Oxidative decolorization of methylene blue using pelagite

Zhu, Mao‐Xu; Wang, Zheng; Zhou, Ling

doi:10.1016/j.jhazmat.2007.04.042

Cited by 30 publications

(28 citation statements)

References 35 publications

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“…At pH higher than 4.5, the surface of Mn 3 O 4 becomes negatively charged due to deprotonation and the negative charge is increased with the increase of medium pH, which favors the formation of surface precursor complex due to electrostatic attraction. However, in the present study, experiments show that the degradation of MB is increased with the decrease in medium pH, which suggests that it is due to heterogeneous surface oxidation [40]. Though low pH inhibited the formation of surface precursor complex, but according to Nernst equation, high H + concentration could improve the reducing potential of the system resulting in more degradation of MB.…”

Section: Effect Of Medium Ph On Mb Degradationcontrasting

confidence: 55%

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Oxidative Degradation of Methylene Blue Using Mn3O4 Nanoparticles

Ullah

Kibria

Akter

et al. 2017

Water Conserv Sci Eng

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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.

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Section: Effect Of Medium Ph On Mb Degradationcontrasting

confidence: 55%

“…The oxidative degradation of MB could be quantitatively assessed using reaction kinetics, and possible reaction mechanism can be predicted using the rate expressions obtained from kinetic modeling [40]. The pseudo-first-order kinetics was expressed in terms of Langmuir-Hinshelwood (L-H) model [41].…”

Section: Kinetics Of Mb Degradationmentioning

confidence: 99%

Oxidative Degradation of Methylene Blue Using Mn3O4 Nanoparticles

Ullah

Kibria

Akter

et al. 2017

Water Conserv Sci Eng

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“…To resolve this problem two additives are added to Fe 0 : granular activated carbon (GAC) and manganese dioxide (MnO 2 ). GAC is a pure adsorbent for MB [25] whereas reductive dissolution of MnO 2 has been reported to decolorize MB [39]. The presentation above shows that MnO 2 should re-oxidise reduced LMB (no discoloration).…”

Section: Background Of the Experimental Methodologymentioning

confidence: 86%

“…MnO 2 was mainly used to control the availability of in situ generated oxides from Fe 0 corrosion [36,45]. Reductive dissolution of MnO 2 has been reported to degrade a number of organic pollutants [39,46 and Ref. therein].…”

Section: Solid Materialsmentioning

confidence: 99%

Characterizing the discoloration of methylene blue in Fe0/H2O systems

Noubactep¹

2009

Journal of Hazardous Materials

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Methylene blue (MB) was used as a model molecule to characterize the aqueous reactivity of metallic iron in Fe(0)/H(2)O systems. Likely discoloration mechanisms under used experimental conditions are: (i) adsorption onto Fe(0) and Fe(0) corrosion products (CP), (ii) co-precipitation with in situ generated iron CP, (iii) reduction to colorless leukomethylene blue (LMB). MB mineralization (oxidation to CO(2)) is not expected. The kinetics of MB discoloration by Fe(0), Fe(2)O(3), Fe(3)O(4), MnO(2), and granular activated carbon were investigated in assay tubes under mechanically non-disturbed conditions. The evolution of MB discoloration was monitored spectrophotometrically. The effect of availability of CP, Fe(0) source, shaking rate, initial pH value, and chemical properties of the solution were studied. The results present evidence supporting co-precipitation of MB with in situ generated iron CP as main discoloration mechanism. Under high shaking intensities (>150 min(-1)), increased CP generation yields a brownish solution which disturbed MB determination, showing that a too high shear stress induced the suspension of in situ generated corrosion products. The present study clearly demonstrates that comparing results from various sources is difficult even when the results are achieved under seemingly similar conditions. The appeal for an unified experimental procedure for the investigation of processes in Fe(0)/H(2)O systems is reiterated.

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“…In addition, the diffraction peaks of supported MnO 2 with low crystallinity might influences structure of kaolinite, resulting in weaker peak intensity of kaolinite peaks than that of pure kaolinite. Zhu et al [20] found that poor crystallization of pelagite tend to larger surface area, strong adsorbing power and high redox activity for removal of methylene blue. Fig.…”

Section: Methodsmentioning

confidence: 99%

Oxidation of Chlorophenols by MnO<sub>2</sub> Supported on Kaolinite

Yang¹

2017

IJEPP

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Chlorophenols (CPs) are of significant concern because of their wide use, toxicity and persistence in environments.In the present study, α-MnO 2 supported on kaolinite was used as an oxidant to oxidize three kinds of CPs, 4-chlorophenol (CP), 2, 4-dichlorophenol(DCP) and 2, 4, 6-trichlorophenol(TCP). XRD pattern showed that the synthetic MnO 2 has a poor crystallinity, and SEM results revealed that MnO 2 was evenly coated on kaolinite with a loading amount of 8.64mg/g. All three CPs were efficiently degraded by supported MnO 2 with a removal order of 2, 4, 6-TCP>2, 4-DCP>4-CP. The degradation of CPs obviously accompanied with the release of Mn 2+. Results also showed the increased oxidant's dosage promotes the removal of CPs. The reaction of CPs with MnO 2 is strictly pH-dependent, the removal of CPs decreased with pH increasing.

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Oxidative decolorization of methylene blue using pelagite

Cited by 30 publications

References 35 publications

Oxidative Degradation of Methylene Blue Using Mn3O4 Nanoparticles

Oxidative Degradation of Methylene Blue Using Mn3O4 Nanoparticles

Characterizing the discoloration of methylene blue in Fe0/H2O systems

Oxidation of Chlorophenols by MnO<sub>2</sub> Supported on Kaolinite

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Oxidative decolorization of methylene blue using pelagite

Cited by 30 publications

References 35 publications

Oxidative Degradation of Methylene Blue Using Mn3O4 Nanoparticles

Oxidative Degradation of Methylene Blue Using Mn3O4 Nanoparticles

Characterizing the discoloration of methylene blue in Fe0/H2O systems

Oxidation of Chlorophenols by MnO&lt;sub&gt;2&lt;/sub&gt; Supported on Kaolinite

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Oxidation of Chlorophenols by MnO<sub>2</sub> Supported on Kaolinite