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Photocatalytic hydrophobic concrete coatings to combat air pollution

Paper ID Volume ID Publish Year Pages File Format Full-Text
53566 46974 2016 9 PDF Available
Title
Photocatalytic hydrophobic concrete coatings to combat air pollution
Abstract

•SiO2 sol added to coating composition improved MB dye bleaching.•SiO2–TiO2 coating presented enhanced photocatalytic degradation of NOx.•Hydrophobic TiO2–siloxane coated concrete showed excellent NOx conversion.•Adsorption vs. photo-oxidation compromise for increasing photoefficiency.•TiO2 content threshold: 1% for hydrophilic vs. 5% for hydrophobic coatings.

Several low cost, user-friendly photocatalytic surface coatings were applied to cementitious surfaces and tested as a remediation technique for transportation NOx emissions and organic pollutants. All of the sols (aqueous suspensions of nanoparticles) coatings showed very high nitrogen oxide (NO) conversion (∼90%) and Methylene Blue dye bleaching when applied to concrete surfaces, even when the coatings were extremely thin or diluted, independently on the deposition method (spraying or dip coating). A novel hydrophobic coating based on photocatalyst nanoparticles suspended in a siloxane sealant showed similar conversion at low NO concentrations but required a greater loading of TiO2. At high NO concentrations the hydrophobic coating was less effective, even at greater TiO2 loadings, suggesting that the adsorption is the rate limiting step in this conversion process. A threshold of 1% TiO2 loading in hydrophilic coating and 5% in the case of hydrophobic was needed to obtain a quantitative NOx conversion. A home-made TiO2 sol showed lower NOx photodegradation but a more homogeneous and bonded layer.

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Keywords
Concrete; Hydrophobic; Photocatalysis; Self-cleaning; Air pollution; NOx; Siloxane
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Photocatalytic hydrophobic concrete coatings to combat air pollution
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Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 259, Part 1, 1 January 2016, Pages 228–236
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