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Optimisation of degradation conditions of 1,8-diazabicyclo[5.4.0]undec-7-ene in water and reaction kinetics analysis using a cocurrent downflow contactor photocatalytic reactor

Paper ID Volume ID Publish Year Pages File Format Full-Text
48902 46526 2007 10 PDF Available
Title
Optimisation of degradation conditions of 1,8-diazabicyclo[5.4.0]undec-7-ene in water and reaction kinetics analysis using a cocurrent downflow contactor photocatalytic reactor
Abstract

The photocatalytic degradation of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU, a non-biodegradable nitrogenous organic compound) in water was optimised under UV radiation using titanium dioxide photocatalyst. The reactor used was a pilot scale cocurrent downflow contactor photocatalytic reactor (CDCPR), a system offering very high mass transfer efficiency. The effect of photocatalyst loading, initial substrate concentration, temperature, pH, and different combinations of UV, O2, H2O2 and TiO2 on the photocatalytic oxidation of DBU was investigated. The TiO2 photocatalyst used was Degussa VP Aeroperl P25/20, a granulated form of Degussa P-25, recently developed to ameliorate downstream catalyst separation problems. The CDCPR was fitted with an internally and vertically mounted 1.0 kW UV lamp. The reactions were carried out at 40–60 °C and 1 barg, with the reactor being operated in closed loop recycle mode and suspended photocatalyst being re-circulated. Optimisation of reaction conditions using a combination of TiO2, UV radiation and O2 gave the most rapid degradation and mineralisation of the DBU in comparison with other processes. Under optimised conditions, 100% degradation of DBU was achieved in 45 min, with a quantum yield of 7.39, using a 1 kW lamp, 0.5 g/dm3 TiO2, 100 mg/dm3 DBU, 1 barg, 50 °C and pH of 3.17. Investigating the reaction pathway and its modelling showed a first order dependency, incorporating the effect of first intermediates of degradation. The activation energy was found to be 54.68 kJ mol−1 showing a significant influence of temperature on the photocatalytic degradation of DBU.

Keywords
Cocurrent downflow contactor; Optimisation; Photocatalysis; Environment; Kinetics
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Optimisation of degradation conditions of 1,8-diazabicyclo[5.4.0]undec-7-ene in water and reaction kinetics analysis using a cocurrent downflow contactor photocatalytic reactor
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 73, Issues 3–4, 11 May 2007, Pages 259–268
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