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Boparai HK, El-Sharnouby O, O'Carroll DM. Catalytic dechlorination of 1,2-DCA in nano Cu 0-borohydride system: effects of Cu 0/Cu n+ ratio, surface poisoning, and regeneration of Cu 0 sites. Sci Rep 2023; 13:11883. [PMID: 37482593 PMCID: PMC10363550 DOI: 10.1038/s41598-023-38678-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 07/12/2023] [Indexed: 07/25/2023] Open
Abstract
Aqueous-phase catalyzed reduction of organic contaminants via zerovalent copper nanoparticles (nCu0), coupled with borohydride (hydrogen donor), has shown promising results. So far, the research on nCu0 as a remedial treatment has focused mainly on contaminant removal efficiencies and degradation mechanisms. Our study has examined the effects of Cu0/Cun+ ratio, surface poisoning (presence of chloride, sulfides, humic acid (HA)), and regeneration of Cu0 sites on catalytic dechlorination of aqueous-phase 1,2-dichloroethane (1,2-DCA) via nCu0-borohydride. Scanning electron microscopy confirmed the nano size and quasi-spherical shape of nCu0 particles. X-ray diffraction confirmed the presence of Cu0 and Cu2O and x-ray photoelectron spectroscopy also provided the Cu0/Cun+ ratios. Reactivity experiments showed that nCu0 was incapable of utilizing H2 from borohydride left over during nCu0 synthesis and, hence, additional borohydride was essential for 1,2-DCA dechlorination. Washing the nCu0 particles improved their Cu0/Cun+ ratio (1.27) and 92% 1,2-DCA was removed in 7 h with kobs = 0.345 h-1 as compared to only 44% by unwashed nCu0 (0.158 h-1) with Cu0/Cun+ ratio of 0.59, in the presence of borohydride. The presence of chloride (1000-2000 mg L-1), sulfides (0.4-4 mg L-1), and HA (10-30 mg L-1) suppressed 1,2-DCA dechlorination; which was improved by additional borohydride probably via regeneration of Cu0 sites. Coating the particles decreased their catalytic dechlorination efficiency. 85-90% of the removed 1,2-DCA was recovered as chloride. Chloroethane and ethane were main dechlorination products indicating hydrogenolysis as the major pathway. Our results imply that synthesis parameters and groundwater solutes control nCu0 catalytic activity by altering its physico-chemical properties. Thus, these factors should be considered to develop an efficient remedial design for practical applications of nCu0-borohydride.
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Affiliation(s)
- Hardiljeet Kaur Boparai
- Department of Civil and Environmental Engineering, Western University, 1151 Richmond Rd, London, ON, N6A 5B8, Canada
- Department of Civil and Mineral Engineering, University of Toronto, 35 St. George Street, Toronto, ON, M5S 1A4, Canada
| | - Omneya El-Sharnouby
- Department of Civil and Environmental Engineering, Western University, 1151 Richmond Rd, London, ON, N6A 5B8, Canada
| | - Denis M O'Carroll
- School of Civil and Environmental Engineering, Water Research Laboratory, University of New South Wales, Sydney, NSW, 2052, Australia.
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2
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Hyldegaard BH, Ottosen LM, Alshawabkeh AN. Transformation of tetrachloroethylene in a flow-through electrochemical reactor. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 707:135566. [PMID: 31767295 PMCID: PMC6980996 DOI: 10.1016/j.scitotenv.2019.135566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 11/04/2019] [Accepted: 11/15/2019] [Indexed: 06/10/2023]
Abstract
Electrochemical transformation of harmful tetrachloroethylene (PCE) is evaluated as a method for management of groundwater plumes to protect the drinking water resource, its consumers and the environment. In contrast to previous work that reported transformation of trichloroethylene, a byproduct of PCE, this work focuses on transformation of PCE in a saturated porous matrix and the influence of design parameters on the removal performance. Design parameters investigated were electrode configuration, catalyst load, electrode spacing, current intensity, orientation of reactor and flow through a porous matrix. A removal of 86% was reached in the fully liquid-filled, horizontally oriented reactor at a current of 120 mA across a cathode → bipolar electrode → anode arrangement with a Darcy velocity of 0.03 cm/min (150 m/yr). The palladium load on the cathode significantly influenced the removal. Enhanced removal was observed with increased electrode spacing. Presence of an inert porous matrix improved PCE removal by 9%-point compared to a completely liquid-filled reactor. Normalization of the data indicated, that a higher charge transfer per contaminant mass is required for removal of low PCE concentrations. No chlorinated intermediates were formed. The results suggest, that PCE can be electrochemically transformed in reactor designs replicating that of a potential field-implementation. Further work is required to better understand the reduction and oxidation processes established and the parameters influencing such. This knowledge is essential for optimization towards testing in complex conditions and variations of contaminated sites.
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Affiliation(s)
- Bente H Hyldegaard
- Department of Waste & Contaminated Sites, COWI, Parallelvej 2, 2800 Kgs. Lyngby, Denmark; Department of Civil Engineering, Brovej, Building 118, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark; Department of Civil & Environmental Engineering, 501 Stearns, 360 Huntington Avenue, Boston, MA 02115, United States of America.
| | - Lisbeth M Ottosen
- Department of Civil Engineering, Brovej, Building 118, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Akram N Alshawabkeh
- Department of Civil & Environmental Engineering, 501 Stearns, 360 Huntington Avenue, Boston, MA 02115, United States of America
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3
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Hyldegaard BH, Jakobsen R, Ottosen LM. Electrochemical transformation of an aged tetrachloroethylene contamination in realistic aquifer settings. CHEMOSPHERE 2020; 243:125340. [PMID: 31760284 DOI: 10.1016/j.chemosphere.2019.125340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 11/06/2019] [Accepted: 11/07/2019] [Indexed: 06/10/2023]
Abstract
Electrochemical removal of chlorinated ethenes in groundwater plumes may potentially overcome some of the challenges faced by current remediation technologies. So far, studies have been conducted in simplified settings of synthetic groundwater and inert porous matrices. This study is a stepwise investigation of the influence of field-extracted groundwater, sandy sediment and groundwater aquifer temperatures on the removal of an aged partially degraded contamination of tetrachloroethylene (PCE) at a typical groundwater flow rate. The aim is to assess the potential for applying electrochemistry at contaminated sites. At a constant current of 120 mA, pH and conductivity were unaffected downgradient the electrochemical zone. Major groundwater species were reduced and oxidized. Some minerals deposited, others dissolved. Hydrogen peroxide, a strong oxidant, was formed in levels up to 5 mg L-1 with a limited distribution into the sandy sediment. Trichloromethane was formed, supposedly by oxidation of organic matter in the sandy sediment in the presence of chloride. The more realistic the settings, the higher the PCE removal, bringing concentrations down to 7.8 ± 2.3 μg L-1. A complete removal of trichloroethylene and cis-1,2-dichloroethylene was obtained. The results suggest that competing reactions related to the natural complex hydrogeochemistry are insignificant in terms of affecting the electrochemical degradation of PCE and chlorinated intermediates.
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Affiliation(s)
- Bente H Hyldegaard
- Department of Waste & Contaminated Sites, COWI A/S, Parallelvej 2, 2800, Kgs. Lyngby, Denmark; Department of Civil Engineering, Brovej, Building 118, Technical University of Denmark, 2800, Kgs. Lyngby, Denmark.
| | - Rasmus Jakobsen
- Department of Geochemistry, Geological Survey of Denmark and Greenland, Øster Voldgade 10, 1350, København K, Denmark
| | - Lisbeth M Ottosen
- Department of Civil Engineering, Brovej, Building 118, Technical University of Denmark, 2800, Kgs. Lyngby, Denmark
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4
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Hyldegaard BH, Jakobsen R, Weeth EB, Overheu ND, Gent DB, Ottosen LM. Challenges in electrochemical remediation of chlorinated solvents in natural groundwater aquifer settings. JOURNAL OF HAZARDOUS MATERIALS 2019; 368:680-688. [PMID: 30735892 DOI: 10.1016/j.jhazmat.2018.12.064] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 12/09/2018] [Accepted: 12/17/2018] [Indexed: 06/09/2023]
Abstract
Establishment of electrochemical zones for remediation of dissolved chlorinated solvents in natural settings was studied. An undivided 1D-experimental column set-up was designed for the assessment of the influence of site-extracted contaminated groundwater flowing through a sandy aquifer material, on the execution of laboratory testing. A three-electrode system composed of palladium coated pure iron cathodes and a cast iron anode was operated at 12 mA under varying flow rates. The natural settings added complexity through a diverse groundwater chemistry and resistance in the sand. In addition, significant precipitation of iron released through anode corrosion was observed. Nevertheless, the complex system was successfully modelled with a simple geochemical model using PHREEQC. A ranking of the significances of system parameters on the laboratory execution of electrochemical remediation in natural settings was proposed: Geological properties > anode corrosion > site-extracted contaminated groundwater > the carbonate system > sulphate > hydrology > less significant unidentified parameters. This study provides insight in actual challenges that need to be overcome for in situ electrochemical remediation.
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Affiliation(s)
- Bente H Hyldegaard
- COWI A/S, Department of Waste and Contaminated Sites, 2800 Kongens Lyngby, Denmark; DTU (Technical University of Denmark), Department of Civil Engineering, 2800 Kongens Lyngby, Denmark.
| | | | - Eline B Weeth
- COWI A/S, Department of Waste and Contaminated Sites, 2800 Kongens Lyngby, Denmark
| | - Niels D Overheu
- CRD (Capital Region of Denmark), Centre for Regional Development, 3400 Hillerød, Denmark
| | - David B Gent
- USACE (US Army Corps of Engineers), Engineer Research and Development Center, 39180 MS, United States
| | - Lisbeth M Ottosen
- DTU (Technical University of Denmark), Department of Civil Engineering, 2800 Kongens Lyngby, Denmark
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5
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Nazari R, Rajić L, Ciblak A, Hernández S, Mousa IE, Zhou W, Bhattacharyya D, Alshawabkeh AN. Immobilized palladium-catalyzed electro-Fenton's degradation of chlorobenzene in groundwater. CHEMOSPHERE 2019; 216:556-563. [PMID: 30390586 PMCID: PMC6293191 DOI: 10.1016/j.chemosphere.2018.10.143] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 10/17/2018] [Accepted: 10/19/2018] [Indexed: 05/23/2023]
Abstract
This study investigates the effect of palladium (Pd) form on the electrochemical degradation of chlorobenzene in groundwater by palladium-catalyzed electro-Fenton (EF) reaction. In batch and flow-through column reactors, EF was initiated via in-situ electrochemical formation of hydrogen peroxide (H2O2) supported by Pd on alumina powder or by palladized polyacrylic acid (PAA) in a polyvinylidene fluoride (PVDF) membrane (Pd-PVDF/PAA). In a mixed batch reactor containing 10 mg L-1 Fe2+, 2 g L-1 of catalyst in powder form (1% Pd, 20 mg L-1 of Pd) and an initial pH of 3, chlorobenzene was degraded under 120 mA current following a first-order decay rate showing 96% removal within 60 min. Under the same conditions, a rotating Pd-PVDF/PAA disk produced 88% of chlorobenzene degradation. In the column experiment with automatic pH adjustment, 71% of chlorobenzene was removed within 120 min with 10 mg L-1 Fe2+, and 2 g L-1 catalyst in pellet form (0.5% Pd, 10 mg L-1 of Pd) under 60 mA. The EF reaction can be achieved under flow, without external pH adjustment and H2O2 addition, and can be applied for in-situ groundwater treatment. Furthermore, the rotating PVDF-PAA membrane with immobilized Pd-catalyst showed an effective and low maintenance option for employing Pd catalyst for water treatment.
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Affiliation(s)
- Roya Nazari
- Department of Civil and Environmental Engineering, Northeastern University, 400 Snell Engineering, 360 Huntington Avenue, Boston, MA, 02115, USA
| | - Ljiljana Rajić
- Pioneer Valley Coral and Natural Science Institute, 1 Mill Valley Road, Hadley, MA, 01035, USA
| | - Ali Ciblak
- Geosyntec Consultants, 1255 Roberts Boulevard, suite 200, Kennesaw, GA, 30144, USA
| | - Sebastián Hernández
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, 40506, USA
| | - Ibrahim E Mousa
- Department of Environmental Biotechnology, Genetic Engineering and Biotechnology Research Institute, University of Sadat City, Menoufia, 22857, Egypt
| | - Wei Zhou
- Department of Civil and Environmental Engineering, Northeastern University, 400 Snell Engineering, 360 Huntington Avenue, Boston, MA, 02115, USA; Department of Energy Science and Engineering, Harbin Institute of Technology, Harbin, 150001, PR China
| | - Dibakar Bhattacharyya
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, 40506, USA
| | - Akram N Alshawabkeh
- Department of Civil and Environmental Engineering, Northeastern University, 400 Snell Engineering, 360 Huntington Avenue, Boston, MA, 02115, USA.
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6
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Frontistis Z, Mantzavinos D, Meriç S. Degradation of antibiotic ampicillin on boron-doped diamond anode using the combined electrochemical oxidation - Sodium persulfate process. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2018; 223:878-887. [PMID: 29990877 DOI: 10.1016/j.jenvman.2018.06.099] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 06/18/2018] [Accepted: 06/30/2018] [Indexed: 06/08/2023]
Abstract
In this work, the electrochemical oxidation of antibiotic ampicillin (AMP) on a boron-doped diamond anode in the presence of sodium persulfate (SPS) was investigated (EO/SPS process). Experiments were conducted at AMP concentrations between 0.8 and 3 mg/L, SPS concentrations between 100 and 500 mg/L, current densities between 5 and 110 mA/cm2, in three water matrices (ultrapure water, bottled water and secondary treated wastewater), using 0.1 M Na2SO4 as the supporting electrolyte. AMP degradation follows a pseudo-first order kinetic expression with the apparent rate constant increasing with (i) increasing SPS concentration (from 0.08 min-1 to 0.36 min-1 at 0 and 500 mg/L SPS, respectively, 1.1 mg/L AMP, 25 mA/cm2), (ii) increasing current (from 0.08 min-1 to 0.6 min-1 at 5 and 110 mA/cm2, respectively, 1.1 mg/L AMP, 250 mg/L SPS), and (iii) decreasing AMP concentration (from 0.16 min-1 to 0.31 min-1 at 3 and 0.8 mg/L, respectively, 250 mg/L SPS, 25 mA/cm2). The presence of various anions (mainly bicarbonates) in bottled water did not impact AMP degradation. The observed kinetic constant decreased by 40% in the presence of 10 mg/L humic acid. On the other hand, process efficiency was enhanced almost 3.5 times in secondary effluent due to the electrogeneration of active chlorine species that promote indirect oxidation reactions in the bulk solution. The efficacy of the EO/SPS process was compared to and found to be considerably greater than a process where SPS was activated by simulated solar irradiation at an intensity of 7.3 × 10-7 E/(L.s) (SLR/SPS process). Coupling the two processes (EO/SLR/SPS) resulted in a cumulative, in terms of AMP degradation, effect. The combined process was tested for AMP degradation, mineralization and inhibition to Vibrio fischeri in wastewater; fast AMP removal was accompanied by low mineralization and incomplete toxicity removal.
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Affiliation(s)
- Zacharias Frontistis
- Department of Environmental Engineering, University of Western Macedonia, GR-50100, Kozani, Greece.
| | - Dionissios Mantzavinos
- Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504, Patras, Greece
| | - Sureyya Meriç
- Department of Environmental Engineering, Tekirdag Namik Kemal University, Corlu 59860, Tekirdag, Turkey
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7
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Lei Y, Song B, Saakes M, van der Weijden RD, Buisman CJN. Interaction of calcium, phosphorus and natural organic matter in electrochemical recovery of phosphate. WATER RESEARCH 2018; 142:10-17. [PMID: 29807252 DOI: 10.1016/j.watres.2018.05.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 04/30/2018] [Accepted: 05/19/2018] [Indexed: 05/24/2023]
Abstract
To address the issues of eutrophication and the potential risk of phosphorus (P) shortage, it is essential to remove and recover P from P-containing streams to close this nutrient cycle. Electrochemical induced calcium phosphate (CaP) precipitation was shown to be an efficient method for P recovery. However, the influence of natural organic matter (NOM) is not known for this treatment. In this paper, the behavior of NOM and its effect on CaP precipitation was studied. In contrast to studies where NOM hindered CaP precipitation, results show that the interaction of NOM with CaP improves the removal of P, independent of the types of NOM. The P removal at the average increased from 43.8 ± 4.9% to 58.5 ± 1.2% in the presence of 1.0 mg L-1 NOM. Based on the yellow color of the CaP product, NOM is co-precipitated. The bulk solution pH with and without buffers has totally different effects on the precipitation process. Without buffer, CaP precipitates on the cathode surface in a wide pH range (pH 4.0-10.0). However, the precipitation process is completely inhibited when the bulk solution is buffered at pH 4.0 and 6.0. This is probably due to neutralization of OH- by the buffers. Regardless of the presence or absence of NOM and solution pH, the recovered products are mainly amorphous CaP unless the electrolysis time was increased to seven days with 4.0 A m-2, in which crystalline CaP formed. These findings advance our understanding on the interaction of Ca, P and NOM species for the application of electrochemical method for P recovery from real wastewater.
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Affiliation(s)
- Yang Lei
- Wetsus, Centre of Excellence for Sustainable Water Technology, P.O. Box 1113, 8900CC Leeuwarden, The Netherlands; Sub-department Environmental Technology, Wageningen University and Research, P.O. Box 17, 6700AA Wageningen, The Netherlands.
| | - Bingnan Song
- Sub-department Environmental Technology, Wageningen University and Research, P.O. Box 17, 6700AA Wageningen, The Netherlands
| | - Michel Saakes
- Wetsus, Centre of Excellence for Sustainable Water Technology, P.O. Box 1113, 8900CC Leeuwarden, The Netherlands
| | - Renata D van der Weijden
- Wetsus, Centre of Excellence for Sustainable Water Technology, P.O. Box 1113, 8900CC Leeuwarden, The Netherlands; Sub-department Environmental Technology, Wageningen University and Research, P.O. Box 17, 6700AA Wageningen, The Netherlands.
| | - Cees J N Buisman
- Wetsus, Centre of Excellence for Sustainable Water Technology, P.O. Box 1113, 8900CC Leeuwarden, The Netherlands; Sub-department Environmental Technology, Wageningen University and Research, P.O. Box 17, 6700AA Wageningen, The Netherlands
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8
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Liu B, Zhang H, Lu Q, Li G, Zhang F. A CuNi bimetallic cathode with nanostructured copper array for enhanced hydrodechlorination of trichloroethylene (TCE). THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 635:1417-1425. [PMID: 29710594 DOI: 10.1016/j.scitotenv.2018.04.238] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 04/01/2018] [Accepted: 04/17/2018] [Indexed: 06/08/2023]
Abstract
To address the challenges of low hydrodechlorination efficiency by non-noble metals, a CuNi bimetallic cathode with nanostructured copper array film was fabricated for effective electrochemical dechlorination of trichloroethylene (TCE) in aqueous solution. The CuNi bimetallic cathodes were prepared by a simple one-step electrodeposition of copper onto the Ni foam substrate, with various electrodeposition time of 5/10/15/20 min. The optimum electrodeposition time was 10 min when copper was coated as a uniform nanosheet array on the nickel foam substrate surface. This cathode exhibited the highest TCE removal, which was twice higher compared to that of the nickel foam cathode. At the same passed charge of 1080C, TCE removal increased from 33.9 ± 3.3% to 99.7 ± 0.1% with the increasing operation current from 5 to 20 mA cm-2, while the normalized energy consumption decreased from 15.1 ± 1.0 to 2.6 ± 0.01 kWh log-1 m-3. The decreased normalized energy consumption at a higher current density was due to the much higher removal efficiency at a higher current. These results suggest that CuNi cathodes prepared by simple electrodeposition method represent a promising and cost-effective approach for enhanced electrochemical dechlorination.
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Affiliation(s)
- Bo Liu
- School of Environment and State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China.
| | - Hao Zhang
- School of Environment and State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China
| | - Qi Lu
- Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.
| | - Guanghe Li
- School of Environment and State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China.
| | - Fang Zhang
- School of Environment and State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China.
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9
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Gayen P, Spataro J, Avasarala S, Ali AM, Cerrato JM, Chaplin BP. Electrocatalytic Reduction of Nitrate Using Magnéli Phase TiO 2 Reactive Electrochemical Membranes Doped with Pd-Based Catalysts. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:9370-9379. [PMID: 30039962 DOI: 10.1021/acs.est.8b03038] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
This research focused on synthesis, characterization, and application of point-of-use catalytic reactive electrochemical membranes (REMs) for electrocatalytic NO3- reduction. Deposition of Pd-Cu and Pd-In catalysts to the REMs produced catalytic REMs (i.e., Pd-Cu/REM and Pd-In/REM) that were active for NO3- reduction. Optimal performance was achieved with a Pd-Cu/REM and upstream counter electrode, which reduced NO3- from 1.0 mM to below the EPAs regulatory MCL (700 μM) in a single pass through the REM (residence time ∼2 s), obtaining product selectivity of <2% toward NO2-/NH3. Nitrate reduction was not affected by dissolved oxygen and carbonate species and only slightly decreased in a surface water sample due to Ca2+ and Mg2+ scaling. Energy consumption to treat surface water was 1.1 to 1.3 kWh mol-1 for 1 mM NO3- concentrations, and decreased to 0.19 and 0.12 kWh mol-1 for 10 and 100 mM NaNO3 solutions, respectively. Electrocatalytic reduction kinetics were shown to be an order of magnitude higher than catalytic NO3- reduction kinetics. Conversion of up to 67% of NO3-, with low NO2- (0.7-11 μM) and NH3 formation (<10 μM), and low energy consumption obtained in this study suggest that Pd-Cu/REMs are a promising technology for distributed water treatment.
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Affiliation(s)
- Pralay Gayen
- Department of Chemical Engineering , University of Illinois at Chicago , 810 South Clinton Street , Chicago , Illinois 60607 , United States
| | - Jason Spataro
- Department of Chemical Engineering , University of Illinois at Chicago , 810 South Clinton Street , Chicago , Illinois 60607 , United States
| | - Sumant Avasarala
- Department of Civil Engineering, MSC01 1070 , University of New Mexico , Albuquerque , New Mexico 87131 , United States
| | - Abdul-Mehdi Ali
- Department of Earth and Planetary Sciences, MSC03 2040 , University of New Mexico , Albuquerque , New Mexico 87131 , United States
| | - José M Cerrato
- Department of Civil Engineering, MSC01 1070 , University of New Mexico , Albuquerque , New Mexico 87131 , United States
| | - Brian P Chaplin
- Department of Chemical Engineering , University of Illinois at Chicago , 810 South Clinton Street , Chicago , Illinois 60607 , United States
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10
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Fallahpour N, Mao X, Rajic L, Yuan S, Alshawabkeh AN. Electrochemical dechlorination of trichloroethylene in the presence of natural organic matter, metal ions and nitrates in a simulated karst media. JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING 2017; 5:240-245. [PMID: 29744302 PMCID: PMC5937535 DOI: 10.1016/j.jece.2016.11.046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A small-scale flow-through limestone column was used to evaluate the effect of common coexisting organic and inorganic compounds on the electrochemical dechlorination of trichloroethylene (TCE) in karst media. Iron anode was used to produce ferrous ions and promote reducing conditions in the column. The reduction of TCE under 90 mA current, 1 mL min-1 flow rate, and 1 mg L-1 initial TCE concentration, was inhibited in the presence of humic acids due to competition for direct electron transfer and/or reaction with atomic hydrogen produced at the cathode surface by water electrolysis. Similarly, presence of 10 mg L-1 chromate decreased TCE reduction rate to 53%. The hexavalent chromium was completely reduced to trivalent chromium due to the ferrous species produced from iron anode. Presence of 5 mg L-1 selenate decreased the removal of TCE by 10%. Chromium and selenate complexation with dissolved iron results in formation of aggregates, which cover the electrodes surface and reduce TCE dechlorination rate. Presence of 40 mg L-1 nitrates caused reductive transformation of TCE up to 80%. Therefore, TCE removal is influenced by the presence of other contaminants that are present as a mixture in groundwater in the following order: humic acid, chromate, selenate, and nitrate.
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Affiliation(s)
- Noushin Fallahpour
- Civil and Environmental Engineering Department, Northeastern University, Boston, MA, 02115, USA
| | - Xuhui Mao
- Civil and Environmental Engineering Department, Northeastern University, Boston, MA, 02115, USA
- School of Resource and Environmental Science. Wuhan University, Wuhan City, 430072, P. R. China
| | - Ljiljana Rajic
- Civil and Environmental Engineering Department, Northeastern University, Boston, MA, 02115, USA
| | - Songhu Yuan
- Civil and Environmental Engineering Department, Northeastern University, Boston, MA, 02115, USA
- State Key Lab of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, P. R. China
| | - Akram N. Alshawabkeh
- Civil and Environmental Engineering Department, Northeastern University, Boston, MA, 02115, USA
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11
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Rajic L, Fallahpour N, Podlaha E, Alshawabkeh A. The influence of cathode material on electrochemical degradation of trichloroethylene in aqueous solution. CHEMOSPHERE 2016; 147:98-104. [PMID: 26761603 PMCID: PMC4742380 DOI: 10.1016/j.chemosphere.2015.12.095] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 12/22/2015] [Accepted: 12/23/2015] [Indexed: 05/11/2023]
Abstract
In this study, different cathode materials were evaluated for electrochemical degradation of aqueous phase trichloroethylene (TCE). A cathode followed by an anode electrode sequence was used to support reduction of TCE at the cathode via hydrodechlorination (HDC). The performance of iron (Fe), copper (Cu), nickel (Ni), aluminum (Al) and carbon (C) foam cathodes was evaluated. We tested commercially available foam materials, which provide large electrode surface area and important properties for field application of the technology. Ni foam cathode produced the highest TCE removal (68.4%) due to its high electrocatalytic activity for hydrogen generation and promotion of HDC. Different performances of the cathode materials originate from differences in the bond strength between atomic hydrogen and the material. With a higher electrocatalytic activity than Ni, Pd catalyst (used as cathode coating) increased TCE removal from 43.5% to 99.8% for Fe, from 56.2% to 79.6% for Cu, from 68.4% to 78.4% for Ni, from 42.0% to 63.6% for Al and from 64.9% to 86.2% for C cathode. The performance of the palladized Fe foam cathode was tested for degradation of TCE in the presence of nitrates, as another commonly found groundwater species. TCE removal decreased from 99% to 41.2% in presence of 100 mg L(-1) of nitrates due to the competition with TCE for HDC at the cathode. The results indicate that the cathode material affects TCE removal rate while the Pd catalyst significantly enhances cathode activity to degrade TCE via HDC.
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Affiliation(s)
- Ljiljana Rajic
- Department of Civil and Environmental Engineering, Northeastern University, Boston, MA 02115, USA
| | - Noushin Fallahpour
- Department of Civil and Environmental Engineering, Northeastern University, Boston, MA 02115, USA
| | - Elizabeth Podlaha
- Department of Chemical Engineering, Northeastern University, Boston, MA 02115, USA
| | - Akram Alshawabkeh
- Department of Civil and Environmental Engineering, Northeastern University, Boston, MA 02115, USA.
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