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Synergistic effects of the combined use of ozone and sodium percarbonate for the oxidative degradation of dichlorvos

Journal Contribution - Journal Article

Dichlorvos or 2,2-dichlorovinyl dimethyl phosphate (DDVP) is a chlorinated organophosphorus pesticide which is frequently detected in the aqueous environment. In this study, an environmentally friendly and highly efficient oxidant, i.e., sodium percarbonate (SPC, Na2CO3⋅1.5H2O2) was introduced to an ozonation process for the degradation of dichlorvos (DDVP). Experimental results revealed an enhancement of DDVP degradation efficiency via the O3/SPC process compared with O3 alone due to the generation of reactive species (OH• and CO3 • − ) under various conditions. Both processes fitted the pseudo-first-order kinetic model and the reaction rate constant of the O3/SPC process under low SPC dosage (30 mg L-1) was more than two times higher than for O3 alone. The DDVP removal performance was evaluated in terms of initial pH, O3 dosage, SPC dosage and water matrix. The pH played a significant role in DDVP degradation during the O3/SPC process, especially on the occurrence of the different types of reactive species. Based on radical scavenger experiments, OH• were observed over the full pH range but dominated under neutral and alkaline conditions, while less oxidative CO3 • - emerged at lower pH. Furthermore, the complex matrix of real wastewater inhibited the oxidation process due to the competition for oxidative species between organic matter and DDVP. A modified kinetic model based on a steady-state hypothesis was established to predict DDVP degradation via the O3/SPC treatment and provided a fair result under different conditions. This observation suggested that eco-friendly SPC could be considered as a promising alternative for H2O2 in developing sustainable ozone-based oxidation processes for recalcitrant compounds elimination in wastewater treatment.
Journal: Journal Of Water Process Engineering
ISSN: 2214-7144
Volume: 39
Pages: 1 - 8
Publication year:2021
BOF-keylabel:yes
IOF-keylabel:yes
BOF-publication weight:3
CSS-citation score:1
Authors:International
Authors from:Higher Education
Accessibility:Closed