Electrochemical degradation of N,N-diethyl-m-toluamide on a boron-doped diamond electrode

• The oxidation of DEET on BDD is electrochemically irreversible.
• The DEET abatement and TOC removal are in the order BDD > PbO2 > Pt.
• The TOC removal in real environmental matrixes spiked with DEET is compared.
• The apparent rate constants of DEET oxidation are 5.00 × 10−3–8.98 × 10−3 s−1.
• DEET is 100% mineralized in treated wastewater effluent.

This study investigates the electrochemical oxidation of N,N-diethyl-m-toluamide (DEET) on a boron-doped diamond (BDD) anode under different temperatures, current densities, and sample matrixes. For comparison, a commercial Pt electrode and a lab-prepared PbO2 anode were also tested. The oxidation of DEET on BDD was found to be electrochemically irreversible. The degradation of DEET increased with the increase of current density, but was slightly influenced by temperature (25–75 °C). Furthermore, the BDD anode was superior to the Pt and PbO2 electrodes with regard to DEET abatement and total organic carbon (TOC) removal. At 0.75 A/cm2 and 50 °C, the pseudo-first-order rate constants of DEET oxidation were 5.00 × 10−3–8.98 × 10−3 s−1 in DEET-spiked 1 M Na2SO4 solution, municipal wastewater treatment plant secondary effluent (MWTPSE), groundwater (GW), and river water (RW), significantly greater than that (4.73 × 10−4 s−1) in DEET-spiked industrial wastewater (IW). The TOC removal in the real environmental matrixes followed the order MWTPSE > GW ≈ RW ≫ IW. Through electrochemical oxidation, DEET was completely mineralized in the DEET-spiked MWTPSE.