2,4‐dinitroanisole transformation during advanced oxidation with ultraviolet light emitting diodes and hydrogen peroxide

Abstract

This study investigated the kinetics and reaction mechanisms associated with advanced oxidation of 2,4-dinitroanisole (DNAN) with light emitting diodes (LEDs) in the UV/H 2 O 2 process. The pseudo first-order reaction rate constants for DNAN oxidation depended on the H 2 O 2 /DNAN molar ratio and were between 0.017 and 0.026 min À1 .Hydroxyl radical scavenging was strongly implicated by the experimental results. High mass spectrophotometric chromatograms showed the presence of several by-products, including three with ecotoxicity that is greater than that of DNAN. Transformation pathways were analysed using Density Functional Theory (DFT), which helped to predict the presence of experimentally detected DNAN by-products by considering Mulliken charges. This study is the first to elucidate DNAN transformation mechanisms using both experimental studies and computational chemistry.

Hydroxyl radical‐driven transformations of bisphenol A and 2,4‐dinitroanisole: Experimental and computational analysis

“…Their experiments were done over a narrower range of molar peroxide ratios and with higher initial BPA concentrations (0.22 vs. 0.044 mM). The pseudo first‐order rate constants for DNAN removal were similar to those reported by Burdsall et al (2023) and Su et al (2019), who implemented UV/H 2 O 2 to remove DNAN from wastewater in beakers equipped with 13 W mercury lamps. Therefore, the current and previous studies form a clear consensus regarding the removal kinetics of BPA and DNAN.…”

“…Radical abstraction of the methoxy group followed by the addition of •OH to DNAN forms 2,4 DNP and •OCH 3 radicals (Figure 4). Abstraction of o-NO 2 , followed by combining the DNAN radical fragment with •OH, forms 2-hydroxy-4 nitroanisole along with a •NO 2 radical (Burdsall et al, 2023). Abstraction of the p-NO 2 from DNAN, followed by combining with an •OH, forms 2-nitro-4-hydroxyanisole alongside a •NO 2 radical (Burdsall et al, 2023).…”

“…Abstraction of o-NO 2 , followed by combining the DNAN radical fragment with •OH, forms 2-hydroxy-4 nitroanisole along with a •NO 2 radical (Burdsall et al, 2023). Abstraction of the p-NO 2 from DNAN, followed by combining with an •OH, forms 2-nitro-4-hydroxyanisole alongside a •NO 2 radical (Burdsall et al, 2023). Alternatively, if these DNAN radical fragments pick up a hydrogen radical from the solvent, 4-nitroanisole and 2-nitroanisole may form (Figure 4).…”

“…Frontier electron density can help to understand the oxidation of organic pollutants (Burdsall et al, 2023; He et al, 2022; Klein et al, 2021; Lee et al, 2001). Electron density calculations can help predict which positions on the molecule will undergo electrophilic attack (Parr & Yang, 1989).…”

Electrochemical Destruction of Insensitive High Explosives Using Magnéli Phase Titanium Oxide Reactive Electrochemical Membranes

“…Various emerging treatment strategies have been investigated for IHEs. For example, electrochemical reduction, chemical reduction using bimetallic and zerovalent iron particles, − biological degradation, − photochemical degradation, , alkaline hydrolysis, and advanced oxidation processes (AOPs) , have been applied to treat aqueous DNAN solutions. While these studies demonstrated DNAN destruction to varying extents, several of the treatment strategies have serious drawbacks.…”