Selective oxidation of pharmaceuticals and suppression of perchlorate formation during electrolysis of fresh human urine

Clark, James A.; Yang, Yuhang; Ramos, Nathanael C.; Hillhouse, Hugh W.

doi:10.1016/j.watres.2021.117106

Cited by 35 publications

(13 citation statements)

References 91 publications

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“…In fact, the occurrence of the electron transfer from organics to ClO 4 − was very difficult since ClO 4 − reduction to Cl − required a large activation energy (>120 kJ mole −1 ), which was responsible for its incapability to interfere with COD determination. 19 In contrast, ClO − would be completely transformed into HClO and Cl 2 under pH < 4, and the oxidizing power of HClO and Cl 2 is generally regarded to be higher than that of ClO − by 80−100 times. 39 − had the most significant impact on COD determination among various ClO x − (x = 1 to 3) species (Figure S4), which could be ascribed to the reduction of ClO 3 − to Cl − requiring six electrons donated by organic matter.…”

Section: Identification Of Clo Xmentioning

confidence: 99%

“…Given the above perspective, Cl – has an important effect on the BDD applied in wastewater treatment. − However, Cl – can be also converted into undesirable inorganic oxychloride anions (denoted as ClO x – , x = 1 to 4, for convenience) at very high concentration via multistep oxidation on the BDD surface, such as ClO – , ClO 2 – , ClO 3 – , and ClO 4 – (Table S1), − the maximum contaminant level (MCL) of which is stipulated by the U.S. Environmental Protection Agency (EPA) because of health concerns and ecosystem safety. , The electrogeneration of these oxychlorides has gained extensive attention during BDD utilized for COD removal from Cl – -laden wastewaters. For example, oxychlorides including approximately 45 mM ClO 3 – and 5 mM ClO 4 – were electrochemically produced in the 120 min BDD-treated urine wastewater containing 100 mM Cl – at 93 mA cm –2 . In addition, 18 mM ClO 3 – and 3 mM ClO 4 – could be produced when a BDD anode was used in treating the human wastewater within 4 h, where the efficiency in COD removal was 100% .…”

Section: Introductionmentioning

confidence: 99%

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Overevaluation of Electro-oxidation for Chemical Oxygen Demand Removal Using a Boron-Doped Diamond Anode: The Roles of Various Electrogenerated Oxychlorides and Countermeasure

et al. 2023

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Electrochemical oxidation using a boron-doped diamond (BDD) anode has been extensively investigated in various wastewater treatments, where the electrogenerated oxychlorides (ClO x –, x = 1 to 4) from Cl– oxidation have been well illustrated. However, the false chemical oxygen demand (COD) reduction induced by ClO x – adulteration has been almost completely overlooked when evaluating the electrochemical wastewater treatment performance. In this study, it was revealed that all the ClO x – species except ClO4 – served as strong oxidants in lieu of dichromate to degrade organic matter under digestion conditions during the COD test procedure. To eliminate the interference of ClO x – mixtures on the assessment of electrochemical COD removal performance, the modified sulfite-based reduction method was developed for the electrochemical case to remove ClO x – mixtures from the BDD-treated water samples before the COD test. It was demonstrated that the unadulterated COD removal performance of the BDD-based electrochemical system used for both synthetic and real wastewater treatments could be obtained after sulfite-based reduction of the electrogenerated ClO x – mixtures within 30 min in a sealed reaction chamber with the molar [sulfite]ini/[ClO x –]ini ratio of 1–3, where the reactants were isochronously depleted without producing oxidative radicals (SO4 •– and •OH). Due to extreme lack of oxygen in the sealed ClO x –-sulfite system, radical propagation reactions were terminated and ClO x – constituents (ClO3 –, ClO2 –, and ClO–) were reduced by sulfite stoichiometrically via the oxygen transfer process with Cl– and SO4 2– as the final products. This new sulfite-based protocol could be regarded as a robust and adulteration-proof countermeasure for evaluating the real COD removal performance of an electrochemical system.

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Section: Identification Of Clo Xmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Overevaluation of Electro-oxidation for Chemical Oxygen Demand Removal Using a Boron-Doped Diamond Anode: The Roles of Various Electrogenerated Oxychlorides and Countermeasure

et al. 2023

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“…formed in chlorine mediated electro‐oxidation on these electrodes are inevitable, [50] in which occasion some operation parameters should be regulated. For example, the high urea content in fresh human urine could effectively inhibit the over‐generation of oxychlorides ∼1000 times lower than that in hydrolyzed urine matrixes, [51] indicating it is more suitable for the point‐source‐remediation before urine storage and hydrolysis. Additionally, the electrochemical reactor configuration and operation parameters may be another factors which could alter the generation of byproduct during electrolysis, [52] but still limited research lays on this topic.…”

Section: Electrochemical Urea Conversion and Mechanisms Under Differe...mentioning

confidence: 99%

Electrochemical Urea Oxidation in Different Environment: From Mechanism to Devices

Wang

Duan

et al. 2022

ChemCatChem

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Urea has been regarded as an important chemical compound in the food‐water‐energy nexus. However, the emission of urea from human activity, industrial manufacture, and agricultural fertilization into the environment has caused an ecological nitrogen imbalance. Besides addressing the environmental pollution, the applications of clean energy conversion from urea‐rich wastewater has strong potential for resource and energy recovery. Herein, we conducted a comprehensive overview of electrochemical urea oxidation reaction (UOR) for pollution control and energy harvesting. The present mechanisms and behaviors of UOR under different water matrices have been characterized and compared in detail. Additionally, the latest development of electrochemical UOR integrated into electrolyzers and fuel cells are presented. Finally, we discuss the prospects and challenges of UOR technologies, suggesting several directions for the electrochemical conversion of urea‐abundant wastewater in the near future.

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“…As organic and inorganic ions usually accompany in the real urine, they may also be involved in the steps of the urea decomposition process, consequently disturbing the urea oxidation mechanisms and behaviors. For instance, unmetabolized personal pharmaceutical and personal care products (PPCPs) merging with urine did not disturb urea oxidation, [74] but the inorganic phosphate ions inhibited the oxidation activity ascribed to the formation of deactivating inner‐sphere complexes [75] . Thus, it can be inferred that the functions of employed matrix conditions should be more comprehensively considered and deciphered for a broader practical scenario.…”

Section: Challenges and Perspectivesmentioning

confidence: 99%

Solar‐Driven Catalytic Urea Oxidation for Environmental Remediation and Energy Recovery

Sun

Zhang

et al. 2022

ChemSusChem

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The water-energy nexus is highly related to sustainable societal development. As one of the most abundant biowastes discharged into the environment, mild abatements and green conversions of urea wastewater have been widely investigated. Due to abundant sources, global distribution, and easy control, light-based catalytic strategies have become alternative on-site treatment approaches. After comprehensively surveying the recent progress, recent achievements of urea oxidation under light irradiation are reviewed herein. Several typical lightpromoted systems employed in urea conversion, including photocatalysis, photo-electrocatalysis, photo-biocatalysis, and photocatalytic fuel cells, are meticulously introduced and discussed, from catalyst designs and medium conditions to established mechanisms. To realize the goal of sustainability, the chemical energy in urea-rich water could be utilized for the value-added production of hydrogen fuel and electricity. Finally, based on current developments, existing challenges are enumerated and developmental prospects in the future of lightdriven urea conversion technologies are proposed.

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Selective oxidation of pharmaceuticals and suppression of perchlorate formation during electrolysis of fresh human urine

Cited by 35 publications

References 91 publications

Overevaluation of Electro-oxidation for Chemical Oxygen Demand Removal Using a Boron-Doped Diamond Anode: The Roles of Various Electrogenerated Oxychlorides and Countermeasure

Overevaluation of Electro-oxidation for Chemical Oxygen Demand Removal Using a Boron-Doped Diamond Anode: The Roles of Various Electrogenerated Oxychlorides and Countermeasure

Electrochemical Urea Oxidation in Different Environment: From Mechanism to Devices

Solar‐Driven Catalytic Urea Oxidation for Environmental Remediation and Energy Recovery

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