Fenton-based electrochemical degradation of metolachlor in aqueous solution by means of BDD and Pt electrodes: influencing factors and reaction pathways
- 51 Downloads
This work explores the role of electrode material and the oxidation ability of electrochemical advanced oxidation processes (EAOPs), such as electro-oxidation (EO) with or without H2O2 production, electro-Fenton (EF), and UVA photoelectron-Fenton (PEF), in the degradation of metolachlor. The performance of the EAOPs using Boron-doped diamond (BDD) or Pt as anode has been compared from the analysis of decay kinetics, mineralization profile, and energy consumption using small undivided batch cell. Metolachlor concentration always decays following a pseudo-first-order kinetics. Using the Pt anode, none of the processes reaches 30% mineralization, including PEF. In contrast, the BDD anode showed a higher mineralization rate allowing almost total mineralization in PEF due to the synergetic action of UVA light and oxidant hydroxyl radicals formed in the bulk from Fenton’s reaction, as well as in the BDD, which has large reactivity to oxidize the pollutants. The increase in current density and decrease in metolachlor concentration accelerated the mineralization in PEF, although lower current efficiency and higher energy consumption was obtained. The GC-MS and HPLC analysis allowed the identification of up to 17 aromatics intermediates and 7 short-chain carboxylic acids. Finally, a reaction pathway for metolachlor mineralization by EAOPs is proposed. PEF with BDD allowed total removal of the herbicide in real water matrix and a high mineralization (83.82%).
KeywordsMetolachlor Electrochemical oxidation Electro-Fenton Oxidation products Photoelectro-Fenton, real wastewater
CONICYT (Chile) provided the financial support under FONDECYT postdoctorado projects no. 3160753, Fondecyt Iniciación no. 11170882, and Fondecyt regular no. 1170352.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- © World Health Organization (1993) Guidelines for Drinking-Water Quality - WHO 1993. 1:11. https://doi.org/10.1017/CBO9781107415324.004
- Barra Caracciolo A, Giuliano G, Grenni P, Guzzella L, Pozzoni F, Bottoni P, Fava L, Crobe A, Orrù M, Funari E (2005) Degradation and leaching of the herbicides metolachlor and diuron: a case study in an area of northern Italy. Environ Pollut 134:525–534. https://doi.org/10.1016/j.envpol.2004.08.014 CrossRefGoogle Scholar
- Brillas E, Boye B, Sirés I, Garrido JA, Rodrı́guez RḾ, Arias C, Cabot PĹ, Comninellis C (2004) Electrochemical destruction of chlorophenoxy herbicides by anodic oxidation and electro-Fenton using a boron-doped diamond electrode. Electrochim Acta 49:4487–4496. https://doi.org/10.1016/j.electacta.2004.05.006 CrossRefGoogle Scholar
- El-Ghenymy A, Rodríguez RM, Brillas E et al (2014) Electro-Fenton degradation of the antibiotic sulfanilamide with Pt/carbon-felt and BDD/carbon-felt cells. Kinetics, reaction intermediates, and toxicity assessment. Environ Sci Pollut Res 21:8368–8378. https://doi.org/10.1007/s11356-014-2773-3 CrossRefGoogle Scholar
- Feng L, van Hullebusch ED, Rodrigo MA, Esposito G, Oturan MA (2013) Removal of residual anti-inflammatory and analgesic pharmaceuticals from aqueous systems by electrochemical advanced oxidation processes. A review. Chem Eng J 228:944–964. https://doi.org/10.1016/j.cej.2013.05.061 CrossRefGoogle Scholar
- Guinea E, Garrido JA, Rodríguez RM, Cabot PL, Arias C, Centellas F, Brillas E (2010) Degradation of the fluoroquinolone enrofloxacin by electrochemical advanced oxidation processes based on hydrogen peroxide electrogeneration. Electrochim Acta 55:2101–2115. https://doi.org/10.1016/j.electacta.2009.11.040 CrossRefGoogle Scholar
- Isarain-Chávez E, Arias C, Cabot PL, Centellas F, Rodríguez RM, Garrido JA, Brillas E (2010) Mineralization of the drug β-blocker atenolol by electro-Fenton and photoelectro-Fenton using an air-diffusion cathode for H2O2 electrogeneration combined with a carbon-felt cathode for Fe2+ regeneration. Appl Catal B Environ 96:361–369. https://doi.org/10.1016/j.apcatb.2010.02.033 CrossRefGoogle Scholar
- Lanzarini-Lopes M, Garcia-Segura S, Hristovski K, Westerhoff P (2017) Electrical energy per order and current efficiency for electrochemical oxidation of p-chlorobenzoic acid with boron-doped diamond anode. Chemosphere 188:304–311. https://doi.org/10.1016/j.chemosphere.2017.08.145 CrossRefGoogle Scholar
- Mendy A, Thiaré DD, Sambou S, Khonté A, Coly A, Gaye-Seye MD, Delattre F, Tine A (2016) New method for the determination of metolachlor and buprofezin in natural water using orthophthalaldehyde by thermochemically-induced fluorescence derivatization (TIFD). Talanta 151:202–208. https://doi.org/10.1016/j.talanta.2016.01.036 CrossRefGoogle Scholar
- Moreira FC, Garcia-Segura S, Vilar VJP, Boaventura RAR, Brillas E (2013) Decolorization and mineralization of sunset yellow FCF azo dye by anodic oxidation, electro-Fenton, UVA photoelectro-Fenton and solar photoelectro-Fenton processes. Appl Catal B Environ 142–143:877–890. https://doi.org/10.1016/j.apcatb.2013.03.023 CrossRefGoogle Scholar
- Oturan N, Hamza M, Ammar S, Abdelhédi R, Oturan MA (2011) Oxidation/mineralization of 2-nitrophenol in aqueous medium by electrochemical advanced oxidation processes using Pt/carbon-felt and BDD/carbon-felt cells. J Electroanal Chem 661:66–71. https://doi.org/10.1016/j.jelechem.2011.07.017 CrossRefGoogle Scholar
- Ruiz EJ, Arias C, Brillas E, Hernández-Ramírez A, Peralta-Hernández JM (2011) Mineralization of acid yellow 36 azo dye by electro-Fenton and solar photoelectro-Fenton processes with a boron-doped diamond anode. Chemosphere 82:495–501. https://doi.org/10.1016/j.chemosphere.2010.11.013 CrossRefGoogle Scholar
- Salazar R, Brillas E, Sirés I (2012) Finding the best Fe2+/Cu2+ combination for the solar photoelectro-Fenton treatment of simulated wastewater containing the industrial textile dye disperse blue 3. Appl Catal B Environ 115–116:107–116. https://doi.org/10.1016/j.apcatb.2011.12.026 CrossRefGoogle Scholar
- Skoumal M, Rodríguez RM, Cabot PL, Centellas F, Garrido JA, Arias C, Brillas E (2009) Electro-Fenton, UVA photoelectro-Fenton and solar photoelectro-Fenton degradation of the drug ibuprofen in acid aqueous medium using platinum and boron-doped diamond anodes. Electrochim Acta 54:2077–2085. https://doi.org/10.1016/j.electacta.2008.07.014 CrossRefGoogle Scholar
- Thiam A, Zhou M, Brillas E, Sirés I (2014) Two-step mineralization of tartrazine solutions: study of parameters and by-products during the coupling of electrocoagulation with electrochemical advanced oxidation processes. Appl Catal B Environ 150–151:116–125. https://doi.org/10.1016/j.apcatb.2013.12.011 CrossRefGoogle Scholar