Electrochemical wastewater treatment: influence of the type of carbon and of nitrogen on the organic load removal

Fernandes, Annabel; Coelho, João; Ciríaco, Lurdes; Lopes, Ana

doi:10.1007/s11356-016-6851-6

Cited by 9 publications

(3 citation statements)

References 22 publications

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“…Although the chloride concentration in this sample was lower, both PFOA and PFOS concentrations were reduced to levels below the limits of quantification (1.38 μg/L for PFOA, 2.72 μg/L for PFOS) after 16 hr of continuous EO treatment (Exhibit ). This result is consistent with previous studies that reducing the content of coexisting organic compounds led to faster EO of organic pollutants from wastewaters (Fernandes, Coelho, Ciríaco, Pacheco, & Lopes, ). Therefore, treatment of PFOA and PFOS in highly concentrated still bottom to nondetectable levels by EO is achievable, as long as the interfering substances, such as organic matter, methanol, and radical scavenging phenolic compounds, are within certain ranges.…”

Section: Resultssupporting

confidence: 93%

Electrochemical oxidation of PFOA and PFOS in concentrated waste streams

Liang¹,

Pierce

Lin

et al. 2018

Remediation Journal

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The electrochemical oxidation (EO) of environmentally persistent perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) with a Magnéli phase Ti4O7 electrode was investigated in this study. After 3 hours (hr) of electrolysis, 96.0 percent of PFOA (10 milligrams per liter [mg/L] in 100 milliliters [mL] 100 millimolar [mM] Na2SO4 solution) was removed following pseudo first‐order kinetics (k = 0.0226 per minute [min]) with the degradation half‐life of 30.7 min. Under the same treatment conditions, PFOS (10 mg/L in 100 mL 100 mM Na2SO4 solution) removal reached 98.9 percent with a pseudo first‐order degradation rate constant of 0.0491/min and the half‐life of 14.1 min. Although, the degradation of PFOA was slower than PFOS, when subjected to EO treatment in separate solutions, PFOA appeared to degrade faster than PFOS when both are present in the same solution, indicating possible competition between PFOA and PFOS during Ti4O7 anode‐based EO treatment with PFOA having the competitive advantage. Moreover, the EO treatment was applied to degrade highly concentrated PFOA (100.5 mg/L) and PFOS (68.6 mg/L) in ion‐exchange resin regenerant (still bottom) with high organic carbon content (15,800 mg/L). After 17‐hr electrolysis, the total removal of PFOA and PFOS was 77.2 and 96.5 percent, respectively, and the fluoride concentration increased from 0.84 mg/L to 836 mg/L. Also, the dark brown color of the original solution gradually faded during EO treatment. In another test using still bottom samples with lower total organic carbon (9,880 mg/L), the PFOA (15.5 mg/L) and PFOS (25.5 mg/L) concentrations were reduced to levels below the limits of quantification after 16‐hr treatment. In addition, the performance of EO treatment using different batch reactor setups was compared in this study, including one‐sided (one anode:one cathode) and two‐sided (one anode:two cathodes) setups. The two‐sided reactor configuration significantly enhanced the degradation efficiency, likely due to the larger anode area available for reactions.

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Section: Resultssupporting

confidence: 93%

Electrochemical oxidation of PFOA and PFOS in concentrated waste streams

Liang¹,

Pierce

Lin

et al. 2018

Remediation Journal

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“…In the work of Oliveira et al (2018) focusing on the electrooxidation of industrial phenolic wastewaters, it was shown that the presence of chloride in the wastewater favored the electrogeneration of strong oxidant species, (mainly hypochlorous acid, but also chlorine, and hypochlorite) and increased the efficiency of the process. The effect of the presence of chloride ion on the oxidation process of various synthetic samples was also studied by Fernandes et al (2016a), who reported that the presence of chlorides enhanced the removal of organic matter and nitrogen. The same research group (Fernandes et al, 2016b) studied the EO of HA and sanitary landfill leachate samples.…”

Section: Effect Of Water Matricesmentioning

confidence: 99%

Electrochemical oxidation of butyl paraben on boron doped diamond in environmental matrices and comparison with sulfate radical-AOP

Pueyo

Ormad

Miguel

et al. 2020

Journal of Environmental Management

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The electrochemical oxidation (EO) of butyl paraben (BP) over boron-doped diamond (BDD) anode was studied in this work. Emphasis was put on degradation performance in various actual water matrices, including secondary treated wastewater (WW), bottled water (BW), surface water (SW), ultrapure water (UW), and ultrapure water spiked with humic acid (HA). Experiments were performed utilizing 0.1 M Na 2 SO 4 as the electrolyte. Interestingly, matrix complexity was found to favor BP degradation, i.e. in the order WW~BW>SW>UW, thus implying some kind of synergy between the water matrix constituents, the reactive oxygen species (ROS) and the anode surface.The occurrence of chloride in water matrices favors reaction presumably due to the formation of chlorine-based oxidative species, and this can partially offset the need to work at increased current densities in the case of chlorine-free electrolytes. No pH effect in the range 3-8 on degradation was recorded. EO oxidation was also compared with a sulfate radical process using carbon black as activator of sodium persulfate. The matrix effect was, in this case, detrimental (i.e. UW>BW>WW), pinpointing the different behavior of different processes in similar environments.

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“…However, when NaCl was used, TN concentration decreased by more than 50%. According to the literature, organic nitrogen is converted to NH 4 + in the EO using a BDD anode, which in turn is oxidized mainly to nitrate and nitrogen gas as NH 4 + oxidation takes place by indirect oxidation through active chlorine species [41,42]. It was also observed that, for the solutions containing chloride, TN removal was energetically more efficient at the highest current density.…”

Section: Resultsmentioning

confidence: 99%

Ecotoxicological Evaluation of Methiocarb Electrochemical Oxidation

et al. 2020

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The ecotoxicity of methiocarb aqueous solutions treated by electrochemical oxidation was evaluated utilizing the model organism Daphnia magna. The electrodegradation experiments were performed using a boron-doped diamond anode and the influence of the applied current density and the supporting electrolyte (NaCl or Na2SO4) on methiocarb degradation and toxicity reduction were assessed. Electrooxidation treatment presented a remarkable efficiency in methiocarb complete degradation and a high potential for reducing the undesirable ecological effects of this priority substance. The reaction rate followed first-order kinetics in both electrolytes, being more favorable in a chloride medium. In fact, the presence of chloride increased the methiocarb removal rate and toxicity reduction and favored nitrogen removal. A 200× reduction in the acute toxicity towards D. magna, from 370.9 to 1.6 toxic units, was observed for the solutions prepared with NaCl after 5 h treatment at 100 A m−2. An increase in the applied current density led to an increase in toxicity towards D. magna of the treated solutions. At optimized experimental conditions, electrooxidation offers a suitable solution for the treatment and elimination of undesirable ecological effects of methiocarb contaminated industrial or agricultural wastewaters, ensuring that this highly hazardous pesticide is not transferred to the aquatic environment.

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Electrochemical wastewater treatment: influence of the type of carbon and of nitrogen on the organic load removal

Cited by 9 publications

References 22 publications

Electrochemical oxidation of PFOA and PFOS in concentrated waste streams

Electrochemical oxidation of PFOA and PFOS in concentrated waste streams

Electrochemical oxidation of butyl paraben on boron doped diamond in environmental matrices and comparison with sulfate radical-AOP

Ecotoxicological Evaluation of Methiocarb Electrochemical Oxidation

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