1 shows very good (92–95%) arsenic(III) removal efficiency from water, which is 30–35% higher than pristine iron-aluminium oxide (HIAMO) from an aqueous solution (5.0 mg AsIII•L−1) at pH 7.0 (± 0.2) and 303 K.The kinetic data agree more closely with pseudo-first order equation (R2 = 0.98–0.99) than pseudo-second order equation (R2 = 0.92–0.93). The equilibrium data describe the Langmuir isotherm (R2 = 0.97–0.98) better than the Freundlich isotherm (R2 = 0.91–0.92), showing the Langmuir monolayer capacity 42.2836 mg•g−1 at 293 K which drops to 24.9170 mg•g−1 at 313 K.
Similarly, GIAMO-3 showed highest fluoride adsorption capacity (qe, mg g−1) at pH ∼ 7.0 and ambient temperature. The material showed an increase of qe with pH up to ∼5.5, and then reduced. Kinetically, fluoride adsorption took place obeying the pseudo-second order model. The Langmuir adsorption isotherm described the equilibrium data best with monolayer adsorption capacities 22.13, 22.90 and 27.75 mg g−1 at 288, 308 and 318 K, respectively, indicating endothermic nature of adsorption process, which was also confirmed from the thermodynamic analysis of equilibrium data. Fluoride adsorption efficiency of HIAGO had been predicted by modelling a single stage batch adsorber design parameters.
