Rapid and efficient photocatalytic reduction of hexavalent chromium by using “water dispersible” TiO2 nanoparticles

Wang, Lei; Kang, Shi‐Zhao; Li, Xiangqing; Qin, Lixia; Yan, Hao; Mu, Jin

doi:10.1016/j.matchemphys.2016.05.004

Cited by 6 publications

(2 citation statements)

References 27 publications

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“…4 Among different detoxifying treatments (such as chemical precipitation, ion exchange, membrane separation, adsorption and photocatalysis), photocatalysis has been proven to be a useful approach in reducing Cr(VI) to Cr(III). [5][6][7] So far, most reported photocatalysts have been based on semiconductors such as TiO 2 , [5][6][7] CdS, 8 SnS 2 , 9 and Ag 2 S. 10 It is known that reactant adsorption or permeation plays an important role in quantum efficiency of the photocatalysis process. [11][12][13] Increasing the surface area of photocatalysts has been proven to be an effective way to provide more reactive sites and better adsorption properties and thus improve the photocatalytic activity.…”

Section: Introductionmentioning

confidence: 99%

Integration of nanosized ZIF-8 particles onto mesoporous TiO₂ nanobeads for enhanced photocatalytic activity

Liu

Zhou

et al. 2017

RSC Adv.

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Section: Introductionmentioning

confidence: 99%

Integration of nanosized ZIF-8 particles onto mesoporous TiO₂ nanobeads for enhanced photocatalytic activity

Liu

Zhou

et al. 2017

RSC Adv.

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“…Further, the crystallinity and stability of the nanocomposite is also found without any significant change despite the completion of five catalytic cycles as shown in Figure B and C. All the above observations clearly demonstrate that PANI/MnO 2 /TiO 2 is highly stable and does not decompose from the matrix despite performing in various catalytic reaction cycles. PANI/MnO 2 /TiO 2 is comparable vis-à-vis catalytic activity as summarized in Table . ,,− ,− …”

Section: Resultsmentioning

confidence: 94%

Reduction of Cr⁶⁺ from Wastewater Using a Novel in Situ-Synthesized PANI/MnO₂/TiO₂ Nanocomposite: Renewable, Selective, Stable, and Synergistic Catalysis

Balakumar¹,

Prakash²,

Nagulan³

2017

ACS Sustainable Chem. Eng.

108

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An in situ synthesis of a new nanocomposite, polyaniline/manganese dioxide/ titanium dioxide (PANI/MnO 2 /TiO 2 ), via a one-pot oxidative polymerization method at room temperature is described in this article. The characterization was done on the synthesized nanocomposite using UV−vis, FT-IR, XRD, TGA, SEM, and TEM analysis. A superior catalytic activity is exhibited by the synergistic PANI/MnO 2 /TiO 2 nanocomposite in the conversion of toxic Cr 6+ to benign Cr 3+ in comparison with PANI, MnO 2 , TiO 2 , PANI/MnO 2 , PANI/TiO 2 , MnO 2 /TiO 2 , and other nanocomposite materials reported. The reduction rate is dependent on the concentration of substrate (Cr 6+ ), oxidant (HCOOH), and catalyst, pH, temperature, and foreign ions. The PANI/MnO 2 /TiO 2 reveals an excellent conversion (99.9%), rate constant (15.97 × 10 −2 min −1 ), and turnover frequency (0.3333 mmol/mg/min) in the reduction of Cr 6+ . The results obtained from this study illustrate that the prepared nanocomposite, PANI/MnO 2 /TiO 2 , can be very well used as an effective and economically viable catalyst for the reduction of toxic contaminant Cr 6+ from wastewater.

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Preparation, characterization and application of phase-pure anatase and rutile TiO2 nanoparticles by new green route

Spada

Pereira

Montanhera

et al. 2017

J Mater Sci: Mater Electron

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some distinct properties of TiO 2 , among which high redox potential, high chemical stability, low cost, and no toxicity stand out. These properties depend on many factors, such as the crystal structure, crystallite size, particle shape, and specific surface area, which are also strongly dependent on the method of synthesis. In terms of its crystal structure, TiO 2 exists as three important polymorphs: rutile (tetragonal), anatase (tetragonal), and brookite (orthorhombic) [6]. Rutile is the only stable phase; anatase and brookite are metastable at all temperatures and can be converted to rutile after heat treatment at high temperatures. Dependent on structure and particle size, each crystalline phase exhibits different physical properties best suited to different applications. For example, the anatase phase has a band gap of 3.2 eV, which means that it can be activated by UV light illumination. This is one of the reasons why it is often preferred for applications in photocatalysis [7-9]. The photocatalytic activity of TiO 2 originates from the presence of photo-generated electrons (e −) in the conduction band and holes (h +) in the valence band under irradiation with UV light. These holes have high oxidation power, thus they can easily react with adsorbed hydroxide ions to produce hydroxyl radicals, the main oxidizing species that are responsible for the photo-oxidation of organic compounds. The photocatalytic performance of anatase is considered superior to the more stable rutile (3.0 eV); this is attributed to a higher density of localized states and slower charge carrier recombination [10]. On the other hand, it has been reported that the presence of a small fraction of the rutile phase in intimate contact with anatase TiO 2 can improve its photocatalytic performance [11-13]. Pure anatase phase can be synthesized by many methods, such as the hydrothermal method, the sol gel method, the chemical method, and electrodeposition [14-19]. While all these methods have their own important benefits, the

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Rapid and efficient photocatalytic reduction of hexavalent chromium by using “water dispersible” TiO2 nanoparticles

Cited by 6 publications

References 27 publications

Integration of nanosized ZIF-8 particles onto mesoporous TiO₂ nanobeads for enhanced photocatalytic activity

Integration of nanosized ZIF-8 particles onto mesoporous TiO₂ nanobeads for enhanced photocatalytic activity

Reduction of Cr⁶⁺ from Wastewater Using a Novel in Situ-Synthesized PANI/MnO₂/TiO₂ Nanocomposite: Renewable, Selective, Stable, and Synergistic Catalysis

Preparation, characterization and application of phase-pure anatase and rutile TiO2 nanoparticles by new green route

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Rapid and efficient photocatalytic reduction of hexavalent chromium by using “water dispersible” TiO2 nanoparticles

Cited by 6 publications

References 27 publications

Integration of nanosized ZIF-8 particles onto mesoporous TiO2 nanobeads for enhanced photocatalytic activity

Integration of nanosized ZIF-8 particles onto mesoporous TiO2 nanobeads for enhanced photocatalytic activity

Reduction of Cr6+ from Wastewater Using a Novel in Situ-Synthesized PANI/MnO2/TiO2 Nanocomposite: Renewable, Selective, Stable, and Synergistic Catalysis

Preparation, characterization and application of phase-pure anatase and rutile TiO2 nanoparticles by new green route

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Integration of nanosized ZIF-8 particles onto mesoporous TiO₂ nanobeads for enhanced photocatalytic activity

Integration of nanosized ZIF-8 particles onto mesoporous TiO₂ nanobeads for enhanced photocatalytic activity

Reduction of Cr⁶⁺ from Wastewater Using a Novel in Situ-Synthesized PANI/MnO₂/TiO₂ Nanocomposite: Renewable, Selective, Stable, and Synergistic Catalysis