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Enhanced Cu activity in catalytic ozonation of clofibric acid by incorporation into ammonium dawsonite

Paper ID Volume ID Publish Year Pages File Format Full-Text
46716 46446 2011 9 PDF Available
Title
Enhanced Cu activity in catalytic ozonation of clofibric acid by incorporation into ammonium dawsonite
Abstract

Clofibric acid (CFA) degradation by ozonation in the presence of Cu-dawsonites was studied. Cu-dawsonite materials were synthesized via co-precipitation of Al(NO3)3 and Cu(NO3)2 by (NH4)2CO3 at pH 7.5–8.0. The as-synthesized and the calcined samples were characterized using XRD, FTIR, N2-physisorption, TEM and XPS techniques. The CFA degradation was carried out using the as-synthesized and the calcined Cu-dawsonites, dissolved Cu2+ and CuO supported on Al2O3. The heterogeneous as-synthesized Cu-dawsonite catalysts showed more efficient performance with respect to the other catalysts, despite of significant Cu leaching detected at the end of the reactions. The reactions carried out using the homogeneous dissolved Cu2+ (in the concentration range of the leached Cu) indicated low contribution of dissolved Cu2+ in the mineralization of CFA and its intermediates; the efficiency was mainly devoted to the activity of Cu incorporated in the dawsonite structure. Characterization of Cu-dawsonites revealed a possibility of Cu localization in the NH4+ position, which is higher exposed to leaching than that of Al. The reaction performed at initial pH 10 (pH higher than pHPZC of as-synthesized Cu-dawsonite) resulted to a higher TOC and COD reduction after 2 h compared with the reaction at pH 3.7. Also lowest Cu leaching was obtained under these conditions. Enhanced activity of Cu incorporated into the structure of dawsonite in the catalytic ozonation of CFA is probably due to the presence of Cu(I) located in the structure of dawsonite revealed by XPS. Some of the main intermediates have been identified by HPLC–MS suggesting three routes for CFA destruction by ozonation using Cu-dawsonite including, C1–O and C4–Cl bond breaking and aromatic ring cleavage.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights• Dawsonite-incorporated Cu presents high activity in catalytic ozonation. • The contribution of dissolved Cu2+ in ozonation is not significant. • Cu appears as Cu(I) within the structure of ammonium dawsonite. • The reaction at initial pH 10 results to highest efficiency and lowest Cu loss.

Keywords
Catalytic ozonation; Cupper; Dawsonite; Clofibric acid
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Enhanced Cu activity in catalytic ozonation of clofibric acid by incorporation into ammonium dawsonite
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 107, Issues 1–2, 31 August 2011, Pages 9–17
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