Synthesis of α-MnO2 Nanomaterial from a Precursor γ-MnO2: Characterization and Comparative Adsorption of Pb(II)‎ and Fe(III)‎

Abstract EN

α-MnO2 nanostructure was successfully synthesized via hydrothermal treatment of a precursor γ-MnO2.

Structure, morphology, and BET surface area were characterized using X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM), and Brunauer-Emmett-Teller nitrogen adsorption (BET-N2 adsorption).

Thermal analysis result showed that α-MnO2 nanorods were formed from γ-MnO2 at 600°C.

In addition, Pb(II) and Fe(III) adsorptive properties were investigated in an optimal condition.

Results showed that equilibrium adsorption was obtained after 60 minutes for Pb(II) at pH = 4.0 and 80 minutes for Fe(III) at pH = 3.5 with 240 rpm of shaking speed overall.

Experimental data was analyzed using three models: Langmuir, Freundlich, and Sips.

Adsorption capacities (qm) from the Langmuir isotherm models are 124.87 mg/g for Pb(II) and 30.83 mg/g for Fe(III).

Along with the highest corelation coefficients, it is clear that the adsorption of Pb(II) and Fe(III) ions on α-MnO2 surface followed Sips model.

Kinetic studies indicated that the uptake of Pb(II) and Fe(III) occurred in the pseudo-second-order model with two stages for Pb(II) and three stages for Fe(III).