Correlation between degradation pathway and toxicity of acetaminophen and its by-products by using the electro-Fenton process in aqueous media

Abstract

The evolution of the degradation by-products of an acetaminophen (ACE) solution was monitored by HPLC-UV/MS and IC in parallel with its ecotoxicity (Vibrio fischeri 81.9%, Microtox screening tests) during electro-Fenton (EF) oxidation performed on carbon felt. The aromatic compounds 2-hydroxy-4-(N-acetyl) aminophenol, 1,4-benzoquinone, benzaldehyde and benzoic acid were identified as toxic sub-products during the first stage of the electrochemical treatment, whereas aliphatic short-chain carboxylic acids (oxalic, maleic, oxamic, formic, acetic and fumaric acids) and inorganic ions (ammonium and nitrate) were well identified as non-toxic terminal sub-products. Electrogenerated hydroxyl radicals then converted the eco-toxic and bio-refractory property of initial ACE molecule (500 mL, 1 mM) and subsequent aromatic sub-products into non-toxic compounds after 2 h of EF treatment. The toxicity of every intermediate produced during the mineralization of ACE was quantified, and a relationship was established between the degradation pathway of ACE and the global toxicity evolution of the solution. After 8 h of treatment, a total organic carbon removal of 86.9% could be reached for 0.1 mM ACE at applied current of 500 mA with 0.2 mM of Fe used as catalyst.

Efficiency of plasma elaborated sub-stoichiometric titanium oxide (Ti4O7) ceramic electrode for advanced electrochemical degradation of paracetamol in different electrolyte media

“…Oxidation of 2-hydroxyl-4-(N-acetyl) aminophenol could also proceed via dealkylation at amine group with formation of 1,2,4-trihydroxyl benzene, which was identified by GC-MS. Similar oxidation products have been previously reported for the degradation of PCM by O 3 , H 2 O 2 /UVA and Fe 3+ + Cu 2+ /O 3 /UVA as well as EF using platinum electrode, with the % OH oxidation of PCM leading to the formation of 2-hydroxyl-4-(Nacetyl) aminophenol and hydroquinone as well as accelerated their degradation into benzoquinone [32,58]. The oxidation of aryl moiety of the aromatic by-products (hydroquinone and benzoquinone) gives short-chain carboxylic acids such as oxalic, maleic and glycoxylic acids, whereas oxamic acid was formed either from the degradation of 2-hydroxyl-4-(N-acetyl) aminophenol or oxidation of acetamide.…”

Acetaminophen Removal from Water by Microalgae and Effluent Toxicity Assessment by the Zebrafish Embryo Bioassay

“…These authors [42] concluded that photocatalytically treated model water containing acetaminophen revealed no toxicity to Vibrio fischeri. Similarly, Le et al [43] coupled ecotoxicity (Vibrio fischeri 81.9%, Microtox®screening tests) and chemical analysis monitoring during the electro-fenton oxidation of acetaminophen thus establishing a very useful relationship between the degradation pathway of acetaminophen and the global toxicity evolution of the solution.…”

A comprehensive study on bisphenol A degradation by newly isolated strains Acinetobacter sp. K1MN and Pseudomonas sp. BG12

“…The standard protocol 81.9% Basic Test was done during which all samples were diluted with 2% NaCl at 81.9% of the initial sample concentration. The toxicity units (TU = 1/ EC 50 -1 9 100) were calculated using the Micro-toxOmni (Microbics Corp, 1992) program (Le et al 2017).…”