Electrochemical oxidation of N-nitrosodimethylamine with boron-doped diamond film electrodes

Brian P. Chaplin, Glenn L Schrader, James Farrell

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

This research investigated NDMA oxidation by boron-doped diamond (BDD) film electrodes. Oxidation rates were measured as a function of electrode potential, current density, and temperature using rotating disk and flow-through reactors. Final NDMA reaction products were carbon dioxide, ammonium, and nitrate, with dimethylamine and methylamine as intermediate products. Reaction rates were first-order with respect to NDMA concentration and surface area normalized oxidation rates as high as 850 ± 50 L/m2-hr were observed at a current density of 10 mA/cm2. The flow-through reactor yielded mass transfer limited reaction rates that were first-order in NDMA concentration, with a half-life of 2.1±0.1 min. Experimental evidence indicates that NDMA oxidation proceeds via a direct electron transfer at potentials >1.8 V/SHE with a measured apparent activation energy of 3.1 ± 0.5 kJ/mol at a potential of 2.5 V/SHE. Density functional theory calculations indicate that a direct two-electron transfer can produce a stable NDMA(+2) species that is stabilized by forming an adduct with water. The transfer of two electrons from NDMA to the electrode allows an activation-less attack of hydroxyl radicals on the NDMA(+2) water adduct. At higher overpotentials the oxidation of NDMA occurs by a combination of direct electron transfer and hydroxyl radicals produced via water electrolysis.

Original languageEnglish (US)
Pages (from-to)8302-8307
Number of pages6
JournalEnvironmental Science and Technology
Volume43
Issue number21
DOIs
StatePublished - Nov 1 2009

Fingerprint

Dimethylnitrosamine
Boron
Electrochemical oxidation
Diamond films
boron
diamond
electrode
oxidation
Oxidation
Electrodes
electron
Electrons
hydroxyl radical
Hydroxyl Radical
reaction rate
Reaction rates
Water
Current density
Rotating disks
density current

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry

Cite this

Electrochemical oxidation of N-nitrosodimethylamine with boron-doped diamond film electrodes. / Chaplin, Brian P.; Schrader, Glenn L; Farrell, James.

In: Environmental Science and Technology, Vol. 43, No. 21, 01.11.2009, p. 8302-8307.

Research output: Contribution to journalArticle

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