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Washcoated Pd/Al2O3 monoliths for the liquid phase hydrodechlorination of dioxins

Paper ID Volume ID Publish Year Pages File Format Full-Text
40702 45863 2012 9 PDF Available
Title
Washcoated Pd/Al2O3 monoliths for the liquid phase hydrodechlorination of dioxins
Abstract

The catalytic activity and durability of 2 wt.% Pd/Al2O3 in powder and washcoated on cordierite monoliths were examined for the liquid phase hydrodechlorination (LPHDC) of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/Fs), also known as dioxins. NaOH was employed as a neutralizing agent, and 2-propanol was used as a hydrogen donor and a solvent. Fresh and spent powder and monolith samples were characterized by elemental analysis, surface area, hydrogen chemisorption, scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX), and transmission electron microscopy/energy dispersive X-ray spectroscopy (TEM/EDX). Three reactor configurations were compared including the slurry and monolith batch reactors as well as the bubble loop column resulting in 100, 70, and 72% sample toxicity reduction, respectively, after 5 h of reaction. However, the slurry and monolith batch reactors lead to catalyst sample loss via a filtration process (slurry) and washcoat erosion (monolith batch), as well as rapid deactivation of the powder catalyst samples. The monolith employed in the bubble loop column remained stable and active after four reaction runs. Three preemptive regeneration methods were evaluated on spent monolith catalyst including 2-propanol washing, oxidation/reduction, and reduction. All three procedures reactivated the spent catalyst samples, but the combustion methods proved to be more efficient at eliminating the more stable poisons.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (108 K)Download as PowerPoint slideHighlights► Pd/Al2O3 washcoated monoliths were tested on liquid phase HDC of dioxins. ► Slurry and monolith reactors, and bubble loop column configurations were compared. ► The monoliths were active and more resistant to deactivation. ► The spent monoliths were regenerated by washing, oxidation/reduction, and reduction.

Keywords
Pd/Al2O3 catalyst; Washcoated monoliths; Catalyst deactivation; Dioxins; Fly ash
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Washcoated Pd/Al2O3 monoliths for the liquid phase hydrodechlorination of dioxins
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volumes 445–446, 28 November 2012, Pages 83–91
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