Mineralization of synthetic and industrial pharmaceutical effluent containing trimethoprim by combining electro-Fenton and activated sludge treatment

International audienceA combined process coupling of an electro-Fenton and a biological degradation was investigated in order to mineralize synthetic and industrial pharmaceutical effluent containing trimethoprim, a bacteriostatic antibiotic. Electro-Fenton degradation of trimethoprim was optimized by means of a Doehlert experimental design, showing that 0.69 mM Fe2+, 466 mA and 30 min electrolysis time were optimal, leading to total trimethoprim removal, while mineralization remained limited, 12% for 30 min electrolysis times. The aromatic and aliphatic by-products were identified and a plausible degradation pathway was proposed. Biodegradability was improved, since the BOD5/COD ratio increased from 0.11 initially to 0.32 and 0.52 after 30 and 60 min electrolysis times respectively, confirmed by activated sludge culture, 47 and 59% mineralization of the byproducts from electrolysis.The relevance of the proposed combined process was then confirmed on an industrial pharmaceutical effluent. Its electrolysis under the above conditions showed an almost total removal of trimethoprim after 180 min of electrolysis, while TOC removal remained low, 14 and 16% for 180 and 300 min reaction times, respectively. Overall removal yields of the industrial effluent during the combined process were therefore 80 and 89% for 180 and 300 min of effluent pretreatment followed by 15 days activated sludge culture, respectively

A DFT and experimental investigation of the electron affinity of the triscyclopentadienyl uranium complexes Cp3UX

International audienceRelativistic Density Functional Theory (DFT) based methods coupled with the Conductor-like Screening Model (COSMO) for a realistic solvation approach are used to investigate the electron affinity (EA) of a series of triscyclopentadienyl uranium complexes Cp3UX (X = Cl, BH4, SPh, SiPr and OiPr) related to the U(IV)/U(III) redox system. E1/2 half-wave potentials have been measured in solution (THF) under the same rigorous conditions for all the species under consideration. A good correlation (r2 = 0.99) is found between the computed EA values, either in the gas phase or in solution, and the experimental half-wave potentials; the study brings to light the importance of spin-orbit coupling effects which must be taken into account in order to achieve the observed agreement between theory and experiment. The influence of the electron donating character of the X ligand on the orbital involved in the reduction process, namely the lowest unoccupied molecular orbital (LUMO) of the neutral U(IV) complexes, and on the EAs is discussed

Improvement of the activated sludge treatment by its combination with electro Fenton for the mineralization of sulfamethazine

International audienceA combined process coupling an electro-Fenton pretreatment and a biological degradation in order to mineralize sulfamethazine (SMT) was investigated. The electro-Fenton pretreatment of SMT was first examined and the intermediates products were identified for an initial SMT amount of 0.36 mM, after 1 h electrolysis at pH 3, 18 °C, 200 mA. 94.2% SMT was degraded but the level of mineralization remained low (6.5%), ensuring significant residual organic content for a subsequent biological treatment. Two possible degradation reaction pathways involving all the identified and quantified intermediates are proposed. In a second part, biological treatments with fresh activated sludge were performed to complete the mineralization of the electrolyzed solution of SMT, showing an increase of the mineralization yield with time duration of the pretreatment. For an initial SMT concentration of 0.2 mM, a ferrous ions concentration of 0.5 mM, at pH 3, 18 °C and 500 mA, the mineralization yield during the biological treatment increased as follows: 61.4, 78.8 and 93.9% for 0.5, 1 and 4 h pretreatment, confirming the relevance of the proposed combined process

Phenolic composition, in vitro antioxidant effects and tyrosinase inhibitory activity of three Algerian Mentha species: M. spicata (L.), M. pulegium (L.) and M. rotundifolia (L.) Huds (Lamiaceae)

International audienceThe leaves of three Mentha species harvested in Algeria, Mentha spicata L. (MS), Mentha pulegium L. (MP) and Mentha rotundifolia (L.) Huds (MR) were examined for their content in polyphenols and for some activities-linked biological properties these could impart. The contents in total phenolics (TPC) and flavonoids (TFC) were evaluated by the Folin–Ciocalteu and the aluminum chloride methods, respectively. Whereas MS showed the highest TPC (12.0 ± 0.3 mg gallic acid equivalents/g of dry weight), MR had the highest content in TFC (3.3 ± 0.1 mg quercetin equivalents of dry weight). The pharmacological properties of these extracts were evaluated by assessing in vitro their antioxidant and antityrosinase activities. The modulation of mushroom tyrosinase activity was measured by colorimetry of the melanins formed in the presence of tyrosine. MS exhibited the strongest radical scavenging activity (RSA) in all assays: (i) the IC50s values to neutralize the 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) cation radicals (ABTS+) and the 2,2′-diphenyl-1-picrylhydrazyl radicals (DPPH) were 10.3 ± 0.9 and 16.2 ± 0.2 μg/mL, respectively; and (ii) its original electrochemically measured superoxide quenching index value is 188 ± 37 μg/mL (AI50). MR however showed the highest tyrosinase inhibitory activity (IC50 = 108 ± 20 μg/mL). A silica gel thin-layer chromatography (TLC) technique revealed the presence of caffeic and rosmarinic acids and diosmin in all extracts. These results were confirmed by high performance liquid chromatography with diode array detection (HPLC/DAD

A new ternary ruthenium(III) complex with 1,3-bis(salicylideneamino) propan-2-ol and 3-picolylamine: Synthesis, characterization, density functional theory and preparation of electrochemical sensor for nitrite analysis.

International audienceA novel electrochem. sensor based on graphite (G) functionalised with a new ternary ruthenium(III) complex was developed and applied to detect nitrite in aq. soln. The Ru(III) complex was synthesized using 1,3-bis(salicylideneamino) propan-2-ol polydentate Schiff base (BSAP) and 3-Picolylamine (PLA), and was characterized by elemental anal., Fourier transform IR spectroscopy (FT-IR), UV-visible spectrophotometry (UV-Visible), gradient-assisted hetero nuclear single quantum coherence spectroscopy (gHSQC) and cyclic voltammetry technique. In addn., the structure of the synthesized complex was optimized using d. functional theory (DFT). The results showed that the ternary Ru(III)-BSAP-PLA complex was formed and the adapted structure was an tetrahedral geometry.The electrochem. behavior of nitrite at the sensor prepd. using G/Ru(III)-BSAP-PLA composite shows that the evaluated electron transfer coeff. (α = 0.83) indicates a very significant electrocatalytic mechanism for oxidn. of nitrite in the presence of the Ru(III)-BSAP-PLA complex.Comparing to other published works, the sensor developed using G/Ru(III)-BSAP-PLA exhibited low limit of detection (LOD = 1.81 μM) around pH = 7. [on SciFinder(R)

Phenolic compounds, antioxidant and antibacterial activities of three Ericaceae from Algeria

International audienceHerbs of the Ericaceae family are commonly found in Algeria and used in traditional medicine as antiseptic, diuretic, astringent, depurative, and to treat scalds and wounds. The methanolic extracts of three species, Arbutus unedo L. (A. unedo, leaves), Erica arborea L. (E. arborea, flowered aerial parts), and Erica multiflora L. (E. multiflora, flowered aerial parts), were compared regarding their content in phenolic compounds, their antioxidant, and antibacterial activities. A. unedo harbors the highest content in total phenolics and flavonoids, followed by E. arboreaE. multiflora. The contents in total phenolics and flavonoids showed a correlation with the measured antioxidant (hydrogen-donating) activities; this was particularly the case for flavonoids content. The A. unedo extract showed antibacterial activity against all the tested strains (Staphylococcus aureus ATCC 6538, S. aureus C100459, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 9027); however, the E. arborea and E. multiflora extracts showed antibacterial activity only against Gram positive bacteria. Some polyphenols were identified in the three herbs by thin-layer chromatography and high-performance liquid chromatography coupled with diode array and mass spectrometry detection; from these, caffeic acid, p-coumaric acid, naringin, quercetin and kaempferol are reported for the first time in E. multiflora

Détail d'une structure régionale majeure par méthodes géophysiques combinées - cas de la faille de Fécamp-Lillebonne (Seine-Maritime, France)

International audienceLa faille de Lillebonne-Fécamp est une faille normale-décrochante dextre (Hauchard et Laignel, 2008 ; Wazi, 1988), orientée N150° (orientation armoricaine) à regard vers l'ouest, à rejet vertical variable (150 m dans le secteur de Bolbec, 40 m dans le secteur de Lillebonne). Il s'agit d'une structure géologique régionale majeure qui traverse le Pays de Caux sur plus de 25 km et se prolonge en Manche au large de Fécamp en prenant progressivement une orientation E-O. Au sud, cette structure n'atteindrait pas la Seine et viendrait buter contre l'accident de Notre-Dame-de-Gravenchon-Villequier, orienté N060° (orientation varisque). A l'échelle du Bassin de Paris, cette structure s'inscrit dans la continuité des failles de la Seine, de Rambouillet et d'Etampes, et présente la même orientation que la structure du Bray. Dans le paysage structural du Pays de Caux, la faille de Lillebonne-Fécamp est également associée à de larges structures plicatives à faible pendage, globalement parallèles à la faille (Ragot, 1988). En 2017, des investigations géophysiques ont été réalisées par le BRGM dans le secteur de Bolbec pour améliorer les connaissances géologiques et structurales dans la zone. L'interprétation et la corrélation conjointe des profils géo-électriques, sismiques et de la carte gravimétrique a permis de confirmer la thèse de Ragot sur la géométrie en faisceau de la faille, et de proposer une nouvelle carte structurale pour le secteur de Bolbec

Réactivité de composés phénoliques vis-à-vis de radicaux (étude mécanistique par électrochimie et applications)

Des radicaux libres sont produits en permanence dans le corps humain et sont impliqués dans le vieillissement cellulaire, les cancers et certaines maladies dégénératives. Le radical anion superoxyde présent in vivo est un radical très important puisque que, d une part, il est responsable de désordres biologiques, et d autre part il est à l origine de la formation d autres radicaux très réactifs. Dans une première partie, un mécanisme réactionnel global a été établi afin d étudier par électrochimie et simulation le mécanisme réactionnel des composés phénoliques (molécules antioxydantes) vis-à-vis du radical superoxyde électrogénéré. Dans une deuxième partie, des microélectrodes bandes fonctionnant en mode générateur/collecteur ont été élaborées par sérigraphie afin de coupler une séparation chromatographique à une détection électrochimique de composés phénoliques.Free radicals are produced permanently in human body and are involved in aging, cancers and several degenerative diseases. The anion radical superoxide present in vivo is a radical very important, because of its involving in biological disorders and because of it is at the origin of the formation of other very reactive radicals. So, the knowledge of the effect of antioxydant molecules (like phenolic compounds) is essential. In a first part, a global mechanism has been established in order to study by electrochemistry and simulation the mechanism of the reaction between the phenolic compounds and the electrogenerated superoxide radical. In a second part, screen-printed band microelectrodes working as generator/collector have been elaborated to use it in chromatographic separation coupled with electrochemical detection of phenolic compounds.RENNES1-BU Sciences Philo (352382102) / SudocSudocFranceF

New Detection Method for Alkylphenol Traces in Water Based on an Integrated Electrochemical Cell Sensor

In order to evaluate the efficiency and to monitor the treatment of organic micropollution by advanced oxidation processes, we have developed a new detection method based on the use of an electrochemical sensor for alkylphenol detection in water. This sensor, integrating a three-electrode cell configuration, is a commercial screen-printed electrode (SPE-110GPH) that can be used for alkylphenol detection continuously by mean of a derived flow cell. The working electrode is modified by a graphene layer that enhances the sensor sensibility. The experimental conditions were optimized for the sensor incorporated into the flow cell. Linearity ranges, repeatability and accuracy were studied as well as the detection limits for each alkylphenol. The lowest detection limit was obtained with bisphenol A (60 nM) and the measurement ranges achievable with the SPE-110GPH electrode allow the continuous monitoring of treatment processes.Dans le cadre de l’évaluation de l’efficacité et du suivi du traitement de la micropollution organique, par procédés d’oxydation avancée, nous avons développé une nouvelle méthode de détection qui repose sur l’utilisation d’un capteur électrochimique pour la détection des alkylphénols dans les eaux. Ce capteur, qui intègre une configuration de cellule électrochimique à trois électrodes, est une électrode sérigraphiée commerciale (SPE-110GPH) utilisée pour détecter les alkylphénols en continu dans une cellule de mesure à circulation. Le fonctionnement du capteur incorporé dans cette cellule à circulation a ainsi été optimisé. Les domaines de linéarité, la répétabilité des analyses et la justesse des réponses ont été étudiés ainsi que la limite de détection. La limite de détection la plus basse a été obtenue avec le bisphénol A (60 nM) et les plages de mesure accessibles avec l’électrode SPE-110GPH permettent d’envisager le contrôle en continu des procédés de traitement

Scaled-up electrochemical reactor with a fixed bed three-dimensional cathode for electro-Fenton process: Application to the treatment of bisphenol A

International audienceThe authors report on the development of an open undivided electrochem. reactor with a compact fixed bed of glassy C pellets as three-dimensional cathode for the application of electro-Fenton process. Bisphenol A (BPA) was chosen as model mol. to improve its efficiency to the treatment of persistent pollutants. The study of the BPA removal efficiency in function of the applied current intensity was studied to det. the limiting current of O2 redn. (optimal conditions of H2O2 prodn. at flow rate of 0.36 m3 h-1) which was 0.8 A (0.5 A/100 g of glassy C pellets). Many parameters were carried out using this electro-Fenton reactor degrdn. kinetics, influence of anodic reactions on DSA, effect of initial pollutant concn. In the optimal current condition, the global prodn. rate of H2O2 and ·OH was studied. The yield of electro-Fenton reaction (conversion of H2O2 to ·OH) was very high (> 90%). The abs. rate of BPA degrdn. was detd. as 4.3 × 109 M-1 s-1. COD, TOC and BOD5 measurements indicated that only few minutes of treatment by electro-Fenton process were needed to eliminate BPA for dil. solns. (10 and 25 mg L-1). In this case, the biodegradability of the treated solns. occurred rapidly. For higher concn. levels, an efficient removal of BPA appeared for treatment time >1 h and >90 min were necessary to obtain the biodegradability of BPA solns. In optimum conditions, the scale-up of the electrochem. reactor applied to electro-Fenton process was suggested and depended on the concn. level of the pollutant. The operating parameters of the scaled-up reactor might be deduced from the new section of each fixed bed exposed to the flow, from values of liq. flow velocity and from the corresponding limiting c.d. obtained with the reactor at lab. scale. The compact fixed bed cathode in an open undivided electrochem. reactor appears as an appropriate soln. as pre-treatment electro-Fenton process followed by the biol. treatment of persistent pollutant