Application of boron-doped diamond electrodes for the anodic oxidation of pesticide micropollutants in a water treatment process: a critical review

• Published in: Environmental science water research & technology Vol. 5; no. 12; pp. 29 - 217
• Main Authors: McBeath, Sean T, Wilkinson, David P, Graham, Nigel J. D
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 01.12.2019
• Subjects: Aliphatic compounds; Anodizing; Aqueous solutions; Aromatic compounds; Boron; By-products; Byproducts; Chemical evolution; Contaminants; Degradation; Diamonds; Drinking water; Electrodes; Free radicals; Hydroxyl radicals; Kinetics; Mass transport; Micropollutants; Mineralization; Oxidation; Oxygen; Performance degradation; Pesticides; Reaction kinetics; Wastewater; Wastewater pollution; Wastewater treatment; Water treatment
• ISSN: 2053-1400; 2053-1419
• DOI: 10.1039/c9ew00589g

Boron-doped diamond (BDD) electrodes have the greatest known oxygen overpotential range; a characteristic that has allowed the material to be well suited for electro-oxidation processes in aqueous media. When operating in a potential range of water decomposition, strongly oxidising hydroxyl radicals are formed while oxygen evolution is minimised. The majority of research studies undertaken to-date have focused on the application of BDDs for the remediation of wastewater contaminants, however there is an increasing need for a suitable technology to address recalcitrant micropollutants in a drinking water context. Pesticide micropollutants are widely detected in surface- and ground-waters and are of increasing concern. In this paper, the treatment of pesticides by BDD electro-oxidation is reviewed. Their degradation and mineralisation, as well as the effect of operating conditions, formation of intermediate by-products, reaction pathways and kinetics are summarized. In general, BDD electro-oxidation was found to be effective for the degradation of pesticides with the degradation performance proportional to the electrolytic current, due principally to the increased generation of &z.rad;OH radicals. Most contaminants followed pseudo first-order reaction kinetics under mass transport limitations. Generally, the same aromatic and aliphatic by-products were formed through similar oxidation pathways. Finally, research gaps and potential future research topics are discussed. Boron-doped diamond (BDD) electrodes have the greatest known oxygen overpotential range; a characteristic that has allowed the material to be well suited for electro-oxidation processes in aqueous media.