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General chemistry, physical chemistry, Chimie générale, chimie physique, Energy, Énergie, Chemical engineering, Génie chimique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Physicochimie des réactions induites par rayonnements, particules et ultrasons, Physical chemistry of induced reactions (with radiations, particles and ultrasonics), Photochimie, Photochemistry, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Cinétique, Kinetics, Cinética, Modélisation, Modeling, Modelización, Oxydation, Oxidation, Oxidación, Oxygène, Oxygen, Oxígeno, Photocatalyse, Photocatalysis, Fotocatálisis, Photochimie, Photochemistry, Fotoquímica, Photosensibilisation, Photosensitization, Fotosensibilización, Protection environnement, Environmental protection, Protección medio ambiente, Résonance, Resonance, Resonancia, Spin, Electron spin resonance, Environmental photochemistry, and Kinetic modeling

Photooxidation of Fe(II) at acidic pH occurs in photocatalytic processes of Fe(III) species, but its reaction mechanism is not well understood. The kinetics of Fe(II) oxidation in irradiated aqueous solutions at pH 3.0 have been investigated in terms of kinetic modeling approach, rate constant estimation and the significance of various oxidation pathways. Fe(II) oxidation kinetics strongly rely on the availability of UV light, Fe(III) ions and oxygen. The presence of a portion of Fe(III) in Fe(II)-containing solutions favors the rapid oxidation of Fe(II). At high concentration of Fe(II), excitation of Fe(III) species may be quenched by Fe(II) in deaerated systems or may sensitize Fe(II) oxygenation under oxic conditions. By incorporation of this photosensitization pathway, the established model in this study is shown to be able to adequately describe the oxidation of Fe(II) at pH 3.0. Sensitivity analysis indicates that photolysis of Fe(III) species is critically important for overall Fe(II) oxidation kinetics. Fe(III)-catalyzed oxygenation of Fe(II), and oxidation of Fe(II) by HO2• and •OH also exerts a marked impact on the oxidation of Fe(II). Therefore, Fe(III)-catalyzed oxygen activation and their secondary reactive oxygen species (ROS) account for the oxidation kinetics of FE(II) at acidic pH.

Chemical engineering, Génie chimique, Computer science, Informatique, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Energie, Energy, Combustibles, Fuels, Industrie gazière, Gas industry, Traitements et conditionnement des gaz. Désulfuration. Liquéfaction, Gas conditioning and treatments. Desulphurization. Liquefaction, Energie. Utilisation thermique des combustibles, Energy. Thermal use of fuels, Utilisation rationnelle de l'énergie: récupération et économies d'énergie, Rational use of energy: conservation and recovery of energy, Chaudière récupération, Waste heat boiler, Caldera recuperación, Cinétique, Kinetics, Cinética, Conception ingénierie, Engineering design, Concepción ingeniería, Désulfuration, Desulfurization, Desulfuración, Energie totale, Total energy, Energía total, Four, Furnace, Horno, Modèle cinétique, Kinetic model, Modelo cinético, Modélisation, Modeling, Modelización, Optimisation, Optimization, Optimización, Production combinée, Cogeneration, Producción combinada, Réacteur, Reactor, Récupération chaleur, Heat recovery, Recuperación calor, Récupération énergie, Energy recovery, Recuperación energía, Usine chimique, Chemical plant, Fábrica productos químicos, Vapeur eau, Water vapor, Vapor agua, Acid gas, Claus process, Detailed kinetics, and Total plant optimization

Multi-scale process modeling is very appealing methodology for process optimization since it highlights certain issues that remain unexplored with conventional methodologies and debottlenecks certain potentialities that remain unexploited in chemical plants. In this work, a kinetic model with 2400 reactions and 140 species is implemented in a proper reactor network to characterize the thermal furnace and the waste heat boiler of sulfur recovery units; the network with detailed kinetics is the kernel of a Claus process simulation that includes all the unit operations and the catalytic train. By doing so, reliable estimation of acid gas conversion, elemental sulfur recovery, and steam generation is achieved with the possibility to carry out an integrated process-energy optimization at the total plant scale.

General chemistry, physical chemistry, Chimie générale, chimie physique, Energy, Énergie, Chemical engineering, Génie chimique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Physicochimie de surface, Surface physical chemistry, Echange d'ions, Ion-exchange, Zéolites: préparations et propriétés, Zeolites: preparations and properties, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Catalyseur, Catalyst, Catalizador, Cinétique, Kinetics, Cinética, Epuration effluent gazeux, Flue gas purification, Depuración efluente gaseoso, Gaz échappement, Exhaust gas, Gas escape, Modélisation, Modeling, Modelización, Oxydation, Oxidation, Oxidación, Urée, Urea, Urées, Ureas, Zéolite, Zeolite, Zeolita, Cold start, Kinetic modeling, NO oxidation, Urea-SCR, and Zeolite catalyst

In this contribution a mathematical model suitable to simulate cold start effects over metal-promoted zeolite SCR catalysts is developed and included into an existing SCR converter model. We start from a recently published microkinetic scheme, which describes the NO2 related SCR reactions at temperatures above about 100 C on the basis of a complex reaction network, taking into account NO2 storage with formation of nitrates and their subsequent decomposition/reactivity. In order to describe material and thermal cold start effects observed from room temperature we extend such a kinetic scheme to include the low-T NO oxidation to NO2, NO2 physisorption and H2O adsorption. The rate parameters are fitted to our data from lab-scale runs analyzing each individual step. We show that the resulting model can reproduce the transient effects related to cold start both at the lab scale and in engine test bench experiments.

General chemistry, physical chemistry, Chimie générale, chimie physique, Energy, Énergie, Chemical engineering, Génie chimique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Cinétique, Kinetics, Cinética, Liquide ionique, Ionic liquid, Líquido iónico, Lubrifiant, Lubricant, Lubricante, Méthode séquentielle, Sequential method, Método secuencial, Protection environnement, Environmental protection, Protección medio ambiente, Réaction catalytique, Catalytic reaction, Reacción catalítica, Transestérification, Transesterification, Transesterificación, Oléique acide ester méthyle, Technologie bas carbone, Bio-lubricant, and Heteropolyanion

The kinetics of ionic liquid-heteropolyanion (IL-HPA) salts catalyzed transesterification of oleic acid methyl ester (OAME) was studied via a sequential method. The method can be separated into two parts. The first part was to analyze the kinetics of transesteriifcation of OAME catalyzed by a novel catalyst and to provide a way to simulate the reaction rate profile. The second part was to verify the appropriateness of kinetic parameters calculated in the first part. Kinetic parameters were properly determined and reaction rate profiles were adequately simulated by regarding transesterification as a second order reaction. A good agreement between the experimental data and theoretically predicted values is obtained. This method may be applicable to most of three-step consecutive reaction whose tmax.firtintermediate and tmax.second intermediate at the maximum concentration are acquirable, representatively and reliably.

General chemistry, physical chemistry, Chimie générale, chimie physique, Energy, Énergie, Chemical engineering, Génie chimique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Métal transition, Transition metal, Metal transición, Tobamovirus, Virus, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Chrome, Chromium, Cromo, Cinétique, Kinetics, Cinética, Dichromate, Dichromates, Dicromato, Mécanisme, Mechanism, Mecanismo, Palladium, Paladio, Platinoïde, Platinoid, Platinoide, Protection environnement, Environmental protection, Protección medio ambiente, Réaction catalytique, Catalytic reaction, Reacción catalítica, Réduction chimique, Chemical reduction, Reducción química, Structure, Estructura, Synthèse, Synthesis, Síntesis, Virus mosaïque tabac, Tobacco mosaic virus, Agent structurant, Template, Nanocatalyseur, Nanocatalyst, Technologie bas carbone, Dichromate reduction, Langmuir-Hinshelwood mechanism, Palladium nanocatalyst, Synthesis-structure-activity, and Tobacco mosaic virus (TMV)

We report on examination of the dichromate reduction reaction mechanism and synthesis-structure-activity relationship of palladium (Pd) nanoparticles formed on surface-assembled viral templates. By employing Langmuir-Hinshelwood mechanism, the adsorption of formic acid on the catalytic sites is found to be substantially higher (~300 times) than that of dichromate ions. The viral-templated Pd nanocatalysts with optimized synthesis conditions are demonstrated to have higher catalytic activity per unit Pd mass for the dichromate reduction reaction than the commercial Pd/C catalysts. The effects of catalyst synthesis conditions on the catalyst properties (i.e. Pd particle size and loading) and on the catalytic activity are also investigated via Grazing Incidence Small Angle X-ray Scattering (GI-SAXS) and reaction kinetics studies. The changes in our biotemplated nanocatalyst synthesis conditions contribute to the changes in the Pd particle size and surface loading density, leading to predictable manipulation of the catalytic activity. We expect that the new insights on the reaction kinetics and reactant adsorption behavior as well as the catalyst synthesis-structure-activity relationship reported in this work can be readily extended or applied to other catalysts and reaction systems.

General chemistry, physical chemistry, Chimie générale, chimie physique, Energy, Énergie, Chemical engineering, Génie chimique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Acide carboxylique, Carboxylic acid, Acido carboxílico, Aldéhyde, Aldehyde, Aldehído, Acide acétique, Acetic acid, Acético ácido, Activation, Activación, Acétaldéhyde, Acetaldehyde, Acetaldehído, Acétonitrile, Acetonitrile, Acetonitrilo, Cinétique, Kinetics, Cinética, Complexe de fer, Iron complex, Hierro complejo, Fer III, Iron III, Hierro III, Nitrile, Nitrilo, Oxydation, Oxidation, Oxidación, Oxygène, Oxygen, Oxígeno, Protection environnement, Environmental protection, Protección medio ambiente, Température ambiante, Room temperature, Temperatura ambiente, Technologie bas carbone, Acetaldehyde oxidation, Dioxygen activation, Iron-oxygen complex, and Michaelis-Menten kinetics

We show that highly efficient acetaldehyde-to-acetic acid oxidation is achieved in a diluted FeCl3-acetonitrile solution (5-100 μM), which proceeds rather rapidly and follows the enzymatic-like Michaelis-Menten kinetics. Interestingly, by adjusting the concentration of FeCl3. we are able to accelerate or shut down the oxidation process conveniently. Based on the catalytic results, spectroscopic evidences and successive DFT calculations, a reactant-initiated, putative mononuclear non-heme iron-oxygen complex, [FeCl(MeCN)4(O)]2+, is proposed as the active oxidizing species to conduct the room temperature reaction with relatively high TOF values (~1.2s-1). Finally, the putative iron-oxygen complexes are employed to the selective oxidation of benzyl alcohol under ambient conditions.

Environment, Environnement, Pollution, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Adsorption, Pollution, Adsorption, Adsorción, Ammoniac, Ammonia, Amoníaco, Cinétique, Kinetics, Cinética, Combustible, Fuel, Diffusion, Difusión, Désorption, Desorption, Desorción, Désulfuration, Desulfurization, Desulfuración, Encombrement stérique, Steric hindrance, Embarazo estérico, Imprégnation, Impregnation, Impregnación, Isotherme Langmuir, Langmuir isotherm, Isoterma Langmuir, Isotherme adsorption, Adsorption isotherm, Isotermo adsorción, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Modélisation, Modeling, Modelización, Ordre 2, Second order, Orden 2, Sorbant, Sorbent, Sorbente, Spectrométrie absorption atomique, Atomic absorption spectrometry, Espectrometría absorción atómica, Structure 3 dimensions, Three dimensional structure, Estructura 3 dimensiones, Isotherm equations, Lewis acid sites, Mesoporous Ni-AlKIT-6, and Simulated fuels

High performance nickel supported on mesoporous AlKIT -6 (Si/Al = 15, 25, 50, 100) sorbents were prepared by incipient wetness impregnation (IWI) with ultrasonic aid for adsorptive desulfurization of commercial diesel and simulated fuels. The sorbents were characterized by N2 adsorption-desorption, XRD, NH3-TPD, Py-FT-IR, HRTEM, SEM and atomic absorption spectroscopy techniques. The analysis results confirmed that Aluminum atoms entered the framework and 20%Ni-AlKIT-6(15) can still retain three dimensional structure of AlKIT-6(15) and Ni is highly dispersed in the support. The kinetic pseudo second-order model and Langmuir isotherm are shown to exhibits the best fits of experimental data for the adsorption of thiophene (T), benzothiophene (BT) and dibenzothiophene (DBT) over AlKIT -6 and 5-30%Ni-AlKIT-6. Intraparticle diffusion and steric hindrance were the rate controlling step of the adsorption of T and DBT over AlKIT-6(15) and 20%Ni-AlKIT-6(15) as verified through the intraparticle diffusion model. The characterization of regenerated 20%Ni-AlKIT-6(15) revealed that three-dimensional cubic Ia3d symmetric structure was maintained in the sorbent after 6 successive desulfurization-regeneration cycles.

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Hydrodynamique des appareils de contact, Hydrodynamics of contact apparatus, Fluidisation, Fluidization, Systèmes solides-solides, Solid-solid systems, Divers, Miscellaneous, Angle contact, Contact angle, Angulo contacto, Capacimètre, Capacitance meter, Capacimétro, Capacité électrique, Capacitance, Capacitancia, Cinétique, Kinetics, Cinética, Craquage catalytique fluide, Fluid catalytic cracking, Craqueo catalítico fluido, Fluidisation, Fluidization, Fluidización, Hydrodynamique, Hydrodynamics, Hidrodinámica, Lit fluidisé, Fluidized bed, Lecho fluidizado, Modélisation, Modeling, Modelización, Surveillance, Vigilancia, Tension superficielle, Surface tension, Tensión superficial, Viscosité, Viscosity, Viscosidad, Débit fluide, Agglomerate formation, Capacitance sensor, Fluid Coking, and Liquid injection

Uniform distribution of liquid feed on fluidized particles increases the yield of valuable products and improves operability in processes such as Fluid Coking™ and Fluid Catalytic Cracking. Contact between the injected liquid and the bed particles can be greatly affected by the liquid properties and local bed hydrodynamics. In this study, the effect of viscosity, contact angle, surface tension, fluidization velocity and atomization gas flowrate on the distribution of liquid sprayed into a fluidized bed was investigated with a reliable and fast response capacitance meter. This method was also extended to monitor the agglomerate breakup kinetics.

Environment, Environnement, Pollution, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Sécurité, Safety, Pollution, Composé organique, Organic compounds, Compuesto orgánico, Carcinogène, Carcinogen, Carcinógeno, Champ température, Temperature distribution, Campo temperatura, Cinétique, Kinetics, Cinética, Explosif, Explosives, Explosivo, Explosion thermique, Thermal explosion, Explosión térmica, Hexogène, Hexogen, Hexogeno, Modélisation, Modeling, Modelización, Mutagène, Mutagen, Mutágeno, Mécanisme réaction, Reaction mechanism, Mecanismo reacción, Méthode analyse, Analysis method, Método análisis, Risque accidentel, Hazard, Riesgo accidente, Stockage, Storage, Almacenamiento, Sécurité, Safety, Seguridad, Isothermal, PBXs, RDX, and Reaction models

In this paper, the decomposition reaction models and thermal hazard properties of 1,3,5-trinitro-1,3,5-triazinane (RDX) and its PBXs bonded by Formex P1, Semtex 1A. C4. Viton A and Fluorel polymer matrices have been investigated based on isoconversional and combined kinetic analysis methods. The established kinetic triplets are used to predict the constant decomposition rate temperature profiles, the critical radius for thermal explosion and isothermal behavior at a temperature of 82 C. It has been found that the effect of the polymer matrices on the decomposition mechanism of RDX is significant resulting in very different reaction models. The Formex P1. Semtex and C4 could make decomposition process of RDX follow a phase boundary controlled reaction mechanism, whereas the Viton A and Fluorel make its reaction model shifts to a two dimensional Avrami-Erofeev nucleation and growth model. According to isothermal simulations, the threshold cook-off time until loss of functionality at 82 C for RDX-C4 and RDX-FM is less than 500 days, while it is more than 700 days for the others. Unlike simulated isothermal curves, when considering the charge properties and heat of decomposition, RDX-FM and RDX-C4 are better than RDX-SE in storage safety at arbitrary surrounding temperature.

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Systèmes solides-solides, Solid-solid systems, Divers, Miscellaneous, Sécurité, Safety, Cinétique, Kinetics, Cinética, Combustion, Combustión, Dimension particule, Particle size, Dimensión partícula, Distribution dimension particule, Particle size distribution, Distribución dimensión partícula, Déflagration, Deflagration, Deflagración, Explosion, Explosions, Explosión, Mélangeage, Mixing, Mezclado, Particule fine, Fine particle, Partícula fina, Poussière, Dust, Polvo, Risque accidentel, Hazard, Riesgo accidente, Aluminum, Deflagration index, and Polydispersity

This paper reports experimental results elucidating the effect of particle size polydispersity (σD) on the explosion severity of aluminum dust. Five mixtures with a median diameter (D50) of 15 μm and σD values of 0.95,1.17,1.48, 1.87, and 2.51, were systematically prepared by mixing original aluminum samples having narrow size distributions. The explosion severity of each sample was determined in a 36 L dust explosion vessel by measuring the maximum pressure (Pmax), the maximum rate of pressure rise ((dP/dt)max), and the deflagration index (KSt). Interestingly, we found that values of Pmax and KSt revealed an increase in explosion severity as σD increases, where the latter presented a more dramatic effect due to the contribution of fine particles on the combustion kinetics. The effect of dust concentration on the explosion propagation was analyzed comparing the time span to reach (dP/dt)max, (τ), during a dust explosion. τ was obtained from the experimental pressure traces of the original samples and their mixtures. The values of Pmax and KSt were plotted as a function of the median diameter (D50) and the volume- (D4,3) and surface- (D3,2) weighted mean diameter. We observed that D3,2 provided a better description of the average sample size and D50 is inadequately related to the real hazard potential of aluminum dust. Therefore, we suggest that the explosion hazard characterization of these types of materials should be reported in terms of D3.2 and σD.

Environment, Environnement, Pollution, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Réacteurs, Reactors, Séparations mécaniques liquide-liquide et fluide-solide, Liquid-liquid and fluid-solid mechanical separations, Décantation, sédimentation, Settling, Pollution, Aire surface spécifique, Specific surface area, Cinétique, Kinetics, Cinética, Dimension particule, Particle size, Dimensión partícula, Désorption, Desorption, Desorción, En discontinu, Batchwise, En discontinuo, Hystérésis, Hysteresis, Histéresis, Lavage, Washing, Lavado, Mobilité, Mobility, Movilidad, Particule colloïdale, Colloid particle, Partícula coloidal, Pluie, Rain, Lluvia, Polluant, Pollutant, Contaminante, Réacteur, Reactor, Silt, Limo, Sorption, Sorción, Stéroïde, Steroid, Esteroide, Sédimentation, Sedimentation, Sedimentación, Tamis, Sieve, Tamiz, Testostérone, Testosterone, Testosterona, Transport facilité, Facilitated transport, Transporte facilitada, Particle size fraction, and Soil

Soils contain a wide range of particles of different diameters with different mobility during rainfall events. Effects of soil particles on sorption and desorption behaviors of steroid hormones have not been investigated. In this study, wet sieve washing and repeated sedimentation methods were used to fractionate the soils into five ranges. The sorption and desorption properties and related mechanisms of testosterone in batch reactors filled with fractionated soil particles were evaluated. Results of sorption and desorption kinetics indicate that small soil particles have higher sorption and lower desorption rates than that of big ones. Thermodynamic results show the sorption processes are spontaneous and exothermal. The sorption capacity ranks as clay > silt > sand, depending mainly on specific surface area and surface functional groups. The urea control test shows that hydrogen bonding contributes to testosterone sorption onto clay and silt but not on sand. Desorption tests indicate sorption is 36-65% irreversible from clay to sand. Clays have highest desorption hysteresis among these five soil fractions, indicating small particles like clays have less potential for desorption. The results provide indirect evidence on the colloid (clay)-facilitated transport of hormones (micro-pollutants) in soil environments.

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Adsorption, Systèmes solides-solides, Solid-solid systems, Divers, Miscellaneous, Adsorption, Adsorción, Antibiotique, Antibiotic, Antibiótico, Capacité adsorption, Adsorption capacity, Capacidad adsorción, Cinétique, Kinetics, Cinética, Complexe superficiel, Surface complex, Complejo superficial, En discontinu, Batchwise, En discontinuo, Interaction électrostatique, Electrostatic interaction, Interacción electrostática, Isotherme adsorption, Adsorption isotherm, Isotermo adsorción, Poudre, Powder, Polvo, Solution aqueuse, Aqueous solution, Solución acuosa, Système binaire, Binary system, Sistema binario, pH, Composed materials, Iron oxide, Mesoporous silica, Minocycline adsorption, Solid-water interface, and Surface complexes

The remotion of the antibiotic minocycline (MC) on mesoporous silica (SiO2) and on the binary system iron(III) oxide-SiO2 (Fe-SiO2) has been studied in batch experiments by performing adsorption isotherms/kinetics under different conditions of pH, KCI concentration and temperature. The adsorption of MC on the studied materials is strongly dependent on pH, increasing as pH decreases. The incorporation of a low concentration of iron (1.03 wt.%, mainly as amorphous Fe2O3) on the SiO2 matrix not only increases the adsorption capacity but also changes the adsorption mechanism. The adsorption of MC on SiO2 strongly decreases as KCl concentration increases but it is not significantly affected by varying the temperature. This is attributed to electrostatic attractions and H-bond formations between dimethylamino, amide, carbonylic and phenolic groups of the antibiotic and the functional groups of silica particles. The adsorption of MC on Fe-SiO2, on the contrary, strongly increases as temperature increases but remains invariable by varying the KCl concentration. This suggests that the formation of inner-sphere complexes between the functional groups of the antibiotic and the active sites of Fe2O3 plays a key role on the adsorption mechanism. The analysis of adsorption thermodynamic parameters is also reported and discussed. The synthesized materials can act as excellent adsorbents for environmental and engineering processes.

Environment, Environnement, Pollution, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Adsorption, Pollution, Adsorption, Adsorción, Capacité adsorption, Adsorption capacity, Capacidad adsorción, Captation, Uptake, Captación, Cinétique, Kinetics, Cinética, Diffusion, Difusión, Gel silice, Silica gel, Gel sílice, Isotherme Langmuir, Langmuir isotherm, Isoterma Langmuir, Isotherme adsorption, Adsorption isotherm, Isotermo adsorción, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Milieu poreux, Porous medium, Medio poroso, Modélisation, Modeling, Modelización, Méthode fonctionnelle densité, Density functional method, Ordre 2, Second order, Orden 2, Propriété thermodynamique, Thermodynamic properties, Propiedad termodinámica, Solution aqueuse, Aqueous solution, Solución acuosa, Thermogravimétrie, Thermogravimetry, Termogravimetría, pH, Hg(II), PAMAM dendrimers, Salicylaldehyde, and Synthesis

A series of silica gel supported salicylaldehyde modified PAMAM dendrimers (SiO2-G0-SA~SiO2-G2.0-SA) were synthesized and their structures were characterized by FTIR, XRD, SEM, TGA, and porous structure analysis. The feasibility of these adsorbents for the removal of Hg(II) from aqueous solution was first described and the adsorption mechanism was proposed. The adsorption was found to depend on solution pH, the generation number of salicylaldehyde modified PAMAM dendrimers, contact time, temperature, and initial concentration. Results showed that the optimal pH was about 6 and the adsorption capacity increased with the increasing of generation number. Density functional theory (DFT) method was used to investigate the coordination geometries and the chelating mechanism. Adsorption kinetics was found to follow the pseudo-second-order model with film diffusion process as rate controlling step. Adsorption isotherms revealed that adsorption capacities increased with the increasing of temperature. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models were employed to analyze the equilibrium data. The adsorption can be well described by Langmuir isotherm model and took place by chemical mechanism. The thermodynamics properties indicated the adsorption processes were spontaneous and endothermic nature. The maximum adsorption capacity of SiO2-G0-SA. SiO2-G1.0-SA, and SiO2-G2.0-SA were 0.91, 1.52, and 1.81 mmol g-1, respectively. The considerable higher adsorption capacity compared with other adsorbents indicates SiO2-GO-SA~SiO2-G2.0-SA are favorable and useful for the uptake of Hg (II), and can be potentially used as promising adsorbents for the effective removal of Hg(II) from aqueous solution.

Environment, Environnement, Pollution, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Adsorption, Pollution, Pollution atmosphérique, Atmospheric pollution, Généralités, General, Adsorption, Adsorción, Aérosol, Aerosols, Aerosol, Charbon actif, Activated carbon, Carbón activado, Cinétique, Kinetics, Cinética, Colorant, Dyes, Colorante, Diffraction RX, X ray diffraction, Difracción RX, En discontinu, Batchwise, En discontinuo, Fer II, Iron II, Hierro II, Matériau composite, Composite material, Material compuesto, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Microscopie électronique transmission, Transmission electron microscopy, Microscopía electrónica transmisión, Modèle cinétique, Kinetic model, Modelo cinético, Modélisation, Modeling, Modelización, Nanocomposite, Nanocompuesto, Nanoparticule, Nanoparticle, Nanopartícula, Nanostructure, Nanoestructura, Ordre 2, Second order, Orden 2, Particule ultrafine, Ultrafine particle, Partícula ultrafina, Pollution air, Air pollution, Contaminación aire, Propriété magnétique, Magnetic properties, Propiedad magnética, Précurseur, Precursor, Saturation, Saturación, Spectrométrie FTIR, Fourier-transformed infrared spectrometry, Espectrometría FTIR, Composite materials, and Nanostructures

The adsorption of acid yellow 17 dye on activated carbon/α-Fe2O3 nanocomposite prepared by simple pyrolytic method using iron(II) gluconate was investigated by batch technique. The composite was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). The size of iron oxide nanoparticles formed from iron(II) gluconate precursor is in the range 5―17nm. The saturation magnetization (Ms), remanence (Mr) and coercivity (Hc) of the magnetic carbon nanocomposite is 5.6 emu/g, 1.14 emu/g and 448 Oe, respectively. The adsorption data are found to fit well with Langmuir and, fairly well with Freundlich and Tempkin isotherms at higher concentration of dye (40―100 mg/L). Kinetics data indicate that the adsorption of dye follows pseudo-second order kinetics model.

Environment, Environnement, Pollution, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Transferts de chaleur et de matière. Garnissages, plateaux de contact, Heat and mass transfer. Packings, plates, Adsorption, Pollution, Adsorption, Adsorción, Agent surface non ionique, Non ionic surfactant, Agente superficie no iónica, Aire superficielle, Surface area, Area superficial, Amphotère, Amphoteric, Anfótero, Azote, Nitrogen, Nitrógeno, Capacité adsorption, Adsorption capacity, Capacidad adsorción, Charbon actif, Activated carbon, Carbón activado, Cinétique, Kinetics, Cinética, Colorant, Dyes, Colorante, Condensation, Condensación, Diffraction RX, X ray diffraction, Difracción RX, Diffusion, Difusión, Décoloration, Discoloration, Decoloración, Epuration physicochimique, Physicochemical purification, Depuración fisicoquímica, Interaction électrostatique, Electrostatic interaction, Interacción electrostática, Microscopie électronique transmission, Transmission electron microscopy, Microscopía electrónica transmisión, Modélisation, Modeling, Modelización, Ordre 2, Second order, Orden 2, Phosphate, Phosphates, Fosfato, Précurseur, Precursor, Solution aqueuse, Aqueous solution, Solución acuosa, Sorption, Sorción, Thermogravimétrie, Thermogravimetry, Termogravimetría, Transfert masse, Mass transfer, Transferencia masa, Periodic mesoporous organosilicas, and Phosphonic acid

Periodic mesoporous organosilicas (PMOs) with benzene bridging groups in the silica wall were functionalized with a tunable content of phosphonic acid groups. These bifunctional materials were synthesized by co-condensation of two different organosilane precursors, that is, 1,4-bis(triethoxysilyl)benzene (BTEB) and sodium 3-(trihydroxysilyl)propyl methyl phosphate (SPMP), under acidic conditions using nonionic surfactant Brij-S10 as template. The materials exhibited well-ordered mesostructures and were characterized by X-ray diffraction, nitrogen sorption, TEM, TGA, FTIR, and solid-state NMR measurements. The materials thus obtained were employed as adsorbents to remove different types of dyes, for example, cationic dyes methylene blue and phenosafranine, anionic orange II, and amphoteric rhodamine B, from aqueous solutions. The materials exhibited a remarkably high adsorption capacity than activated carbon due to their ordered mesostructures, a large number of phosphonic acid groups, and high surface areas. The adsorption was mainly governed by electrostatic interaction, but also involved π-π stacking interaction as well as hydrogen bonding. The adsorption kinetics can be better fitted by the pseudo-second order model. The adsorption process was controlled by the mechanisms of external mass transfer and intraparticle diffusion. The materials retained more than 97% dye removal efficiency after use for five consecutive cycles.

Environment, Environnement, Pollution, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Adsorption, Echange d'ions, Ion exchange, Pollution, Traitement et pollution des eaux, Water treatment and pollution, Pollution des eaux naturelles, Natural water pollution, Phénomènes biologiques et physicochimiques, Biological and physicochemical phenomena, Adsorption, Adsorción, Analyse corrélation, Correlation analysis, Análisis correlación, Champ magnétique, Magnetic field, Campo magnético, Cinétique, Kinetics, Cinética, Corrélation, Correlation, Correlación, Echange ion, Ion exchange, Cambio iónico, Ion métallique, Metal ion, Ión metálico, Isotherme adsorption, Adsorption isotherm, Isotermo adsorción, Matériau composite, Composite material, Material compuesto, Matériau magnétique, Magnetic material, Material magnético, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Microscopie électronique transmission, Transmission electron microscopy, Microscopía electrónica transmisión, Modélisation, Modeling, Modelización, Métal lourd, Heavy metal, Metal pesado, Ordre 2, Second order, Orden 2, Plomb, Lead, Plomo, Pollution eau, Water pollution, Contaminación agua, Solution aqueuse, Aqueous solution, Solución acuosa, Sorbant, Sorbent, Sorbente, Sorption, Sorción, Séparation magnétique, Magnetic separation, Separación magnética, Adsorption kinetics, Fe3O4-GS, Heavy metal ions, and Thermodynamics

In the present study, a kind of graphenes magnetic material (Fe3O4-GS) was prepared by compositing graphene sheet with ferroferric oxide, and shown to be effictive for removing Cr(VI), Pb(II), Hg(II), Cd(II) and Ni(II) ions from aqueous solution. The synthesized sorbent was characterized by SEM, TEM, FTIR, XRD, XPS and BET, respectively. The pHZPC value of the sorbent was estimated to be 3.5 by alkaline-titration methods. Fe3O4-GS can be simply recovered from water with magnetic separation at low magnetic field within one minute. The sorption capacities of the metals were 17,29, 27.95, 23.03, 27.83 and 22.07 mg g-1 for Cr(VI), Pb(II), Hg(II), Cd(II) and Ni(II), respectively. Kinetic data showed good correlation with pseudo-second-order equation and the Freundlich model was found to fit for the isotherm data of all the heavy metal ions. It was found that the metals sorption was accomplished mainly via chelation or ion exchange. The results of thermodynamic studies illustrate that the adsorption process was endothermic and spontaneous in nature.

Environment, Environnement, Geology, Géologie, Pollution, Toxicology, Toxicologie, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Réactions catalytiques, Catalytic reactions, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Réacteurs, Reactors, Pollution, Aire superficielle, Surface area, Area superficial, Bisphénol A, Bisphenol A, Bisfenol, Catalyseur, Catalyst, Catalizador, Chargement, Loading, Cargamento, Cinétique, Kinetics, Cinética, Devenir polluant, Pollutant behavior, Evolución contaminante, Dégradation photochimique, Photochemical degradation, Degradación fotoquímica, Matériau composite, Composite material, Material compuesto, Ordre 1, First order, Orden 1, Oxyde de titane, Titanium oxide, Titanio óxido, Perturbateur endocrinien, Endocrine disruptor, Disruptor endocrino, Photocatalyse, Photocatalysis, Fotocatálisis, Rayonnement UV, Ultraviolet radiation, Radiación ultravioleta, Synergie, Synergism, Sinergia, Zéolite, Zeolite, Zeolita, BPA, Cu2O, TiO2, photodegradation, and zeolite

In this study, TiO2/zeolite (TZ)-based composite was utilized to degrade bisphenol A (BPA) under ultraviolet (UV) irradiation. The effects of the TiO2 and Cu2O doses in TZ and Cu2O/TiO2/zeolite (CTZ) on the rate of BPA removal were identified, respectively. The surface area of TZ declined as the TiO2 loading increased. The photodegradation rate (k) of BPA in the TZ and CTZ systems fitted pseudo-first-order kinetics. Under UV (365 nm) irradiation, the k values of TiO2 (20%)/zeolite (80%), TiO2 (40%)/zeolite (60%), TiO2 (60%)/zeolite (40%), and TiO2 (80%)/zeolite (20%) were 0.51, 0.55, 0.97, and 0.91 h-1, respectively. In the UV (365 nm)/TiO2 (60%)/zeolite (40%) system, the k values of CTZ with 1%, 5%, 10%, 20%, and 30% Cu2O added were 1.50, 1.04, 1.15, 1.88, and 0.47 h-1, respectively. The photocatalytic activity of TZ was enhanced by adding Cu2O. The optimal dosage of TiO2 in the TZ system was 60% and that of Cu2O in the CTZ system was 20%. p-Hydroxybenzaldehyde (p-HBA), p-hydroxyacetophenone (p-HAP), p-hydroxybenzoic acid (p-HBA acid) and hydroquinone (HQ) were intermediates of BPA photodegradation in the UV/TZ system and the rates of degradation followed the order HQ > p - HBA acid > BPA > p - HAP > p - HBA.

Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, General chemistry, physical chemistry, Chimie générale, chimie physique, Chemical engineering, Génie chimique, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Physicochimie de surface, Surface physical chemistry, Interface solide-liquide, Solid-liquid interface, Etat colloïdal et états dispersés, Colloidal state and disperse state, Matériaux poreux, Porous materials, Membranes, Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Formes d'application et semiproduits, Forms of application and semi-finished materials, Résines échangeuses et membranes, Exchange resins and membranes, Mammalia, Rodentia, Vertebrata, Ammoniac, Ammonia, Amoníaco, Bioréacteur, Bioreactor, Biorreactor, Cellule, Cell, Célula, Cinétique, Kinetics, Cinética, Foie, Liver, Hígado, Membrane polymère, Polymeric membrane, Membrana polímero, Membrane poreuse, Porous membrane, Membrana porosa, Microporosité, Microporosity, Microporosidad, Modèle, Models, Modelo, Mouillabilité, Wettability, Remojabilidad, Oxygène, Oxygen, Oxígeno, Propène polymère, Propylene polymer, Propeno polímero, Rat, Rata, Consumption kinetics, Liver cells, and Membrane wettability

Polymeric membranes used in bioreactors for bioartificial livers are generally chosen for their transport and separation properties to provide liver cells with adequate nutrients supply and avoid rejection. Possible effects of membrane surface properties on cell metabolism are generally given little consideration. The reported effects of membrane surface wettability on adherent liver cells are qualitative and inconsistent, possibly due to the variation of other surface properties and the culture in Petri dishes, often at confluence, under uncontrolled time- and space-varying metabolite concentrations. In this investigation, rat liver cells were cultured in sub-confluent adhesion on model membranes hydrophilized by physical treatment featuring varying surface wettability in a continuous-flow recycle bioreactor. Bioreactor optimization permitted to culture cells at uniform and measurable pericellular concentrations of metabolic substrates, and to challenge them with controlled increasing ammonia concentrations. Membrane surface wettability was characterized in terms of water sorption, dynamic contact angle, and oxygen content by XPS. The kinetics of oxygen consumption, ammonia elimination and urea synthesis of cells adherent on membranes with increasing wettability was characterized at increasing ammonia concentrations. Cells exhibited increasingly better metabolic functions on membranes with increasing surface wettability. Metabolic reaction rate differences were increasingly more evident at increasing ammonia concentrations. Membrane surface wettability appeared to mainly affect cell capacity to respond to the ammonia challenge.

Environment, Environnement, Geology, Géologie, Pollution, Toxicology, Toxicologie, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Adsorption, Pollution, Traitement et pollution des eaux, Water treatment and pollution, Pollution des eaux naturelles, Natural water pollution, Phénomènes biologiques et physicochimiques, Biological and physicochemical phenomena, Pollution atmosphérique, Atmospheric pollution, Généralités, General, Aire superficielle, Surface area, Area superficial, Arsenic, Arsénico, Arséniate, Arsenates, Arseniato, Aérosol, Aerosols, Aerosol, Cartographie, Cartography, Cartografía, Cinétique, Kinetics, Cinética, Diffraction RX, X ray diffraction, Difracción RX, Haute résolution, High resolution, Alta resolucion, Isotherme adsorption, Adsorption isotherm, Isotermo adsorción, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Microscopie électronique transmission, Transmission electron microscopy, Microscopía electrónica transmisión, Métal zérovalent, Zerovalent metal, Metal cerovalente, Nanoparticule, Nanoparticle, Nanopartícula, Nettoyage, Cleaning, Limpieza, Particule ultrafine, Ultrafine particle, Partícula ultrafina, Passivation, Pasivación, Pollution air, Air pollution, Contaminación aire, Pollution eau, Water pollution, Contaminación agua, Solution aqueuse, Aqueous solution, Solución acuosa, Sorption, Sorción, pH, arsenic, nZVI, sorption process, surface reconstruction, and water pollution

We consider the use of metallic iron nanoparticles for cleaning contaminated water, focusing our study in the sorption of arsenic compounds. In particular, we discuss the results of their sorption process on the surface of zerovalent iron nanoparticles (nZVI) by performing a complete characterization of the surface modifications. Using scanning electron microscopy, X-ray diffraction analysis and high-resolution transmission electron microscopy, spectroscopy diffraction measurements and elemental mapping, we typify the surface reconstruction during the sorption process of As(V) from aqueous solutions using nZVI when it goes into a crystalline parasymplesite structure. The experimental results were correlated to the Freundlich isotherm sorption where the sorption capacity is depleted by the increase in the pH from 4 to 7 and associated with the surface passivation of nZVI. These techniques confirm the dependence of the sorption of arsenic as a function of pH and describe the specific details on the modification of the surface area of the nanoparticles.

Environment, Environnement, Geology, Géologie, Pollution, Toxicology, Toxicologie, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Réactions catalytiques, Catalytic reactions, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Réacteurs, Reactors, Pollution, Traitement et pollution des eaux, Water treatment and pollution, Eaux usées, Wastewaters, Procédés généraux d'épuration, General purification processes, Ammoniac, Ammonia, Amoníaco, Azote, Nitrogen, Nitrógeno, Catalyse, Catalysis, Catálisis, Cinétique, Kinetics, Cinética, Condition opératoire, Operating conditions, Condición operatoria, DCO, Chemical oxygen demand, Eau usée, Waste water, Agua residual, En continu, Continuous process, En continuo, Etat supercritique, Supercritical state, Estado supercrítico, Fabrication, Manufacturing, Fabricación, Induction, Inducción, Loi puissance, Power law, Ley poder, Oxydation, Oxidation, Oxidación, Production, Producción, Période induction, Induction period, Período inducción, Qualité eau, Water quality, Calidad agua, Radical libre, Free radical, Réacteur, Reactor, acrylic acid, induction time, kinetics, supercritical water oxidation, and wastewater

Supercritical water oxidation (SCWO) of wastewater from an acrylic acid manufacturing plant has been studied on a continuous flow experimental system, whose reactor was made of Hastelloy C-276. Experimental conditions included a reaction temperature (T) ranging from 673 to 773 K, a residence time (t) ranging from 72.7 to 339 s, a constant pressure (P) of 25 MPa and a fixed oxidation coefficient (a) of 2.0. Experimental results indicated that reaction temperature and residence time had significant influences on the oxidation reaction, and increasing the two operation parameters could improve both degradation of chemical oxygen demand (COD) and ammonia nitrogen (NH3 - N). The COD removal efficiency could reach up to 98.73% at 25 MPa, 773 K and 180.1 s, whereas the destruction efficiency of NH3 - N was only 43.71%. We further carried out a kinetic analysis considering the induction period through free radical chain mechanism. It confirms that the power-law rate equation for COD removal was 345 exp(-52200/RT)[COD]1.98[O2]0.17 and for NH3-N removal was 500 exp(-64492.19/RT)[NH3-N]1.87[O2]0.03. Moreover, the induction time formulations for COD and NH3 - N were suspected to be exp(38250/RT)/ 173 and exp(55690/RT)/15231, respectively. Correspondingly, induction time changed from 2.22 to 5.38 s for COD and 0.38 to 1.38 s for NH3 - N. Owing to the catalysis of reactor inner wall surface, more than 97% COD removal was achieved in all samples.