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The Fe3O4/TBADT composite catalyst (M-DT) can efficiently oxidize aromatic amine compounds selectively into nitroso compounds in the presence of H2O2. The high efficiency is due to the strong interaction between Fe3O4 and TBADT.

Understanding the hydrogeological functioning of aquifers is essential in contexts where water resources are intensively used. Moreover, climate change can have long-term effects on groundwater in terms of availability, residence and transit times. Thus, careful management of groundwater resources require the understanding of the aquifer’s characteristics that can allow then the setting of sustainable yields values in contexts where water is exploited. This understanding requires in particular the estimation of the age of the groundwaters as well as the transfers/transit times within the aquifers. Our study focuses on the Volvic volcanic aquifer (Chaîne des Puys, France), where the question of water use has increasingly raised for several years, given the significant use of drinking water, both for the public drinking water network and bottled water, and the decrease of precipitations (and groundwater recharge) over the watershed due to climate change. Previous studies on Volvic watershed allow defining the overall functioning of the system and comparing withdrawals and recharge on an annual scale, but groundwater ages have been only roughly defined even if they appear as a key point for addressing the question of the resource decrease. We propose then a multi-tracers approach, based on hydrogeological monitoring (hydrodynamical and meteorological data’s), including the estimation of groundwater ages (CFCs, tritium (3H)), major and traces elements chemistry and water stable isotopes (18O/2H) to better characterise this resource decrease and more peculiarly its origin and its impact on the environment that has never been addressed. The relative fractions of modern and ancient water contributions to the Volvic aquifer will thus be estimated as well as the apparent ages of groundwaters. We highlight here the complementarity of tracers used in the dating of waters, which allows a better definition of recharge sources and flow paths within the aquifer. This will provide key information about the time of the recharge and the time when the decrease began due to increase of abstraction, climate change or a combination of both of these effects.

The preparation of anodic TiO

International audience; In the present work, the photo-Fenton-like process based on the use of the Fe2.5Co0.3Zn0.2O4/CuCr-LDH composite was applied for the removal of green algal cells. First, the biological activity of the composite was proved with the antibacterial tests against the S. aureus; thereafter, it was used for the removal of Scenedesmus quadricauda algal cells under the photo-Fenton-like process. Interestingly, compared with the individual processes, the photo-Fenton-like process displayed a synergistic effect in the deactivation of green algal cells. The effect of various parameters such as the initial concentration of the algal cells, concentration of the hydrogen peroxide (HP), and the solution pH on the total algal. The maximuml was assessed. Maximum algal removal efficiency was obtained in the presence of the algal cell concentration of 3.5 × 109 cells mL−1, 0.1 g L−1 composite, and HP concentration of 10 mM. Furthermore, the microscopic and SEM images of the algal cells before and after the photo-Fenton-like process proved their appropriate destruction. The reduction of the chlorophyll content after 60 and 120 min of the process was observed revealing the destruction of the algal cell walls. Finally, the disintegration of the macromolecules in the algal cell walls was proved by the GC-MS technique.

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Photo-Fenton processes activated by biodegradable Fe(III)–EDDS complexes have attracted huge attention from the scientific community, but the operative mechanism of the photo-activation of H2O2 in the presence of Fe(III)–EDDS has not been fully clarified yet. The application of the Fe(III)–EDDS complex in Fenton and photo-Fenton (mainly under UV-B light) processes, using 4-chlorophenol (4-CP) as a model pollutant was explored to give insights into the operative mechanism. Furthermore, the potential synergistic contribution of soybean peroxidase (SBP) was investigated, since it has been reported that upon irradiation of Fe(III)–EDDS the production of H2O2 can occur. SBP did not boost the 4-CP degradation, suggesting that the possibly produced H2O2 reacts immediately with the Fe(II) ion with a quick kinetics that does not allow the diffusion of H2O2 into the bulk of the solution (i.e., outside the solvent cage of the complex). So, a concerted mechanism in which the photochemically produced H2O2 and Fe(II) react inside the hydration sphere of the Fe(III)–EDDS complex is proposed. Graphical abstract

International audience; In this study, a series of Fe-doped g-C3N4 (Fe–C3N4) samples was synthesized and characterized via X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflection spectroscopy (UV-vis DRS), and photoluminescence (PL) spectroscopy. The photocatalytic activity of the synthesized Fe–C3N4 was investigated toward methylene blue (MB) degradation with hydrogen peroxide (H2O2) assistance. The results showed that the Fe–C3N4 heterogeneous photo-Fenton-like system showed excellent catalytic performance when the pH value was varied from 3.0 to 9.0. Evaluating the effects of various inorganic anions in the Fe–C3N4 heterogeneous photo-Fenton-like system, HCO3− showed a dual effect on MB degradation, and Cl− and NO3− showed an inhibitory effect on MB degradation. Evaluating the effects of inorganic cations, Al3+, Mg2+, and Ca2+ strongly inhibited MB degradation. Recycling experiments demonstrated that Fe–C3N4 possesses good reusability and stability. Quenching experiments were carried out, and it was found that hydroxyl radicals (·OH) were the primary active species in the system. Besides, nine intermediates were identified via LC/MS, and a possible MB degradation pathway in the system was proposed. This study could promote the application of this Fe–C3N4 heterogeneous photo-Fenton-like system in realistic dye wastewater.

International audience; This paper outlines the synthesis and application of a sustainable composite for the photo-Fenton-like degradation of caffeine, bisphenol A, and simazine. The phase, morphology, optical and magnetic properties of the samples were evaluated by different characterization techniques. The composite of Fe2.5Co0.3Zn0.2O4 and copper-chromium layered double hydroxide (CuCr-LDH) was determined to be the most favorable photocatalyst in the photo-Fenton-like process when compared with Fe3O4, Fe2.5Co0.3Zn0.2O4, CuCr-LDH, and Fe3O4/CuCr-LDH composite. Studying the efficiency of the photo-Fenton-like degradation process in the presence of the Fe2.5Co0.3Zn0.2O4/CuCr-LDH composite revealed a degradation rate constant of caffeine twice more than the sum of those obtained for the individual processes. This ascribes to the synergistic effect by which the photo-generated electron-hole from the catalyst and the efficient reduction of Fe3+, Cu2+, etc. during the photo-Fenton-like reaction is accelerated. Moreover, under the optimal condition and after 120 min of heterogenous photo-Fenton-like process at natural pH, > 90% of pollutants mixture was decomposed. The experiments fulfilled in near-real conditions demonstrated I) the high stability and magnetically recoverability of the photocatalyst and II) the proper degradation performance of the applied heterogenous photo-Fenton-process in the removal of pollutant mixture in different water bodies and in the presence of chloride and bicarbonate ions.photo-Fenton-like process at natural pH, > 90% of pollutants mixture was decomposed. The experiments fulfilledin near-real conditions demonstrated I) the high stability and magnetically recoverability of the photocatalys

The decolorization of azo dye Orange II using a UVA-Fe3+-PMS-oxalate system was studied. A series of experiments was performed to investigate the effects of several variables, including the pH, PMS dosage, Fe3+ concentration, oxalate concentration, and coexisting anions. The results revealed that a lower pH facilitated the decolorization, and relatively high decolorization efficiency (97.5%) could be achieved within 5 min at pH 3.0. The electron paramagnetic resonance (ESR) and radical quenching experiments revealed that SO4•− played a crucial role in the decolorization of Orange II (85.8%), •OH was of secondary importance (9%), and 1O2 made a small contribution to the decolorization (5.2%). Furthermore, the formation of •OH in the experimental system strongly depended on HO2•/O2•−. These reactive oxidants were able to directly attack the azo bond of the luminescent group in Orange II and initiate the decolorization process. The efficient UVA-Fe3+-PMS-oxalate system showed great application potential in the treatment of wastewater contaminated by azo dyes.

The Allier River and its alluvial aquifer constitute a shallow but highly productive water resource due to their hydrodynamic properties. This hydrosystem provides almost all of the water requirements for domestic supply and irrigation. Recent dry summers (such as those in 2015, 2019, and 2022) and the lack of winter recharge have led managers to question the sustainability of this resource. We proposed the use of hydrological modelling with Gardenia with which the water balance can be determined at the watershed scale (7020 km2) and with which forecasting simulations can be performed for 2030–2070. Thus, this work was divided into (1) model calibration (2000–2020), (2) the determination of the main drivers of the water balance (2000–2020), (3) and river flow and groundwater level simulation (2030–2070). For the latter, Gardenia was used considering a “better case”, using the RCM Aladin63 in RCP2.6, and considering a “worst case”, using the RCM RegCM4-6 in RCP8.5. The calibration for 2000–2014 showed good reproducibility of river flows (NSE = 0.91) and groundwater levels (NSE = 0.85). The model showed that the major drivers in 2000–2020 were actual evapotranspiration and effective precipitation, which, respectively, represented 68% and 32% of mean annual precipitation. Water withdrawals did not significantly contribute to the water balance with the exception of those in very dry summers, such as those in 2003, 2005, 2015, and 2019. Climate appeared, therefore, as a prevalent factor of the Allier hydrosystem functioning compared to global withdrawals except for that during these dry years. Prospective simulations showed a decline in annual river flows and groundwater levels by a maximum of −15% and −0.08 m asl (“worst case”), respectively. These simulations showed that the Allier hydrosystem will be able to meet the water needs for various uses until 2070. In detail, it is likely that summer shortages will no longer be compensated by the Naussac Dam if the hydrosystem faces more than two years of drought. In this case, water-saving solutions will have to be found. This study is, thus, a good example of the application of hydrological modelling to address management issues in such a hydrosystem.

International audience; The crucial role of manganese(III) species in the oxidative and catalytic reactivity of manganese oxides have been widely reported. However, the direct activation of radical precursors by Mn(III) oxides is still a matter of discussion. In this work, the ability of Mn(III)-bearing oxide (Mn2O3) for activation of peroxydisulfate (PS) and peroxymonosulfate (PMS) was evaluated and compared using caffeine (CAF) as a model pollutant. Complete CAF removal was achieved with 5 mM of PS or PMS after 8 h of reaction time, whereas 48% of mineralization was obtained after 70 h of reaction when PMS was used as oxidant. Electron paramagnetic resonance spin trapping (EPR) and radical scavenging experiments showed that the sulfate radical (SO4•–) was the dominant radical in the Mn2O3/PMS system. In comparison, a non-radical mechanism such as Mn2O3 surface-activated PS promoted the removal of CAF in the system of Mn2O3/PS. Liquid chromatography coupled to mass spectrometry analyses enabled the detection of main degradation products and the proposition of the CAF degradation pathways. Investigations in the real sewage treatment plant water showed that the decrease of CAF removal observed in wastewater as compared to pure water can be alleviated by increasing the Mn2O3 dosage. These findings highlight the great ability of Mn-species in PS or PMS activation in different water matrices, which have important implications for the development of novel wastewater treatment technologies.

International audience; In this paper, the degradation of three endocrine-disrupting chemicals (EDCs): bisphenol A (BPA), 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) by manganite (γ-MnOOH) activated peroxymonosulfate (PMS) was investigated. Preliminary optimisation experiments showed that complete degradation of the three EDCs was achieved after 30 min of reaction using 0.1 g L−1 of γ-MnOOH and 2 mM of PMS. The degradation rate constants were determined to be 0.20, 0.22 and 0.15 min−1 for BPA, E2 and EE2, respectively. Combining radical scavenging approaches, Electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS) analyses, we revealed for the first time that about 40% of EDCs degradation can be attributed to heterogeneous electron transfer reaction involving freshly generated Mn(IV), and 60% to sulfate radical degradation pathway. The influence of various inorganic ions on the γ-MnOOH/PMS system indicated that removal efficiency was slightly affected by chloride and carbonate ions, while nitrate and nitrite ions had negligible impacts. The application of γ-MnOOH/PMS system in real sewage treatment plant water (STPW) showed that degradation rate constants of EDCs decreased to 0.035–0.048 min−1 and complete degradation of the three EDCs after 45 min. This study provides new insights into the reactivity of combined γ-MnOOH and PMS, and opens new ways for the application of Mn-bearing species in wastewater treatment technologies.

International audience; In this work, the photo reactivity of ferric oxalate (Fe(III)-Ox) complex in atmospheric particles was investigated. Raman spectroscopy was used to explore the mechanism and kinetics of Fe(III)-Ox photolysis occurring at the aqueous/gas interface, inside the droplet and in bulk solution. Ferrous carbonate (FeCO3) was detected indicating that carbonate ion (CO32−) formed inside the droplets would compete with oxalate ligands for iron complexation. A higher concentration of photoproduct Fe(II)-Ox was observed at the surface and inside of the droplets than in bulk solution. In particular, Fe(III)-Ox on the droplet surface was quickly reduced with light and Fe(II)-Ox concentration gradually decreased with irradiation time. The evolution of Fe(II)-Ox concentration was similar inside the droplet and in bulk solution with a trend of first increasing and then gradually decreasing during irradiation time. Although FeCO3 would hinder Fenton intermediate reaction, the photolysis rate of Fe(III)-Ox in droplets was almost two orders of magnitude times faster than that observed during bulk experiment. In general, the photolysis mechanism and kinetics of Fe(III)-Ox in aqueous/air interface, inside of droplet and bulk solution were distinct, and the production of oxide species from the atmospheric Fe(III)-Ox droplets was underestimated.

Despite the widespread presence of hydrogen peroxide (H

In the present study, comparison of activation efficiencies of hydrogen peroxide (H2O2) and persulfate (PS, Na2S2O8) induced by Fe(III)-Ethylenediamine-N,N'-disuccinic acid (EDDS) under polychromatic irradiation UVA and visible region at same conditions was studied for the first time. The effects of pH, Fe(III)-EDDS concentration, H2O2 and PS concentrations were investigated. p-hydroxyphenylacetic acid (p-HPA) was taken as a model pharmaceutical intermediate pollutant to estimate the oxidative process efficiency. In these two systems, the degradation rate of p-HPA increased (not linearly) using higher concentrated solution of H2O2 and Na2S2O8. However, when Fe(III)-EDDS concentration exceeding 250 μM, the degradation efficiency of p-HPA began to decrease. Surprisingly, results of pH effects showed that Fe(III)-EDDS/H2O2/UV system presents much higher degradation efficiency than Fe(III)-EDDS/PS/UV whatever the solution pH’s, especially in neutral and alkaline solutions. In the Fe(III)-EDDS/H2O2/UV reaction, p-HPA degradation rate (Rp-HPA) increased fast from pH 2.5 to 7.5, then it began to decrease when pH increased to 9.0. While Rp-HPA started to decrease with pH increase to 3.9 in Fe(III)-EDDS/PS/UV system. To explain this phenomenon, the second order constant of p-HPA (for both molecular and mono-anionic forms) with HO and SO4 − radicals were determined by laser flash photolysis (LFP) experiments for the first time. Results showed that k p − H P A , H O • was higher than k p − H P A , S O 4 • − for both anionic and molecular forms of pollutant. These results demonstrated that iron-complex induced photo-Fenton process is more efficient than activation of persulfate process, particularly at environmentally closed pH values and sun-simulated wavelengths (λ > 300 nm).

International audience; Abstract. Eighteen free amino acids (FAAs) were quantified in cloud water sampled at the Puy de Dôme station (PUY – France) during 13 cloud events. This quantification has been performed without concentration or derivatization, using liquid chromatography hyphened to mass spectrometry (LC-MS) and the standard addition method to correct for matrix effects. Total concentrations of FAAs (TCAAs) vary from 1.2 to 7.7 µM, Ser (serine) being the most abundant AA (23.7 % on average) but with elevated standard deviation, followed by glycine (Gly) (20.5 %), alanine (Ala) (11.9 %), asparagine (Asn) (8.7 %), and leucine/isoleucine (Leu/I)​​​​​​​ (6.4 %). The distribution of AAs among the cloud events reveals high variability. TCAA constitutes between 0.5 and 4.4 % of the dissolved organic carbon measured in the cloud samples. AA quantification in cloud water is scarce, but the results agree with the few studies that investigated AAs in this aqueous medium. The environmental variability is assessed through a statistical analysis. This work shows that AAs are correlated with the time spent by the air masses within the boundary layer, especially over the sea surface before reaching the PUY. The cloud microphysical properties' fluctuation does not explain the AA variability in our samples, confirming previous studies at the PUY. We finally assessed the sources and the atmospheric processes that potentially explain the prevailing presence of certain AAs in the cloud samples. The initial relative distribution of AAs in biological matrices (proteins extracted from bacterial cells or mammalian cells, for example) could explain the dominance of Ala, Gly, and Leu/I. AA composition of aquatic organisms (i.e., diatom species) could also explain the high concentrations of Ser in our samples. The analysis of the AA hygroscopicity also indicates a higher contribution of AAs (80 % on average) that are hydrophilic or neutral, revealing the fact that other AAs (hydrophobic) are less favorably incorporated into cloud droplets. Finally, the atmospheric aging of AAs has been evaluated by calculating atmospheric lifetimes considering their potential transformation in the cloud medium by biotic or abiotic (mainly oxidation) processes. The most concentrated AAs encountered in our samples present the longest atmospheric lifetimes, and the less dominant ones are clearly efficiently transformed in the atmosphere, potentially explaining their low concentrations. However, this cannot fully explain the relative contribution of several AAs in the cloud samples. This reveals the high complexity of the bio-physico-chemical processes occurring in the multiphase atmospheric environment.

International audience; Owing to their diverse functional groups, antibiotics can easily form complexes with heavy metals; the complexation alters the migration and transformation behavior of both antibiotics and heavy metals. In this study, we investigated the co-adsorption mechanism of sulfamethazine (SMT) and cadmium (Cd2+) heavy metal ions and created an ideal water model containing two major contaminants: sulfamethazine and heavy metal cadmium ions. Combined with the experimental analysis of the interaction mechanism, the results indicate the heterogeneous multilayer adsorption of SMT on the surface of activated carbon (AC). The bridging role of cadmium ions promotes the adsorption of SMT through the formation of SMT-Cd2+-AC ternary complexes on the surface of activated carbon. Characterization experiments provided further insight into the adsorption behavior of Cd2+ and SMT on activated carbon, revealing a strong correlation between the Cd2+-SMT complexation and the SMT adsorption capacity. These results indicate that the effects of the coexistence of antibiotics and heavy metal ions should be fully taken into account when investigating the environmental behavior of antibiotics and heavy metal ions.

In this paper, the degradation of three endocrine-disrupting chemicals (EDCs): bisphenol A (BPA), 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) by manganite (γ-MnOOH) activated peroxymonosulfate (PMS) was investigated. Preliminary optimisation experiments showed that complete degradation of the three EDCs was achieved after 30 min of reaction using 0.1 g L

[EN] Enrofloxacin (ENR) belongs to the fluoroquinolone (FQ) antibiotics family, which are contaminants of emerging concern frequently found in effluents. Although many works studying photo-Fenton process for FQ degradation have been reported, there are no reports analysing in deep the effect of iron complexation, as well as other metals, towards FQs' photolysis, which, evidently, also contributes in the overall degradation of the pollutant. Therefore, in this work, we report a comparative study between the photochemical fate of ENR and its complex with Fe(III) under simulated sunlight irradiation. In addition, the effect of dissolved oxygen, self-sensitization process, and H2O2 addition on the studied photochemical systems are also investigated. Results indicate that, for free and iron-complexed ENR, singlet oxygen (O-1(2)) is generated from the interaction of its triplet state with ground state oxygen. Half-life time (t(1/2)) of ENR under sun simulated conditions is estimated to be around 22 min, while complexation with iron enhances its photostability, leading to a t(1/2) of 2.1 h. Such finding indicates that at least the presence of iron, might notably increase the residence time of these pollutants in the environment. Eventually, only with the addition of H2O2, the FQ-iron complex is efficiently degraded due to photo-Fenton process even at circumneutral pH values due to the high stability of the formed complex. Finally, after LC/FT-ICR MS analysis, 39 photoproducts are detected, of which the 14 most abundant ones are identified. Results indicate that photoproducts formation is pH and iron dependent., This paper is part of a project that has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 765860 (AQUAlity). The paper reflects only the authors' view and the Agency is not responsible for any use that may be made of the information it contains. M.B. and G. M. acknowledge financial support from the CAP 20-25 I-site project.

Desulfurized gypsum (DG) as a soil modifier imparts it with bulk solid sulfite. The Fe(III)–sulfite process in the liquid phase has shown great potential for the rapid removal of As(III), but the performance and mechanism of this process using DG as a sulfite source in aqueous solution remains unclear. In this work, employing solid CaSO3 as a source of SO32−, we have studied the effects of different conditions (e.g., pH, Fe dosage, sulfite dosage) on As(III) oxidation in the Fe(III)–CaSO3 system. The results show that 72.1% of As(III) was removed from solution by centrifugal treatment for 60 min at near-neutral pH. Quenching experiments have indicated that oxidation efficiencies of As(III) are due at 67.5% to HO•, 17.5% to SO5•− and 15% to SO4•−. This finding may have promising implications in developing a new cost-effective technology for the treatment of arsenic-containing water using DG.

International audience; Herein, a stable and S-scheme Fe 3 O 4 @CuCr-LDH nanocomposite was synthesized and used for the photocatalytic degradation of diethyl phthalate (DEP) through the activation of peroxymonosulfate (PMS). In comparison with pure Fe 3 O 4, and LDH, the Fe 3 O 4 @CuCr-LDH nanocomposite demonstrated significantly enhanced photocatalytic activity due to its Sscheme charge-carrier migration mechanism. The prepared composite was also magnetically recoverable from the treated water which is favorable to avoid the production of secondary pollution. The integration of the composite and visible light showed the presence of a synergy factor of 14 for the degradation of diethyl phthalate. However, the photocatalytic performance of Fe 3 O 4 @CuCr-LDH was dependent on the different physicochemical parameters; wherein, the higher degradation efficiency was achieved using the solution pH of 8, the catalyst, DEP, and PMS concentrations of 1 g L-1 , 20 mg L-1 , and 8 mM, respectively. The high photocatalytic activity of the catalyst was maintained after 5 consecutive reaction runs and the stability of the material was proved by the XPS. Moreover, the ICP-AES analysis proved that the leaching of Fe, Cr, and Cu is lower than the standard concentration in the drinking water. Finally, the mineralization ability and the decreased toxicity of the treated solution of DEP were assessed.

International audience; Iron species have essential influence on the environmental/geochemical behaviors of arsenic species in water and soil. Colloidal ferric hydroxide (CFH) induces photooxidation of arsenite (As(III)) to arsenate (As(V)) in water at neutral pH through surface complexation and ligand-to-metal charge transfer (LMCT). However, the effect of the co-existing natural organic matter (NOM) on the complexation-photolysis in this process has remained unclear. In the present work, the photooxidation of As(III) induced by CFH was investigated in the presence of various carboxylic acids and polyphenols as simple model compounds of NOM. Two different light sources of ultraviolet A (UVA) (λ max = 365 nm) and ultraviolet B (UVB) (λ max = 313 nm) were used for photooxidation treatment of the experimental ternary system and the control binary system respectively. The obtained results demonstrated that all investigated NOM inhibited the photooxidation of As(III) in the As(III)/CFH system at pH 7. Moreover, the correlation analysis between the pseudo-first order rate constant k obs and various property parameters of NOM showed that the stable constant for the complexation between Fe(III) and NOM (logK Fe-NOM) as well as the molecular weight of NOM and the percentages of total acidity of NOM exhibited significant correlations. A simple quantitative structure-activity relationship (QSAR) model was established between k obs and these three parameters utilizing a multiple linear regression method, which can be employed to estimate the photooxidation efficiency of As(III) in the presence of ferric iron and NOM. Thus, the present work contributes to the understanding of the environmental interactions between NOM and iron.

International audience; Magnetic particles (MPs) coated with humic acid (HA) prepared under anoxic atmosphere were tested as heterogeneous photo-Fenton catalyst for the activation of hydrogen peroxide (H 2 O 2) and persulfate (S 2 O 8 2−) using Bisphenol A (BPA) as a model pollutant. The role of HA coating, pH value and H 2 O 2 /S 2 O 8 2− concentration were investigated. A positive contribution of HA coating on H 2 O 2 and S 2 O 8 2− activation was found. The highest BPA degradation rates were achieved at acidic conditions (pH 3) with both H 2 O 2 and S 2 O 8 2− , however persulfate showed a significant efficiency even at pH 6, interesting feature in the light of decreasing the wastewater treatment costs. By the addition of selective quenching agents, % OH and SO 4 %-were identified as the main reactive species involved in the BPA abatement. An important contribution of the S 2 O 8 2− photolysis on the overall BPA transformation was highlighted. The reuse of the catalyst was investigated and similar efficiency using H 2 O 2 and S 2 O 8 2− activation was observed until the third catalytic cycle. Experiments carried out using real wastewater samples, showed a good, even if less efficient compared to pure water, BPA removal.

International audience; In this work, the decomposition of phenanthrene (PHE) in mimic and real soil washing (SW) effluents was investigated using UVB light assisted activation of hydrogen peroxide (H2O2) and peroxydisulfate (PDS) oxidation processes. The impact of oxidant concentration, initial pH, and coexisting inorganic anions (Cl, HCO3 and NO3) on PHE removal was evaluated. PHE degradation efficiency under UVB irradiation followed the order of UVB/PDS > UVB/H2O2 > UVB. The increase of PHE decomposition efficiency was observed with increasing oxidant dose in the range of 2e30 mM upon the two processes. It was found Cl played different roles in the two activation systems depending on the solution pH and Clconcentration. The influence of HCO3 on PHE elimination was negligible in the UVB/PDS process, while an inhibitory effect was observed in the UVB/H2O2 system. Nitrate inhibited the PHE decay in both UVB/ H2O2 and UVB/PDS processes at the investigated pH 3.3, 7.1 and 8.6. Finally, the application of the two activation processes to the treatment of real SW effluents indicated that up to 85.0% of PHE degradation could be reached under 6 h UVB irradiation with PDS, indicating UVB/PDS process is a promising alternative for SW effluent treatment.

International audience; Despite the widespread presence of hydrogen peroxide (H2O2) in surface water and groundwater systems, little is known about the impact of environmental levels of H2O2 on the redox activity of minerals. Here we demonstrate that environmental concentrations of H2O2 can alter the reactivity of birnessite-type manganese oxide, an earth-abundant functional material, and decrease its oxidative activity in natural systems across a wide range of pH values (4-8). The H2O2-induced reductive dissolution generates Mn(ii) that will re-bind to MnO2 surfaces, thereby affecting the surface charge of MnO2. Competition of Bisphenol A (BPA), used as a target compound here, and Mn(ii) to interact with reactive surface sites may cause suppression of the oxidative ability of MnO2. This suppressive effect becomes more effective in the presence of oxyanions such as phosphate or silicate at concentrations comparable to those encountered in natural waters. Unlike nitrate, adsorption of phosphate or silicate onto birnessite increased in the presence of Mn(ii) added or generated through H2O2-induced reduction of MnO2. This suggests that naturally occurring anions and H2O2 may have synergetic effects on the reactivity of birnessite-type manganese oxide at a range of environmentally relevant H2O2 amounts. As layered structure manganese oxides play a key role in the global carbon cycle as well as pollutant dynamics, the impact of environmental levels of hydrogen peroxide (H2O2/MnO2 molar ratio

International audience; In this work, the cubic cobalt and zinc doped and co-doped magnetite nanocatalysts were synthesized and characterized using different analysis. The so-synthesized photocatalysts were used for the activation of hydrogen peroxide (HP) and persulfate (PS) under UVA irradiation. The integration of Fe2.5Co0.3Zn0.2O4 improved the activation of PS and HP; wherein, the UVA/Fe2.5Co0.3Zn0.2O4/PS process demonstrated higher degradation performance for Sulfalene (SFL) as a veterinary pharmaceutical contaminant in water. Afterward, the effect of different physicochemical parameters was studied and the radicals generated through the process were identified using chemical scavengers. UVA/Fe2.5Co0.3Zn0.2O4/PS process brought about 67% of SFL degradation in real wastewater. Moreover, 85% of TOC removal was achieved within 15 h of the above-mentioned process. Eventually, the phototoxicity of the untreated and treated SFL solution after 120 min of the UVA/Fe2.5Co0.3Zn0.2O4/PS process was studied using Lemna minor aquatic species.

International audience; The degradations of sulfasalazine and also sulfapyridine have been investigated by using the sodium decatungstate Na4W10O32 as a photocatalyst in the presence of hydrogen peroxide as a sacrifial agent. The selective irradiation of decatungstate, W10O324−, in the presence of the pollutants at 365 nm and at pH = 4.0 leads to the reduction of hydrogen peroxide via a Fenton like reaction involving the reduced species, W10O325-. Such process represents an efficient way for the formation of the highly reactive species, namely the hydroxyl radicals. The process appears then to be highly efficient for the oxidation of the pollutants sulfasalazine and sulfapyridine. Under our experimental conditions, the process was optimized in terms of concentrations of the photocatalyst, hydrogen peroxide and pollutant concentrations and also in term of pH. For both pollutants, the analysis of the generated by-products, using HPLC/MS, shows that the degradation proceeds primarily through three and common chemical processes: i) hydroxylation ii) desulfurization and iii) scission at the azo group -N = N-. The attack of the hydroxyl radical is clearly the main species for the degradation processes. As clearly demonstrated by the TOC experiments, the combination of W10O324−/H2O2/hν system permitted a total mineralization of the solution indicating its high efficiency for the a potential application of water depollution.

International audience; Fenton-like system had long been modified to promote its adaptability and efficiency by adding extra components like metal chelators or reducers. Nonetheless, chelator such as ethylene diamine tetraacetic acid (EDTA) was harmful in high dosage. While strong reducers could efficiently promote the generation speed of hydroxyl radicals (HO•), they could also get oxidized easily during storage time, for which further application was costly. In this study, (+)-catechin (CAT), an environmental- friendly component, was proved to be an efficient promoter of Fenton-like system on Bisphenol A (BPA) degradation. The modified system achieved 92% of BPA removal in one hour. The mechanism was studied, and the reaction procedure between CAT and Fe(III) together with the degradation pathways of CAT were identified. Fe(III) got chelated first by CAT and quickly reduced to Fe(II) via a single inner-compound electron transfer. The intermediates of CAT could further reduce one and a half more potion of Fe(III) on average. Consequently, massive amount of Fe(II) turned Fenton-like procedure to Fenton reaction and thus promoted the generation of HO•. The main radicals contributed on BPA degradation was HO•. BPA could be efficiently degraded at pH 6.5 or acidic pH range, but the degradation was completely inhibited with the pH higher than 8.0. The optimal mole ratio between Fe(III) and CAT was 6:1 and the degradation pathway of BPA was deduced

International audience; In the present work, the degradation of three estrogens (17β-estradiol (E2), estrone (E1) and 17α-ethinylestradiol (EE2)) was investigated under photoactivation of hydrogen peroxide and persulfate. Lab-scale irradiation experiments showed that both UVA and UVB radiations are able to photoactivate the oxidant precursors, although UVB is more efficient to generate radicals and therefore to degrade the targets. The efficiency of both oxidant precursors was investigated showing higher efficiency in the system with persulfate. The pseudo-first order degradation rate constants and the second order rate constants between the hydroxyl or the sulfate radicals and estrogens were measured. In order to evaluate the process efficiency in real treatment conditions, the degradation of the estrogens spiked into sewage treatment plant effluent was studied. Measurements of second order rate constants between the radical and the effluent organic matter by laser flash photolysis allowed to understand the involved quenching mechanisms. A Yeast Estrogen Screen (YES) assay was used to follow the decrease in estrogenic activity during the estrogen degradation. This assay permitted to ensure that the studied processes are not only able to degrade the estrogens but also to remove their estrogenic activity.

International audience; In this work, we investigated the photochemical degradation of the complex Fe(III)-EDDS which is increasingly used in studies of advanced oxidation processes. After irradiation of the aqueous solution, HPLC-HRMS analyses are used to identify the degradation products of EDDS. Six different products are separated and identified with specific chemical formulas. Proposed mechanisms based on the initial photo-redox process can explain the formation of all the products. They correspond to oxidized products with a shorter carbon chain and aldehyde and/or carboxylic acid functions. Among, them the formation of formaldehyde is also proposed in the mechanisms. This study is the first one that identifies degradation products of Fe(III)-EDDS complex and proposes a complete mechanism of degradation that can be applied for other iron complexes.

International audience; The present work reported a modified persulfate activation process with a microbial siderophore named desferrioxamine B (DFOB). DFOB was a natural complexing agent and could complex with Fe3+ strongly. The photochemical reactivity of Fe(III)-DFOB was studied. Fe2+ and HO• were produced from Fe(III)-DFOB photolysis. Furthermore, the degradation of atenolol (ATL) was followed in light/persulfate (PS)/Fe(III)-DFOB system. The main oxidative radicals were SO4 •− in this system. The results of pH effect showed that there was no obviously fluctuation on ATL degradation efficiency with the pHincreased from 2.5 to 8.4. Moreover, kSO4•−,DFOB was determined by laser flash photolysis (LFP) experiments. DFOB had positive effect on Fe2+ formation but negative effect on ATL degradation due to the high react rate constant between DFOB and SO4•−. The effects of chloride and carbonate ion were also investigated. The results in this study proposed the reaction mechanism of the modified persulfate activation process, and it could be applied in neutral and weak-alkaline pH range.

In this work, UVA radiation that is part of solar light is taken as the irradiation source and radicals (HO, SO