Oxidative Degradation of Methylene Blue Using Mn3O4 Nanoparticles

Abstract

Mn 3 O 4 nanoparticles were synthesized from one-step reduction of KMnO 4 with glycerol at 80°C. The structural and surface morphological characterizations were carried out using FT-IR, XRD, and FESEM analyses. The elemental composition was evidenced from EDX analysis. XRD analysis showed the tetragonal crystal geometry of Mn 3 O 4 nanoparticles with an average crystallite size of ∼20 nm. The surface morphology of the Mn 3 O 4 nanoparticles was found to be spherical from the FESEM image. The Mn 3 O 4 nanoparticles were then tested as a potential oxidant for the decolorization of methylene blue (MB) and found to be capable of N-demethylation of MB forming thionine as the final product, and removing 80% of the dye in approximately 1 h. The decolorization of MB by Mn 3 O 4 occurred through a surface mechanism, i.e., formation of surface precursor complex between MB and surface-bound Mn (II, III), where, electron transfer occurs within the surface complex. The effect of suspension pH (3-4 < pH pzc ; 5-10 > pH pzc ) on MB decolorization was assessed. Suspension pH exerted double-edged effects on MB decolorization by influencing the formation of surface precursor complex, and reducing potential of the system.

Green synthesis of Bryophyllum pinnatum aqueous leaf extract mediated bio-molecule capped dilute ferromagnetic α-MnO2 nanoparticles

“…The elemental composition of the prepared α-MnO 2 nanoparticles was analyzed using EDX analysis as shown in figure 3(a). The lines observed at 5.90, 6.52, 0.64, and 0.52 keV are associated for K (α, β), L lines of the Mn element, and K line of the O elements, respectively [6]. The atomic percentage of Mn and O were 29 and 41 respectively indicating the formation of non-stoichiometric MnO 2 with oxygen vacancy which indicates that the material might show better photocatalytic activity [31].…”

“…Nano-manganese oxides have been the focus of various researchers because of their prospective properties and enormous applications in high -Tc semiconductors, high density magnetic storage, electrochemical storage material, solar energy transformation, giant magnetoresistance, ion-exchange material, catalysis, and molecular adsorption [1][2][3][4][5][6]. These wide range of applications and distinctive properties have attracted broad attention to the polymorphic forms of MnO 2 (α-, β-, and γtype).…”

Challenges in Determining the Location of Dopants, to Study the Influence of Metal Doping on the Photocatalytic Activities of ZnO Nanopowders

“…The combination of several different characterization techniques revealed that addition of manganese ions resulted in Mn 3 O 4 grafted on the surface of the ZnO nanoparticles. Mn 3 O 4 has photocatalytic properties [55,56] but only at a pH below 4 [57]. In the present study, Rhodamine-B, an acidic dye, was used as a model organic pollutant to examine the photocatalytic activity of manganese-added ZnO.…”

“…In our study, the Rhodamine-B solution was highly diluted (0.0096 g/L) to minimize its visible-light absorption and thus had a pH of 6.5. At this near-neutral pH, one cannot expect photocatalytic activity from Mn 3 O 4 alone [57].…”

Efficient catalytic degradation of single and binary azo dyes by a novel triple nanocomposite of Mn3O4/Ag/SiO2

“…Ullah et al used Mn 3 O 4 nanoparticles for oxidative degradation of methylene blue. [ 9 ] Sreekala et al found that Mn 3 O 4 was an efficient photocatalyst for the removal of Malachite green. [ 10 ] Noble metal nanoparticles have shown remarkable potential for many applications in electronic, chemical, biological, and catalytic fields due to their distinctive properties, when compared to their bulk counterparts.…”