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

Environmental contextHydrochlorothiazide, a common diuretic pharmaceutical, occurs in environmental waters because current treatment technologies are unable to eliminate it from wastewater. To remove this environmentally hazardous chemical from water, we developed an advanced electrochemical oxidation process to efficiently degrade and mineralise the compound. Wider application of the process holds the promise of general, efficient destruction of pharmaceuticals in aqueous media. AbstractThe degradation and the mineralisation of the diuretic hydrochlorothiazide were studied by an advanced electrochemical oxidation process, ‘electro-Fenton’, which generates in situ hydroxyl radicals that are able to successfully oxidise or mineralise organic pollutants. In this study, a 0.1mM (29.8mgL−1) hydrochlorothiazide solution was completely oxidatively degraded in 15min under constant current electrolysis at 500 mA. The absolute kinetic rate constant of the oxidation reaction was also determined as (4.37±0.04)×109M−1s−1. The quasi-complete mineralisation of the solution was obtained with electrolysis for 6h under the same applied current. Several oxidation reaction intermediates were identified using gas chromatography-mass spectrometry (GC-MS). The formed carboxylic acids during the mineralisation process were also studied; oxamic, oxalic, acetic and maleic acids were identified and their concentrations were monitored throughout the electrolysis. The ions released during the treatment were also considered. Based on these data and the total organic carbon (TOC) removal results, a possible mineralisation pathway was proposed. These findings enable the conclusion that the electro-Fenton process is an efficient and environmentally-friendly method to eliminate the hazardous drug hydrochlorothiazide from an aqueous environment.

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Aloe Vera-Mediated Te Nanostructures: Highly Potent Antibacterial Agents and Moderated Anticancer Effects

Nanomaterials ◽

10.3390/nano11020514 ◽

2021 ◽

Vol 11 (2) ◽

pp. 514

Author(s):

David Medina-Cruz ◽

Ada Vernet-Crua ◽

Ebrahim Mostafavi ◽

María Ujué González ◽

Lidia Martínez ◽

...

Keyword(s):

Biomedical Applications ◽

Aqueous Media ◽

Aloe Vera ◽

Multidrug Resistant ◽

Dermal Fibroblasts ◽

Anticancer Properties ◽

Green Approach ◽

Anticancer Effects ◽

Synthesis Of Nanomaterials ◽

By Products

Cancer and antimicrobial resistance to antibiotics are two of the most worrying healthcare concerns that humanity is facing nowadays. Some of the most promising solutions for these healthcare problems may come from nanomedicine. While the traditional synthesis of nanomaterials is often accompanied by drawbacks such as high cost or the production of toxic by-products, green nanotechnology has been presented as a suitable solution to overcome such challenges. In this work, an approach for the synthesis of tellurium (Te) nanostructures in aqueous media has been developed using aloe vera (AV) extracts as a unique reducing and capping agent. Te-based nanoparticles (AV-TeNPs), with sizes between 20 and 60 nm, were characterized in terms of physicochemical properties and tested for potential biomedical applications. A significant decay in bacterial growth after 24 h was achieved for both Methicillin-resistant Staphylococcus aureus and multidrug-resistant Escherichia coli at a relative low concentration of 5 µg/mL, while there was no cytotoxicity towards human dermal fibroblasts after 3 days of treatment. AV-TeNPs also showed anticancer properties up to 72 h within a range of concentrations between 5 and 100 µg/mL. Consequently, here, we present a novel and green approach to produce Te-based nanostructures with potential biomedical applications, especially for antibacterial and anticancer applications.

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Efficient degradation of tetracycline by heterogeneous electro-Fenton process using Cu-doped Fe@Fe2O3: Mechanism and degradation pathway

Chemical Engineering Journal ◽

10.1016/j.cej.2019.122970 ◽

2020 ◽

Vol 382 ◽

pp. 122970 ◽

Cited By ~ 11

Author(s):

Ting Luo ◽

Haopeng Feng ◽

Lin Tang ◽

Yue Lu ◽

Wangwang Tang ◽

...

Keyword(s):

Degradation Pathway ◽

Fenton Process

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Electrochemical degradation of diazinon from aqueous media using graphite anode: Effect of parameters, mineralisation, reaction kinetic, degradation pathway and optimisation using central composite design

International Journal of Environmental & Analytical Chemistry ◽

10.1080/03067319.2020.1742893 ◽

2020 ◽

pp. 1-26 ◽

Cited By ~ 2

Author(s):

Mohammad Molla Mahmoudi ◽

Ramin Khaghani ◽

Abdollah Dargahi ◽

Ghazaleh Monazami Tehrani

Keyword(s):

Central Composite Design ◽

Reaction Kinetic ◽

Aqueous Media ◽

Degradation Pathway ◽

Anode Effect ◽

Graphite Anode ◽

Electrochemical Degradation ◽

Central Composite

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Flavan derivatives. XVII. Epimerization of the benzylic 4-hydroxyl group in flavan-3,4-diols and the formation of 4-alkyl ethers by solvolysis

Australian Journal of Chemistry ◽

10.1071/ch9672151 ◽

1967 ◽

Vol 20 (10) ◽

pp. 2151

Author(s):

JW Clark-Lewis ◽

LR Williams

Keyword(s):

Aqueous Media ◽

Cyclic Ether ◽

Hydroxyl Group ◽

Mechanism Of Formation ◽

Enol Ether ◽

Mild Conditions ◽

Ethoxyl Group ◽

Alkyl Ethers ◽

By Products ◽

Thermodynamic Factors

Epimerization and solvolysis of the benzylic 4-hydroxyl group is shown to be a general property of flavan-3,4-diols, and the diols give 4- ethoxyflavan-3-ols with ethanolic hydrochloric acid (1%). The diols are first converted into epimeric mixtures of 3,4-cis- and 3,4-trans-diols and in aqueous media cis-cis-flavan-3,4-diols yield mainly 2,3-cis-3,4- trans-diols. These 2,3-cis-3,4-diols undergo solvolysis to yield 2,3- cis-3,4-trans-4-ethoxyflavan-3-ols in which the 3,4-trans- stereochemistry is controlled by participation of the neighbouring 3ax- hydroxyl group. 2,3-trans-Flavan-3,4-diols give mixtures of trans- trans-diols and 2,3-trans-3,4-cis-diols and solvolysis first yields 2.3-trans-3,4-cis-4-ethoxyflavan-3-ols and then mixtures of the 3,4- cis- and 3,4-trans-ethers; the final proportion of these two ethers is controlled by thermodynamic factors. Solvolysis under mild conditions gives minor products considered to be 3-oxoflavans (or their enols) because of their immediate conversion into antho-cyanidins by cold acids in the presence of air, and from the formation of an enol-ether on prolonged solvolysis under more vigorous conditions. The relevance of these observations to the mechanism of formation of anthocyanidins from flavan-3,4-diols is discussed. Other by-products of solvolysis reactions include a dimeric cyclic ether (dioxan derivative) of 2,3- trans-3,4-cis-7,8,4?-trimethoxyflavan-3,4-diol. The structure and stereochemistry of solvolysis products were established by N.M.R. data; the 4-ethoxyl group in the ethers generally gave rise to an ABX3 multiplet.

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Impurity profiling of trandolapril under stress testing: Structure elucidation of by-products and development of degradation pathway

International Journal of Pharmaceutics ◽

10.1016/j.ijpharm.2012.08.048 ◽

2012 ◽

Vol 438 (1-2) ◽

pp. 61-70 ◽

Cited By ~ 7

Author(s):

M. Dendeni ◽

N. Cimetiere ◽

A. Amrane ◽

N. Ben Hamida

Keyword(s):

Structure Elucidation ◽

Stress Testing ◽

Degradation Pathway ◽

Impurity Profiling ◽

By Products

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Degradation of Oxytetracycline by Electrochemical, Fenton and Electro-fenton Processes Using SS316 and SS316/β-PbO2 Anodes: Process Optimization Using Rsm-ccd, Bioassay Test and Degradation Pathway

10.21203/rs.3.rs-448258/v1 ◽

2021 ◽

Author(s):

Kamal Hasani ◽

Sama Hosseini ◽

Heliya Gholizadeh ◽

Abdollah Dargahi ◽

Mehdi Vosoughi

Keyword(s):

Degradation Pathway ◽

Electrochemical Process ◽

Fenton Process ◽

Optimal Conditions ◽

Optimal Value ◽

Anode Electrode ◽

Optimal Values ◽

Electrochemical Fenton ◽

And Staphylococcus Aureus ◽

Central Composite

Abstract The aim of the present study was to evaluate the efficiency of advanced oxidation processes (electrochemical, Fenton and electro-Fenton) in the removal of oxytetracycline using SS316 and SS316/β-PbO2 anodes. This study was performed experimentally on a laboratory scale in a 250 mL reactor. First, experiments were designed for the electrochemical process using a central composite design, and the optimal conditions for the variables pH(3.53), electric current density(3.85mA/cm2), initial concentration of oxytetracycline (20mg/L) and electrolysis time (42.35min) was obtained; then, under these conditions, the efficiency of Fenton process with FeSO4 variable without the presence of electrodes was evaluated, and its optimal value was 0.3 g/L, and then in the presence of optimal values of the above 5 variables, the efficiency of electro-Fenton process with H2O2 changes were investigated and the optimal value of 0.12 was obtained for H2O2. The removal efficiencies of oxytetracycline in electrochemical, Fenton, and electro-Fenton processes were 84.7%, 73.4%, and 98.2%, respectively. Under optimal conditions, the SS316/β-PbO2 anode electrode enhanced the oxytetracycline efficiency by electron-Fenton process to 100%. The results of bioassay with microorganisms showed that the reduction of toxicity of the effluent treated by electro-Fenton process for Pseudomonas aeruginosa and Staphylococcus aureus was 84.5% and 69%, respectively.

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Photocatalytic degradation of aromatic and alicyclic pollutants in water: by-products, pathways and mechanisms

Water Science & Technology ◽

10.2166/wst.1997.0089 ◽

1997 ◽

Vol 35 (4) ◽

pp. 73-78 ◽

Cited By ~ 5

Author(s):

Pierre Pichat

Keyword(s):

Superoxide Dismutase ◽

Active Species ◽

Oh Radicals ◽

Coupling Reactions ◽

Fenton Process ◽

Cation Radicals ◽

Primary Products ◽

Cl Atom ◽

Fe Ions ◽

By Products

Pyridine, 1-2-dimethoxybenzene, morpholine and lindane are mineralized by the TiO2-UV process. In the studies briefly reviewed here, their intermediate products, in particular the aliphatics, were identified both to determine what are the compounds that may be left in the treated water and to increase our understanding of the photocatalytic pathways. In addition to the oxidation and cleavage of the bonds, H(Cl) atom addition (or transfer) and coupling reactions were found to occur, which illustrates the complexity of photocatalytic degradations. Moreover, a comparison of the primary products of quinoline degraded either by photocatalysis or by the photo-Fenton process (Fe ions-H2O2-UV) showed that OH° radicals are not the only active species involved in photocatalytic degradations. From the effects of adding superoxide dismutase, it was inferred thatin situ formed O2−o anion-radicals intervene chemically, possibly by reacting with quinoline cation-radicals generated via electron transfer from quinoline to TiO2.

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