Effect of current density and sulfuric acid concentration on persulfuric acid generation by boron-doped diamond film anodes

Davis, Jake R.; Baygents, James C.; Farrell, James

doi:10.1007/s10800-014-0692-0

Cited by 41 publications

(25 citation statements)

References 8 publications

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“…These studies have reported that persulfate can be produced at Faradaic current efficiencies greater than 95% using low current densities in sulfuric acid solutions with concentrations greater than 2 M. A previous study in our laboratory found that Faradaic efficiencies for persulfate generation were only 59 to 66% in 2.5 M sulfuric acid at current densities ranging from 80 to 280 mA cm À2 [13]. This difference in Faradaic efficiencies suggests that there may be different mechanisms contributing to persulfate production at low and high current densities.…”

Section: Introductionmentioning

confidence: 80%

Understanding Persulfate Production at Boron Doped Diamond Film Anodes

Davis

Baygents

Farrell

2014

Electrochimica Acta

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167

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Section: Introductionmentioning

confidence: 80%

Understanding Persulfate Production at Boron Doped Diamond Film Anodes

Davis

Baygents

Farrell

2014

Electrochimica Acta

Self Cite

167

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“…4, 85% DEX removal was achieved after 15 min with 50 mg L −1 SPS, and this increased to 95% with 150–250 mg L −1 SPS. Sulfate radicals can be produced electrochemically from persulfate (Eqn (5)), which can partly be regenerated at the anode (Eqn (6)) in a cyclic process: 17,18

S_{2} O_{8}^{2 -} + e^{-} \to {SO}_{4}^{∙ -} + {SO}_{4}^{2 -}

2 normalS O_{4}^{2 -} + e^{-} \to {S_{2} normalO}_{8}^{2 -} + 2 e^{-}

Moreover, persulfate can react with the electrogenerated hydroxyl radicals at the anode surface and produce more sulfate radicals, according to Eqn (7):

S_{2} O_{8}^{2 -} + {normalH normalΟ}^{∙} \overset{⟶}{true} {HSO}_{4}^{-} + {SO}_{4}^{∙ -} + 0.5 O_{2}

The role of SPS in DEX degradation is not limited to the generation of extra radicals but also involves its direct participation as an oxidant itself; this is demonstrated in Fig. 4, where 80% DEX removal was reached after 45 min with 150 mg L −1 SPS in the absence of current.…”

Section: Resultsmentioning

confidence: 99%

“…Persulfate has a long half‐life, ease of storage and transportation and can be activated via transition metals, ultraviolet irradiation and electrochemical techniques 16 . Sulfate radicals can be formed at the BDD anode via oxidation of sulfate ions to sulfate radicals, whose partial recombination can generate persulfate 17,18 …”

Section: Introductionmentioning

confidence: 99%

Degradation of dexamethasone in water using BDD anodic oxidation and persulfate: reaction kinetics and pathways

Grilla

Taheri

Miserli

et al. 2021

J of Chemical Tech & Biotech

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BACKGROUND The presence of micro‐pollutants in conventional wastewater treatment plants raises environmental concerns due to their insufficient removal. Non‐biological methods are needed to treat such compounds and this work demonstrates the use of electrochemical oxidation for the degradation of the drug dexamethasone (DEX). RESULTS A cell consisting of a boron‐doped diamond anode and a stainless steel or carbon cloth cathode was employed, with Na2SO4 being the electrolyte. DEX degradation rate, at the low level of mg L−1 (0.25–2 mg L−1), increases with increasing current (0.02–0.2 A m−2), as well as in the presence of sodium persulfate (50–250 mg L−1); the latter is electrochemically activated to produce additional oxidants and enhances degradation in a synergistic way. A rate constant of 0.194 min−1 was recorded for 0.5 mg L−1 DEX degradation at 0.2 A m−2 with 150 mg L−1 persulfate. The water matrix had little effect on performance compared to experiments in pure water; the only exception was the presence of chloride (50–250 mg L−1), which substantially improved rates due to the formation of active chlorine species (up to about five times). Carbon cloth accelerated DEX removal by up to three times compared to stainless steel and this was partly due to its adsorptive capacity; similarly, reactions involving DEX transformation products (TPs) also occurred faster. Seven TPs were identified and profiles were followed; reaction pathways involve hydroxylation, oxidation, decarboxylation and ring‐opening reactions, followed by fluorine release in the liquid phase. CONCLUSION A hybrid technology based on electrochemical oxidation and persulfate activation is proposed for the treatment of residual pharmaceuticals in environmental matrices. © 2021 Society of Chemical Industry (SCI).

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“…While certain redox titrants can be used for the specific quantification of S2O8 2-, SO5 2-, or H2O2 (Table 1), these are tedious to perform, and generate large quantities of aqueous waste containing toxic arsenic, vanadium and manganese salts. Alternatively, quantitative methods based on polarography 7 or ion chromatography 8,9 had been reported, which will require access to dedicated analytical instruments. Furthermore, analysis of S2O8 2by ion chromatography is particularly challenging, requiring special measures to elute the large and highly polar anion.…”

Section: S2o8 2-+ H + + H2o  Hso5 -+ H2so4mentioning

confidence: 99%