Éditeur(s) : HAL CCSD
Résumé : The use of Xylopia frutescens extract as a C38 steel corrosion inhibitor in 1 M HCl solution was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. Potentiodynamic polarization curves indicated that Xylopia frutescens extract behaves as mixed-type inhibitor. Graphical methods are illustrated by synthetic data to determine the parameter of CPE (α, Q). The adsorption of the extract constituents was further discussed in view of Langmuir adsorption isotherm. The effect of temperature on the inhibition efficiency was investigated using EIS and potentiodynamic polarization. SEM and EDX observations confirmed the existence of protective inhibitor film on metal surface.
ISSN: 1938-6737

hal-01304527
https://hal.archives-ouvertes.fr/hal-01304527
DOI : 10.1149/06426.0001ecst
PRODINRA : 351608

Éditeur(s) : HAL CCSD
Résumé : International audience
Abstract View references (38)This work presents a facile, scalable method for the fabrication of graphene oxide-iron oxide (GO-Fe3O4) nanocomposites produced by co-precipitation of iron ions onto the GO surfaces in basic aqueous media. FTIR and XRD characterisation suggests that Fe3O4 was chemically anchored to the GO sheets, possibly via the carboxyl and hydroxyl groups. Small GO loadings of 0.5 and 1 wt% were not sufficient to alter the Fe3O4 structures. However, increasing the GO loading to 5 and 10 wt% resulted in significant loss in pore volume, thus suggesting the lamellar GO sheets decorated with Fe3O4 were assembling into GO-Fe3O4 nanocomposite stacks. It was found that the GO-Fe3O4 nanocomposites had an enhanced catalytic activity in the heterogeneous Fenton-like oxidation of Acid Orange 7 (AO7) compared to pure GO flat sheets and Fe3O4 nanoparticles. Interestingly, the GO-Fe3O4 nanocomposite with 5 wt% loading ratio exhibited the best catalytic activity with 76% degradation of AO7 dye observed within 90 min of reaction. This was attributed to the synergistic effect of GO by enriching the adsorbed AO7 molecules onto the nanocomposite to be further oxidised in the vicinities of active sites. This finding suggests the promising employment of GO-Fe3O4 nanocomposites in removing organic dyes from polluted water by heterogeneous Fenton-like reaction. © 2014 by American Scientific Publishers.
SCIENCE OF ADVANCED MATERIALS

hal-01683207
https://hal.univ-antilles.fr/hal-01683207
DOI : 10.1166/sam.2014.1812

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
A new portable sampling system was developed to extract Radium isotopes from large volumes (up to 300 L) of fresh surface- and ground-waters of low Ra-activities (<5 mBq/L). Ra is quantitatively adsorbed on a small amount (6.5 g) of MnO2-coated acrylic fibers, which are then dried and burned at 600 °C in the laboratory. The resulting Mn-oxide powder (about 2 cm3 when compacted) is then analyzed through gamma-ray spectrometry which allows measurement of the whole Ra quartet (226Ra, 228Ra, 224Ra and 223Ra) in a single counting of a few days. The usual relative standard combined uncertainties (1σ) are 2–3% for 226Ra, 228Ra and 224Ra; and less than 10% for 223Ra. This method was applied to the analysis of Ra in karstic waters of the Lez aquifer, and surface- and ground-waters of the upper and middle Vidourle watershed (South of France). The analyzed waters have relatively low 226Ra activities (1–4 mBq/L) in both cases, regardless of the contrasted geology (Mesozoic limestone vs crystalline Variscan basement), but clearly distinct (228Ra/226Ra) ratios in agreement with the differences in Th/U ratios of the two drained areas. Short-lived Ra isotopes (224Ra and 223Ra) appear to be mainly influenced by near-surface desorption/recoil processes for most of the sampling sites.
ISSN: 0969-8043

hal-01491281
https://hal.archives-ouvertes.fr/hal-01491281
DOI : 10.1016/j.apradiso.2016.12.010

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The Roussillon sedimentary Basin (South France) is a complex multi-layered aquifer, close to the Mediterranean Sea facing seasonally increases of water abstraction and salinization issues. We report geochemical and isotopic vertical variability in this aquifer using groundwater sampled with a Westbay System® at two coastal monitoring sites: Barcarès and Canet. The Westbay sampling allows pointing out and explaining the variation of water quality along vertical profiles, both in productive layers and in the less permeable ones where most of the chemical processes are susceptible to take place.The aquifer layers are not equally impacted by salinization, with electrical conductivity ranging from 460 to 43,000 μS·cm− 1. The δ2H–δ18O signatures show mixing between seawater and freshwater components with long water residence time as evidenced by the lack of contribution from modern water using 3H, 14C and CFCs/SF6. S(SO4) isotopes also evidence seawater contribution but some signatures can be related to oxidation of pyrite and/or organically bounded S. In the upper layers 87Sr/86Sr ratios are close to that of seawater and then increase with depth, reflecting water–rock interaction with argillaceous formations while punctual low values reflect interaction with carbonate. Boron isotopes highlight secondary processes such as adsorption/desorption onto clays in addition to mixings. At the Barcarès site (120 m deep), the high salinity in some layers appear to be related neither to present day seawater intrusion, nor to Salses-Leucate lagoonwater intrusion. Groundwater chemical composition thus highlights binary mixing between fresh groundwater and inherited salty water together with cation exchange processes, water–rock interactions and, locally, sedimentary organic matter mineralisation probably enhanced by pyrite oxidation.Finally, combining the results of this study and those of Caballero and Ladouche (2015), we discuss the possible future evolution of this aquifer system under global change, as well as the potential management strategies needed to preserve quantitatively and qualitatively this water resource.
ISSN: 0048-9697

hal-01685219
https://hal-brgm.archives-ouvertes.fr/hal-01685219
DOI : 10.1016/j.scitotenv.2016.05.016

Éditeur(s) : HAL CCSD IWA Publishing
Résumé : International audience
The widely occurring degradation product aminomethylphosphonic acid (AMPA) is a result of glyphosate and amino-polyphosphonate degradation. Massive use of the parent compounds leads to the ubiquity of AMPA in the environment, and particularly in water. The purpose of this review is to summarize and discuss current insights into AMPA formation, transport, persistence and toxicity. In agricultural soils, AMPA is concentrated in the topsoil, and degrades slowly in most soils. It can reach shallow groundwater, but rarely managed to enter deep groundwater. AMPA is strongly adsorbed to soil particles and moves with the particles towards the stream in rainfall runoff. In urban areas, AMPA comes from phosphonates and glyphosate in wastewater. It is commonly found at the outlets of Wastewater Treatment Plants (WWTP). Sediments tend to accumulate AMPA, where it may be biodegraded. Airborne AMPA is not negligible, but does wash-out with heavy rainfall. AMPA is reported to be persistent and can be biologically degraded in soils and sediments. Limited photodegradation in waters exists. AMPA mainly has its sources in agricultural leachates, and urban wastewater effluents. The domestic contribution to urban loads is negligible. There is a critical lack of epidemiological data - especially on water exposure - to understand the toxicological effects, if any, of AMPA on humans. Fortunately, well operated water treatment plants remove a significant proportion of the AMPA from water, even though there are not sufficient regulatory limits for metabolites.
ISSN: 0043-1354

hal-01516026
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01516026
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01516026/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01516026/file/Grandcoin%20et%20al.%20-%20AminoMethylPhosphonic%20acid%20%28AMPA%29%20in%20natural%20water.pdf
DOI : 10.1016/j.watres.2017.03.055

Éditeur(s) : Gauthier-Villars
Résumé : The dissolved Mn distribution on an oceanographic section along 50-degrees-W in the western North Atlantic shows decreasing concentrations in the offshore direction in the surface layer and with depth at the deep water stations. Leachable particulate Mn concentrations are low in the open ocean surface waters and elevated at intermediate depths. Dissolved Al concentrations in the surface layer are higher in the open ocean than on the shelf and the vertical distributions are characterized by surface maxima, a subsurface minimum at almost-equal-to 1 000 m and increasing concentrations in the deep waters. Leachable particulate Al concentrations are elevated on the shelf and in open ocean surface waters compared to the intermediate and deep waters. The Deep Western Boundary Current has high levels of dissolved Al and leachable particulate Mn and Al, and low levels of dissolved Mn. The distribution of dissolved Al is controlled primarily by inputs from atmospheric dust and removal onto biogenic particles. Both fluvial and atmospheric inputs affect dissolved Mn levels with removal occurring primarily by oxidation of Mn2+. The Al distribution is characterized by short residence times in shelf and surface waters and relatively constant distribution coefficients. The Mn distribution is characterized by longer surface water residence times, shorter deep water residence times, and more widely varying distribution coefficients than Al. Removal of Al by a surface adsorption mechanism and Mn by slower oxidation of Mn2+ are consistent with these observations. A model of Mn oxidation kinetics accurately predicts the intermediate depth leachable particulate Mn maximum.
Oceanologica Acta (0399-1784) (Gauthier-Villars), 1992 , Vol. 15 , N. 6 , P. 609-619

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00101/21186/18803.pdf
http://archimer.ifremer.fr/doc/00101/21186/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The present study reports data on CO2-rich geothermal waters and their associated carbonate deposits from the SW part of the Permian Lodève Basin (South of France). Both waters and carbonates are enriched in 226Ra, with activities up to 2.2 Bq/L and 3.5 Bq/g respectively. A series of carbonate samples precipitated around the studied wells since 1990 were dated through the 226Ra-210Pb and 228Ra-228Th methods, and the results are discussed in a new Concordia diagram. While both methods give comparable dates for many samples, Ra-Pb ages are sometimes much older than Ra-Th ages. We propose that these discrepancies result from the adsorption of 222Rn daughter nuclides in such a Rn-rich environment. The (228Ra/226Ra)0 activity ratios calculated at the time of deposition are remarkably constant for about 12 years, suggesting the presence of a steady-state aquifer. The low (228Ra/226Ra)0 ratios (0.348 ± 0.008) are best explained if most of the Ra derives from the Cambrian carbonate series (mainly dolostone) underlying the Permian Basin, which have low Th/U and similar (228Ra/226Ra) ratios. This study suggests that Ra and other alkaline-earth elements do not necessarily originate from the rocks surrounding the deep geothermal reservoir, but rather may be introduced into the CO2-rich water during its transfer towards the surface and interaction with carbonate rocks.
ISSN: 0009-2541

hal-01053715
https://hal.archives-ouvertes.fr/hal-01053715
DOI : 10.1016/j.chemgeo.2014.02.008

Éditeur(s) : HAL CCSD Elsevier
Résumé : Several nuclides of the ;238;U (;234;U, ;230;Th, ;226;Ra, ;210;Pb) and ;235;U (;231;Pa, ;227;Ac) decay series have been measured through gamma spectrometry in the U-bearing episyenites of the Bernardan mine (northwest Massif Central, France), in order to study recent mobilizations in the U-deposit and their time-scales. (;230;Th/;238;U) and (;231;Pa/;235;U) ratios show that U has been little affected during the last 350 ky, especially in the U-rich samples. In contrast, ;226;Ra was subjected to a general redistribution, with a clear tendency for Ra to be lost from the U-rich samples and added to U-poor samples. The highest Ra excesses are present in low-U samples, and are related to adsorption onto iron hydroxides. Ra appears to have been redistributed within the mineralised episyenitic bodies, which seem to remain in ;226;Ra–;238;U radioactive equilibrium, a result consistent with the earlier study of Leroy [1984. Episyénitisation dans le gisement d'uranium du Bernardan (Marche): Comparaison avec des gisements similaires du Nord-Ouest du Massif Central français. Miner. Depos. 19, 26–35]. As shown by the ;226;Ra and ;210;Pb data, the Ra redistribution was very active between 8 and 0.1 ky, and this might be a consequence of the hydrological changes in groundwater circulation accompanying the Holocene climate warming.
ISSN: 0009-2541

hal-00407600
https://hal.archives-ouvertes.fr/hal-00407600
DOI : 10.1016/j.chemgeo.2007.06.020

Éditeur(s) : HAL CCSD MDPI
Résumé : International audience
This work investigates the structural formation and analyses of titania membranes (TM) prepared using different vacuum exposure times for molecular weight (MW) cut-off performance and oil/water separation. Titania membranes were synthesized via a sol-gel method and coated on macroporous alumina tubes followed by exposure to a vacuum between 30 and 1200 s and then calcined at 400 °C. X-ray diffraction and nitrogen adsorption analyses showed that the crystallite size and particle size of titania increased as a function of vacuum time. All the TM membranes were mesoporous with an average pore diameter of ~3.6 nm with an anatase crystal morphology. Water, glucose, sucrose, and polyvinylpyrrolidone with 40 and 360 kDa (PVP-40 kDa and PVP-360 kDa) were used as feed solutions for MW cut-off and hexadecane solution for oil filtration investigation. The TM membranes were not able to separate glucose and sucrose, thus indicating the membrane pore sizes are larger than the kinetic diameter of sucrose of 0.9 nm, irrespective of vacuum exposure time. They also showed only moderate rejection (20%) of the smaller PVP-40 kDa, however, all the membranes were able to obtain an excellent rejection of near 100% for the larger PVP-360 kDa molecule. Furthermore, the TM membranes were tested for the separation of oil emulsions with a high concentration of oil (3000 ppm), reaching high oil rejections of more than 90% of oil. In general, the water fluxes increased with the vacuum exposure time indicating a pore structural tailoring effect. It is therefore proposed that a mechanism of pore size tailoring was formed by an interconnected network of Ti-O-Ti nanoparticles with inter-particle voids, which increased as TiO2 nanoparticle size increased as a function of vacuum exposure time, and thus reduced the water transport resistance through the TM membranes. © 2016 by the authors.
ISSN: 1996-1944

hal-01683214
https://hal.univ-antilles.fr/hal-01683214
DOI : 10.3390/ma9110938

Résumé : Ce travail porte sur l'inhibition de l'acier C38 en milieu acide HC1 1M par les extraits alcaloïdes issus de 2 plantes : aspidosperma album et geissospermum laeve. Biodégradables et respectueux de l'environnement, les alcaloïdes pourraient être utilisés temporairement pour prévenir la corrosion de l'acier C39 avec des taux d'inhibition supérieurs à ceux décrits dans la littérature. Dans la première partie du travail, l'influence de la concentration, du temps d'immersion et de la température sur le processus de corrosion de l'acier C38 en milieu HC1 1M en absence de polarisation et spectroscopie d'impédance électrochimique. Les analyses de surface effectuées par microscopie électronique a balayage montrent la présence d'une couche constituée d'un mélange d'oxyde de fer incorporant les alcaloïdes et qui conduit à la diminution de la vitesse de corrosion. La deuxième partie de ce travail a été consacrée à l'isolement des alcaloïdes des deux extraits afin de déterminer le ou les alcaloïdes responsables de l'activité inhibitrice et ainsi remonter aux mécanismes d’adsorption. Il a été montré que l'alcaloïde majoritaire des extraits est responsable de l'inhibition
This work is devoted to the corrosion inhibition of C38 steel in 1M HCL acid medium by alkaloids extracts from two plants : aspidosperma album and geissospermum laeve. Biodegradable and environmentally friendly, alkaloids could be used temporarily to prevent the corrosion of C38 steel with inhibition rates higher than those described in the literature. The first part of this work studies the influence of concentration, immersion time and temperature on the corrosion inhibitor by electrochemical measurements : polarization curves and electrochemical impedance spectroscopy. The surface analyses conducted by scanning electron microscopy showed the presence of a layer composed of an iron oxide mixture incorporating alkaloids extracts and which leads to the decrease of the corrosion rate. The second part of this work was devoted to the isolation of alkaloids of two extracts in order to determine the alkaloids responsible of the inhibitory activity and thus to determine the adsorption mechanisms. It was showed that the major alkaloids of two extracts is responsible of the inhibition activity

http://www.theses.fr/2013AGUY0578/document

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Diesel exhaust particles (DEPs) are common environmental air pollutants primarily affecting the lung. DEPs or chemicals adsorbed on DEPs also exert extra-pulmonary effects, including alteration of hepatic drug detoxifying enzyme expression. The present study was designed to determine whether organic DEP extract (DEPe) may target hepatic drug transporters that contribute in a major way to drug detoxification. Using primary human hepatocytes and transporter-overexpressing cells, DEPe was first shown to strongly inhibit activities of the sinusoidal solute carrier (SLC) uptake transporters organic anion-transporting polypeptides (OATP) 1B1, 1B3 and 2B1 and of the canalicular ATP-binding cassette (ABC) efflux pump multidrug resistance-associated protein 2, with IC50 values ranging from approximately 1 to 20 μg/mL and relevant to environmental exposure situations. By contrast, 25 μg/mL DEPe failed to alter activities of the SLC transporter organic cation transporter (OCT) 1 and of the ABC efflux pumps P-glycoprotein and bile salt export pump (BSEP), whereas it only moderately inhibited those of sodium taurocholate co-transporting polypeptide and of breast cancer resistance protein (BCRP). Treatment by 25 μg/mL DEPe was next demonstrated to induce expression of BCRP at both mRNA and protein level in cultured human hepatic cells, whereas it concomitantly repressed mRNA expression of various transporters, including OATP1B3, OATP2B1, OCT1 and BSEP. Such changes in transporter expression were found to be highly correlated to those caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a reference activator of the aryl hydrocarbon receptor (AhR) pathway. This suggests that DEPe, which is enriched in known ligands of AhR like polycyclic aromatic hydrocarbons, alters drug transporter expression via activation of the AhR cascade. Taken together, these data established human hepatic transporters as targets of organic chemicals containing in DEPs, which may contribute to their systemic effects through impairing hepatic transport of endogenous compound or drug substrates of these transporters.
ISSN: 1932-6203

Droits : http://creativecommons.org/licenses/by/
hal-01138535
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01138535
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01138535/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01138535/file/Regulation%20of%20human%20hepatic%20drug.pdf
DOI : 10.1371/journal.pone.0121232

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The high proportion of crystallized apatite forming the bones and teeth should theoretically allow the use of fission track analysis to date vertebrate fossils when burying of the fossiliferous series did not subject them to temperatures exceeding 60 degrees C. However several major obstacles arise such as the complexity of fossils' internal structures, diagenetic modifications and substitutions of the hydroxyapatite by other minerals, and massive U uptake or loss during diagenesis. In this work, those various problems are addressed combining optical microscope observation of the fossils, a systematic fission track analysis of the best samples, alpha and gamma spectrometry and Secondary Ion Mass Spectrometry. Even if the problems caused by internal structures and mineral substitutions can be solved, U movements in and out of the fossils are generally too complex to allow fission track analysis dating of the fossils.
ISSN: 0009-2541

hal-00411880
https://hal.archives-ouvertes.fr/hal-00411880
DOI : 10.1016/j.chemgeo.2007.10.009

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Thermogravimetric results on the thermal degradation of isolated components extracted from shells of tropical fruit stones and seeds allowed us to establish the dependence of the yield of char obtained by high-temperature pyrolysis (600-900 °C) of lignocellulosic raw materials on the content of components in precursors...
ISSN: 1387-1811

hal-00809743
https://hal.univ-antilles.fr/hal-00809743
DOI : 10.1016/S1387-1811(03)00288-9

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Cyanobacteria are ubiquitous microorganisms considered as important contributors to the formation of Earth's atmosphere and nitrogen fixation. However, they are also frequently associated with toxic blooms. Indeed, the wide range of hepatotoxins, neurotoxins and dermatotoxins synthesized by these bacteria is a growing environmental and public health concern. This paper provides a state of the art on the occurrence and management of harmful cyanobacterial blooms in surface and drinking water, including economic impacts and research needs. Cyanobacterial blooms usually occur according to a combination of environmental factors e.g., nutrient concentration, water temperature, light intensity, salinity, water movement, stagnation and residence time, as well as several other variables. These environmental variables, in turn, have promoted the evolution and biosynthesis of strain-specific, gene-controlled metabolites (cyanotoxins) that are often harmful to aquatic and terrestrial life, including humans. Cyanotoxins are primarily produced intracellularly during the exponential growth phase. Release of toxins into water can occur during cell death or senescence but can also be due to evolutionary-derived or environmentally-mediated circumstances such as allelopathy or relatively sudden nutrient limitation. Consequently, when cyanobacterial blooms occur in drinking water resources, treatment has to remove both cyanobacteria (avoiding cell lysis and subsequent toxin release) and aqueous cyanotoxins previously released. Cells are usually removed with limited lysis by physical processes such as clarification or membrane filtration. However, aqueous toxins are usually removed by both physical retention, through adsorption on activated carbon or reverse osmosis, and chemical oxidation, through ozonation or chlorination. While the efficient oxidation of the more common cyanotoxins (microcystin, cylindrospermopsin, anatoxin and saxitoxin) has been extensively reported, the chemical and toxicological characterization of their by-products requires further investigation. In addition, future research should also investigate the removal of poorly considered cyanotoxins (β-methylamino-alanine, lyngbyatoxin or aplysiatoxin) as well as the economic impact of blooms.
Environment International

hal-00875835
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00875835
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00875835/document
DOI : 10.1016/j.envint.2013.06.013
PUBMED : 23892224

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : Increasing interest in understanding tension stress generation in tension wood with fibres having a gelatinous layer (G-layer) has focused attention on the specific role of this layer. To distinguish its contribution from those of other wall layers, the G-layer of wood sections was isolated by ultrasonication. The aim of this study was to assess the effect of sectioning and of the ultrasonic treatment on the mesoporosity of tension wood using nitrogen adsorption-desorption analysis. The results showed that the process of isolating the G-layer using ultrasonication strongly affects its mesoporosity. Most damage was found to occur during sectioning rather than as a result of the 15-min ultrasonic treatment.
ISSN: 0043-7719

hal-01601127
https://hal.archives-ouvertes.fr/hal-01601127
DOI : 10.1007/s00226-017-0890-0
PRODINRA : 401888

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
In order to progress in the understanding of mechanical stress generation, the mesoporosity of the cell wall and its changes during maturation of poplar (Populus deltoides x P. nigra) tension wood (TW) and opposite wood (OW) were measured by nitrogen adsorption–desorption. Variations in the thickness of the gelatinous layer (G-layer) were also measured to clarify whether the mesoporosity change simultaneously with the deposition of the G-layer in TW. Results show that mesoporous structures of TW and OW were very similar in early development stages before the deposition of G-layers. With the formation of the S2 layer in OW and the G-layer in TW, the mesopore volume decreased steeply before lignification. However, in TW only, the decrease in mesopore volume occurred together with the pore shape change and a progressive increase in pore size. The different patterns observed in TW revealed that pores from G-layers appear with a different shape compared to those of the compound middle lamella, and their size increases duringthe maturation process until stabilising in mature wood. This observation strongly supports the hypothesis of the swelling of the G-layer matrix during maturation as the origin of maturation stress in poplar tension wood.
ISSN: 0028-646X

hal-01081834
https://hal.archives-ouvertes.fr/hal-01081834
https://hal.archives-ouvertes.fr/hal-01081834/document
https://hal.archives-ouvertes.fr/hal-01081834/file/Chang_al_Mesoporosity_changes_New-Phyto._2015.pdf
DOI : 10.1111/nph.13126