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Issue 6, 2018
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TiO2 composited with carbon nanofibers or nitrogen-doped carbon nanotubes synthesized using coal fly ash as a catalyst: bisphenol-A photodegradation efficiency evaluation

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Abstract

Coal fly ash (CFA) was used as a catalyst for the synthesis of nitrogen-doped carbon nanotubes (NCNTs) and carbon nanofibers (CNFs) by chemical vapor deposition. Carbon nanomaterials (CNMs) were successfully purified by sequential treatment in 5% HF and then in a dil. HNO3/H2SO4 mixture, as was shown by SEM, TGA, and XRD. The purified NCNTs and CNFs were composited with TiO2 nanoparticles at varying loadings (i.e. 1, 5 and 20% CNF/NCNT loadings) by a surfactant wrapping sol–gel/hydrothermal method and used for the photodegradation of bisphenol-A (BPA) in water with light being sourced from a solar simulator. It was shown by TEM that the CNMs were completely coated with TiO2 nanoparticles and interactions between the CNMs and TiO2 were demonstrated using PXRD and laser Raman spectroscopy. Photoluminescence measurements showed that compositing TiO2 with CNMs, especially NCNTs significantly reduced its emission intensity suggesting a reduced electron/hole recombination rate. Unbound TiO2 was used to optimize the photodegradation experimental conditions, i.e. solution pH, the mass of the photocatalyst, the initial concentration of BPA and solution temperature. The photocatalytic efficiency of the various TIO2 and CNFs/NCNTs was assessed using the optimized conditions where it was observed that the composites containing 1 and 5% loadings of CNMs outperformed TiO2. The photocatalytic efficiency of the NCNT based composites was higher than that of the CNF based composites. This work shows that CFA, a toxic material, could be used to synthesize materials useful for cleaning water.

Graphical abstract: TiO2 composited with carbon nanofibers or nitrogen-doped carbon nanotubes synthesized using coal fly ash as a catalyst: bisphenol-A photodegradation efficiency evaluation

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Publication details

The article was received on 05 Dec 2017, accepted on 05 Feb 2018 and first published on 06 Feb 2018


Article type: Paper
DOI: 10.1039/C7NJ04787H
Citation: New J. Chem., 2018,42, 4531-4542
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    TiO2 composited with carbon nanofibers or nitrogen-doped carbon nanotubes synthesized using coal fly ash as a catalyst: bisphenol-A photodegradation efficiency evaluation

    L. Hlekelele, P. J. Franklyn, F. Dziike and S. H. Durbach, New J. Chem., 2018, 42, 4531
    DOI: 10.1039/C7NJ04787H

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