Commenced in January 2007
Paper Count: 31100
Palladium-Catalyzed Hydrodechlorination for Water Remediation: Catalyst Deactivation and Regeneration
Abstract:Palladium-catalyzed hydrodechlorination is a promising alternative for the treatment of environmentally relevant water bodies, such as groundwater, contaminated with chlorinated organic compounds (COCs). In the aqueous phase hydrodechlorination of COCs, Pd-based catalysts were found to have a very high catalytic activity. However, the full utilization of the catalyst-s potential is impeded by the sensitivity of the catalyst to poisoning and deactivation induced by reduced sulfur compounds (e.g. sulfides). Several regenerants have been tested before to recover the performance of sulfide-fouled Pd catalyst. But these only delivered partial success with respect to re-establishment of the catalyst activity. In this study, the deactivation behaviour of Pd/Al2O3 in the presence of sulfide was investigated. Subsequent to total deactivation the catalyst was regenerated in the aqueous phase using potassium permanganate. Under neutral pH condition, oxidative regeneration with permanganate delivered a slow recovery of catalyst activity. However, changing the pH of the bulk solution to acidic resulted in the complete recovery of catalyst activity within a regeneration time of about half an hour. These findings suggest the superiority of permanganate as regenerant in re-activating Pd/Al2O3 by oxidizing Pd-bound sulfide.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1058489Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1864
 Lowry, G. V.; Reinhard, M. Hydrodehalogenation of 1- to 3-carbon halogenated organic compounds in water using a palladium catalyst and hydrogen gas. Environ. Sci. Technol. 1999, 33, 1905-1910.
 Schueth, C.; Reinhard, M. Hydrodechlorination and hydrogenation of aromatic compounds over palladium on alumina in hydrogen-saturated water. Appl. Catal. B 1998, 18, 215-221.
 Fritsch, D.; Kuhr, K.; Mackenzie, K.; Kopinke, F.-D. Hydrodechlorination of chloroorganic compounds in ground water by palladium catalysts: Part 1. Development of polymer-based catalysts and membrane reactor tests. Catal. Today 2003, 82, 105-118.
 Schueth, C.; Disser S.; Schueth F.; Reinhard M. Tailoring catalysts for hydrodechlorinating chlorinated hydrocarbon contaminants in groundwater. Appl. Catal. B 2000, 28, 147-152.
 Angeles-Wedler, D.; Mackenzie, K.; Kopinke, F.-D. Permanganate oxidation of sulfur compounds to prevent poisoning of Pd catalysts in water treatment processes. Environ. Sci. Technol. in press.
 Chaplin, B. P.; Shapley J. R.; Werth C. J. Regeneration of sulfur-fouled bimetallic Pd-based catalysts. Environ. Sci. Technol. 2007, 41, 5491- 5497.
 Lowry, G. V.; Reinhard M. Pd-Catalyzed TCE dechlorination in groundwater: Solute effects, biological control, and oxidative catalyst regeneration. Environ. Sci. Technol. 2000, 34, 3217-3223.
 Kopinke, F.-D.; Mackenzie K.; Koehler R. Catalytic hydrodechlorination of groundwater contaminants in water and in the gas phase using Pd/╬│-Al2O3. Appl. Catal. B 2003, 44, 15-24.
 Yu, T. C.; Shaw, H. The effect of sulfur poisoning on methane oxidation over palladium supported on g-alumina catalysts. Appl. Catal. B 1998, 18, 105-114.
 Jones, J. M.; Dupont, V. A.; Brydson, R.; Fullerton, D. J.; Nasri, N. S.; Ross, A. B.; Westwood, A. V. K. Sulphur poisoning and regeneration of precious metal catalysed methane combustion. Catal. Today 2003, 81, 589-601.