Percarbonate mediated advanced oxidation completely degrades recalcitrant pesticide imidacloprid: Role of reactive oxygen species and transformation products

Michael M. Sablas, Mark Daniel G. de Luna, Sergi Garcia-Segura, Chiu Wen Chen, Chih Feng Chen, Cheng Di Dong

Research output: Contribution to journalArticle

Abstract

Pesticides are vital and indispensable especially in agricultural production. However, pesticide contamination is also a serious threat to human health and the environment. Imidacloprid (IMD), an archetypal neonicotinoid insecticide, is commonly used to protect a variety of crops worldwide. This study examined the destruction of IMD contaminant in wastewater via catalytic oxidation with sodium percarbonate (SPC). The process exemplified 100% removal at optimum condition. Rates of reaction were expressed in terms of the apparent rate constants (kapp) and were observed to satisfactorily follow pseudo-first-order kinetics. Inhibitory effects of humic acid and various coexisting ions on IMD degradation were examined and the trend was observed as follows: NO2 > PO43− > NH4+ > Cl > NO3. In addition, we elucidated the participation of [rad]OH (hydroxyl), [rad]O2 (superoxyl), and HO2[rad] (perhydroxyl) radicals in the process by performing scavenging experiments for these reactive oxygen species. A likely IMD degradation pathway was proposed based on the intermediate species identified via gas chromatography/mass spectroscopy electron ionization procedure. Overall, the present study established SPC as a cleaner alternative to other oxidants for pesticide degradation as it is non-toxic, safe to handle, and produces by-products that inherently exist in the natural water matrix.

Original languageEnglish (US)
Article number117269
JournalSeparation and Purification Technology
Volume250
DOIs
StatePublished - Nov 1 2020

Keywords

  • Advanced oxidation processes
  • Imidacloprid
  • Inorganic ions
  • Natural organic matter
  • Reactive oxygen species

ASJC Scopus subject areas

  • Analytical Chemistry
  • Filtration and Separation

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