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Removal of polycyclic aromatic hydrocarbons (PAHs) from groundwater by heterogeneous photocatalysis under natural sunlight

Paper ID Volume ID Publish Year Pages File Format Full-Text
27077 43999 2012 9 PDF Available
Title
Removal of polycyclic aromatic hydrocarbons (PAHs) from groundwater by heterogeneous photocatalysis under natural sunlight
Abstract

Polycyclic aromatic hydrocarbons (PAHs) are a class of persistent organic pollutants of special concern because they are carcinogenic and mutagenic compounds. In this paper, photodegradation of a mixture of six PAHs in groundwater at pilot plant scale is reported. Semiconductor materials (ZnO and TiO2) as photocatalysts in tandem with Na2S2O8 as oxidant under natural sunlight were used. The PAHs were benzo[a]pyrene, benzo[b]fluoranthene, benzo[ghi]perylene, benzo[k]fluoranthene, fluoranthene, and indene[1,2,3-cd]pyrene. As expected, the influence of both semiconductors on the degradation of PAHs was very significant in all cases. Photocatalytic experiments show that the addition of photocatalyst, especially for ZnO/Na2S2O8 system, strongly improves the elimination of PAHs in comparison with photolytic tests; significantly increasing the reaction rates. The first-order equation (monophasic model) satisfactorily explained the disappearance process although it ignores small residues remaining late in the process. These residues are important from an environmental point of view and the Hoerl function (biphasic model) better predict the results obtained. In our conditions, the time required for 90% degradation was in the range 7–15 min and 18–76 min for ZnO and TiO2 systems, respectively. Thus, the use of the tandem ZnO/Na2S2O8 makes possible the economical decontamination of groundwater containing non-biodegradable pollutants like PAHs.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The photodecomposition of six PAHs in groundwater was studied. ► PAHs can be leached through the soil columns although in small proportions. ► The study was designed at pilot plant scale under solar irradiation. ► ZnO enhances photodegradation in comparison with TiO2 and photolytic tests. ► Disappearance time (90%) was lower than 15 min by use of the tandem ZnO/Na2S2O8.

Keywords
Groundwater; Photodegradation; Polycyclic aromatic hydrocarbons; Titanium dioxide; Zinc oxide
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Removal of polycyclic aromatic hydrocarbons (PAHs) from groundwater by heterogeneous photocatalysis under natural sunlight
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 232, 15 March 2012, Pages 32–40
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
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