Mineralization of phthalic acid by solar photoelectro-Fenton with a stirred boron-doped diamond/air-diffusion tank reactor: Influence of Fe3+ and Cu2+ catalysts and identification of oxidation products

Sergio GARCIA SEGURA, Ricardo Salazar, Enric Brillas

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

Here, the substrate decay and mineralization rate for 100 cm3 of a 2.0 mM phthalic acid solution in 0.10 M Na2SO4 of pH 3.0 have been studied by electro-Fenton (EF) and solar photoelectro-Fenton (SPEF). The electrochemical cell was a stirred tank reactor containing a 3 cm2 boron-doped diamond (BDD) anode and a 3 cm2 air-diffusion cathode that generates H2O2. Cu2+ and/or Fe3+ were added as catalysts with total concentration of 0.50 mM and a constant current density of 33.3 mA cm-2 was applied. In EF with Cu2+ or Fe3+ alone and SPEF with only Cu 2+, phthalic acid decayed slowly and poor mineralization was reached because the main oxidant was OH produced at the BDD surface from water oxidation. In contrast, the substrate destruction was largely enhanced using SPEF with 0.50 mM Fe3+ since a high quantity of oxidant OH was produced in the bulk induced by photo-Fenton reaction. This treatment led to an almost total mineralization by the photolysis of generated Fe(III)-carboxylate complexes. In all cases, the decay of phthalic acid obeyed a pseudo-first-order reaction. The combination of Cu2+ and Fe3+ as catalysts accelerated the mineralization process in SPEF because Cu(II)-carboxylate complexes were also removed with OH formed from photo-Fenton reaction. The best SPEF process was found for 0.125 mM Cu2+ + 0.375 mM Fe3+, giving rise to 99% mineralization with 40% current efficiency and 0.294 kWh g-1 TOC energy consumption. Eleven aromatics and six short-linear carboxylic acids were identified as oxidation products. A plausible reaction sequence for phthalic acid mineralization involving all the detected products was finally proposed.

Original languageEnglish (US)
Pages (from-to)609-619
Number of pages11
JournalElectrochimica Acta
Volume113
DOIs
StatePublished - Nov 6 2013
Externally publishedYes

Fingerprint

Diamond
Boron
Diamonds
Oxidation
Catalysts
Acids
Air
Oxidants
Electrochemical cells
Photolysis
Substrates
Carboxylic Acids
Carboxylic acids
Anodes
Cathodes
Current density
Energy utilization
phthalic acid
Water

Keywords

  • Electro-Fenton
  • Oxidation products
  • Phthalic acid
  • Solar photoelectro-Fenton
  • Water treatment

ASJC Scopus subject areas

  • Electrochemistry
  • Chemical Engineering(all)

Cite this

@article{1cf7dc0b48734a03a375ab37154d2b58,
title = "Mineralization of phthalic acid by solar photoelectro-Fenton with a stirred boron-doped diamond/air-diffusion tank reactor: Influence of Fe3+ and Cu2+ catalysts and identification of oxidation products",
abstract = "Here, the substrate decay and mineralization rate for 100 cm3 of a 2.0 mM phthalic acid solution in 0.10 M Na2SO4 of pH 3.0 have been studied by electro-Fenton (EF) and solar photoelectro-Fenton (SPEF). The electrochemical cell was a stirred tank reactor containing a 3 cm2 boron-doped diamond (BDD) anode and a 3 cm2 air-diffusion cathode that generates H2O2. Cu2+ and/or Fe3+ were added as catalysts with total concentration of 0.50 mM and a constant current density of 33.3 mA cm-2 was applied. In EF with Cu2+ or Fe3+ alone and SPEF with only Cu 2+, phthalic acid decayed slowly and poor mineralization was reached because the main oxidant was OH produced at the BDD surface from water oxidation. In contrast, the substrate destruction was largely enhanced using SPEF with 0.50 mM Fe3+ since a high quantity of oxidant OH was produced in the bulk induced by photo-Fenton reaction. This treatment led to an almost total mineralization by the photolysis of generated Fe(III)-carboxylate complexes. In all cases, the decay of phthalic acid obeyed a pseudo-first-order reaction. The combination of Cu2+ and Fe3+ as catalysts accelerated the mineralization process in SPEF because Cu(II)-carboxylate complexes were also removed with OH formed from photo-Fenton reaction. The best SPEF process was found for 0.125 mM Cu2+ + 0.375 mM Fe3+, giving rise to 99{\%} mineralization with 40{\%} current efficiency and 0.294 kWh g-1 TOC energy consumption. Eleven aromatics and six short-linear carboxylic acids were identified as oxidation products. A plausible reaction sequence for phthalic acid mineralization involving all the detected products was finally proposed.",
keywords = "Electro-Fenton, Oxidation products, Phthalic acid, Solar photoelectro-Fenton, Water treatment",
author = "{GARCIA SEGURA}, Sergio and Ricardo Salazar and Enric Brillas",
year = "2013",
month = "11",
day = "6",
doi = "10.1016/j.electacta.2013.09.097",
language = "English (US)",
volume = "113",
pages = "609--619",
journal = "Electrochimica Acta",
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TY - JOUR

T1 - Mineralization of phthalic acid by solar photoelectro-Fenton with a stirred boron-doped diamond/air-diffusion tank reactor

T2 - Influence of Fe3+ and Cu2+ catalysts and identification of oxidation products

AU - GARCIA SEGURA, Sergio

AU - Salazar, Ricardo

AU - Brillas, Enric

PY - 2013/11/6

Y1 - 2013/11/6

N2 - Here, the substrate decay and mineralization rate for 100 cm3 of a 2.0 mM phthalic acid solution in 0.10 M Na2SO4 of pH 3.0 have been studied by electro-Fenton (EF) and solar photoelectro-Fenton (SPEF). The electrochemical cell was a stirred tank reactor containing a 3 cm2 boron-doped diamond (BDD) anode and a 3 cm2 air-diffusion cathode that generates H2O2. Cu2+ and/or Fe3+ were added as catalysts with total concentration of 0.50 mM and a constant current density of 33.3 mA cm-2 was applied. In EF with Cu2+ or Fe3+ alone and SPEF with only Cu 2+, phthalic acid decayed slowly and poor mineralization was reached because the main oxidant was OH produced at the BDD surface from water oxidation. In contrast, the substrate destruction was largely enhanced using SPEF with 0.50 mM Fe3+ since a high quantity of oxidant OH was produced in the bulk induced by photo-Fenton reaction. This treatment led to an almost total mineralization by the photolysis of generated Fe(III)-carboxylate complexes. In all cases, the decay of phthalic acid obeyed a pseudo-first-order reaction. The combination of Cu2+ and Fe3+ as catalysts accelerated the mineralization process in SPEF because Cu(II)-carboxylate complexes were also removed with OH formed from photo-Fenton reaction. The best SPEF process was found for 0.125 mM Cu2+ + 0.375 mM Fe3+, giving rise to 99% mineralization with 40% current efficiency and 0.294 kWh g-1 TOC energy consumption. Eleven aromatics and six short-linear carboxylic acids were identified as oxidation products. A plausible reaction sequence for phthalic acid mineralization involving all the detected products was finally proposed.

AB - Here, the substrate decay and mineralization rate for 100 cm3 of a 2.0 mM phthalic acid solution in 0.10 M Na2SO4 of pH 3.0 have been studied by electro-Fenton (EF) and solar photoelectro-Fenton (SPEF). The electrochemical cell was a stirred tank reactor containing a 3 cm2 boron-doped diamond (BDD) anode and a 3 cm2 air-diffusion cathode that generates H2O2. Cu2+ and/or Fe3+ were added as catalysts with total concentration of 0.50 mM and a constant current density of 33.3 mA cm-2 was applied. In EF with Cu2+ or Fe3+ alone and SPEF with only Cu 2+, phthalic acid decayed slowly and poor mineralization was reached because the main oxidant was OH produced at the BDD surface from water oxidation. In contrast, the substrate destruction was largely enhanced using SPEF with 0.50 mM Fe3+ since a high quantity of oxidant OH was produced in the bulk induced by photo-Fenton reaction. This treatment led to an almost total mineralization by the photolysis of generated Fe(III)-carboxylate complexes. In all cases, the decay of phthalic acid obeyed a pseudo-first-order reaction. The combination of Cu2+ and Fe3+ as catalysts accelerated the mineralization process in SPEF because Cu(II)-carboxylate complexes were also removed with OH formed from photo-Fenton reaction. The best SPEF process was found for 0.125 mM Cu2+ + 0.375 mM Fe3+, giving rise to 99% mineralization with 40% current efficiency and 0.294 kWh g-1 TOC energy consumption. Eleven aromatics and six short-linear carboxylic acids were identified as oxidation products. A plausible reaction sequence for phthalic acid mineralization involving all the detected products was finally proposed.

KW - Electro-Fenton

KW - Oxidation products

KW - Phthalic acid

KW - Solar photoelectro-Fenton

KW - Water treatment

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U2 - 10.1016/j.electacta.2013.09.097

DO - 10.1016/j.electacta.2013.09.097

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JO - Electrochimica Acta

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