Dual strategies to enhance mineralization efficiency in innovative electrochemical advanced oxidation processes using natural air diffusion electrode: Improving both H2O2 production and utilization efficiency

Zhang, Qizhan; Zhou, Minghua; Lang, Zhicheng; Du, Xuedong; Cai, Jingju; Han, Lujie

doi:10.1016/j.cej.2020.127564

Cited by 41 publications

(9 citation statements)

References 60 publications

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“…Thus, it could be concluded that the CF skeleton supported the 3D structure for nanosheet Co 3 O 4 , which provided plenty of active sites for the ENRR. 38 Based on the above analysis, it is believed that Co 3 O 4 /CF is an efficient cathode for reducing nitrates due to its 3D structure and synergistic effect of Co(III) and Co(II).…”

Section: Resultsmentioning

confidence: 96%

“…Additionally, both CoO/CF-PVDF and Co 2 O 3 /CF-PVDF electrodes (56.60% and 43.06%, Figure a) showed lower NO 3 – removal than Co 3 O 4 /CF and Co 3 O 4 /CF-PVDF, indicating that the synergistic effect of Co(III) and Co(II) in the Co(II)–Co(III)–Co(II) redox cycle was also beneficial for the ENRR. Moreover, it was calculated from k of Co 3 O 4 /CF ( k 1 ), CoO/CF-PVDF ( k 2 ), and Co 2 O 3 /CF-PVDF( k 3 ) to obtain 1.6 of ef on the Co 3 O 4 /CF electrode (over 1), implying that both the Co(II)/Co(III) ratio and the 3D structure enhanced the performance of the ENRR on Co 3 O 4 /CF . Based on the above analysis, it is believed that Co 3 O 4 /CF is an efficient cathode for reducing nitrates due to its 3D structure and synergistic effect of Co(III) and Co(II).…”

Section: Resultsmentioning

confidence: 96%

“…The Pseudo first-order and the enhancement factor (ef) could be calculated as where k is the apparent rate constant (s –1 cm –2 ); A is the area of the electrode (cm 2 ); and k 1 , k 2 , and k 3 are the apparent rate constants of Co 3 O 4 /CF, Co 2 O 3 /CF-PVDF, and CoO/CF-PVDF, respectively.…”

Section: Methodsmentioning

confidence: 99%

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Synergistic Effect of Co(III) and Co(II) in a 3D Structured Co₃O₄/Carbon Felt Electrode for Enhanced Electrochemical Nitrate Reduction Reaction

et al. 2021

ACS Appl. Mater. Interfaces

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As nitrate contamination causes serious environmental problems, it is necessary to develop stable and efficient electrocatalysts for efficient electrochemical nitrate reduction reaction (ENRR). Here, a nonprecious Co 3 O 4 /carbon felt (CF) electrode with a 3D structure was prepared by integrating electrodeposition with calcination methods. This 3D structured Co 3 O 4 /CF electrode exhibits a high-rate constant of 1.18 × 10 −4 s −1 cm −2 for the ENRR, surpassing other Co 3 O 4 electrodes in previous literature. Moreover, it also has an excellent stability with a decrease of 6.4% after 10 cycles. Density functional theory calculations, electron spin resonance analysis, and cyclic voltammetry were performed to study the mechanism of the ENRR on the Co 3 O 4 /CF electrode, proving that atomic H* (indirect pathway) plays a prominent role in NO 3 − reduction and clarifying the synergistic effect of Co(III) and Co(II) in the Co(II)−Co(III)−Co(II) redox cycle for the ENRR: Co(III) prefers the adsorption of NO 3 − and Co(II) favors the production of H*. Based on this synergy, a relatively large amounts of Co(II) on the surface of the Co 3 O 4 /CF electrode (1.3 Co(II)/Co(III) ratio) was maintained by controlling the temperature of calcination to 200 °C with a lower energy barrier of H* formation of 0.46 eV than other ratios, which is beneficial for forming H* and enhancing the performance of the ENRR. Thus, this study suggests that building 3D structure and optimizing Co(II)/Co(III) ratio are important for designing efficient Co 3 O 4 electrocatalyst for ENRR. KEYWORDS: electrochemical nitrate reduction reaction, 3D structure, Co 3 O 4 /carbon felt electrode, high-rate nitrate removal, atomic H*, synergistic effect, Co(II)−Co(III)−Co(II) redox cycle

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Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 96%

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Synergistic Effect of Co(III) and Co(II) in a 3D Structured Co₃O₄/Carbon Felt Electrode for Enhanced Electrochemical Nitrate Reduction Reaction

et al. 2021

ACS Appl. Mater. Interfaces

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“…Moreover, limited by the low level of accumulation of H 2 O 2 during the initial stage, the rate of degradation of EF is usually much lower than that of the conventional Fenton process, which becomes one of the technical bottlenecks of current EF. , Therefore, it would be more favorable for enhancing EF efficacy when combined with other AOPs with more active species or radical (e.g., SO 4 •– ) production, which would greatly accelerate the degradation of organic pollutants.…”

Section: Introductionmentioning

confidence: 99%

Mechanistic Insight into the Heterogeneous Electro-Fenton/Sulfite Process for Ultraefficient Degradation of Pollutants over a Wide pH Range

Song

Zhou

et al. 2021

ACS EST Water

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Electro-Fenton (EF) has received widespread attention in terms of water decontamination in advanced oxidation processes but still has the bottlenecks of a narrow pH (∼3) application range and a slow rate of reduction of the iron ion to sustain high treatment efficiency. Herein, an iron–carbon catalyst was synthesized to develop a heterogeneous EF/sulfite (hetero-EF/sulfite) process, which expanded the pH application range to 7 and increased the rate constant of carbamazepine (CBZ) degradation 10.74 times compared with that of the hetero-EF process. The catalyst was systematically characterized; important process factors such as the applied current, initial pH, and CBZ, catalyst, and sulfite dosage were investigated, and a possible degradation mechanism and a possible pathway were proposed. The quenching experiments and electron paramagnetic resonance test revealed the existence of active species such as •OH, SO4 •–, O2 •–, 1O2, and their mutual transformation, in which •OH and O2 •– were dominant. This work also verified the suitability of the hetero-EF/sulfite for different pollutants, and its universal enhancement for different heterogeneous and homogeneous catalysts. This modified EF process expands the pH application range and enables the co-generation and transformation of free radicals, which has broad prospects for application in the effective degradation of organic pollutants for water purification.

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“…Nevertheless, gas diffusion via GDE depends on the O2 supply (pure O2 or air) and electrochemical reactor design, occurring important deficiencies, such as H2O2 yield and production rate, low oxygen utilization rate and higher energy consumption. Then, the highly efficient and economic O2 supply methodologies to the cathode remain a challenge for the effective application of GDE (Zhang et al, 2021a).…”

Section: Ef Process Without Aerationmentioning

confidence: 99%

Recent advances in electro-Fenton process and its emerging applications

Nidheesh

Ganiyu

Martínez‐Huitle

et al. 2022

Critical Reviews in Environmental Science and Technology

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The electro-Fenton (EF) process is a powerful electrochemical advanced oxidation process. Its development has progressed over the past three decades as a clean and effective technique for wastewater treatment. Even though conventional EF has been shown to be a powerful process for efficient degradation/mineralization of toxic and/or persistent organic pollutants; it still suffers from some downsides for industrial-scale development. Recently, research has focused on improving its effectiveness and relevance, mainly by modifying certain operating parameters; improvements in electrode material and reactor configuration, as well as coupling with other treatment methods. Therefore, this review evaluates the current state of the EF process and presents the most recent advances such as 3D-EF, chelate-EF, self-powered EF, pulsed current EF, bio-EF, sono-EF, sulfite-EF, pyrite-EF, and ferrate-EF in addition to its emerging applications like disinfection, generation of value-added products, and removal of emerging pollutants from water. The suitability of different modified or hybrid-EF processes is discussed based on their performance in H2O2 generation, degradation kinetics, mineralization efficiency and cost effectiveness. This review article is intended to be comprehensive, critical and of general interest, covering recent developments and advances in EF process with the aim of providing a powerful method for the treatment of wastewater polluted with biorecalcitrant pollutants.

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Dual strategies to enhance mineralization efficiency in innovative electrochemical advanced oxidation processes using natural air diffusion electrode: Improving both H2O2 production and utilization efficiency

Cited by 41 publications

References 60 publications

Synergistic Effect of Co(III) and Co(II) in a 3D Structured Co₃O₄/Carbon Felt Electrode for Enhanced Electrochemical Nitrate Reduction Reaction

Synergistic Effect of Co(III) and Co(II) in a 3D Structured Co₃O₄/Carbon Felt Electrode for Enhanced Electrochemical Nitrate Reduction Reaction

Mechanistic Insight into the Heterogeneous Electro-Fenton/Sulfite Process for Ultraefficient Degradation of Pollutants over a Wide pH Range

Recent advances in electro-Fenton process and its emerging applications

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Dual strategies to enhance mineralization efficiency in innovative electrochemical advanced oxidation processes using natural air diffusion electrode: Improving both H2O2 production and utilization efficiency

Cited by 41 publications

References 60 publications

Synergistic Effect of Co(III) and Co(II) in a 3D Structured Co3O4/Carbon Felt Electrode for Enhanced Electrochemical Nitrate Reduction Reaction

Synergistic Effect of Co(III) and Co(II) in a 3D Structured Co3O4/Carbon Felt Electrode for Enhanced Electrochemical Nitrate Reduction Reaction

Mechanistic Insight into the Heterogeneous Electro-Fenton/Sulfite Process for Ultraefficient Degradation of Pollutants over a Wide pH Range

Recent advances in electro-Fenton process and its emerging applications

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Product

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Synergistic Effect of Co(III) and Co(II) in a 3D Structured Co₃O₄/Carbon Felt Electrode for Enhanced Electrochemical Nitrate Reduction Reaction

Synergistic Effect of Co(III) and Co(II) in a 3D Structured Co₃O₄/Carbon Felt Electrode for Enhanced Electrochemical Nitrate Reduction Reaction