Electrochemical degradation of the herbicide picloram using a filter-press flow reactor with a boron-doped diamond or β-PbO 2 anode

Pereira, Gabriel Fernandes; Rocha‐Filho, Romeu C.; Bocchi, Nerilso; Biaggio, Sonia R.

doi:10.1016/j.electacta.2015.05.134

Cited by 48 publications

(24 citation statements)

References 58 publications

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“…However, Figure 5 shows that 1, 2-DCB and 1, 4-DCB appears to be destroyed at slower rate using a PbO 2 anode and completely removed in a time much more than 240 min. It is well known that •OH formed at BDD remains mainly free on its surface where it attacks non-selectively and directly organics, whereas this radical is adsorbed on the PbO 2 surface, where it reacts selectively and more slowly with adsorbed organics [35]. According to this behavior, several authors recently reported that phenol, o-substituted phenols and nitrophenol pesticide are more rapidly destroyed with BDD than with PbO 2 using small conventional electrolytic cells [36].…”

Section: Decay Kinetics Of Dichlorobenzenementioning

confidence: 98%

Anodic Oxidation of Chlorinated Pesticides on BDD and PbO2 Electrodes: Kinetics, Influential Factors and Mechanism Determination

Rabaaoui¹,

Kacem²,

Mohamed³

et al. 2017

Mod Chem Appl

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In this work, the removal of two pesticides 1, 2-dichlorobenzene and 1, 4-dichlorobenzene by electrolysis using BDD and Pb/PbO 2 as anodes is studied. Different operating conditions and factors affecting the treatment process including anode material, applied current density, supporting electrolyte and initial pH value were studied and optimized. Results demonstrate, as expected, that the influence of the anode material used on the degradation of pesticides was very significant in all cases. Infact electrolysis with diamond electrodes can attain the complete depletion of the pesticide and its mineralization faster than with PbO 2 anode. Electrolysis experiments strongly improves that the complete degradation of pesticides occurred in the presence of Na 2 SO 4 as conductive electrolyte at current density equals 20 mA cm -2 . Acidic pH would accelerate dichlorobenzene degradation, whereas alkaline condition showed negative effects. The disappearance of the pesticides followed a pseudo-first-order kinetics. Reversed-phase chromatography allows detecting Catechol, 2-chlorophenol and Pyrogallol as primary aromatic intermediates of 1,2-DCB and Hydroquinone, Benzoquinone and 4-chlorophenol for 1,4-DCB. Dechlorination of these products gives chloride ions Cl -. Ion-exclusion chromatography reveals the presence of maleic, formic, fumaric, malonic, glyoxylic, acetic and oxalic acid. An oxidation mechanism is proposed in agreement with other works shown in the literature.

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Section: Decay Kinetics Of Dichlorobenzenementioning

confidence: 98%

Anodic Oxidation of Chlorinated Pesticides on BDD and PbO2 Electrodes: Kinetics, Influential Factors and Mechanism Determination

Rabaaoui¹,

Kacem²,

Mohamed³

et al. 2017

Mod Chem Appl

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“…As pointed out by Kapalka et al [16], BDD is an ideal anode material for the mineralization of organics; thus, it is being widely used nowadays in direct electrooxidation [10,[17][18][19][20] and in combined treatment methods such as electro-Fenton [21][22][23], solar electro-Fenton [22], or sonoelectrochemical [24], as well as in the electrochemical detection [25][26][27], of distinct classes of organic substances. High mineralization rates and current efficiencies are attained with BDD anodes due to properties such as large electrochemical window and good corrosion stability [28], as well as the presence of quasi-free hydroxyl radicals on their surfaces [16,29].…”

Section: Introductionmentioning

confidence: 99%

Electrochemical mineralization of norfloxacin using distinct boron-doped diamond anodes in a filter-press reactor, with investigations of toxicity and oxidation by-products

Coledam

Aquino

Silva³

et al. 2016

Electrochimica Acta

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The contamination of water bodies by antibiotics is a cause of concern due to chronic toxic effects and the possible development of resistance to them by microorganisms, which can lead to serious health problems to humans. Thus, in this work, for the first time the degradation of norfloxacin (100 mg L À1 NOR in 0.1 mol L À1 Na 2 SO 4) is carried out electrochemically, using a filter-press flow reactor with boron-doped diamond (BDD) anodes of distinct characteristics. The investigated variables (and their ranges) were solution pH (3, 7, 10, and without specific control), current density (10, 20, and 30 mA cm À2), temperature (10, 25, and 40 C), and boron content-sp 2 /sp 3 carbon ratio of the BDD anode (100 ppm-215, 500 ppm-325, and 2500 ppm-284). The NOR electrodegradation performance of the distinct anodes was assessed by monitoring the degradation by-products (aromatic compounds and carboxylic acids), NOR concentration and total organic carbon concentration of the electrolyzed solutions, as well as their toxicity to Escherichia coli (i.e. growth inhibition). For the complete removal of NOR, the best condition (not pH dependent) was attained at 10 mA cm À2 and 40 C, when the system is under mass transfer limitations. Concerning NOR oxidation and mineralization rates, mineralization current efficiency, energy consumption, and degradation products, similar results (including the complete detoxification of the electrolyzed solution) were attained for all tested BDD anodes under mass or charge transfer controlled processes. Clearly, the oxidation power of the tested BDD anodes is not affected by the values of their boron content-sp 2 /sp 3 carbon ratio.

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“…The highest adsorption's strength of •OH radicals on each electrode surface (adsorption enthalpy) the lower oxidizing power (Kapałka et al, 2009). Even though, the BDD electrodes are well known by their high oxidizing power (Alfaro et al, 2006;Kapałka et al, 2009Kapałka et al, , 2008, the presence of chloride species can slow down the electrodes performance in the EOCs degradation, and therefore the indirect oxidation by active chlorine species may not occur (Anglada et al, 2009;Mascia et al, 2007;Pereira et al, 2015;Scialdone et al, 2009).…”

Section: Electrochemical Batch Reactor (Ebr): Degradation Kineticsmentioning

confidence: 99%

Emerging organic contaminants in wastewater: Understanding electrochemical reactors for triclosan and its by-products degradation

et al. 2020

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Degradation technologies applied to emerging organic contaminants from human activities are one of the major water challenges in the contamination legacy. Triclosan is an emerging contaminant, commonly used as antibacterial agent in personal care products. Triclosan is stable, lipophilic and it is proved to have ecotoxicology effects in organics. This induces great concern since its elimination in wastewater treatment plants is not efficient and its by-products (e.g. methyl-triclosan, 2,4dichlorophenol or 2,4,6-trichlorophenol) are even more hazardous to several environmental compartments. This work provides understanding of two different electrochemical reactors for the degradation of triclosan and its derivative by-products in effluent. A batch reactor and a flow reactor (mimicking a secondary settling tank in a wastewater treatment plant) were tested with two different working anodes: Ti/MMO and Nb/BDD. The degradation efficiency and kinetics were evaluated to find the best combination of current density, electrodes and set-up design. For both reactors the best electrode combination was achieved with Ti/MMO as anode. The batch reactor at 7 mA/cm2 during 4 h attained degradation rates below the detection limit for triclosan and 2,4,6-trichlorophenol and, 94% and 43% for 2,4-dichlorophenol and methyl triclosan, respectively. The flow reactor obtained, in approximately 1 h, degradation efficiencies between 41% and 87% for the four contaminants under study. This study suggests an alternative technology for emergent organic contaminants degradation, since the combination of a low current density with the flow and matrix induced disturbance increases and speeds up the compounds' elimination in a real environmental matrix.

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Electrochemical degradation of the herbicide picloram using a filter-press flow reactor with a boron-doped diamond or β-PbO 2 anode

Cited by 48 publications

References 58 publications

Anodic Oxidation of Chlorinated Pesticides on BDD and PbO2 Electrodes: Kinetics, Influential Factors and Mechanism Determination

Anodic Oxidation of Chlorinated Pesticides on BDD and PbO2 Electrodes: Kinetics, Influential Factors and Mechanism Determination

Electrochemical mineralization of norfloxacin using distinct boron-doped diamond anodes in a filter-press reactor, with investigations of toxicity and oxidation by-products

Emerging organic contaminants in wastewater: Understanding electrochemical reactors for triclosan and its by-products degradation

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