Synthesis ofα-MnO₂Nanomaterial from a Precursorγ-MnO₂: Characterization and Comparative Adsorption of Pb(II) and Fe(III)

Abstract

α-MnO2nanostructure was successfully synthesized via hydrothermal treatment of a precursorγ-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-N2adsorption). Thermal analysis result showed thatα-MnO2nanorods were formed fromγ-MnO2at 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 onα-MnO2surface 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).

Electrochemical performance of nanosized MnO2 synthesized by redox route using biological reducing agents

“…BET surface area, pore volume and mean pore size, are shown in Table 3. The value S BET of 49.8 m 2 g -1 for GT-MnO 2 can be compared with 9.37 m 2 g -1 for -MnO2 synthesized via hydrothermal treatment of a precursor -MnO2 [54] and SBET=41 m 2 g -1 for -MnO2 synthesized by Pechini technique [55].…”

Oxidative Desulfurization of Petroleum Distillate Fractions Using Manganese Dioxide Supported on Magnetic Reduced Graphene Oxide as Catalyst

“…These confirm the presence of magnetic iron oxides loaded on the surface of GO. Several low intense peaks positioned at 28.6, 37.5, 49.8, 60.1, and 69.1° are attributed to the characteristic crystalline patterns of manganese dioxide (α-MnO 2 ) which match with its reference card No.01-072-1982 [ 37 ]. The low intensity of these peaks may be due to the small concentration of MnO 2 in the composite catalyst.…”

Removal of Radionuclides from Aqueous Solution by Manganese Dioxide-Based Nanomaterials and Mechanism Research: A Review

“…In high-temperature water solvent, the solubility of substances and the activity of ions increase, and precipitates dissolve, recrystallize, nucleate, and grow. The prepared MnO 2 has good dispersibility, stability, and high purity. , So far, the reported hydrothermal method for preparing MnO 2 can be divided into four reaction series: (1) reduction of KMnO 4 , the specific process is shown in Figure a; (2) oxidation of Mn 2+ , , the conversion diagram of this method is similar to Figure a; (3) conversion of MnO 2 precursor, , in which commonly used precursors are layered Na-birnessite (Figure b) and γ-MnO 2 (Figure c); and (4) thermal decomposition of manganese salt. , …”

“…(c) Experimental flowchart of γ-MnO 2 conversion to α-MnO 2 . Reprinted with permission from Dinh et al Copyright 2016 Hindawi Publishing Corporation, licensed under Attribution 4.0 International (CC BY 4.0) and . (d) Schematic illustration of the formation stages of different shapes of the MnO 2 nanostructures.…”