Protection of palladium catalysts for hydrodechlorination of chlorinated organic compounds in wastewaters

Navon, Rotem; Eldad, Shay; Mackenzie, Kenneth D.; Kopinke, Frank‐Dieter

doi:10.1016/j.apcatb.2012.03.002

Cited by 32 publications

(18 citation statements)

References 37 publications

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“…The chloride ions interact with Pd active sites, they may affect the oxidation state of Pd, or facilitate the carbon deposition on the catalyst surface [15,25]. Besides, Pd leaching has been reported due to decrease in pH during hydrodechlorination reactions [32,57]. Similar to the previous sulfur poisoning studies, it was expected that the hydrophobicity of the Pd/SOMS catalyst may provide some protection by repelling the Clions.…”

Section: Pd Leaching With Hclmentioning

confidence: 59%

“…Their results indicated that Pd/Al2O3, which is more acidic, showed faster deactivation than Pd/AC for TCE HDC. Moreover, in order to minimize the contact between Pd metal and ionic poisons such as sulfide-containing species, coating materials such as poly-dimethylsiloxane (PDMS) have been tested for HDC reactions [31,32]. This is to enhance the hydrophobicity of the catalysts thereby repelling ionic poisons dissolved in groundwater.…”

Section: Introductionmentioning

confidence: 99%

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Hydrodechlorination of trichloroethylene over Pd supported on swellable organically-modified silica (SOMS)

Sohn

Çelik

Gündüz

et al. 2017

Applied Catalysis B: Environmental

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The catalytic activity and resistance to poisoning of Pd catalysts supported on swellable organically-modified silica (SOMS) were investigated for hydrodechlorination (HDC) of trichloroethylene (TCE). The promising catalytic activity of 1% Pd/SOMS sample was attributed to the high affinity of SOMS for organics and its high hydrophobicity. While latter characteristic repels water, the adsorptive capacity for organics allows TCE dissolved in aqueous media to concentrate inside the pores, in the vicinity of the active sites, thus helping the kinetics. In the liquid phase, using a continuous flow reactor, higher TCE conversion was obtained over the 1% Pd/SOMS compared to the commercial 1% Pd/Al2O3 catalyst. When the pores of 1% Pd/SOMS sample were fully opened by pre-treating it with ethanol prior to the reaction, HDC activity was seen to significantly increase. In the gas phase, the extent of adsorption was less, reducing the concentration of reactants near the active sites. As a result, 1% Pd/SOMS was less active than 1% Pd/Al2O3 for HDC of TCE. To determine their resistance to poisoning, 1% Pd/SOMS and 1% Pd/Al2O3 catalysts were poisoned ex-situ with Li2S. The ex-situ poisoned Pd/SOMS sample maintained its catalytic activity for HDC of TCE. However, a significant loss in catalytic activity of the Pd/Al2O3 catalyst was observed after poisoning. Protection from aqueous phase sulfide poisoning was attributed to the hydrophobicity of the Pd/SOMS, which would exclude anionic species from the embedded Pd particles. The XPS, STEM and ICP-OES results indicated that when Pd/Al2O3 and Pd/SOMS were treated with 1 M HCl, most of the Pd metal was leached from the Pd/Al2O3 catalyst in contrast to Pd/SOMS, which had negligible leaching. Overall, due to hydrophobicity and high affinity for organics, SOMS has potential as a catalyst scaffold for different reactions in groundwater remediation applications.

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Section: Pd Leaching With Hclmentioning

confidence: 59%

Section: Introductionmentioning

confidence: 99%

Hydrodechlorination of trichloroethylene over Pd supported on swellable organically-modified silica (SOMS)

Sohn

Çelik

Gündüz

et al. 2017

Applied Catalysis B: Environmental

View full text Add to dashboard Cite

show abstract

“…Particular attention should be focused on the removal of chlorinated hydrocarbons like 1,2-dichloroethane (DCA), 1,1,2-trichloroethene (TCE) and 1,1,2,2-tetrachloroethene (PCE), because of their potential carcinogenic and mutagenic effects on living organisms [7][8][9]. The application of Pd in the hydrodechlorination (HDC) processes allows to easily, cheaply and without damage of environment transforming harmful chemicals into less toxic products like ethane or ethene [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Influence of preparation procedure on catalytic activity of PdBEA zeolites in aqueous phase hydrodechlorination of 1,1,2-trichloroethene

Kamińska

Lisovytskiy

Casale

et al. 2017

Microporous and Mesoporous Materials

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Pd-loaded BEA zeolites containing 1 wt % of Pd were prepared by a two-step postsynthesis method (PdSiBEA and PdSiAlBEA) and a conventional wet impregnation (PdHAlBEA). Modification of BEA zeolite resulted in the introduction of Pd ions into zeolite framework as pseudo-tetrahedral Pd(II) and extra-framework octahedral Pd(II) evidenced by XRD, DR UVvis and TPR measurements. Calcination of as prepared zeolites in air at 773 K for 3 h and then reduction in 10 % H 2 /Ar flow at 873 K for 3 h led to obtain red-C-PdSiBEA, red-C-PdSiAlBEA and red-C-PdHAlBEA zeolites with different Pd nanoparticles size distributions showed by TEM. These zeolite materials were found to be active catalysts in aqueous-phase hydrodechlorination of 1,1,2-trichloroethene (TCE). The conducted catalytic reactions have demonstrated that the rate and course of TCE hydrodechlorination depend on the catalysts preparation method and Pd nanoparticles size.

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“…In combination with their toxicity this stimulates researches for reducing their concentration in the ecosystem. PCBs can be hydrodechlorinated using Pd-based catalysts that show a very high potential for the destruction of such contaminants in water [3,4]. This process may be highly efficient and selective in clean water even under mild conditions.…”

Section: Introductionmentioning

confidence: 99%

“…For these reasons, Pd-based catalysts are rarely used for applications in water treatment. Until now only a few field-scale studies have investigated the use of Pd-based catalysts for hydrodechlorination (HDC) in groundwater, but the interest for its application remains very high [3,[7][8][9]. Conventional Pd catalysts have been flanked in HDC processes also by biological dechlorination and reductive dechlorination of PCBs by anaerobic microorganisms has been demonstrated to occur [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Hydrodechlorination of Aroclor 1260 in Aqueous Two-phase Mixture Catalyzed by Biogenerated Bimetallic Catalysts

Baldi

Gallo

Paganelli

et al. 2016

IRJPAC

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Protection of palladium catalysts for hydrodechlorination of chlorinated organic compounds in wastewaters

Cited by 32 publications

References 37 publications

Hydrodechlorination of trichloroethylene over Pd supported on swellable organically-modified silica (SOMS)

Hydrodechlorination of trichloroethylene over Pd supported on swellable organically-modified silica (SOMS)

Influence of preparation procedure on catalytic activity of PdBEA zeolites in aqueous phase hydrodechlorination of 1,1,2-trichloroethene

Hydrodechlorination of Aroclor 1260 in Aqueous Two-phase Mixture Catalyzed by Biogenerated Bimetallic Catalysts

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