Enhanced denitrification of aniline and its derivatives by catalysts, anions, and co-fuels during supercritical water oxidation process

Abstract

We investigated the denitrification performance of aniline and its derivatives (N-methylaniline and N, N-dimethylaniline) in supercritical water oxidation (SCWO) under varying conditions (temperature: 643–743 K, reaction time: 0.5–4 min, pressure: 24.0 MPa, oxidation coefficient: 300%). Cu2 + proved to be an efficient homogeneous catalyst, generating radicals via a Fenton-like reaction. Isopropyl alcohol (IPA) outperformed methanol and ethanol as a co-fuel, enhancing TN removal due to its higher heating value. Nitrogen-containing product distribution revealed that N2 generation correlated with org-N depletion, especially with Cu2 + and IPA. A denitrification mechanism was elucidated using DFT, with Fukui indices, EHOMO, and ELUMO highlighting aniline's greater susceptibility compared to MA and DMA. Our findings provide insights into optimizing SCWO denitrification using aniline derivatives, shedding light on sustainable nitrogen removal processes.