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Xiang T, Liang Y, Zeng Y, Deng J, Yuan J, Xiong W, Song B, Zhou C, Yang Y. Transition Metal Single-Atom Catalysts for the Electrocatalytic Nitrate Reduction: Mechanism, Synthesis, Characterization, Application, and Prospects. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2303732. [PMID: 37300329 DOI: 10.1002/smll.202303732] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 05/30/2023] [Indexed: 06/12/2023]
Abstract
Excessive accumulation of nitrate in the environment will affect human health. To combat nitrate pollution, chemical, biological, and physical technologies have been developed recently. The researcher favors electrocatalytic reduction nitrate reaction (NO3 RR) because of the low post-treatment cost and simple treatment conditions. Single-atom catalysts (SACs) offer great activity, exceptional selectivity, and enhanced stability in the field of NO3 RR because of their high atomic usage and distinctive structural characteristics. Recently, efficient transition metal-based SACs (TM-SACs) have emerged as promising candidates for NO3 RR. However, the real active sites of TM-SACs applied to NO3 RR and the key factors controlling catalytic performance in the reaction process remain ambiguous. Further understanding of the catalytic mechanism of TM-SACs applied to NO3 RR is of practical significance for exploring the design of stable and efficient SACs. In this review, from experimental and theoretical studies, the reaction mechanism, rate-determining steps, and essential variables affecting activity and selectivity are examined. The performance of SACs in terms of NO3 RR, characterization, and synthesis is then discussed. In order to promote and comprehend NO3 RR on TM-SACs, the design of TM-SACs is finally highlighted, together with the current problems, their remedies, and the way forward.
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Affiliation(s)
- Tianyi Xiang
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, P. R. China
| | - Yuntao Liang
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, P. R. China
| | - Yuxi Zeng
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, P. R. China
| | - Jie Deng
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, P. R. China
| | - Jili Yuan
- Department of Polymer Materials and Engineering, College of Materials and Metallurgy, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Weiping Xiong
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, P. R. China
| | - Biao Song
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, P. R. China
| | - Chengyun Zhou
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, P. R. China
- Jiangxi Province Key Laboratory of Drinking Water Safety, Nanchang, Jiangxi Province, 330013, P. R. China
| | - Yang Yang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada
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Li Y, Xie S, Yao J. Singlet oxygen generation for selective oxidation of emerging pollutants in a flow-by electrochemical system based on natural air diffusion cathode. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:17854-17864. [PMID: 36201074 DOI: 10.1007/s11356-022-23364-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Accepted: 09/26/2022] [Indexed: 06/16/2023]
Abstract
The decay of free radicals involved in side reactions is one of the challenges faced by electrochemical degradation of organic pollutants. To this end, a non-radical oxidation system was constructed by a natural air diffusion cathode (ADC) and a Ti-based dimensional stable anode coated by RuO2 (RuO2-Ti anode) for cathodic hydrogen peroxide activation by anodic chlorine evolution. The ADC fabricated by the carbon black of BP2000 produced a stable concentration of hydrogen peroxide of 339.94 mg L-1 (current efficiency of 73.4%) without aeration, which was superior to the cathode made by the XC72 carbon black. The flow-by ADC-RuO2 system consisted of an ADC and a RuO2-Ti anode showed high selectivity to aniline (AN) compared to benzoate (BA) in a NaCl electrolyte, whose degradation efficiencies were 97.72% and 1.3%, respectively. Rapid degradations of a mixture of emerging pollutants and AN were also observed in the ADC-RuO2 system, with pseudo-first-order kinetic constants of 0.51, 1.29, 0.89, and 0.99 min-1 for Bisphenol A (BPA), tetracycline (TC), sulfamethoxazole (SMX) and AN, respectively. Quenching experiments revealed the main reactive oxygen species for the pollutant degradation was singlet oxygen (1O2), which was also identified by the electron spin resonance (ESR) analysis. Finally, the steady-stable content of 1O2 was quantitatively determined to be 6.25 × 10-11 M by the method of furfuryl alcohol (FFA) probe. Our findings provide a fast, low energy consumption and well controlled electrochemical oxidation method for selective degradation of organic pollutants. H2O2 generated on an air diffusion cathode by naturally diffused O2, reacts with ClO- produced from chloride oxidation on the RuO2-Ti anode to form singlet oxygen (1O2). The electrochemical system shows an efficient oxidation to electron-rich emerging pollutants including bisphenol A, tetracycline, sulfamethoxazole and aniline, but a poor performance on the electron-deficient compounds (e.g., benzoate).
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Affiliation(s)
- Yi Li
- School of Urban Construction, Wuhan University of Science and Technology, Wuhan, 430065, People's Republic of China
| | - Shiwei Xie
- School of Urban Construction, Wuhan University of Science and Technology, Wuhan, 430065, People's Republic of China.
- Institute of High Performance Engineering Structure, Wuhan University of Science and Technology, Wuhan, 430065, People's Republic of China.
| | - Jiaxiong Yao
- School of Urban Construction, Wuhan University of Science and Technology, Wuhan, 430065, People's Republic of China
- Shenzhen Bao'an Songgang Water Supply Co., Ltd., Shenzhen, 518100, People's Republic of China
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Kim JG, Kim HB, Lee S, Kwon EE, Baek K. Mechanistic investigation into flow-through electrochemical oxidation of sulfanilamide for groundwater using a graphite anode. CHEMOSPHERE 2022; 307:136106. [PMID: 35988764 DOI: 10.1016/j.chemosphere.2022.136106] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/28/2022] [Accepted: 08/15/2022] [Indexed: 06/15/2023]
Abstract
The technical effectiveness/merit of electrochemical oxidation (EO) has been recognized. Nonetheless, its practical application to groundwater remediation has not been fully implemented due to several technical challenges. To overcome the technical incompleteness, this study adopted a graphite anode in the flow-through system and studied the mechanistic roles of a graphite anode. To this end, groundwater contaminated with sulfanilamide was remediated by means of EO, and sulfanilamide oxidation was quantitatively determined in this study. Approximately 60% of sulfanilamide was degraded at the anode zone, and such observation offered that the removal of sulfanilamide was not closely related with current variations (10-100 mA). However, this study delineated that sulfanilamide removal is contingent on the flow speed. For example, the removal of sulfanilamide was lowered from 59 to 25% owing to a short contact time when the flow velocity was increased from 0.14 to 0.55 cm/min. This study also delineated that a shorter anode-cathode distance could offer a favorable chance to enhance the removal of sulfanilamide even under an identical current. A shorter distance could offer a chance to save energy due to the lower voltage operation. This study also offered that chloride (Cl-) and sulfate (SO42-) electrolytes served a crucial role in the generation of active species. In contrast, bicarbonate (HCO3-) and synthetic groundwater electrolytes impeded the oxidation rate because HCO3- scavenged the other active species. In an effort to seek the oxidation mechanisms of a graphite anode, scavenger, cyclic voltammetry test, and electron https://en.wikipedia.org/wiki/Electron_paramagnetic_resonanceparamagnetic resonance (EPR) analysis were done. From a series of the tests, it was inferred that a graphite anode did not directly affect the generation of the active species. Thus, the prevalence of the oxygenated functional groups on an anode surface could be the main mechanism in sulfanilamide removal due to the enhanced electron transfer.
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Affiliation(s)
- Jong-Gook Kim
- Department of Environment & Energy (BK21 FOUR), Jeonbuk National University, 567 Baekje-daero, Deokjin, Jeonju, Jeollabukdo, 54896, Republic of Korea; Soil Environment Research Center, Jeonbuk National University, 567 Baekje-daero, Deokjin, Jeonju, Jeollabukdo, 54896, Republic of Korea
| | - Hye-Bin Kim
- Department of Environment & Energy (BK21 FOUR), Jeonbuk National University, 567 Baekje-daero, Deokjin, Jeonju, Jeollabukdo, 54896, Republic of Korea; Soil Environment Research Center, Jeonbuk National University, 567 Baekje-daero, Deokjin, Jeonju, Jeollabukdo, 54896, Republic of Korea
| | - Sumin Lee
- Department of Environment & Energy (BK21 FOUR), Jeonbuk National University, 567 Baekje-daero, Deokjin, Jeonju, Jeollabukdo, 54896, Republic of Korea; Soil Environment Research Center, Jeonbuk National University, 567 Baekje-daero, Deokjin, Jeonju, Jeollabukdo, 54896, Republic of Korea
| | - Eilhann E Kwon
- Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul, Republic of Korea
| | - Kitae Baek
- Department of Environment & Energy (BK21 FOUR), Jeonbuk National University, 567 Baekje-daero, Deokjin, Jeonju, Jeollabukdo, 54896, Republic of Korea; Soil Environment Research Center, Jeonbuk National University, 567 Baekje-daero, Deokjin, Jeonju, Jeollabukdo, 54896, Republic of Korea; School of Civil/Environmental/Resource and Energy Engineering, Jeonbuk National University, 567 Baekje-daero, Deokjin, Jeonju, Jeollabukdo, 54896, Republic of Korea.
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Fu Y, Yin Z, Qin L, Huang D, Yi H, Liu X, Liu S, Zhang M, Li B, Li L, Wang W, Zhou X, Li Y, Zeng G, Lai C. Recent progress of noble metals with tailored features in catalytic oxidation for organic pollutants degradation. JOURNAL OF HAZARDOUS MATERIALS 2022; 422:126950. [PMID: 34449327 DOI: 10.1016/j.jhazmat.2021.126950] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 08/10/2021] [Accepted: 08/16/2021] [Indexed: 05/23/2023]
Abstract
With the increasing serious water pollutions, an increasing interest has given for the nanocomposites as environmental catalysts. To date, noble metals-based nanocomposites have been extensively studied by researchers in environmental catalysis. In detail, serving as key functional parts, noble metals are usually combined with other nanomaterials for rationally designing nanocomposites, which exhibit enhanced catalytic properties in pollutants removal. Noble metals in the nanocomposites possess tailored properties, thus playing different important roles in catalytic oxidation reactions for pollutants removal. To motivate the research and elaborate the progress of noble metals, this review (i) summarizes advanced characterization techniques and rising technology of theoretical calculation for evaluating noble metal, and (ii) classifies the roles according to their disparate mechanism in different catalytic oxidation reactions. Meanwhile, the enhanced mechanism and influence factors are discussed. (iii) The conclusions, facing challenges and perspectives are proposed for further development of noble metals-based nanocomposites as environmental catalysts.
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Affiliation(s)
- Yukui Fu
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China
| | - Zhuo Yin
- Department of Urology, Second Xiangya Hospital, Central South University, Changsha 410011, PR China
| | - Lei Qin
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China
| | - Danlian Huang
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China
| | - Huan Yi
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China
| | - Xigui Liu
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China
| | - Shiyu Liu
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China
| | - Mingming Zhang
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China
| | - Bisheng Li
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China
| | - Ling Li
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China
| | - Wenjun Wang
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China
| | - Xuerong Zhou
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China
| | - Yixia Li
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China
| | - Guangming Zeng
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China; Department of Urology, Second Xiangya Hospital, Central South University, Changsha 410011, PR China.
| | - Cui Lai
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China.
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Liu M, Feng Z, Luan X, Chu W, Zhao H, Zhao G. Accelerated Fe 2+ Regeneration in an Effective Electro-Fenton Process by Boosting Internal Electron Transfer to a Nitrogen-Conjugated Fe(III) Complex. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:6042-6051. [PMID: 33616409 DOI: 10.1021/acs.est.0c08018] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The regeneration rate of Fe2+ from Fe3+ dictates the performance of the electro-Fenton (EF) process, represented by the amount of produced hydroxyl radicals (·OH). Current strategies for the acceleration of Fe2+ regeneration normally require additional chemical reagents, to vary the redox potential of Fe2+/Fe3+. Here, we report an attempt at using the intrinsic property of the electrode to our advantage, i.e., nitrogen-doped carbon aerogel (NDCA), as a reducing agent for the regeneration of Fe2+ without using foreign reagents. Moreover, the pyrrolic N in NDCA provides unpaired electrons through the carbon framework to reduce Fe3+, while the graphitic and pyridinic N coordinate with Fe3+ to form a C-O-Fe-N2 bond, facilitating electron transfer from both the external circuit and pyrrolic N to Fe3+. Our Fe2+/NDCA-EF system exhibits a 5.8 ± 0.3 times higher performance, in terms of the amount of generated ·OH, than a traditional Fenton system using the same Fe2+ concentration. In the subsequent reaction, the Fe2+/NDCA-EF system demonstrates 100.0% removal of dimethyl phthalate, 3-chlorophenol, bisphenol A, and sulfamethoxazole with a low specific energy consumption of 0.17-0.36 kW·h·g-1. Furthermore, 90.1 ± 0.6% removal of dissolved organic carbon and 83.3 ± 0.9% removal of NH3-N are achieved in the treatment of domestic sewage. The purpose of this work is to present a novel strategy for the regeneration of Fe2+ in the EF process and also to elucidate the role of different N species of the carbonaceous electrode in contributing to the redox cycle of Fe2+/Fe3+.
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Affiliation(s)
- Mingyue Liu
- School of Chemical Science and Engineering, Shanghai Key Lab of Chemical Assessment and Sustainability, Key Laboratory of Yangtze River Water Environment, Tongji University, Siping Road 1239, Shanghai 200092, P. R. China
| | - Zhiyuan Feng
- School of Chemical Science and Engineering, Shanghai Key Lab of Chemical Assessment and Sustainability, Key Laboratory of Yangtze River Water Environment, Tongji University, Siping Road 1239, Shanghai 200092, P. R. China
| | - Xinmiao Luan
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Siping Road 1239, Shanghai 200092, P. R. China
| | - Wenhai Chu
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Siping Road 1239, Shanghai 200092, P. R. China
| | - Hongying Zhao
- School of Chemical Science and Engineering, Shanghai Key Lab of Chemical Assessment and Sustainability, Key Laboratory of Yangtze River Water Environment, Tongji University, Siping Road 1239, Shanghai 200092, P. R. China
| | - Guohua Zhao
- School of Chemical Science and Engineering, Shanghai Key Lab of Chemical Assessment and Sustainability, Key Laboratory of Yangtze River Water Environment, Tongji University, Siping Road 1239, Shanghai 200092, P. R. China
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An J, Li N, Zhao Q, Qiao Y, Wang S, Liao C, Zhou L, Li T, Wang X, Feng Y. Highly efficient electro-generation of H 2O 2 by adjusting liquid-gas-solid three phase interfaces of porous carbonaceous cathode during oxygen reduction reaction. WATER RESEARCH 2019; 164:114933. [PMID: 31382153 DOI: 10.1016/j.watres.2019.114933] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 07/04/2019] [Accepted: 07/29/2019] [Indexed: 06/10/2023]
Abstract
Equilibrium of three reactants (oxygen, proton and electron) in oxygen reduction reaction at large current flux is necessary for highly efficient electro-generation of H2O2. In this work, we investigated reactants equilibrium and H2O2 electrochemical production in liquid-gas-solid three phase interfaces on rolling cathodes with high electroactive area. Electrocatalytic reaction accelerated the electrolyte intrusion into hydrophobic porous catalyst layer for higher electroactive surface area, resulting in a 21% increase of H2O2 yield at 15 mA cm-2. Air aerated cathode submerged in air/O2 aeration solution was unable to produce H2O2 efficiently due to the lack of O2 in three phase interfaces (TPIs), especially at current density > 2.5 mA cm-2. For air breathing cathode, stable TPIs inside the active sites was created by addition of gas diffusion layer, to increase H2O2 production from 11 ± 2 to 172 ± 11 mg L-1 h-1 at 15 mA cm-2. Pressurized air flow application enhanced both oxygen supply and H2O2 departure transfer to obtain a high H2O2 production of 461 ± 11 mg L-1 h-1 with CE of 89 ± 2% at 35 mA cm-2, 45% higher than passive gas transfer systems. Our findings provided a new insight of carbonaceous air cathode performance in producing H2O2, providing important information for the practical application and amplification of cathodes in the future.
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Affiliation(s)
- Jingkun An
- School of Environmental Science and Engineering, Tianjin University, No. 92 Weijin Road, Nankai District, Tianjin, 300072, China; Academy of Environment and Ecology, Tianjin University, No. 92 Weijin Road, Nankai District, Tianjin, 300072, China
| | - Nan Li
- School of Environmental Science and Engineering, Tianjin University, No. 92 Weijin Road, Nankai District, Tianjin, 300072, China; Academy of Environment and Ecology, Tianjin University, No. 92 Weijin Road, Nankai District, Tianjin, 300072, China.
| | - Qian Zhao
- School of Environmental Science and Engineering, Tianjin University, No. 92 Weijin Road, Nankai District, Tianjin, 300072, China
| | - Yujie Qiao
- School of Environmental Science and Engineering, Tianjin University, No. 92 Weijin Road, Nankai District, Tianjin, 300072, China
| | - Shu Wang
- School of Environmental Science and Engineering, Tianjin University, No. 92 Weijin Road, Nankai District, Tianjin, 300072, China
| | - Chengmei Liao
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin, 300350, China
| | - Lean Zhou
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin, 300350, China
| | - Tian Li
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin, 300350, China
| | - Xin Wang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin, 300350, China
| | - Yujie Feng
- School of Environmental Science and Engineering, Tianjin University, No. 92 Weijin Road, Nankai District, Tianjin, 300072, China; Academy of Environment and Ecology, Tianjin University, No. 92 Weijin Road, Nankai District, Tianjin, 300072, China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No. 73 Huanghe Road, Nangang District, Harbin, 150090, China.
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Nazari R, Rajić L, Xue Y, Zhou W, Alshawabkeh AN. Degradation of 4-Chlorophenol in Aqueous Solution by Sono-Electro-Fenton Process. INT J ELECTROCHEM SC 2018; 13:9214-9230. [PMID: 30568538 PMCID: PMC6296483 DOI: 10.20964/2018.09.46] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Electro-Fenton (EF) and ultrasound radiation (US) have been of interest for the removal of chlorinated compounds from water. This study evaluates the effects of different parameters on sono-electro-Fenton (SEF) for degradation of 4-chlorophenol (4-CP) in an aqueous solution. This study uses pulsing US waves along with Pd-catalyzed EF to degrade contaminants in water while maintaining temperature. The usage of pulsing US waves along with Pd catalyzed EF to remove contaminants while maintaining temperature has not been reported previously. SEF ability to degrade 4-CP was compared with the performance of each process (EF and sonolysis) alone. Initial pH, current density, background electrolyte, Fe2+ concentration, Pd/Al2O3 catalyst concentration, US waves, and sonifier amplitude were optimized in a two electrode (Ti/mixed metal oxide or Ti/MMO) batch system. The degradation of 4-CP increased from 1.85% by US to 83% by EF to nearly >99.9% by coupled SEF. With US radiation under 70% amplitude and 1:10 ON/OFF ratio, the removal rate of 4-CP increased to 98% compared to 62% under EF alone within the first 120 min in the presence of 80 mg L-1 Fe2+, 16.94 mA cm-2 of current density, 1 g L-1 Pd/Al2O3 catalyst (10 mg Pd), and initial pH of 3. However, the degradation rate decreased after 120 min of treatment, and complete 4-CP removal was observed after 300 minutes. The sonolysis impacted the 4-CP removal under coupled SEF, mostly due to the contribution of mass transfer (micromixing), while radical formation was found to be absent under the conditions tested (20kHz). The pulsed US was found to increase the temperature by only 8.7°C, which was found not to impact the 4-CP volatilization or degradation. These results imply that low-level US frequency through pulses is a practical and efficient approach to support electro-Fenton reaction, improving reaction rates without the need for electrolyte cooling.
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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
- Department of Civil and Environmental Engineering, Northeastern University, 400 Snell Engineering, 360 Huntington Avenue, Boston, MA 02115, USA
| | - Yunfei Xue
- Department of Civil and Environmental Engineering, Northeastern University, 400 Snell Engineering, 360 Huntington Avenue, Boston, MA 02115, USA.,State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, Shanghai 200237, P.R. China
| | - 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, P.R. China
| | - 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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Zhang H, Wan X, Li G, Zhang F. A Three-electrode Electro-Fenton System Supplied by Self-generated Oxygen with Automatic pH-regulation for Groundwater Remediation. Electrochim Acta 2017. [DOI: 10.1016/j.electacta.2017.08.040] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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9
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Pd/Fe3O4 nanocatalysts for highly effective and simultaneous removal of humic acids and Cr(VI) by electro-Fenton with H2O2 in situ electro-generated on the catalyst surface. J Catal 2017. [DOI: 10.1016/j.jcat.2017.06.004] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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10
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Georgi A, Velasco Polo M, Crincoli K, Mackenzie K, Kopinke FD. Accelerated Catalytic Fenton Reaction with Traces of Iron: An Fe-Pd-Multicatalysis Approach. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:5882-5891. [PMID: 27167833 DOI: 10.1021/acs.est.6b01049] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
An accelerated catalytic Fenton (ACF) reaction was developed based upon a multicatalysis approach, facilitating efficient contaminant oxidation at trace levels of dissolved iron. Beside the Fe(II)/H2O2 catalyst/oxidant pair for production of OH-radicals, the ACF system contains Pd/H2 as catalyst/reductant pair for fast reduction of Fe(III) back to Fe(II) which accelerates the Fenton cycle and leads to faster contaminant degradation. By this means, the concentration of the dissolved iron catalyst can be reduced to trace levels (1 mg L(-1)) below common discharge limits, thus eliminating the need for iron sludge removal, which is one of the major drawbacks of conventional Fenton processes. ACF provides fast degradation of the model contaminant methyl tert-butyl ether (MTBE, C0 = 0.17 mM) with a half-life of 11 min with 1 mg L(-1) dissolved iron, 500 mg L(-1) H2O2, 5 mg L(-1) Pd (as suspended Pd/Al2O3 catalyst) and 0.1 MPa H2, pH 3. The effects of pH, H2 partial pressure and H2O2 concentration on MTBE degradation rates were studied. Results on kinetic deuterium isotope effect and quenching studies are in conformity with OH-radicals as main oxidant. The heterogeneous Pd/Al2O3 catalyst was reused within six cycles without significant loss in activity.
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Affiliation(s)
- Anett Georgi
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Engineering, Permoserstrasse 15, D-04318 Leipzig, Germany
| | - Miriam Velasco Polo
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Engineering, Permoserstrasse 15, D-04318 Leipzig, Germany
| | - Klara Crincoli
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Engineering, Permoserstrasse 15, D-04318 Leipzig, Germany
| | - Katrin Mackenzie
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Engineering, Permoserstrasse 15, D-04318 Leipzig, Germany
| | - Frank-Dieter Kopinke
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Engineering, Permoserstrasse 15, D-04318 Leipzig, Germany
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Shih YH, Chen MY, Su YF, Tso CP. Concurrent oxidation and reduction of pentachlorophenol by bimetallic zerovalent Pd/Fe nanoparticles in an oxic water. JOURNAL OF HAZARDOUS MATERIALS 2016; 301:416-423. [PMID: 26410270 DOI: 10.1016/j.jhazmat.2015.08.059] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 08/19/2015] [Accepted: 08/28/2015] [Indexed: 06/05/2023]
Abstract
Under the oxic condition, the most effective removal of pentachlorophenol (PCP) with Pd/Fe nanoparticles (NPs) is demonstrated as compared to the anoxic condition. Concurrent oxidation and reduction of polychlorinated compounds such as PCP by zerovalent Pd/Fe were first observed. The optimal Pd content of the bimetallic NPs is only around 0.54 mg g(-1) Fe. Increases in both dosage of Pd/Fe NPs and temperature enhance degradation rates and efficiency. The activation energy of 29 kJ/mol indicates that the degradation is a surface-mediated mechanism. The removal mechanism also includes adsorption, which explains that the dechlorination of Cl on PCP molecules at ortho and meta positions is easier than that at para position. Overall, Pd/Fe NPs can apply directly to degrade polyhalogenated compounds in water without deaeration.
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Affiliation(s)
- Yang-hsin Shih
- Department of Agricultural Chemistry, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617 Taiwan.
| | - Meng-yi Chen
- Department of Agricultural Chemistry, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617 Taiwan
| | - Yuh-fan Su
- Department of Agricultural Chemistry, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617 Taiwan
| | - Chih-ping Tso
- Department of Agricultural Chemistry, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617 Taiwan
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12
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Liu Y, Chen S, Quan X, Yu H, Zhao H, Zhang Y. Efficient Mineralization of Perfluorooctanoate by Electro-Fenton with H2O2 Electro-generated on Hierarchically Porous Carbon. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:13528-33. [PMID: 26465252 DOI: 10.1021/acs.est.5b03147] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Perfluorochemicals are environmentally persistent, bioaccumulative, and globally distributed contaminants, which present potential toxicity to both humans and ecosystems. However, rapid mineralization of perfluorochemicals with cost-effective method remains great challenges. Here, an electro-Fenton system was reported for efficient mineralization of perfluorooctanoate (PFOA), where H2O2 was electro-generated in situ from O2 reduction on hierarchically porous carbon (HPC). Benefited from the high H2O2 production rate (41.2-14.0 mM/h) of HPC, PFOA (50 mg/L) was rapidly degraded by electro-Fenton with first-order kinetic constants of 1.15-0.69 h(-1) at low potential (-0.4 V) in a wide range of pH (2-6). Meanwhile, PFOA was effectively mineralized, as revealed by a total organic carbon removal efficiency of 90.7-70.4% (-0.4 V, pH 2-6, 4 h). Moreover, the current efficiency of this electro-Fenton system for PFOA degradation was 1 order of magnitude higher than those of electrochemical oxidation. On the basis of the intermediate analysis, we proposed a possible mechanism for PFOA degradation: PFOA lost one electron to the anode and got decarboxylated. The formed perfluoroalkyl radical was mainly oxidized by hydroxyl radical, resulting in the formation of shorter chain perfluorocarboxylic acid, which followed the same reaction cycle as PFOA until it was mineralized.
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Affiliation(s)
- Yanming Liu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology , Dalian 116024, China
| | - Shuo Chen
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology , Dalian 116024, China
| | - Xie Quan
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology , Dalian 116024, China
| | - Hongtao Yu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology , Dalian 116024, China
| | - Huimin Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology , Dalian 116024, China
| | - Yaobin Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology , Dalian 116024, China
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13
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Yu Y, Chen Z, Guo Z, Liao Z, Yang L, Wang J, Chen Z. Removal of refractory contaminants in municipal landfill leachate by hydrogen, oxygen and palladium: a novel approach of hydroxyl radical production. JOURNAL OF HAZARDOUS MATERIALS 2015; 287:349-55. [PMID: 25679800 DOI: 10.1016/j.jhazmat.2015.01.070] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 01/26/2015] [Accepted: 01/30/2015] [Indexed: 05/23/2023]
Abstract
Municipal solid waste (MSW) leachate contains various refractory pollutants that pose potential threats to both surface water and groundwater. This paper established a novel catalytic oxidation process for leachate treatment, in which OH is generated in situ by pumping both H2 and O2 in the presence of Pd catalyst and Fe(2+). Volatile fatty acids in the leachate were removed almost completely by aeration and/or mechanical mixing. In this approach, a maximum COD removal of 56.7% can be achieved after 4h when 200mg/L Fe(2+) and 1250mg/L Pd/Al2O3 (pH 3.0) are used as catalysts. After oxidation, the BOD/COD ratio in the proposed process increased from 0.03 to 0.25, indicating that the biodegradability of the leachate was improved. By comparing the efficiency on COD removal and economical aspect of the proposed Pd-based in-situ process with traditional Fenton, electro-Fenton and UV-Fenton for leachate treatments, the proposed Pd-based in-situ process has potential economic advantages over other advanced oxidation processes while the COD removal efficiency was maintained.
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Affiliation(s)
- Yingjian Yu
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Zhulei Chen
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China.
| | - Zhiyuan Guo
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Zhuwei Liao
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Lie Yang
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Jia Wang
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Zhuqi Chen
- School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China.
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14
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Sun M, Zhang G, Liu Y, Liu H, Qu J, Li J. Highly Efficient AuPd/Carbon Nanotube Nanocatalysts for the Electro-Fenton Process. Chemistry 2015; 21:7611-20. [DOI: 10.1002/chem.201406676] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Indexed: 11/10/2022]
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15
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Liao P, Al-Ani Y, Malik Ismael Z, Wu X. Insights into the role of humic acid on Pd-catalytic electro-Fenton transformation of toluene in groundwater. Sci Rep 2015; 5:9239. [PMID: 25783864 DOI: 10.1038/srep09239] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 02/16/2015] [Indexed: 11/09/2022] Open
Abstract
A recently developed Pd-based electro-Fenton (E-Fenton) process enables efficient in situ remediation of organic contaminants in groundwater. In the process, H₂O₂, Fe(II), and acidic conditions (~pH 3) are produced in situ to facilitate the decontamination, but the role of ubiquitous natural organic matters (NOM) remain unclear. This study investigated the effect of Aldrich humic acid (HA) on the transformation of toluene by the Pd-based E-Fenton process. At pH 3 with 50 mA current, the presence of HA promoted the efficiency of toluene transformation, with pseudo-first-order rate constants increase from 0.01 to 0.016 as the HA concentration increases from 0 to 20 mg/L. The HA-enhanced toluene transformation was attributed to the accelerated thermal reduction of Fe(III) to Fe(II), which led to production of more hydroxyl radicals. The correlation of the rate constants of toluene transformation and HA decomposition validated hydroxyl radical (·OH) as the predominant reactive species for HA decomposition. The finding of this study highlighted that application of the novel Pd-based E-Fenton process in groundwater remediation may not be concerned by the fouling from humic substances.
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Affiliation(s)
- Peng Liao
- 1] School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, P.R. China [2] State Key Lab of Biogeology and Environmental Geology, China University of Geosciences, Wuhan. 430074, P. R. China
| | - Yasir Al-Ani
- 1] State Key Lab of Biogeology and Environmental Geology, China University of Geosciences, Wuhan. 430074, P. R. China [2] Faculty of Engineering, University of AL-Anbar, Al-Anbar Governorate, Iraq
| | - Zainab Malik Ismael
- 1] State Key Lab of Biogeology and Environmental Geology, China University of Geosciences, Wuhan. 430074, P. R. China [2] Faculty of Engineering, University of AL-Anbar, Al-Anbar Governorate, Iraq
| | - Xiaohui Wu
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, P.R. China
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Wang L, Cao M, Ai Z, Zhang L. Design of a highly efficient and wide pH electro-Fenton oxidation system with molecular oxygen activated by ferrous-tetrapolyphosphate complex. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:3032-9. [PMID: 25631474 DOI: 10.1021/es505984y] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In this study, a novel electro-Fenton (EF) system was developed with iron wire, activated carbon fiber, and sodium tetrapolyphosphate (Na6TPP) as the anode, cathode, and electrolyte, respectively. This Na6TPP-EF system could efficiently degrade atrazine in a wide pH range of 4.0-10.2. The utilization of Na6TPP instead of Na2SO4 as the electrolyte enhanced the atrazine degradation rate by 130 times at an initial pH of 8.0. This dramatic enhancement was attributed to the formation of ferrous-tetrapolyphosphate (Fe(II)-TPP) complex from the electrochemical corrosion (ECC) and chemical corrosion (CC) of iron electrode in the presence of Na6TPP. The Fe(II)-TPP complex could provide an additional molecular oxygen activation pathway to produce more H2O2 and (•)OH via a series single-electron transfer processes, producing the Fe(III)-TPP complex. The cycle of Fe(II)/Fe(III) was easily realized through the electrochemical reduction (ECR) process on the cathode. More interestingly, we found that the presence of Na6TPP could prevent the iron electrode from excessive corrosion via phosphorization in the later stage of the Na6TPP-EF process, avoiding the generation of iron sludge. Gas chromatograph-mass spectrometry, liquid chromatography-mass spectrometry, and ion chromatography were used to investigate the degradation intermediates to propose a possible atrazine oxidation pathway in the Na6TPP-EF system. These interesting findings provide some new insight on the development of a low-cost and highly efficient EF system for wastewater treatment in a wide pH range.
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Affiliation(s)
- Li Wang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental Chemistry, Central China Normal University , Wuhan 430079, P. R. China
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Bañuelos JA, El-Ghenymy A, Rodríguez F, Manríquez J, Bustos E, Rodríguez A, Brillas E, Godínez LA. Study of an Air Diffusion Activated Carbon Packed Electrode for an Electro-Fenton Wastewater Treatment. Electrochim Acta 2014. [DOI: 10.1016/j.electacta.2014.05.078] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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18
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Tong M, Yuan S, Zhang P, Liao P, Alshawabkeh AN, Xie X, Wang Y. Electrochemically induced oxidative precipitation of Fe(II) for As(III) oxidation and removal in synthetic groundwater. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:5145-53. [PMID: 24708303 PMCID: PMC6321744 DOI: 10.1021/es500409m] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Mobilization of Arsenic in groundwater is primarily induced by reductive dissolution of As-rich Fe(III) oxyhydroxides under anoxic conditions. Creating a well-controlled artificial environment that favors oxidative precipitation of Fe(II) and subsequent oxidation and uptake of aqueous As can serve as a remediation strategy. We reported a proof of concept study of a novel iron-based dual anode system for As(III) oxidation and removal in synthetic groundwater. An iron anode was used to produce Fe(II) under iron-deficient conditions, and another inert anode was used to generate O2 for oxidative precipitation of Fe(II). For 30 min's treatment, 6.67 μM (500 μg/L) of As(III) was completely oxidized and removed from the solution during the oxidative precipitation process when a total current of 60 mA was equally partitioned between the two anodes. The current on the inert anode determined the rate of O2 generation and was linearly related to the rates of Fe(II) oxidation and of As oxidation and removal, suggesting that the process could be manipulated electrochemically. The composition of Fe precipitates transformed from carbonate green rust to amorphous iron oxyhydroxide as the inert anode current increased. A conceptual model was proposed for the in situ application of the electrochemically induced oxidative precipitation process for As(III) remediation.
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Affiliation(s)
- Man Tong
- State Key Lab of Biogeology and Environmental Geology, China University of Geosciences, 388 Lumo Road, Wuhan, 430074, P. R. China
| | - Songhu Yuan
- State Key Lab of Biogeology and Environmental Geology, China University of Geosciences, 388 Lumo Road, Wuhan, 430074, P. R. China
| | - Peng Zhang
- State Key Lab of Biogeology and Environmental Geology, China University of Geosciences, 388 Lumo Road, Wuhan, 430074, P. R. China
| | - Peng Liao
- State Key Lab of Biogeology and Environmental Geology, China University of Geosciences, 388 Lumo Road, Wuhan, 430074, P. R. China
| | - Akram N. Alshawabkeh
- Department of Civil and Environmental Engineering, Northeastern University, 400 Snell Engineering, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Xianjun Xie
- State Key Lab of Biogeology and Environmental Geology, China University of Geosciences, 388 Lumo Road, Wuhan, 430074, P. R. China
| | - Yanxin Wang
- State Key Lab of Biogeology and Environmental Geology, China University of Geosciences, 388 Lumo Road, Wuhan, 430074, P. R. China
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19
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Yuan S, Liao P, Alshawabkeh AN. Electrolytic manipulation of persulfate reactivity by iron electrodes for trichloroethylene degradation in groundwater. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:656-63. [PMID: 24328192 PMCID: PMC3916217 DOI: 10.1021/es404535q] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Activated persulfate oxidation is an effective in situ chemical oxidation process for groundwater remediation. However, reactivity of persulfate is difficult to manipulate or control in the subsurface causing activation before reaching the contaminated zone and leading to a loss of chemicals. Furthermore, mobilization of heavy metals by the process is a potential risk. An effective approach using iron electrodes is thus developed to manipulate the reactivity of persulfate in situ for trichloroethylene (TCE) degradation in groundwater and to limit heavy metals mobilization. TCE degradation is quantitatively accelerated or inhibited by adjusting the current applied to the iron electrode, following k1 = 0.00053·Iv + 0.059 (-122 A/m(3) ≤ Iv ≤ 244 A/m(3)) where k1 and Iv are the pseudo first-order rate constant (min(-1)) and volume normalized current (A/m(3)), respectively. Persulfate is mainly decomposed by Fe(2+) produced from the electrochemical and chemical corrosion of iron followed by the regeneration via Fe(3+) reduction on the cathode. SO4(•-) and ·OH cocontribute to TCE degradation, but ·OH contribution is more significant. Groundwater pH and oxidation-reduction potential can be restored to natural levels by the continuation of electrolysis after the disappearance of contaminants and persulfate, thus decreasing adverse impacts such as the mobility of heavy metals in the subsurface.
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Affiliation(s)
- Songhu Yuan
- State Key Lab of Biogeology and Environmental Geology, China University of Geosciences, 388 Lumo Road, Wuhan, 430074, P. R. China
- Department of Civil and Environmental Engineering, Northeastern University, 400 Snell Engineering, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
- To whom correspondence should be addressed: (S. Yuan), Phone: +86-27-67848629. Fax: +86-27-67883456; (A. Alshawabkeh), Phone: 617 373 3994. Fax: 617 373 4419
| | - Peng Liao
- State Key Lab of Biogeology and Environmental Geology, China University of Geosciences, 388 Lumo Road, Wuhan, 430074, P. R. China
| | - Akram N. Alshawabkeh
- Department of Civil and Environmental Engineering, Northeastern University, 400 Snell Engineering, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
- To whom correspondence should be addressed: (S. Yuan), Phone: +86-27-67848629. Fax: +86-27-67883456; (A. Alshawabkeh), Phone: 617 373 3994. Fax: 617 373 4419
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20
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Luo M, Yuan S, Tong M, Liao P, Xie W, Xu X. An integrated catalyst of Pd supported on magnetic Fe3O4 nanoparticles: simultaneous production of H2O2 and Fe2+ for efficient electro-Fenton degradation of organic contaminants. WATER RESEARCH 2014; 48:190-199. [PMID: 24119931 DOI: 10.1016/j.watres.2013.09.029] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 09/11/2013] [Accepted: 09/13/2013] [Indexed: 06/02/2023]
Abstract
A novel electro-Fenton process based on Pd-catalytic production of H2O2 from H2 and O2 has been proposed recently for transforming organic contaminants in wastewaters and groundwater. However, addition of Fe(II) complicates the operation, and it is difficult to recycle Pd catalyst after treatment. This study attempts to synthesize an integrated catalyst by loading Pd onto magnetic Fe3O4 nanoparticles (Pd/MNPs) so that H2O2 and Fe(2+) can be produced simultaneously in the electrolytic system. In an undivided electrolytic cell, phenol, a probe organic contaminant, is degraded by 98% within 60 min under conditions of 50 mA, 1 g/L Pd/MNPs (5 wt% Pd), pH 3 and 20 mg/L initial concentration. The degradation rate peaks at pH 3, increases with increasing Pd loading and electric current and decreases with increasing initial concentration. A distinct mechanism, reductive dissolution of solid Fe(III) in Fe3O4 by atomic H chemisorbed on Pd surface, is responsible for Fe(2+) production from Pd/MNPs. The efficiency of phenol degradation can be sustained at the same level for ten times of repeated treatment using the Pd/MNPs catalyst. The variations of main crystal structure and magnetic property of catalysts are minimal after treatment, but low concentrations of Pd leached, which needs further evaluation.
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Affiliation(s)
- Mingsen Luo
- State Key Lab of Biogeology and Environmental Geology, China University of Geosciences, 388 Lumo Road, Wuhan 430074, PR China
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Qian A, Liao P, Yuan S, Luo M. Efficient reduction of Cr(VI) in groundwater by a hybrid electro-Pd process. WATER RESEARCH 2014; 48:326-34. [PMID: 24134802 DOI: 10.1016/j.watres.2013.09.043] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Revised: 09/06/2013] [Accepted: 09/23/2013] [Indexed: 05/16/2023]
Abstract
Pd-catalytic process is effective for reducing a wide range of contaminants in groundwater. However, limited attention is paid to Cr(VI) reduction presumably due to the weakly oxidizing potential of Cr(VI) under circumneutral conditions. In this study, a new concept of in situ reducing Cr(VI) in groundwater by a hybrid electro-Pd process with automatic pH adjustments is proposed and justified. In an undivided electrolytic cell, Cr(VI) at 5 mg/L is reduced by 95% within 30 min under conditions of pH 3, 1 g/L Pd/Al2O3 and 20 mA current. Reduction of Cr(VI) increases with decreasing pH and increasing current and Pd/Al2O3 dosage. Inhibition of anodic O2 is significant but decreases with drop of pH. Atomic H is assigned as the predominant reactive species contributing to Cr(VI) reduction. Although H2O2 is effective for reducing Cr(VI), its production on Pd surface is completed inhibited by the presence of Cr(VI). The concept is ultimately justified using a specially configured three-electrode column. Cr(VI) is effectively reduced to Cr(3+) in the locally acidic Pd zone, and Cr(3+) is then precipitated in the downstream neutral zone. This hybrid electro-Pd process could be potentially applied in the in situ remediation of Cr(VI)-contaminated groundwater.
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Affiliation(s)
- Ao Qian
- State Key Lab of Biogeology and Environmental Geology, China University of Geosciences, 388 Lumo Road, Wuhan, Hubei 430074, PR China
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