Decomposition of N, N-diethyl-m-toluamide by water plasma with mist generation

Abstract

The study presents the decomposition of a high concentration of N, N-diethyl-m-toluamide (DEET) by water plasma with mist generation at atmosphere pressure. The water mist generated from the DEET solution was used for the plasma. The relationship between operational arc currents and DEET decomposition was discussed in detail. The results showed that the decomposition rate of the DEET was improved as an increase of arc current at torch powers of 1.07–1.39 kW. Major effluent gases were H2, CO2, CO, and N2. The total organic carbon (TOC) for the effluent liquid was reduced up to 98%. The H, O, and OH as reactive species generated by the dissociation of water molecules were verified, and the plasma temperatures were estimated at over 8000 K. A possible decomposition pathway was deduced based on the identification of intermediate products by optical emission spectroscopy (OES), UV–visible (UV–vis) spectroscopy, and quadrupole time of flight mass spectrometer (QTOF-MS). Electron dissociation and hydroxylation were found to play important roles in ring opening and initial cleavage of the alkyl chains at the beginning of decomposition. The water plasma shows a robust driving force for processing organic wastes as an alternative green technology.