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A comparative study on the removal of cylindrospermopsin and microcystins from water with NF-TiO2-P25 composite films with visible and UV–vis light photocatalytic activity

Paper ID Volume ID Publish Year Pages File Format Full-Text
46173 46433 2012 10 PDF Available
Title
A comparative study on the removal of cylindrospermopsin and microcystins from water with NF-TiO2-P25 composite films with visible and UV–vis light photocatalytic activity
Abstract

In this investigation, in order to develop photocatalyst materials with improved photo-efficiency and visible light response compared to the state of the art materials, the role of Evonik Aeroxide® P25-TiO2 (P25) nanoparticles incorporated in a modified sol–gel process to yield composite nitrogen and fluorine doped TiO2-P25 (NF-TiO2-P25) films was investigated. The addition of P25 nanoparticles in the sol leads to higher BET surface area, pore volume, porosity and total TiO2 mass, as well as larger thickness and roughness of the films after heat treatment. Microscopy techniques confirmed partial sintering of NF-TiO2 sol–gel formed and P25 nanoparticles having different average size. The existence of well defined regions of only anatase from NF-TiO2 and anatase–rutile mix from P25 was verified in the micro-Raman spectra. The photocatalytic degradation of four microcystins (microcystin-LR, -RR, -LA and -YR) and cylindrospermopsin was evaluated with NF-TiO2 and NF-TiO2-P25 films under visible and UV–vis light. The general reactivity for the microcystins under acidic conditions (pH 3.0) was: MC-LA > MC-LR ≥ MC-YR > MC-RR where the highest initial degradation rate was achieved with the NF-TiO2-P25 films (5 g L−1 of P25 in sol when irradiated with visible light and 15 g L−1 of P25 in sol when irradiated with UV–vis light). Cylindrospermopsin showed negligible adsorption at pH 3.0 for all films. Nevertheless, significant photocatalytic removal was found under UV–vis light with maximum P25 loaded films indicating that the degradation was mediated by the involvement of photogenerated reactive oxygen species and not by the trapping reaction of the positive hole.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Improved physicochemical properties and photocatalytic activity of NF-TiO2 with the addition of P25-TiO2 nanoparticles. ► The optimum P25-TiO2 loading was 5 g L−1 in the modified sol. ► The general reactivity of the microcystins with the composite films at pH 3.0 was MC-LA > MC-LR ≥ MC-YR > MC-RR. ► Cylindrospermopsin was efficiently removed under UV–vis light despite negligible adsorption at pH 3.0.

Keywords
Nitrogen doping; Fluorine doping; P25; TiO2; Photocatalysis; Photocatalytic; Cylindrospermopsin; Microcystins; Visible; UV–vis; Water treatment
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A comparative study on the removal of cylindrospermopsin and microcystins from water with NF-TiO2-P25 composite films with visible and UV–vis light photocatalytic activity
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volumes 121–122, 13 June 2012, Pages 30–39
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us