pH-dependent mechanisms of methylene blue reacting with tunneled manganese oxide pyrolusite

Kuan, Wen-Hui; Chan, Yen-Chuan

doi:10.1016/j.jhazmat.2012.08.051

Cited by 47 publications

(38 citation statements)

References 39 publications

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“…To our knowledge, MnO 2 cannot oxidize MB under high pH conditions (pH = 11); therefore, the discoloration process cannot be attributed to oxidization, as in previous reports (Kuan et al 2012; (Fig. 9c,d) by sonication for 4 h. These broken nanobelts, aggregated into nanobelt bundles, were unable to adsorb MB from the solution as efficiently as the intact nets.…”

Section: Adsorption Mechanism Analysismentioning

confidence: 46%

Highly efficient removal of methylene blue from aqueous solution by a novel fishing-net effect of manganese oxide nano-sheets

Peng

Liu

Zeng

et al. 2016

Clean Techn Environ Policy

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Manganese (IV) oxide (MnO 2 ) nano-sheets were synthesized using tetramethylamine, H 2 O 2 , and MnCl 2 Á4H 2 O and used in suspension for removal of methylene blue (MB). Up to 95 % removal was achieved for MB concentrations less than 500 mg/L. The adsorption data fitted better with the Freundlich isotherm model than the Langmuir model, indicating a heterogeneous adsorption of MB on MnO 2 nano-sheets. The maximum adsorption capacity of MnO 2 nano-sheets was approximately 4300 mg/g, which is the highest yet reported. Suspensions of MnO 2 nano-sheets aggregated as precipitates after adsorption of MB. Using a suite of analyses, including X-ray diffraction and X-ray photoelectron spectroscopy, the high adsorption capacity was mainly attributed to ion exchange, coordination, and a fishing-net effect. The term, 'fishing-net effect,' is proposed here for the first time, to explain the extremely high adsorption capacity of nano-sheets, which increased with increasing ionic strength and sorbate concentration. Our results demonstrate that dispersive MnO 2 nano-sheets have a potential application in adsorption of organics from strongly basic solutions with high salinity.

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Section: Adsorption Mechanism Analysismentioning

confidence: 46%

Highly efficient removal of methylene blue from aqueous solution by a novel fishing-net effect of manganese oxide nano-sheets

Peng

Liu

Zeng

et al. 2016

Clean Techn Environ Policy

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“…The mechanism for the decomposition of the organic compounds by MnO 2 has been well established [46,63]. Generally, the degradation is an adsorption-oxidation-desorption process which occurs via a surface mechanism [63]. The organic compounds are first adsorbed onto the surface of MnO 2 to form a surface precursor complex.…”

Section: Decolorization Of Mbmentioning

confidence: 99%

“…Moreover, this oxidative degradation is much favorable at low pH conditions [33]. Importantly, Mn(II) can be oxidized to Mn(IV) and precipitated as manganese hydrated oxide; hence, MnO x nanoparticles act as an active catalyst during the oxidative decolorization [63]. The main products of MB mineralization include mainly SO Figures S5 and S6, Supplementary Materials.…”

Section: Decolorization Of Mbmentioning

confidence: 99%

Borax-Cross-Linked Guar Gum-Manganese Dioxide Composites for Oxidative Decolorization of Methylene Blue

Dassanayake

Rajakaruna

Abidi

2019

Journal of Nanomaterials

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Borax-cross-linked guar gum-manganese dioxide (GGB-MnO2) composite was synthesized using an environmentally friendly synthesis route and investigated for its efficiency of decolorizing methylene blue (MB) dye solution by an ultraviolet-visible (UV-Vis) spectrophotometric study. The GGB-MnO2 composite was characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). The composite (1.2 g/L) exhibited excellent oxidative decolorization of MB (30 mg/L, 50 mL) solution to over 99% in 6, 13, and 40 min at pH 4, 7, and 10, respectively. The complete decolorization of MB occurred via a catalytic adsorption-oxidation-desorption mechanism. The GGB-MnO2 composite showed very good reusability and was stable after ten successive cycles with negligible losses of the decolorization efficiency.

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“…It was obviously that the maximum absorption peaks for MB, MO and RhB and pure MoS 2 NSs only had intensity decreasing, however, absorption peaks for TiO 2 NBs and T@M had not only intensity decreasing but also blue shift. It has been reported there are two pathways to degrade MB, MO and RhB . One is the cleavage of whole conjugated chromospheres structure by active groups that degrade MB, MO and RhB to final products, such as CO 2 , H 2 O and SO 4 2− etc .…”

Section: Resultsmentioning

confidence: 99%

Photocatalytic Behaviors of TiO₂ Nanoblets Coated with MoS₂ Nanosheets for Solar‐Driven Photocatalysis

et al. 2019

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TiO2 nanoblets coated with MoS2 nanosheets, donated as T@M, were successfully prepared by a facile hydrothermal method. In comparison with pristine TiO2 nanoblets, the composite of MoS2 nanosheets could enlarge the spectral response of sunlight. The surface heterostructures of T@M nanocomposite could effectively separate the photogenerated electron‐hole pairs, and greatly inhibit the recombination of photogenerated electrons and holes. The photocatalytic performances of the as‐synthesized products were investigated in contrast by photodegradation of methylene blue, methyl orange, rhodamine B and levofloxacin. Under 350 W Xe lamp irradiating for 2 h, T@M exhibited excellent degradation performance. Interestingly, blue shifts of the dyes’ absorption peaks were observed, which probably attributed to the incomplete products decomposed by as‐absorbed dye molecules on the surface of TiO2 nanoblets. Compared with pure TiO2 nanoblets, T@M has less amount TiO2, higher separation efficiency of photogenerated electron‐hole pairs and better inhibition efficiency of photogenerated carriers’ recombination, leading less blue shift and higher degradation efficiency.

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pH-dependent mechanisms of methylene blue reacting with tunneled manganese oxide pyrolusite

Cited by 47 publications

References 39 publications

Highly efficient removal of methylene blue from aqueous solution by a novel fishing-net effect of manganese oxide nano-sheets

Highly efficient removal of methylene blue from aqueous solution by a novel fishing-net effect of manganese oxide nano-sheets

Borax-Cross-Linked Guar Gum-Manganese Dioxide Composites for Oxidative Decolorization of Methylene Blue

Photocatalytic Behaviors of TiO₂ Nanoblets Coated with MoS₂ Nanosheets for Solar‐Driven Photocatalysis

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pH-dependent mechanisms of methylene blue reacting with tunneled manganese oxide pyrolusite

Cited by 47 publications

References 39 publications

Highly efficient removal of methylene blue from aqueous solution by a novel fishing-net effect of manganese oxide nano-sheets

Highly efficient removal of methylene blue from aqueous solution by a novel fishing-net effect of manganese oxide nano-sheets

Borax-Cross-Linked Guar Gum-Manganese Dioxide Composites for Oxidative Decolorization of Methylene Blue

Photocatalytic Behaviors of TiO2 Nanoblets Coated with MoS2 Nanosheets for Solar‐Driven Photocatalysis

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Photocatalytic Behaviors of TiO₂ Nanoblets Coated with MoS₂ Nanosheets for Solar‐Driven Photocatalysis