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Persulfate activation by heterogeneous catalysts based on transition metals is of interest in textile effluent treatment processes. Thus, iron-rich electrocoagulation sludge has been thermally treated to obtain new catalysts. The characterization of this catalyst by X-ray diffraction revealed the presence of FeAl

In the present study, experiments were performed to characterize the effectiveness of kaolinite in Cr(III) removal from water in the absence and in the presence of Cr(VI). The results of batch experiments, show that the efficiency of Cr(III) removal by kaolinite increases with the increase of pH and temperature in both cases. The effect of the presence of Cr(VI) on the adsorption of Cr(III) by kaolinite depends on the solution pH and on the concentrations of the two ions. Whatever the system, the removal kinetic of Cr(III) is well described by the pseudo-second order model. Spectroscopic analyses reveal that Cr(III) interaction with kaolinite is mainly electrostatic.

Oil leaks (or spills) into the aquatic environment are considered a natural disaster and a severe environmental problem for the entire planet. Samples of polyurethane (PU) composites were prepared with high specific surface area carbon nanotubes (CNT) to investigate crude oil sorption. Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), density measurements, and mechanical compression tests were used to characterize the polyurethane-carbon PU–CNT prepared samples. The spongy composites exhibited good mechanical behavior and a contact angle of up to 119°. The oleophilic character resulted in increased hydrophobicity, a homogeneous oil distribution inside the sponge, and a sorption capacity in a water/oil mixture of 41.82 g/g. Stress-strain curves of the prepared samples showed the good mechanical properties of the sponge, which maintained its stability after more than six sorption desorption cycles. The CNT–PU composites may prove very effective in solving oil pollution problems.

L’industrie textile consomme de grandes quantités d’eau et utilise des colorants organiques pour teindre ses produits commerciaux. Ces colorants synthétiques sont à la fois toxiques et responsables de la coloration des eaux usées, ce qui nécessite de les traiter avant leur rejet. La plupart des colorants ne sont pas biodégradables et une fois rejetés provoquent une altération du milieu aquatique. Parmi les procédés de traitement des rejets liquides, l’adsorption sur charbon actif est une technique facile à mettre en oeuvre et peu onéreuse. L’objectif de cette étude consiste en la préparation de biochars à partir de roseau commun afin d’obtenir un adsorbant applicable pour la décoloration des effluents de l’industrie textile. Le roseau commun (Phragmites australis) de la rivière de Sed–Ksob de M’sila (Algérie) a été valorisé et utilisé comme précurseur pour la fabrication de biochars par activation à l’acide phosphorique. La chimie de surface des matériaux a été caractérisée par titrage sélectif (dosage de Boehm), analyse thermogravimétrique (ATG) et mesure du point de charge nulle (pHpzc). La texture poreuse a été étudiée par l’adsorption du bleu de méthylène (BM) et la mesure de l’indice d’iode. Les résultats de l’analyse ATG et du dosage de Boehm montrent la présence de nombreux groupes fonctionnels de surface sur les biochars. Les teneurs en groupes fonctionnels oxygénés dépendent du rapport d'imprégnation en acide phosphorique, à l'exception de celui obtenu à un rapport d'imprégnation de 150 %. L’adsorption du BM et le test d’indice d’iode indiquent une augmentation de la surface spécifique lorsqu’on augmente le rapport d'imprégnation. Ceci est dû au développement de la microporosité et de la mésoporosité. Les biochars ont été testés pour leur performance d'adsorption vis-à-vis d'un colorant anionique, le méthylorange (MeO). L’influence de différents paramètres expérimentaux a été étudiée : la concentration, le temps de contact et la température. L’étude des isothermes d'adsorption montre que le modèle de Langmuir décrit bien le processus de l’adsorption du MeO sur les biochars préparés. La cinétique d’adsorption peut être décrite par les modèles de pseudo-second ordre et de diffusion dans le film liquide. Le phénomène d’adsorption est de type physique et endothermique., The textile industry uses large amount of water and organic dyes to tint their products. These synthetic dyes are toxic and cause water coloring. This results in colored wastewater that must be treated before being discharged. In addition, most dyes are not biodegradable, and once released they alter the aquatic environment. Among the processes for treating these effluents, adsorption is an easy and a cost-effective process to implement. The objective of this study is the preparation of biochars from common reed applicable for the discoloration of effluents used in the textile industry. Common reed (Phragmites australis) has been collected from the Sed-Ksob river of M'sila (Algeria) and used as precursor for the production of biochars activated by phosphoric acid. The surface chemistry of the prepared materials has been characterized using selective titration (Boehm assay), TGA analysis and pH of point zero charge (pHpzc) measurements. The porous texture has been investigated by using methylene blue adsorption and iodine number measurements. The results of the TGA analysis and the Boehm assay show the presence of many superficial functional groups on the surface of the biochars. The amount of oxygenated functional groups on all the prepared biochars depends on the impregnation ratio of phosphoric acid, except for the one obtained at 150% impregnation ratio. The adsorption of methylene blue and the iodine test indicate an increase in the specific surface area with an increase in the impregnation ratio due to the development of the microporosity and the mesoporosity. The adsorption properties of methyl orange, an anionic dye, were studied on the prepared biochars as function of concentration, contact time, and temperature. The Langmuir model describes well the equilibrium adsorption of methyl orange on the prepared biochars. The adsorption kinetics are described by the pseudo-second order and the liquid film diffusion models. An endothermic physical adsorption of methyl orange on the prepared biochars has been highlighted.

Enteric viruses are widely spread in water environments, some being harmful for human communities. Regular epidemics highlight the usefulness of analysing such viruses in wastewaters as a tool for epidemiologists to monitor the extent of their dissemination among populations. In this context, CNovel™ Powdered Activated Carbon (PAC) was chosen for its high porosity and high adsorption capacity to investigate sorbent ability to be used as part of of virus detection probes. Self-supported PAC Foils (PAC-F), PAC coated Brushes (PAC-B) and PAC Sampler (PAC-S) were used to prospect PAC efficacy in virus adsorption and above all, the feasibility of virus retrieval from them, allowing to further analysis such as molecular analysis quantification. Aiming at the development of a field-operational tool, PAC saturation and reusability were also investigated, as well as PAC-polarisation effect on its adsorption capacity. Our results pointed out that sorbent-based probes exhibited a high adsorption efficacy of spiked Murine Norovirus (MNV-1) in bare 0.1 M NaCl solution (90 % for PAC-B and86 % for PAC-F at ≈10

Membrane fouling is a continued critical challenge for ultrafiltration membranes performance. In this work, polyether sulfone (PES) ultrafiltration (UF) membranes were fabricated via phase-inversion method by incorporating varying concentrations of APTMS modified activated carbon (mAC). The mAC was thoroughly characterized and the fabricated membranes were studied for their surface morphology, functional groups, contact angle, water retention, swelling (%) porosity, and water flux. The hydrophilicity of mAC membranes also resulted in lower contact angle and higher values of porosity, roughness, water retention as well as water flux. Also, the membranes incorporated with mAC exhibited antibacterial performance against model test strains of gram-negative Ecoil and gram-positive S. aureus. The antifouling studies based on bovine serum albumin protein (BSA) solution filtration showed that mAC membranes have better BSA flux. The higher flux and antifouling characteristics of the mAC membranes were attributed to the electrostatic repulsion of the BSA protein from the unique functional properties of AC and network structure of APTMS. The novel mAC ultrafiltration membranes developed and studied in present work can provide higher flux and less BSA rejection thus can find antifouling applications for the isolation and concentration of proteins and macromolecules.

New types of Cu-doped spherical-shaped activated carbons were prepared by pyrolysis at 700 °C of chitosan hydrogels impregnated with KOH at ratios (mKOH/mchitosan) ranging from 22.5% to 135%. At KOH impregnation ratio lower than 63%, the precursor Cu doping allowed obtaining bead-shaped activated carbons (diameter ~ 2 mm) and the highest specific surface areas (1145 m2 g−1). The absence of copper doping yielded to activated carbon powders whatever the KOH impregnation ratio. As increasing the impregnation ratio higher than 63%, the materials porosity type turns from exclusively microporous to both microporous and mesoporous. The microporous volume, determined by N2 adsorption at 77 K and CO2 adsorption at 273 K, attains a maximum (about 0.5 cm3 g−1) for a 63% impregnation ratio. Scanning Electron Microscopy (SEM) images show a multi-scale porosity for a KOH impregnation ratio higher than 45%. Nanoparticles of Cu and CuO were identified by SEM and Transmission Electron Microscopy in the ACs beads prepared from copper-doped chitosan. Whatever the composition, the beads are formed of N-enriched carbons showing mainly pyridinic and pyrrolic groups evidenced by XPS.

Iron-based nanoparticles were formed in the pores of a micro- and mesoporous activated carbon made from banana spike by the impregnation of iron sulfate at various ratios and further pyrolysis, in order to prepare three catalysts AC@Fe/1, AC@Fe/2, AC@Fe/3 having iron mass contents of 1.6%, 2.2% and 3.3%, respectively. The pore size distributions, transmission electron microscope observations and X-ray photoelectron spectroscopy analyses have revealed that iron-based nanoparticles of 1–50 nm diameter, containing O and P, are located mainly in the supermicropores and mesopores of the activated carbon. Catalysts have been used to remove Rhodamine B in an aqueous solution by the heterogeneous Fenton process. AC@Fe/3 catalyst has allowed achieving 93% of solution discoloration compared to 87.4% for AC@Fe/2 and 78.5% for AC@Fe/1 after 180 min in batch reaction. The catalytic efficiency of AC@Fe/3 is attributed to the highest dispersion of the iron-based nanoparticles in the activated carbon porosity. The effects of hydrogen peroxide and initial dye concentration, pH, catalyst amount and temperature on the Rhodamine B removal kinetics catalyzed by AC@Fe/3 were studied. This catalyst showed remarkable performances of the Rhodamine B mineralization and possibility of recycling.

This work emphazises the importance of the solubilizing conditions for the elaboration of chitosan hydrogel beads, which were produced using electromagnetic laminar jet breakup technology, resulting in dried porous beads by further freeze-drying. Paramaters such as the acid nature and concentration (acetic, formic, citric, lactic, maleic and malic, 0.1 to 0.5 mol·L−1), the chitosan concentration (2 to 5 wt%) and composition of the gelation bath (NaOH, with or without EtOH) were studied. Viscosity versus strain rate measurements were carried out on chitosan acidic solutions and the viscoelastic behaviour was studied on hydrogels. The solutions exhibiting the highest viscosities led to the stiffest macrohydrogels, as a result of chitosan carboxylate interactions. Specific surface areas of the freeze-dried beads were determined in the range from 12 to 107 m2·g−1. Their internal texture was observed by Scanning Electron Microscopy. Water uptake was also measured for further use in the field of water purification.

Response surface methodology based on central composite design was used as a tool to optimize the preparation of micro-/mesoporous activated carbon from plantain spike. The impact of three variables: activation temperature, activation time, and H3PO4 impregnation ratio, were evaluated on the iodine number and the methylene blue (MB) index according to the model-determined conditions. These three variables have been extensively studied using analysis of variance to assess their significance. Each response was described by a second-order regression equation showing good agreement between the predicted and the experimental data as the adjusted correlation coefficients were greater than 0.80. The multi-response optimized conditions have been set at the temperature of 480 °C, the activation time of 113 min, and the impregnation ratio of 3.34/1 (w/w). The activated carbon prepared in these conditions has a specific surface area of 896 m2/g with micro- and mesopore volumes of 34% and 66%, respectively. Water depollution capacity of this activated carbon evaluated by adsorption of MB and iodine was 206 mg/g and 927 mg/g, respectively.

Micron-sized vermiculite (VMT) clay was modified with 3-aminopropyltriethoxysilane (APTES) through sonication. The surface modification was proficient within 30 min of sonication relatively than long reflux times reported prior. A grafted mesoporous silica (GSIL) was synthesized through demineralization of the micron-sized VMT and further functionalized with APTES. The adsorbents were characterized by FTIR, TGA, XRD, and FE-SEM. The pore size distribution and surface area were determined using N 2 adsorption–desorption isotherms. The performance of the synthesized substances as adsorbents was evaluated by the removal of an Alizarin Red S (ARS), organic dye from aqueous solutions. The maximum sorption capacity was 18.2 mg/g for APTES grafted vermiculite and 59.8 mg/g for APTES grafted silica. The adsorbent dose, pH, temperature, dye concentration, and influence of contact time on the removal of ARS were investigated. The ARS adsorption increased with adsorbent dosage and reached a maximum of 0.8 mgmL−1 for both adsorbents. The experimental data were best fitted by the Langmuir isotherm model. The Kinetics of adsorption modeling confirmed that the ARS adsorption pursued a second-order model. The thermodynamic parameters evaluated from van’t Hoff’s model revealed a spontaneous endothermic adsorption process.

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International audience; The present investigation reports the preparation and defluoridation efficiency of Al2O3/ZrO2 xerogel. The material was prepared by environment friendly sol-gel technique using respective metal salts as precursors. FTIR spectra indicated presence of bridged structure (Zr – O – Al) in the material and decrease in intensity of hydroxyl group vibration indicates substitution of surface hydroxyl groups by fluoride through formation of metal – fluoride bonding. The XRD of material showed amorphous characteristics of Al2O3/ZrO2. The morphological feature of the material indicate presence of micro-pore in the structure and the total specific surface area (m2 g−1) and average pore radius (nm) were calculated to be 3.68 and 1736.6, respectively. The molecular interaction/bonding between aluminum-zirconium contributed in enhancing the stability of the material, whereas, the kinetics of thermal degradation pattern is heterogeneous in characteristics. Al2O3/ZrO2 shows almost 98% fluoride removal efficiency where the material-anions equilibrium was reached within 20 min time interval. Fluoride adsorption characteristics was found to be pH dependent influenced by pore diffusion, where the presence of multiple active centers, i.e., Al and Zr in Al2O3/ZrO2 favors fluoride sorption in comparison to ZrO2 xerogel. Fluoride adsorption follows a pseudo-second order kinetic as well as intra-particle diffusion model with almost ≥ 0.99 accuracy. The thermodynamics of fluoride adsorption was found to be spontaneous and exothermic in nature. The adsorbent shows good regeneration efficiency up to 5th cycles of continuous operation with very little effect of co-anions that can be helpful for its sustainable commercial applications.

In order to override the slow adsorption kinetics of micropollutants on an activated carbon fabric (ACF) in water medium, different mixing modes, i.e. orbital stirring (250 rpm), low frequency ultrasonic irradiation with either a 20 kHz probe (volumic power: 80 W/L) or a 38 kHz bath (10 W/L), were compared to promote the adsorption of ibuprofen (4 ppm initial concentration). The used ACF is formed of wowen braids made of three yarns (∼300 µm diameter), each of them being composed of microporous fiber bundles (12.6 µm diameter) and its texture was accurately characterized. The adsorption kinetics were studied in buffered phosphate solution (pH 7.5) on a disk, braids or fiber from the fabric and were simulated by a volume diffusion model. The fitted values of the external mass transfer and the volume diffusion coefficients have demonstrated the limitation of the adsorption kinetics under stirring on the fabric disks and braids by the diffusion step within the yarn in the inter-fiber macroporosity. The 20 kHz sonication coupled to the adsorption on ACF led to the degradation of ibuprofen by OH° radicals issued from water sonolysis but without damaging further the fabric. The low power irradiation at 38 kHz allowed a sharp acceleration of the adsorption kinetics with respect to the one obtained through orbital stirring. This is explained by a fast mobility of the ibuprofen owing to the presence of standing waves and absence of harsh cavitation as compared to 20 kHz probe system, and confirmed by a fitted diffusion coefficient higher than the one of molecular ibuprofen and of two order of magnitude than in stirring conditions.

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International audience; Phosphorus sorption capacity was investigated in surface sediments derived from an abandoned zinc-lead mine area located in northeastern Algeria. The forms and the distribution of phosphorus in the raw sediment were identified using the sequential chemical extractions method. Batch experiments were done to study the adsorption kinetics and isotherms. The pH effect was evaluated by macroscopic and infrared analyses. In raw sediment, speciation results show that phosphorus is dominantly bound to oxyhydroxides. Sorption experiments demonstrate that phosphorus uptake is principally related to sediment composition. The nature of the dominant iron oxyhydroxide has a substantial role in the adsorption capacity and the mechanism interaction. The adsorption kinetics can be described by the second order and Elovich models. The isotherms data are successfully modeled by the Temkin equation. The maximum phosphorus removal is reached under acidic pH. Spectroscopic analyses reveal that the predominance of jarosite implies electrostatic 2 interaction with sediment particles. However, in the case of schwertmannite predominance, phosphate ions are adsorbed by the ligand exchange mechanism.

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International audience; The evolution of the pore structure of compressed expanded vermiculite was investigated in situ under uniaxial stress up to 3200 bar using small-angle neutron and X-ray scattering. The studied samples have a lamellar texture in which the presence of oriented oblate pores was revealed by the anisotropic small-angle scattering patterns. The initial pore size distribution and the mechanical behaviour of the pellets at working pressure conditions are strongly related to the applied initial stresses used to pre-compact the vermiculite powder. Our study shows that the porous structure of the pellets was not modified under compression up to the pre-compaction pressure. Higher densification is associated with increasing anisotropy of the pore–matrix interface structure. The pore–matrix interface could be described with fractal geometry. The stress dependence of the system fractal dimension, apparent specific surface area and total porosity was determined and related to the meso- and macropore evolution under uniaxial stress.

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International audience; Reductive zero-valent iron nanoparticles were prepared for the treatment of Cr(VI) solutions. The ferric ions reduction by borohydride was carried out through mechanical stirring or ultrasound irradiation either in an ultrasonic bath or in a 20 kHz cup-horn reactor.The prepared materials have been characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, and N2 adsorption-desorption at 77 K.The microscopic observations showed iron nanoparticles with diameter in the range 40 nm-80 nm, arranged in chain aggregates regardless the variation of the preparation method. The ultrasonic synthesis allowed to obtain higher BET specific surface area (99 m2. g-1 for nanoparticles prepared in ultrasonic bath and 145 m2. g-1 for the ones prepared by probe sonication) than the ones of samples synthesized in silent conditions (22 m2. g-1).The Cr(VI) ions removal in pure water solution was found significant at acidic pH. The removal kinetics modeled by pseudo first order, are linearly proportional to the BET surface areas. They are rapid (< 30 min to attain equilibrium), and decrease as increasing the Cr(VI) concentration and as decreasing the iron nanoparticles dose. Cr(VI) ions were removed by reduction and co-precipitation of Cr(III) in the form of chromite at pH > 7. The iron nanoparticles were tested for the treatment of metal surface processing wastewater. For such treatment, they have proven to be efficient for removing Cr(VI) together with Ni(II) ions. The iron nanoparticles prepared by 20 kHz ultrasonic probe have been found more effective for Cr(VI) removal than any kind of iron nanoparticles conventionally prepared.

Background: Sulfonated polyimides (SPIs) are considered as the promising alternatives to Nafion as membrane materials for the polymer electrolyte membrane (PEM). They generally exhibit high ionic conductivity, good mechanical properties, excellent thermal and chemical stabilities. The six-membered ring, naphthalenic anhydride-based SPIs, not only exhibit superior chemical and thermo-oxidative stabilities but are also more resistant to hydrolysis than their five-membered phthalic anhydride-based SPIs. The composites based on napthalenic polyimides are also significantly stable in high temperature environment and show better stability to hydrolysis. Incorporation of inorganic fillers into organic polymers has gained tremendous attention and these new materials are called organic-inorganic hybrids. Few patents related to the synthesis and performance PEM materials have been reviewed and cited. Keeping in view the importance of sulfonated polyimide based nanocomposites as potential membrane materials for PEM in fuel cell, we have synthesized SPIs clay based nanocomposite as potential membrane material. The objective of this work was to synthesize clay based SPIs thin films which could be used as membrane materials in PEM fuel cell for energy applications. Methods/Experimental: At the first step the nanometric sheets of vermiculite clay prepared via sonication was surface modified by grafting 3-APTES. Then the SPI was synthesized via one-step high temperature direct imidization method, which serve as a matrix material. The organo modified VMT was dispersed via sonication in the SPI matrix. Four different sets of organic-inorganic nanocomposite membranes thin films, having VMT contents in the range of 1 to 7 wt. were prepared by casting, curing and acidification route. Results: The synthesis of SPIs clay based thin films were carried out at three different steps and fully characterized. The synthesis of SPIs and SPIs clay based thin films were analyzed via different analytical techniques. The XRD analysis tells the successful dispersion of clay in SPI matrix. Different physiochemical tests were conducted for the analysis of these membranes such as water uptake, hydrolytic stability, ion exchange capacity (IEC), dimensional changes and oxidative stability, to check their suitability as membrane materials for PEM. The proton conductivity of these membranes were measured via impedance spectroscopy which discloses three different active regions responsible for proton conduction. The activation energies of the membranes were higher at lower temperature and reaches to 8.2 kJ/mol at higher temperature (90°C). Conclusion: The synthesis of sulfonated polyimide/clay (SPI/clay) based organic-inorganic nanocomposite membranes were achieved successfully. The membrane display good hydrolytic, thermal and oxidative stability at elevated temperature. The proton conductivity of the membrane display an increase together with the frequency but decreases with temperature. Therefore some more efforts are required to achieve high degree of functionalization of both organic and inorganic components, for the �future� PEMs to avoid deterioration and to get improved performance. © 2016 Bentham Science Publishers.

The adsorption isotherms of two new ionic liquids (4-tert-butyl-1-propylpyridinium bromide: IL1 and (4-ter-butyl-1-(2 carboxyethyl) pyridinium bromide: IL2) and ibuprofen (2-[4-(2-methylpropyl) phenyl] propanoic acid: IBP) on an activated carbon cloth were studied at 286, 298 and 313 K. Experimental adsorption isotherms were simulated by a single energy monolayer model using statistical physics, allowing to determine the number of molecules per site ( n ), the density of receptor sites ( N M ) and the concentration at half saturation ( c 1/2 ). Simulation results suggested that two adsorbates were docked per receptor sites of the activated carbon cloth surface. As a function of temperature, the study of the monolayer adsorbed quantity has indicated that the adsorption process is exothermic. The magnitudes of the estimated adsorption energies have indicated that IBP and ILs have been physisorbed on the adsorbent. The conductor-like screening model for real solvents (COSMO-RS) was applied to calculate three specific interaction energies of ILs and IBP with a graphene layer, i.e., the electrostatic misfit energy (E MF ), the hydrogen-bonding energy (E HB ) and the Van der Waals energy (E vdW ). The COSMO-RS model has proved that the interaction of all the three studied adsorbates with a graphene layer mainly depends on the Van der Waals contribution. The highest interaction energies of IL2 and IBP with the carbon surface have been explained by the additional contribution of hydrogen bond attributed to the presence of a carboxyl group on these molecules.

In an adsorption process, spontaneous accumulation of molecules takes place at the surface of solids as compared to the bulk phase. Adsorption is used for the recovery of undesirable components from a liquid mixture by establishing van der Waals bonds between the solid surface and the attracted components. Nowadays, adsorption is recognized as one of the major significant separation processes amid the physical, biological, and chemical processes. Activated carbon adsorption has been widely used for the purification of water and wastewater and for the treatment of numerous environmental problems. In this work, polyurethane (PU) foam-activated carbon composites were synthesized and characterized. The mixing of a number of well-defined ingredients produces flexible foam of alveolar structure after polymerization reactions. The prepared PU-powdered activated carbon composites were used to investigate the sorption of raw crude oil. Multiple experimental manipulations were combined to understand this be...

A new approach model was developed for the pore size characterization of carbon porous materials, using adsorption gases. The experimental adsorption isotherms of CO2 and N2 onto carbon nanoparticles were used to test the validity of such model. The Trimodal-Gauss-Monolayer model has been found to adjust well the experimental data of CO2 sorption at 273 K and has allowed detect the ultra-micropores till 0.7 nm. For the mesopores and macropores, it has been concluded that the N2 sorption isotherms at 77 K are suitable to characterize this kind of porosity. These isotherms have been well fitted with the Gauss-Monolayer/Gauss-Finite Multilayer model derived from the same approach. Thereby, the novel method can be used as a generalized technique for the simulation of type IVa isotherms. Indeed, this novel method agreed with other methods, NLDFT, QSDFT, and VBS available for pore size distribution. Fil: Bergaoui, Manel. Universite de Monastir; Túnez Fil: Aguir, Chadlia. Universite de Monastir; Túnez Fil: Khalfaoui, Mohamed. Universite de Monastir; Túnez Fil: Villarroel Rocha, Jhonny. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; Argentina Fil: Reinert, Laurence. Université Savoie Mont Blanc; Francia Fil: Enciso, Eduardo. Universidad Complutense de Madrid; España Fil: Duclaux, Laurent. Université Savoie Mont Blanc; Francia Fil: Barrera Diaz, Deicy Amparo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; Argentina Fil: Sapag, Manuel Karim. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; Argentina

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International audience; Vermiculite gaskets obtained by pressing vermiculite powders in the range of 17.7–80 MPa, were studied for their sealing (leak rate measurements) and compressive properties (compressibility and resiliency). The in plane permeability at room temperature was found to decrease strongly through increasing elaboration pressure, that reduced both the median pore radius (< 30 nm) and the macropore volume fraction (< 45%), measured by mercury intrusion. After annealing at temperatures of up to 600 °C, the out of plane permeability (measured at room temperature) was increasing from ~ $10^{-20}$ (at 200 °C) to ~ $10^{-24}$ due to the increase in anisotropy related to the densification and the formation of interlayer bonds. The global leak rate was found to be determined exclusively by the contact leak rate and independent of the material's permeability. The leak rates measured at room temperature were also found to be dependent on the gasket's resiliency values. The global helium leak rate (2.5 × $10^{-2}$ atm·$cm^{3}$·$s^{-1}$·$m^{-1}$, for 35 MPa working pressure, under 5 bar helium pressure) was relied neither on the working temperature (25 °C to 800 °C) nor the material porosity for gaskets pressed at 200 °C and 80 MPa. The resiliency (~ 5%) and compressibility (9%) values of these gaskets were reduced, as heating the materials to 800 °C due to the densification induced by both pressure and temperature, increasing their rigidity.

An activated carbon was prepared by phosphoric activation of olive pomace and further oxidation by nitric acid. Another carbon was obtained from β-cyclodextrin dehydration in concentrated sulfuric acid. A composite of the oxidized activated carbon and the carbon from β-cyclodextrin was prepared. The four materials were characterized by N2 adsorption–desorption measurements, X-ray diffraction, infrared and Raman spectroscopies, elemental analysis, “Boehm” titration and measurements of pH of the point zero charge. The obtained adsorbents were tested for boron adsorption in aqueous solution. Despite their lowest specific surface areas, the composite carbon and the amorphous carbon from cyclodextrin dehydration showed the highest boron adsorption uptake (1.41 and 1.68 mg·g−1) compared to the raw (1.05 mg·g−1) and oxidized (0.95 mg·g−1) activated carbons. The surface chemistry particularly rich in phenolic groups was responsible for the high boron adsorption uptake of the carbon composite and the amorphous carbon, both prepared through cyclodextrin dehydration.

Activated carbons obtained from two algal species, green and brown alga (GAAC and BAAC, respectively) were used as adsorbent precursors to remove nickel ion from aqueous solution. The raw materials were impregnated in phosphoric acid at different concentrations and pyrolyzed at temperatures ranging from 400? to 800 °C. The BET model application to evaluate surface area resulted in values of 1400 and 1144 m2/g for the green and brown algae, respectively. The effect of parameters such as impregnation time, pH, carbon dose, and pyrolysis temperature on batch adsorption was also investigated. Selected samples were characterized by FT-IR spectroscopy, BET analysis, pHzpc, Methylene blue index and iodine number analyses. Isotherm constants from experimental data were calculated using Langmuir and Freundlich isotherms models. Respective coverage capacities of brown and green alga for Ni2+ were found to be 64.51 and 91.70 mg/g in comparison with 6.30 mg/g obtained for the commercial activated carbon. The pseudo-second order model best described Ni2+ kinetics. Heat adsorption values showed that adsorbent-adsorbate interactions are physical. Negative values of ΔG° confirm the spontaneity of the adsorption process of Ni2+ for all considered adsorbents. The algal-based adsorbents prepared showed substantial capability to remove nickel ion from its synthetic solutions.

This study aims to investigate the performance of an activated carbon cloth for adsorption of ibuprofen. The cloth was oxidized by a NaOCl solution (0.13 mol L−1) or thermally treated under N2 (700 °C for 1 hour). The raw and modified cloths were characterized by N2 adsorption–desorption measurement at 77 K, CO2 adsorption at 273 K, Boehm titrations, pHPZC measurements, X-ray Photoelectron Spectroscopy analysis, and by infrared spectroscopy. The NaOCl treatment increases the acidic sites, mostly creating phenolic and carboxylic groups and decreases both the specific surface area and slightly the micropore volume. However, the thermal treatment at 700 °C under N2 induced a slight increase in the BET specific surface area and yielded to the only increase in the carbonyl group content. Ibuprofen adsorption studies of kinetics and isotherms were carried out at pH = 3 and 7. The adsorption properties were correlated to the cloth porous textures, surface chemistry and pH conditions. The isotherms of adsorption were better reproduced by Langmuir–Freundlich models at 298, 313 and 328 K. The adsorption of ibuprofen on the studied activated carbon cloths at pH 3 was an endothermic process. The pore size distributions of all studied ibuprofen-loaded fabrics were determined by DFT method to investigate the accessible porosity of the adsorbate. Both treatments do not influence the kind of micropores where the adsorption of ibuprofen occurred.

Ionic liquids (ILs) are considered as emergent pollutants as their synthesis and further use at a large scale might generate environmental problems. The adsorption on activated carbons represents one of the most effective methods to remove ionic liquids and other micropollutants from wastewater. In this work, the adsorption properties on an activated carbon cloth of two pyridinium ionic liquids (4-tert-butyl-1-propylpyridinium bromide (IL1) and 4-tert-butyl-1-(2-carboxyethyl)pyridinium bromide (IL2)) newly synthesized, were compared with the ones of ibuprofen. The adsorption kinetics and isotherms were studied at pH 3 and 7.5. The adsorption thermodynamic parameters calculated from the isotherms indicate an exothermic process, typical of physisorption. The adsorption kinetics of a mixture of the molecules show a competition between ibuprofen and IL2. The location of each adsorbed ionic liquid and ibuprofen into the porosity of the activated carbon cloth was determined from N2 (at 77 K) and CO2 adsorption isotherms (at 273 K). The purification process of an effluent containing the ionic liquids and the ibuprofen in mixture or in single solute could be workable by adsorption on an activated cloth. Keywords: Adsorption, Kinetics, Isotherms, Activated carbon cloth, Ibuprofen, Ionic liquid

The adsorption mechanism of manganese nitrate on vermiculite was studied by analysis of the isotherms of the cations exchanged from the vermiculite (K + and Ca 2 + ) and the ions (NO 3 − and Mn 2 + ) adsorbed on the vermiculite. The Langmuir-type manganese adsorption isotherm of the raw vermiculite shows a maximum uptake of 28.32 mg·g − 1 . The adsorption temperature dependence between 25 °C and 45 °C has demonstrated an endothermic and spontaneous adsorption. The amount of exchanged Mn 2 + ions in equivalent per gram represents only 17% of the total adsorbed uptake, of which 14% have been exchanged against Ca 2 + ions and 3% against K + ions. 83% of the Mn 2 + and NO 3 − ions have been co-adsorbed by complexation at the edges of the layers. The grinding of the vermiculite has involved a decrease in the grains size from 2–3 mm to 100 μm and thus an increase in the edge layer adsorption site content allowing an increase of 19% of the maximum adsorption uptake compared to raw vermiculite. The ultrasonic milling of vermiculite in aqueous dispersion at 20 kHz allowed to decrease the size of the grains further (8 μm) and led to increase the maximum uptake by 31%. The sonication of the vermiculite dispersion in 35% hydrogen peroxide has allowed to obtain a maximum adsorption uptake of 36.77 mg·g − 1 (30% of increase compared to raw vermiculite). The linear variation of the Mn 2 + adsorption capacity with respect to the sum of the estimated geometric perimeter of the sonicated particles (assuming square shaped particles) confirms an adsorption process at the edge of layers.

Organic resin and its derived carbon nanoparticles (CNPs) were prepared and used to adsorb Bovine Serum Albumin (BSA). Characterization by Boehm titrations and X-ray photoelectron spectroscopy showed that resin has the largest densities of oxygen groups with a higher O/C atomic ratio (0.381) compared to CNPs (0.059). Field Emission Scanning Electron Microscopy indicated a spherical shape for both adsorbents with a mean diameter of about 50 nm and 100 nm for CNPs and resin, respectively. The nitrogen adsorption-desorption isotherms showed that CNPs present a high specific surface area, (S BET = 662 m 2 /g) and total pore volume (V T = 1.33 cm 3 /g) compared to the resin. A stepwise shape was observed in the adsorption isotherms indicating two different processes. At low concentration, the resin presented a higher adsorbed uptake (0.38 mg/mg) compared to CNPs (0.21 mg/mg) due to its higher amount of oxygen groups. At high concentration, the adsorbed quantity for CNPs (1.30 mg/mg) was higher than the one for the resin (0.97 mg/mg) which is probably due to the porosity effect. To better understand this adsorption behavior, a new approach based on statistical physics was developed. This theoretical model led us to evaluate the adsorption energy distribution and to confirm the two steps adsorption phenomenon.

Glassy carbon particles (millimetric or micrometric sizes) dispersions in water were treated by ultrasound at 20kHz, either in a cylindrical reactor, or in a "Rosette" type reactor, for various time lengths ranging from 3h to 10h. Further separations sedimentation allowed obtaining few nanoparticles of glassy carbon in the supernatant (diameter

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International audience; The influence of ultrasound radiation on graphite structure was studied by laser light scattering, X-ray diffraction, Raman spectroscopy and Transmission Electron Microscopy. Irradiations of polycrystalline graphite powder suspensions at frequencies of 20 kHz and 500 kHz, were carried out in three different solvents: water (as the best medium for cavitation), a surfactant (OMImBr) aqueous solution and also a mixture of sulfuric and nitric acids which caused the exfoliation by intercalation. The average basal particle size of 168 lm was reduced to 4 lm after ultrasonication delivering a huge energy density up to 1.2 MW/m2. Change of the sonication time and the nature of the solvents produced different reduction of the graphite crystals dimensions, affecting the out of plane thickness and the basal width as well. The ultrasonication promoted the disordering of the graphite tridimensional stacking for all solvents used, with the strongest effect in acidic medium. Turbostratic structures formation and exfoliation of graphene flakes have been observed after the use of surfactant for sonication medium. Intercalation in acid medium prior to the ultrasound treatment produced similar effects.

Three biosorbents: Eucalyptus globulus, Cynara cardunculus, and Prunus cerasefera leaves were tested to remove Methylene Blue from aqueous solutions. The three biosorbents were characterized by the determination of the Methylene Blue accessible surface, iodine number, BET specific surface area using nitrogen adsorption at 77 K, morphological analysis by scanning electron microscopy, pHPZC, and FTIR analysis. The Methylene Blue adsorption uptakes of the biosorbents were studied as a function of pH, biosorbent dose, stirring speed, ionic strength, and contact time. Optimal conditions for maximum removal of Methylene Blue were found to be: a pH of 10, an adsorbent dose of 8 g L−1, and a contact time of 2 h for E. globulus and C. cardunculus, and a pH of 6.5, an adsorbent dose of 4 g L−1 and a contact time of 2 h for P. cerasefera. The Langmuir models as determined from batch experiments yielded a maximum capacity of adsorption by biosorbent prepared from E. globulus leaves of 250 mg g−1 against 333 ...

The adsorption kinetics of nine contaminants (ibuprofen, carbamazepine, ofloxacin, bisphenol-A, diclofenac, mecoprop, pentachlorophenol, benzotriazol and caffeine) on a microporous and a microporous/mesoporous activated carbon cloth were studied in single, two-component and complete mixture at pH 7.5. Adsorption capacities at equilibrium were highest for the highly microporous carbon material, showing that pollutant adsorption mainly takes place in the micropores. This effect was more pronounced for small size adsorbates. Adsorption kinetics were increased for small size adsorbates thanks to their easy diffusion in the narrow porosity. Same behaviors were observed in the complex mixture containing the nine pollutants. Competition and sieving effects were observed in two-component mixtures, while considering two adsorbates having different molecular volumes, as for example caffeine and diclofenac. Moreover, the desorption of the co-adsorbates having the highest Gibbs energy value of adsorption determined from adsorption isotherms at 298 K (caffeine, mecoprop and benzotriazol) was observed for the kinetics of the complex mixture of the nine contaminants and of the two-component mixture. This desorption was provoked by the competition with the contaminants having lower Gibbs energy variation in single adsorption and thus strongly attracted at the adsorbent surface.

The elaboration and characterization of hydrophobic melamine-based sponges are presented. Sponges were obtained by single-step carbonization of commercial melamine foam having a 3D interconnected network. We show that optimized sponges can be elaborated from a simple pyrolysis treatment with rather low temperatures of 500–600 °C. These materials exhibited excellent absorption capacities (they absorbed 90 to 200 times their own weight), a very high porosity of 99.5%, a low density around 7 mg/cm3 and water contact angles ranging from 120° to 140° close to superhydrophobicity. The relationship between hydrophobicity and physicochemical evolution on heat treatment (carbonization process, diffusion of additives, porosity evolution) was studied in detail. The as-prepared carbon sponges are compressible up to 80% with a Young’s modulus ranging from 0.58 kPa to 0.80 kPa, and keep part of their elastic properties after a hundred compression-decompression cycles. The carbonized sponges were characterized by thermogravimetric analysis (TGA), infra-red spectroscopy (FTIR), Raman spectroscopy, elemental analysis (EA), X-ray photoelectron spectroscopy (XPS) and scanning electronic microscopy (SEM). These characteristics make these materials promising absorbents for water depollution: oil-spill clean-ups or removal of oils and organic solvents from water, especially for the recovering of the pollutant by simple squeezing of the absorbent.