Dechlorination Performance Research Articles

Achieving high performance for electrocatalytic dechlorination with magnetic Pd/CoFe2O4 particle electrodes

Moveable catalysts in a three-dimensional (3D) electrochemical reactor offer benefits for pollutant dechlorination because of increased active sites and mass transfer, but they suffer from difficulties in catalyst recovery. Herein, we demonstrate that magnetic Pd/CoFe2O4 catalysts are highly active, durable, and recyclable when used in the electrochemical dechlorination of 2,4-dichlorophenol (2,4-DCP). Highly dispersed nano-sized Pd/CoFe2O4 catalysts were successfully synthesized using an easy chemical deposition method. Tests on the effects of the initial solution pH showed that the alkaline condition was favorable for achieving increased dechlorination performance in terms of increased reaction rate and higher current efficiency. Greater amounts of surface-adsorbed atomic H (Hads*) formed and Pd with an electron-rich state as a consequence of metal-support interaction under the alkaline condition may play important roles in the effectiveness. The Pd/CoFe2O4 particle electrodes in the 3D reactor were effective in removing 2,4-DCP with different concentrations. Notably, at a current density of 2.50 mA cm−2, 200 mg L−1 2,4-DCP can be dechlorinated to phenol within 30 min with current efficiency of 64.4%. The findings demonstrate that magnetic Pd/CoFe2O4 catalysts hold distinct promise for application in the 3D electrochemical dechlorination process.

Retraction of “Dechlorination of Poly(vinyl chloride) Wastes via Hydrothermal Carbonization with Lignin for Clean Solid Fuel Production”

An alternative technology has been proposed for the dechlorination of poly(vinyl chloride) (PVC) wastes by hydrothermal carbonization (HTC) with lignin. The organic chloride in PVC can be converted to inorganic chloride through hydrolysis, defunctionalization, recondensation, and aromatization in the HTC process. Combined with downstream washing processes by recycling the condensed water, the inorganic chloride with high water solubility is removed from the solid products (i.e., hydrochar). The presence of lignin could significantly improve the dechlorination efficiency of PVC in the HTC process. The dechlorination performance of lignocellulosic components is given as follows: lignin > cellulose > hemicellulose. In addition, lignin can adjust the particle sizes of hydrochars by inhibiting agglomeration in the order of lignin > hemicellulose > cellulose. The hydrochar particles with a low chlorine content and a high heating value could be used as a clean coal-alternative fuel.

Zn-Modified Hβ Zeolites Used in the Adsorptive Removal of Organic Chloride from Model Naphtha.

Different metal ions were used to modify Hβ zeolite adsorbents by an impregnation method to remove organic chlorides from the model naphtha. The dechlorination performance of different ion-modified adsorbents was evaluated using a microcoulometer. The effects of calcination time and temperature, metal loading, adsorption time and temperature, and dosage of adsorbent were investigated by batch adsorption experiments. The modified adsorbents were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), NH3-temperature-programmed desorption (TPD), scanning electron microscopy (SEM), infrared spectroscopy of pyridine adsorption (Py-IR), and X-ray photoelectron spectroscopy (XPS). After modification, the modified Zn/Hβ zeolite exhibited the best dechlorination performance among the other metal-loaded zeolites. The removal percentage of organic chloride of the Zn/Hβ adsorbent prepared at optimum preparation and adsorption conditions can reach 72.54%, compared with 34.07% of Hβ zeolite. The Zn/Hβ adsorbent also maintained good dechlorination performance after regeneration by calcination for five times. The characterization results revealed that the concentration of the B acid sites in the zeolite decreased with the introduction of the metals, whereas that of the L acid sites increased. Zn/Hβ zeolite had the lowest B/L ratio but the best dechlorination performance, which meant that the type and amount of acidic sites present in zeolites played a significant role in dechlorination performance and L acid was beneficial for chloride compound removal.

Enhanced electrochemical dechlorination of 4-chlorophenol on a nickel foam electrode modified with palladium, polypyrrole and graphene

A composite electrode of Pd/polypyrrole-reduced graphene oxide/foam nickel (Pd/PPy-rGO/NF) with excellent dechlorination performance was prepared by pulse electrodeposition of Pd nanoparticles on the interlayer of PPy-rGO. The physicochemical properties of the electrode were systematically characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and cyclic voltammetry. 4-chlorophenol (4-CP) was selected as a model chlorinated organic pollutant to investigate the dechlorination property of electrodes and optimize the dechlorination conditions and electrode preparation conditions. The results indicated that the morphology of the Pd/PPy-rGO/NF electrode exhibited porous nano-grids, and the Pd content as low as 0.430 mg/cm2. By using this electrode, 95.8% of 4-CP could be dechlorinated in 120 min with a relatively high current efficiency of 39.9%. A new parameter named as specific current efficiency (SPCE), which can be calculated through dividing the current efficiency by the Pd content on unit electrode surface, was proposed to estimate the role of Pd in dechlorination. The SPCE obtained in this work was as high as 92.9%/(mg/cm2). Compared with the electrode without the interlayer of PPy-rGO, the Pd/PPy-rGO/NF electrode presented higher dechlorination activity and better stability. The studies here may contribute to the development of the electrocatalytic electrode that can be used as a potential candidate for eliminating chlorinated pollutants.

Insights into Electroreductive Dehalogenation Mechanisms of Chlorinated Environmental Pollutants

AbstractThe electroreductive cleavage of carbon‐chloro bonds has attracted increasing attention from both environmental and mechanistic points of view over the past decades, taking into consideration a large variety of chlorinated organic compounds. Important discoveries have been made on the underlying electron/hydrogen transfer mechanisms and the enhancement of dechlorination performance for electrocatalysis purposes over the last years. However, there is still missing a combined knowledge from individual researches to specially elucidate the electroreductive dehalogenation mechanisms of organic chlorides. Herein, we summarize the diverse electrochemical strategies applied to reductive dehalogenation of chlorinated environmental pollutants, including direct electrochemical reduction, electrocatalytic hydro‐dechlorination and electrochemically mediated reduction methods, and, especially, highlight the differences in reductive dehalogenation mechanisms. Specifically, direct electron transfer is the most common dechlorination mechanism involved in the direct electrochemical reduction of organic chlorides, in which the electron transfer to C−Cl bonds can be classified as concerted or stepwise dissociative electron transfer mechanism. Indirect atomic hydrogen reduction is the primary dechlorination mechanism in the electrocatalytic hydro‐dechlorination process, which often competes with the direct electrochemical reduction route. Electrochemically mediated reduction, as another indirect route, uses a redox‐active mediator to indirectly transfer electrons from cathode to organic chlorides, resulting in reductive dehalogenation reaction. Moreover, the effects of critical factors on the dehalogenation reactivity and mechanisms are also discussed to better demonstrate the electroreductive dehalogenation of organic chlorides. Lastly, this contribution highlights recent relevant advances in electroreductive dehalogenation issues, as well as the challenges and potentials of this process.

Deciphering microbiomes in anaerobic reactors with superior trichloroethylene dechlorination performance at low pH conditions

Different pH conditions have been demonstrated to affect the activities of dechlorinating populations participating in the successive dechlorination of trichloroethylene to ethylene. However, the mechanism of the effect of pH conditions on the assembly of dechlorinating populations and their relations to the structure, function, and dynamics of the microbiome are unclear. In this study, we evaluated the effects of pH on microbiomes assembled in anaerobic trichloroethylene-dechlorinating reactors under neutral (pH 7.2), acidic (pH 6.2), and alkaline (pH 8.2) conditions. The results revealed that among the reactors, the acidic reactor had the highest efficiency for dechlorination without accumulation of dechlorinated metabolites, even at high loading rates. The results of high-throughput sequencing of the 16S rRNA gene indicated that the microbiomes in the 3 reactors underwent varied dynamic succession. The acidic reactor harbored a higher degree of complex microbes, dechlorinator diversity, and abundance of the Victoria subgroup of Dehalococcoides (1.2 ± 0.1 × 106 cell/mL), which were approximately 10–102-fold higher than those at neutral and alkaline conditions. The pH settings altered species–species connectivity and complexity of microbial interaction networks, with more commensal interactions in the dechlorinators of the acidic reactor. As predicted, abundances of several functional gene categories were in strong linearity with pH values, and the microbiome possessed significantly more abundant functions in the acidic reactor (P < 0.001), such as potentially stimulating hydrogen production, cobalamin synthesis, cobalt transport, transport and metabolism of amino acids and secondary metabolites, cell motility, and transcription. All results of microbiomic analyses consistently revealed the observed superior dechlorination process and suggested an association of the reductive dechlorination process with the pH-dependent microbiome. The results of this study provide a new insight into the trichloroethylene dechlorination with regards to pH, and they will be useful for improving bioremediation and management of trichloroethylene-contaminated sites.

Enhanced photocatalytic reduction for the dechlorination of 2-chlorodibenzo-p-dioxin by high-performance g-C3N4/NiO heterojunction composites under ultraviolet-visible light illumination

Polychlorinated dibenzo-p-dioxins (PCDDs), characterized by their high persistency and bioaccumulation, are widely detected in the environment. In this study, high-performance g-C3N4/NiO heterojunctions were fabricated to degrade 2-chlorodibenzo-p-dioxin (2-CDD) under ultraviolet-visible (UV–vis) light illumination. Experiments revealed that the pure g-C3N4 and range of g-C3N4/NiO heterojunctions were synthesized by the mixing and heating method, and then were characterized by XRD, TEM, XPS and PL etc. The composites exhibited enhanced dechlorination activities under anoxic conditions. After comparison, the g-C3N4/NiO (4:6) showed optimal dechlorination performance such that 70.4% of 2-CDD was removed within 8 h and 52.3% of 2-CDD was transformed to dibenzo-p-dioxin (DD), about fourfold higher than the pristine g-C3N4. The transformation of 2-CDD was accompanied by the resale of Cl ion, and the additional oxygen was proven to be able to consume electrons and hydrogen ions, thus greatly inhibiting the degradation of PCDD in systems. The g-C3N4/NiO (4:6) can be reused at least seven times, and the mechanism was proposed in detail to promote photoinduced electrohole separation and provide active sites. This study extends the use range of g-C3N4/NiO heterojunctions and develops a new technology to degrade PCDDs with striking activity and stability.

Selective removal of chloride from the adipate formation bath in foil industry by diffusion dialysis

Aluminum electrode foils are the most essential components inside electrolytic capacitors, which are widely used in diverse electronic systems. The production involves the usage of various chemicals, and it generates a huge amount of exhausted bath solution consisting of highly-concentrated ammonium adipate and trace Cl− impurity. The loss of these expensive chemicals is a heavy burden for the foil manufacturers. The current work innovatively applies diffusion dialysis (DD) to selectively remove the chloride from this abandoned solution, which makes the reuse of these chemicals possible. In the process, Cl− ion presents a superior permeability compared with adipate2− ion, and a high permselectivity of 6 is obtained by using conventional anion exchange membranes. The effects of flow intensity and chloride concentration on the selective dechlorination performance have been thoroughly studied, respectively. Furthermore, the long-term stability of the membranes has been carefully investigated, and their performance is unchanged during a six-month period. The overall economics of this new process is very encouraging, and a stunningly short pay-off period (43 days) is achieved. This work not only solves the problem of reusing the exhausted adipate bath solution, but also further demonstrates the great potential of the DD process in selective ion separation applications.

Ultrafast reductive dechlorination of carbon tetrachloride by amorphous Fe78Si9B13 alloy

Amorphous Fe78Si9B13 ribbons and zero-valent iron (ZVI) powder were used to remove carbon tetrachloride (CTC) in the neutral oxic environment. The amorphous Fe78Si9B13 ribbons showed significantly better dechlorination performance than the ZVI powder, and the CTC could be degraded nearly completely within 3 h. The recyclability of amorphous Fe78Si9B13 ribbons was investigated, and the results confirmed their effectiveness and stability to remove the CTC for at least ten times. Our work demonstrates the application potential of amorphous alloys as an alternative to ZVI in the dechlorination of chlorinated organic compounds, and can provide new ideas for designing efficient dechlorinating agent in the actual field groundwater remediation.

Evonik Industries opens new precipitated silica production unit in the US

Aluminum electrode foils are the most essential components inside electrolytic capacitors, which are widely used in diverse electronic systems. The production involves the usage of various chemicals, and it generates a huge amount of exhausted bath solution consisting of highly-concentrated ammonium adipate and trace Cl− impurity. The loss of these expensive chemicals is a heavy burden for the foil manufacturers. The current work innovatively applies diffusion dialysis (DD) to selectively remove the chloride from this abandoned solution, which makes the reuse of these chemicals possible. In the process, Cl− ion presents a superior permeability compared with adipate2− ion, and a high permselectivity of 6 is obtained by using conventional anion exchange membranes. The effects of flow intensity and chloride concentration on the selective dechlorination performance have been thoroughly studied, respectively. Furthermore, the long-term stability of the membranes has been carefully investigated, and their performance is unchanged during a six-month period. The overall economics of this new process is very encouraging, and a stunningly short pay-off period (43 days) is achieved. This work not only solves the problem of reusing the exhausted adipate bath solution, but also further demonstrates the great potential of the DD process in selective ion separation applications.

Turkey: Evonik & Ege Kimya – precipitated silica

Aluminum electrode foils are the most essential components inside electrolytic capacitors, which are widely used in diverse electronic systems. The production involves the usage of various chemicals, and it generates a huge amount of exhausted bath solution consisting of highly-concentrated ammonium adipate and trace Cl− impurity. The loss of these expensive chemicals is a heavy burden for the foil manufacturers. The current work innovatively applies diffusion dialysis (DD) to selectively remove the chloride from this abandoned solution, which makes the reuse of these chemicals possible. In the process, Cl− ion presents a superior permeability compared with adipate2− ion, and a high permselectivity of 6 is obtained by using conventional anion exchange membranes. The effects of flow intensity and chloride concentration on the selective dechlorination performance have been thoroughly studied, respectively. Furthermore, the long-term stability of the membranes has been carefully investigated, and their performance is unchanged during a six-month period. The overall economics of this new process is very encouraging, and a stunningly short pay-off period (43 days) is achieved. This work not only solves the problem of reusing the exhausted adipate bath solution, but also further demonstrates the great potential of the DD process in selective ion separation applications.

Enhanced electrocatalytic hydrodechlorination of 2,4-dichlorophenoxyacetic acid by a Pd-Co3O4/Ni foam electrode.

A new Pd-Co3O4/Ni foam electrode was synthesized by a facile two-step method comprising co-electrodeposition and calcination. Compared with Ni foam-supported Pd electrodes obtained by electrodeposition or chemical deposition, the new Pd-Co3O4/Ni foam electrode exhibited greatly enhanced catalytic hydrodechlorination activity. The introduction of Co3O4 reduced the amount of Pd required. For the same degree of dechlorination of 2,4-D, only 25% of the Pd was required in the Pd-Co3O4/Ni foam electrode compared with the Ni foam electrode prepared by chemical deposition. Various characterizations indicated that Co3O4 on the surface of the Ni foam enhanced catalytic performance through accelerated generation of atomic H*. In addition, the good distribution of macropores, providing a larger specific surface area and lower electron transfer impedance, enabled more adsorption of atomic .

Fabrication of mediator-free g-C3N4/Bi2WO6 Z-scheme with enhanced photocatalytic reduction dechlorination performance of 2,4-DCP

Chlorophenols (CPs) have been considered as a kind of priority environmental pollutants for their potential detrimental effects, and photocatalytic reduction dechlorination tend to be a promising approach to CPs’ removal. In this work, 2,4-dichlorophenol (2,4-DCP) was adopted as the model pollutant of CPs, and a simple mixing and heating method was employed to prepare graphitic carbon nitride and bismuth tungstate (g-C3N4/Bi2WO6) binary photocatalysts. Under UV–vis light irradiation and anoxic atmosphere, the g-C3N4/Bi2WO6 samples exhibited enhanced photocatalytic activities. The optimal dechlorination rate constant of 2,4-DCP over g-C3N4/Bi2WO6 (weight ratio 3:7) was 1.13 h−1, 7.6 and 8.9 times higher than that of pristine g-C3N4 and Bi2WO6 respectively. The enhanced activities originated from the effective suppression of charge recombination and extended spectrum absorption range. Kinetic studies revealed that the dechlorination processes followed the pseudo-first-order model. The photocatalytic mechanism of 2,4-DCP over g-C3N4/Bi2WO6 was discussed in detail, and based on which, a mediator-free Z-scheme mechanism was proposed. This work extends the application range of g-C3N4/Bi2WO6 photocatalyst and provides a new insight into environmental remediation.

Polydopamine enabled palladium loaded nanofibrous membrane and its catalytic performance for trichloroethene dechlorination

We report a facile and green approach for the synthesis of novel Pd-loaded nanofibrous membrane and its catalytic performance for dechlorinating trichloroethylene. An analogue of mussel adhesive protein, polydopamine (PDA), was used as an active and green platform for the in situ Pd reduction by taking advantage of its high adhesion and reducing activity. A PDA layer was firstly coated on the surface of a nanofibrous membrane. Soaking this PDA-coated membrane into Pd solution led to spontaneous generation of Pd nanoparticles. The resulting membrane achieved a Pd loading of 4.56 wt.%. When applied for treating trichloroethylene in an aqueous solution, the Pd-loaded nanofibrous membrane showed excellent dechlorination performance (degree of TCE dechlorination can reach up to 96.5 (±0.32) %) with high recyclability.

The important role of polyvinylpyrrolidone and Cu on enhancing dechlorination of 2,4-dichlorophenol by Cu/Fe nanoparticles: Performance and mechanism study

The important role of polyvinylpyrrolidone (PVP) and Cu on the reductive dechlorination of 2,4-dichlorophenol (2,4-DCP) by Cu/Fe bimetal nanoparticles has been investigated. The synthesized PVP coated Cu/Fe bimetal nanoparticles with different Cu/Fe ratios were systematically characterized by FTIR, XRD, TEM and magnetic hysteresis loops. The Cu/Fe ratio and the PVP loading were optimized for dechlorination performance, and the optimum ratio of PVP to Cu/Fe was found to be 0.35 and the content of Cu in Cu/Fe nanoparticles was 41%. The presence of PVP as a dispersant/stabilizer results in a highly-dispersed Cu/Fe NPs and increase the reactivity of Cu/Fe NPs for 2,4-DCP removal. The dechlorination rate was enhanced at lower pH and higher temperature conditions. The presence of humic acid, PO43–, NO3–, SO42– leads to a slightly decreased removal efficiency of 2,4-DCP. The magnetic property of PVP-Cu/Fe nanoparticles allows rapid magnetic separation of the catalysts after reaction. A galvanic corrosion model was proposed where iron corrodes and transfers electrons to Cu-rich catalytic regions of the nanoparticles, and finally accelerating the reduction efficiency of 2,4-DCP.

Effects of Sulfate Reduction on Trichloroethene Dechlorination by Dehalococcoides-Containing Microbial Communities.

In order to elucidate interactions between sulfate reduction and dechlorination, we systematically evaluated the effects of different concentrations of sulfate and sulfide on reductive dechlorination by isolates, constructed consortia, and enrichments containing Dehalococcoides sp. Sulfate (up to 5 mM) did not inhibit the growth or metabolism of pure cultures of the dechlorinator Dehalococcoides mccartyi 195, the sulfate reducer Desulfovibrio vulgaris Hildenborough, or the syntroph Syntrophomonas wolfei In contrast, sulfide at 5 mM exhibited inhibitory effects on growth of the sulfate reducer and the syntroph, as well as on both dechlorination and growth rates of D. mccartyi Transcriptomic analysis of D. mccartyi 195 revealed that genes encoding ATP synthase, biosynthesis, and Hym hydrogenase were downregulated during sulfide inhibition, whereas genes encoding metal-containing enzymes involved in energy metabolism were upregulated even though the activity of those enzymes (hydrogenases) was inhibited. When the electron acceptor (trichloroethene) was limiting and an electron donor (lactate) was provided in excess to cocultures and enrichments, high sulfate concentrations (5 mM) inhibited reductive dechlorination due to the toxicity of generated sulfide. The initial cell ratio of sulfate reducers to D. mccartyi (1:3, 1:1, or 3:1) did not affect the dechlorination performance in the presence of sulfate (2 and 5 mM). In contrast, under electron donor limitation, dechlorination was not affected by sulfate amendments due to low sulfide production, demonstrating that D. mccartyi can function effectively in anaerobic microbial communities containing moderate sulfate concentrations (5 mM), likely due to its ability to outcompete other hydrogen-consuming bacteria and archaea.IMPORTANCE Sulfate is common in subsurface environments and has been reported as a cocontaminant with chlorinated solvents at various concentrations. Inconsistent results for the effects of sulfate inhibition on the performance of dechlorination enrichment cultures have been reported in the literature. These inconsistent findings make it difficult to understand potential mechanisms of sulfate inhibition and complicate the interpretation of bioremediation field data. In order to elucidate interactions between sulfate reduction and reductive dechlorination, this study systematically evaluated the effects of different concentrations of sulfate and sulfide on reductive dechlorination by isolates, constructed consortia, and enrichments containing Dehalococcoides sp. This study provides a more fundamental understanding of the competition mechanisms between reductive dechlorination by Dehalococcoides mccartyi and sulfate reduction during the bioremediation process. It also provides insights on the significance of sulfate concentrations on reductive dechlorination under electron donor/acceptor-limiting conditions during in situ bioremediation applications. For example, at a trichloroethene-contaminated site with a high sulfate concentration, proper slow-releasing electron donors can be selected to generate an electron donor-limiting environment that favors reductive dechlorination and minimizes the sulfide inhibition effect.

A quint-wavelength UV spectroscopy for simultaneous determination of dichlorobenzene, chlorobenzene, and benzene in simulated water reduced by nanoscale zero-valent Fe/Ni bimetal

A quint-wavelength UV spectroscopy for rapid determination of dichlorobenzene (DCB), chlorobenzene (CB) and benzene (B) was developed for the dechlorination process of DCB reduced by nanoscale zero-valent Fe/Ni bimetal. Based on the absorbance measurements at 260, 269, 277, 290 and 300nm, the equations for calculating the concentration of DCB and CB and B were established, in which the spectral interference from the nanoparticles could be effectively minimized. The results show that the present method has a good measurement precision (the relative standard deviations are within 2.0%) and accuracy (the recoveries are between 89 and 111%) in the DCB, CB and B's quantification. The present method is simple, rapid, and such a methodology is very suitable to be used for evaluating the dechlorination performance of chlorinated aromatic compounds in the presence of bimetal nanoparticle.

Modification of a Pd-loaded electrode with a carbon nanotubes–polypyrrole interlayer and its dechlorination performance for 2,3-dichlorophenol

A novel Pd loaded Ti electrode was prepared with a carbon nanotubes and polypyrrole interlayer modification, referred to as a Pd/CNTs–PPy/Ti electrode with high electrocatalytic activity for dechlorination.

Hydrothermal carbonization of medical wastes and lignocellulosic biomass for solid fuel production from lab-scale to pilot-scale

An alternative way has been proposed for the PVC-containing medical wastes valorization by co-hydrothermal carbonization (HTC) with lignocellulosic biomass. The organic-Cl in PVC can be converted to the inorganic-Cl via hydrolysis, defunctionalization, recondensation, and aromatization in the HTC process. Followed by the washing process with the condensed water, the inorganic-Cl with high water-solubility could be removed from the solid products (i.e. hydrochar). Lignin as a biomass component can significantly improve the dechlorination efficiency of PVC in the HTC process. Here, the dechlorination performance of lignocellulosic components is given as the following order: lignin > cellulose > hemicellulose. In addition, lignin can adjust the particle sizes of solid products by inhibiting the agglomeration in the order of lignin > hemicellulose > cellulose. In the pilot-scale HTC process, the addition of woodchips improves the dechlorination efficiency of hospital wastes (HW). The hydrochar particles with low-chlorine content and higher heating value could be used as a clean coal-alternative fuel.

Improvement of electrochemical reductive dechlorination of 2,4-dichlorophenoxyacetic acid using palladium catalysts prepared by a pulsed electrodeposition method

A nickel-foam, supporting palladium particles (PE-Pd/foam-Ni), was fabricated by pulsed electrodeposition. The PE-Pd/foam-Ni was proven to be a promising electrode for electro-catalytic reductive dechlorination of 2,4-dichlorophenoxyacetic acid (2,4-D) in aqueous solution. Compared to the traditional chemical deposition of palladium on a foam-nickel electrode, the PE-Pd/foam-Ni exhibits markedly improved removal efficiency and current efficiency (CE) for the dechlorination of 2,4-D. The PE-Pd/foam-Ni electrode with 0.67mg Pd loading could achieve a maximum 2,4-D removal efficiency of 98% and a CE of 14% after 3h at a current density of 1.5mAcm−2. Moreover, the PE-Pd/foam-Ni maintained stable performance throughout three successive recyclability tests. As supported by physical-chemical characterization, the palladium catalysts originated from pulse electrodeposition possess a higher percentage of exposed {111} facets and a higher number of low-coordinated (edge/corner) sites, associated with a smaller particle size, in comparison with catalysts obtained from chemical deposition. Since the palladium atoms located on the edge/corner sites facilitate the catalytic reaction and the exposed {111} facets favor the generation and stabilization of chemisorbed active hydrogen, the enhanced electrocatalytic dechlorination performance of PE-Pd/foam-Ni electrode can be ascribed to the improved intrinsic properties of the Pd catalyst.