Gas chromatography–mass spectrometry analysis of organic pollutants in French soils irrigated with agro-industrial wastewater

The use of agro-industrial wastewater in the agricultural sector is an interesting practice to save resources but it can bring various contaminants to the receiving soils. In this study 19 organic pollutants [8 polycyclic aromatic hydrocarbons (PAH), 6 BTEX, 4-tert-octylphenol, 4-octylphenol, 4-n-nonylphenol, tributyltin and diethylphtalate] were analyzed by gas chromatography-mass spectrometry (GC-MS) in soils irrigated with agro-industrial wastewater from sugar refinery. The soils were sampled at five different locations to evaluate the contamination heterogeneity. Microwave-assisted extraction (MAE) was performed using methanol and hexane and extraction yields ranged from 44% to 96%. The detection limits of the method were between 1.6 and 64 μg·L−1 for polycyclic aromatic hydrocarbons, 0.42 μg·L−1 for diethylphthalate, 0.77 μg·L−1 for tributyltin and until 9.8 μg·L−1 for phenol compounds. The highest contaminant concentrations measured in the soil samples, between 0.4 and 1.2 ng·g−1, were monitored for polycyclic aromatic hydrocarbons molecules, including napthalene, anthracene, fluoranthene, indeno(1,2,3-c,d)pyrene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, and benzo[ghi]perylene. Toluene, ethylbenzene, xylene isomers accounted from 21 to 66 ng·g−1 (mostly toluene). Benzene, 4-tert-octylphenol, 4-octylphenol, 4-n-nonylphenol, tributyltin and diethylphtalate were not detected in soils. The proposed method enables analysis of a wide variety of regulated compounds in a unique preparation step and a unique analytical method. The mean amounts of pollutants were in agreement with measurements or estimates performed in similar contexts

Tetra­kis{2-[2-(2,6-dichloro­anilino)phen­yl]ethano­ato-κ2 O:O′}bis­[(dimethyl sulfoxide-κO)copper(II)](Cu—Cu): a binuclear CuII complex with the non-steroidal anti-inflammatory drug diclofenac

The title compound, [Cu2(C14H10Cl2NO2)4(C2H6OS)2], comprises a CuII 2 core that is quadruply bridged by four carboxyl­ate ligands with the dimethyl sulfoxide ligands binding along the Cu⋯Cu axis. The four carboxyl­ate ligands bind in a bidentate syn–syn bridging mode. Mol­ecules reside on crystallographic inversion centres bis­ecting the mid-point of the Cu⋯Cu axis. There are no inter­molecular inter­actions of note

Electrodeposition of biphasic calcium phosphate coatings with improved dissolution properties

Biphasic calcium phosphate coatings (hydroxyapatite/β-tricalcium phosphate) on titanium substrate (Ti6Al4V) are synthetized by pulsed current electrodeposition coupled to a thermal treatment under controlled atmosphere. The experimental conditions of the process such as the hydrogen peroxide amount and the treatment temperature are optimized in order to obtain different coatings compositions. The physico-chemical and structural characterizations of the coatings are carried out respectively by scanning electron microscopy associated with energy dispersive X-ray spectroscopy (SEM-EDXS) and X-ray diffraction (XRD). The in vitro dissolution-precipitation properties of the coated substrates are investigated by immersions into Dulbecco's Modified Eagle Medium (DMEM) from 1 to 28 days. The calcium and phosphorus concentrations variations in the biological liquid are assessed by Induced Coupled Plasma - Atomic Emission Spectroscopy (ICP-AES) for each immersion time. Furthermore, the corrosion behavior of the coated substrates are investigated using potentiodynamic polarization tests in DMEM and in Ringer's solution. The results show that this innovative process is suitable to synthesize two coatings composed respectively of HAP (37%)/β-TCP (63%) and HAP (62%)/β-TCP (38%) with different morphologies. On the other hand, the in vitro studies reveal that the coatings composition greatly influences their behavior in physiological medium, i.e. their dissolution-precipitation and their corrosion protection properties

Aging Effect on Zn Retention on a Calcareous Soil: Column Experiments and Synchrotron X-ray Micro-Spectroscopic Investigation

In this study, a combination of column experiments and micro-analytical techniques exploiting synchrotron generated X-rays was used to assess the effect of aging time on Zn retention and mobility in the specific case of calcareous soils (high pH value, ≈ 8). The samples were subjected to aging for 2, 6, 17, and 63 days. Freshly added Zn mainly existed as an exchangeable form, and this metal fraction decreased over time due to Zn redistribution to stronger binding sites. Thus, after aging for 63 days, 45% of Zn is remobilized from exchangeable sites to stronger binding sites. μ-XRF maps were used to find correlations among elements in the sample, and μ-XANES spectra were recorded to precise Zn speciation. These analyses evidenced an increasing partitioning of Zn from organic matter to iron oxy(hydr)oxides over time. The occurrence of hydrozincite is evidenced in all samples

Réactivité de nouveaux matériaux hybrides organo-minéraux à base de silice en solution aqueuse (applications électrochimiques)

Cette thèse concerne l'étude de la réactivité en milieu aqueux de matériaux organo-minéraux à base de silice, synthétisés par copolymérisation selon le procédé sol-gel. De par leurs propriétés attrayantes (rigidité, porosité importante, organisation à longue distance), ces composés sont exploitables en tant que modifiants d'électrode pour des applications en électroanalyse. La première partie porte sur l'influence de la structure et de la composition de silices fonctionnalisées par des groupements SH et NH2 sur leur réactivité vis-à-vis des ions Cu2+ et Hg2+ (capacité de fixation, vitesse d'accès aux sites). Les résultats obtenus ont alors permis la synthèse, dans une seconde partie, d'un matériau silicique plus complexe dérivé de la carnosine et son application à la détection électrochimique du cuivre(II). Enfin, une méthode originale d'électrodéposition a permis l'obtention de films sol-gel fonctionnalisés sur électrode d'or, poreux et mécaniquement stables.This thesis deals with the study of the reactivity in aqueous medium of organic-inorganic silica-based materials which were synthesised by copolymerisation according to the sol-gel process. Given their attractive properties (rigidity, great porosity, long range order) these compounds are well-suited as electrode modifiers for applications in electroanalysis. The first part concerns the influence of structure and composition of the SH- and NH2- functionalized silicas towards Cu2+ and Hg2+ ions (uptake and kinetics of complexation). In a second part the obtained results have allowed the preparation of a more complex carnosine-based silica material and its application to the electrochemical detection of Cu2+. Finally a new and versatile method was proposed to generate by electrodeposition porous and mechanically stable functionalized sol-gel films on gold electrode.NANCY1-SCD Sciences & Techniques (545782101) / SudocSudocFranceF

Sorptive removal of enrofloxacin antibiotic from aqueous solution using a ligno-cellulosic substrate from wheat bran

International audienceIn this study, the sorption properties of a ligno-cellulosic substrate derived from wheat bran, an agricultural by-product, were investigated in order to test its ability to remove enrofloxacin fluoroquinolone antibiotic from water. The influence of contact time, pH and concentration was studied. The pH value played an important role in the adsorption process, evidencing different sorption processes as a function of pH. The results showed that the substrate removed 100% of enrofloxacin at pH 6 in less than one hour and more than 80% above pH 4. Three kinetic (pseudo-first order, pseudo-second order and intra-particle diffusion) and three isotherm (Langmuir, Freundlich and Sips) models were tested at pH 3.7 and 6. The kinetics followed the pseudo second-order model at both pH with a higher constant rate k2 at higher pH (3.88 g mg−1 h−1 at pH 6). The slower kinetics at pH 3.7 was due to intra-particle diffusion. The isotherm best fit obtained with Sips model indicated a heterogeneous monolayer adsorption of the antibiotic with a high maximum adsorption capacity of 91.5 mg g−1 at pH 6. The tested ligno-cellulosic substrate has emerged as a very good low-cost candidate for enrofloxacin adsorption both in terms of adsorbed amounts and of adsorption kinetics, compared to other adsorbents proposed for enrofloxacin removal

Adsorption and co-adsorption of diclofenac and Cu(II) on calcareous soils

International audiencePharmaceuticals are emerging contaminants and their presence in different compartments of the environment has been detected in many countries. In this study, laboratory batch experiments were conducted to characterize the adsorption of diclofenac, a widely used non-steroidal anti-inflammatory drug, on six calcareous soils. The adsorption of diclofenac was relatively low, which may lead to a risk of groundwater contamination and plant uptake. A correlation between the soil–water distribution coefficient Kd and soil characteristics has been highlighted. Indeed, diclofenac adsorption as a function of soil organic matter content (% OM) and Rt=% CaCO3/% OM was successfully described through a simple empirical model, indicating the importance of considering the inhibiting effect of CaCO3 on OM retention properties for a better assessment of diclofenac fate in the specific case of calcareous soils.The simultaneous co-adsorption of diclofenac and copper – a ubiquitous pollutant in the environment – at the water/soil interface, was also investigated. It appeared quite unexpectedly that copper did not have a significant influence on diclofenac retention

Process optimization with Box-Behnken experimental design for photocatalytic degradation of thiamethoxam using perlite supported TiO2

International audienceEffective photocatalytic degradation of thiamethoxam (THX) at low concentration was achieved by using perlite supported TiO2 composite material (PST). Box–Behnken experimental design method was employed in order to evaluate the effect of process parameters and also optimize them. Accordingly, effects of three process parameters (pH, load of PST [PT {g/L}], and air flow rate [AF {L/h}]) were investigated on two responses: (i) the THX degradation percentage after 270 min (DEG270 [%]) and (ii) the electric energy per order (EE/O [kWh/m3]). THX degradation was improved by decreasing pH value and increasing air flow rate. Increasing load of PST increased the degradation percentage until a critical value of about 8 g/L, then caused a decrease. Statistically significant second-order polynomial models were developed by regression analysis of experimental data. Optimum conditions were obtained as follows: pH 4, PT 8.30 g/L and AF 18 L/h for an initial THX concentration of 1.46 ppm. These conditions led to a response of 87% ± 5% for DEG270 and 120 ± 21 kWh/m3 for EE/O. Control experiments confirmed a good optimized process and reusability of PST without any regeneration step

Combining sorption experiments and Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) to study the adsorption of propranolol onto environmental solid matrices – Influence of copper(II)

International audienceThe bioavailability of pharmaceuticals is governed by their sorption in soils/sediments, as the retention processes determine their concentration in surface- and ground-water. The adsorption of these contaminants can involve various solid components such as organic matter, clays and metallic oxides, and their distribution among these solid components depends on contaminant and solid properties. In this paper we studied the adsorption of the pharmaceutical propranolol – a beta-blocker – on eight different solids (six soils, one sediment and one kaolinite-based sample) by batch experiments. The influence of contact time, propranolol concentration and pH was considered, as well as the presence of copper(II). The investigated solids displayed a wide variability in terms of CEC (cationic exchange capacity) and organic carbon and carbonates contents. The influence of pH was negligible in the pH range from 5.5 to 8.6. The adsorbed amounts were greatly dependent on the solid and two groups of solids were evidenced: three soils of high CEC and organic carbon contents which retained high amounts of propranolol, and three soils, the sediment and the kaolinite-based sample (low CEC and organic carbon content) displaying a low adsorption capacity for the beta-blocker. A linear model enabling the determination of the sorption parameters Kd and Koc was pertinent to describe the adsorption isotherms but the Koc values showed a great variability. It was shown that organic carbon content alone could not explain propranolol adsorption. The CEC value was identified as influent parameter and a simple empirical model was proposed to describe propranolol adsorption. At microscopic and molecular scales, ToF-SIMS experiments indicated (i) a decrease of potassium on the surface upon propranolol adsorption with a distribution of the beta-blocker similarly to alumino-silicates, iron and organic carbon on the surface confirming a cation exchange mechanism and (ii) the absence of degradation products and copper-propranolol complexes