ORIGINAL RESEARCH
Electrochemical Removal Kinetics of Nitrate Ions
on Copper from Acidic Medium
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Laboratoire des Nanomatériaux- Corrosion et Traitements de Surface (LNCTS), Faculté des Sciences,
Université Badji Mokhtar, BP 12, Annaba, Algérie
Submission date: 2023-02-24
Final revision date: 2023-06-12
Acceptance date: 2023-06-12
Online publication date: 2023-09-25
Publication date: 2023-10-25
Corresponding author
Fatima Guettari
Chemistry, Université Badji Mokhtar, BP 12, Annaba, Algeria., BP 12, 23000, Annaba, Algeria
Pol. J. Environ. Stud. 2023;32(6):5061-5069
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ABSTRACT
The electrocatalytic activity of the copper electrode for nitrate electroreduction was performed
in acidic medium. The mechanism of the reduction reaction was studied by cyclic voltammetry. One
cathodic peak was detected at ca. -0.62 V/SCE, where the charge transfer reaction takes place. The
number of electrons involved in the corresponding potential was determined to be eight. The ratedetermining
step was concluded to be the reduction of nitrate to nitrogen dioxide. According to further
analysis, the reduction reaction of NO3– on the copper electrode proved to be an irreversible process, with
diffusion as its limiting factor. At low concentrations ([NO3–]≤0.1 M), nitrate removal follows first-order
kinetics, while it approaches zero at high concentrations ([NO3–]≥0.1 M). As a result, the adsorption
phenomena associated with the nitrate reduction process follow a Langmuir isotherm adsorption with
a -5.0 Kj mol-1 adsorption Gibbs free energy. The charge transfer due to nitrate reaction and hydrogen
evolution was further verified by EIS measurements at different potentials, where the diffusion of nitrate
ions limits the reaction process. Bulk electrolysis results revealed that current density has a significant
effect on nitrate removal efficiency, as well as a percentage of nitrate destruction of up to 88% after 2h,
indicating the high capacity of copper for nitrate removal.