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General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, 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, Alcool, Alcohol, Composé benzénique, Benzenic compound, Compuesto bencénico, Composé de métal de transition, Transition element compounds, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Cinétique, Kinetics, Cinética, Dégradation photochimique, Photochemical degradation, Degradación fotoquímica, Isotherme adsorption, Adsorption isotherm, Isotermo adsorción, Mécanisme, Mechanism, Mecanismo, Nanomatériau, Nanostructured materials, Oxyde de titane, Titanium oxide, Titanio óxido, Phénol, Phenol, Fenol, Phénols, Phenols, Fenoles, Protection environnement, Environmental protection, Protección medio ambiente, Adsorption isotherms, Formal mechanisms, Photocatalytic degradation, and TiO2 nanomaterials

Anisotropic TiO2 nanomaterials (nanotubes, nanorods, nanoplates, nanospheres, and nanoparticles) with controlled structural and textural properties have been evaluated in the photocatalytic degradation of phenol under UV conditions. The kinetic study of phenol adsorption fits well to a quasi-second-order model whereas the adsorption isotherms of phenol over the different TiO2 nanomaterials follow the Langmuir model and the degradation kinetics the Langmuir-Hinshelwood (L-H) model. TiO2 nanomaterials exposing (001) or (101) anatase facets are less active than TiO2 P25 for the phenol degradation. This is related to their tendency to degrade faster intermediates products (organic acids) rather than phenol itself. A good compromise between anatase crystallinity, crystallites sizes, and specific surface area can however improve the photocatalytic activity of the TiO2 nanomaterials. Results also showed that the degradation mechanism follows pseudo-first order kinetics. Pseudo-rate constants were therefore determined and formal mechanism schemes proposed.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, 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, Composé de métal de transition, Transition element compounds, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Cinétique, Kinetics, Cinética, Colorant, Dyes, Colorante, Décoloration, Discoloration, Decoloración, Ethylène polymère, Polyethylene, Etileno polímero, Film, Película, Mécanisme, Mechanism, Mecanismo, Nettoyage, Cleaning, Limpieza, Oxyde de titane, Titanium oxide, Titanio óxido, Protection environnement, Environmental protection, Protección medio ambiente, Pulvérisation irradiation, Sputtering, Pulverización irradiación, MB self-cleaning, and PE-TiO2 surfaces

Polyethylene-TiO2 (from now on PE-TiO2) transparent, non-scattering sputtered films have been found effective in the discoloration of methylene blue (MB) under low intensity solar simulated light. By Fourier transform attenuated infrared spectroscopy (ATR-FTIR), the systematic shift and decrease in the vs(CH2) and vs(C=C) vibration-rotational bands was observed preceding MB discoloration. RF-pretreatment allowed a significant increase in the TiO2 loading on PE compared to non-pretreated PE as shown by X-ray fluorescence (XRF). The PE-TiO2 photo-switching from a hydrophobic to a hydrophilic surface was observed within 60 min under light while the reverse process was complete within 24 h in the dark. The position of the MB* and MB*/MB+ levels allowing electron injecting into the TiO2cb is discussed. The probability for the MBT deactivation and of MB* reacting with O2 leading to the short lived MB+ cation is estimated. A mechanism for MB discoloration on PE-TiO2 is suggested.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, 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, Métal transition, Transition metal, Metal transición, Ammoniac, Ammonia, Amoníaco, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Catalyseur, Catalyst, Catalizador, Cinétique, Kinetics, Cinética, Fer, Iron, Hierro, Oxydation, Oxidation, Oxidación, Oxyde d'azote, Nitrogen oxide, Nitrógeno óxido, Protection environnement, Environmental protection, Protección medio ambiente, Réaction catalytique, Catalytic reaction, Reacción catalítica, Réduction chimique, Chemical reduction, Reducción química, Zéolite, Zeolite, Zeolita, Ammonia oxidation, Iron zeolite, Nitrogen oxides, and Selective catalytic reduction

The steady-state kinetics of the selective catalytic reduction (SCR) of nitrogen oxides (NO and NO2) with ammonia over a commercial iron zeolite catalyst were studied in the temperature range of 250 to 450°C using an integral tubular reactor. Special attention was paid to the stoichiometric ratio of the conversion of ammonia and nitrogen oxides. For this purpose, both systematic SCR measurements at different feed gas compositions and independent studies of the catalytic oxidation of ammonia in the absence of NO and NO2 were carried out. Under all reaction conditions, a considerable deviation from the expected 1:1 stoichiometry was observed. The steady-state kinetics of the reacting system could be described by global Langmuir-Hinshelwood-type rate equations for standard SCR, fast SCR, NO/NO2 equilibrium and NH3 oxidation. For the correct calculation of the ammonia oxidation it was necessary to include two terms. A first one describing the reaction of NH3 with O2, which becomes important at temperatures above 400°C, and a second rate equation which is not only proportional to NH3 and O2 but also to the NO concentration and which is of particular relevance at low reaction temperatures. Additional measurements with different catalyst particle sizes including industrial extrudates could be successfully described with the aid of a reactor model which took film and pore diffusion phenomena into account.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, 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, Ammoniac, Ammonia, Amoníaco, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Catalyseur sur support, Supported catalyst, Catalizador sobre soporte, Cinétique, Kinetics, Cinética, Modélisation, Modeling, Modelización, Protection environnement, Environmental protection, Protección medio ambiente, Répartition spatiale, Spatial distribution, Distribución espacial, Zéolite, Zeolite, Zeolita, Cu zeolites, Kinetic modeling, NH3 SCR, Spaci-MS, and Spatial distribution measurements

In this study, a kinetic model is developed for NH3-SCR over a honeycomb-monolith-supported Cu-zeolites using intra-catalyst axial species distribution measurements. An ammonia TPD experiment, together with micro calorimetry data were used for tuning the ammonia adsorption and desorption properties. The spatial distribution for NO oxidation, NH3 oxidation and NH3 Standard SCR were modeled between 200 and 400 °C. Four-step protocol measurements were employed in order to validate the transient functions of the model. The resulting kinetic model provides good spatiotemporal simulation of the SCR reaction and component reactions throughout the monolith catalyst system.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, 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, Etat colloïdal et états dispersés, Colloidal state and disperse state, Etudes physiques et chimiques. Granulométrie. Phénomènes électrocinétiques, Physical and chemical studies. Granulometry. Electrokinetic phenomena, Composé de métal de transition, Transition element compounds, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Cinétique, Kinetics, Cinética, Combustible, Fuel, Hydrocarbure, Hydrocarbon, Hidrocarburo, Indium, Indio, Méthane, Methane, Metano, Nanoparticule, Nanoparticle, Nanopartícula, Oxyde de titane, Titanium oxide, Titanio óxido, Photocatalyse, Photocatalysis, Fotocatálisis, Protection environnement, Environmental protection, Protección medio ambiente, Réduction chimique, Chemical reduction, Reducción química, Vapeur, Vapor, CO2 reduction, Hydrocarbon fuels, Indium doped TiO2, and Kinetic study

Indium (In)-doped titanium dioxide (TiO2) nanoparticles were synthesized using a controlled sol-gel method. The structures and properties of the catalysts were characterized by XRD, FE-SEM, TEM, XPS, BET, UV-vis and PL spectroscopy. Indium, present over the TiO2 in metal state, inhibited crystal growth and produced anatase phase of mesoporous TiO2 nanoparticles. Doping In in TiO2 also increased the surface area and enlarged the band gap. The photocatalytic activities of In-doped TiO2 nanoparticles were considerably improved for CO2 reduction with H2O vapors in a cell type photoreactor. CO was observed as the main product over TiO2, but doping In in TiO2 remarkably increased the CH4 yield. CH4 production rate over 10 wt.% In-doped TiO2 was 7.9-fold higher than the bare TiO2 at 100°C and CO2/H2O ratio of 1.43. In addition, C1-3 higher hydrocarbons namely C2H4, C2H6, C3H6 and C3H8 were detected in the product mixture. The enhanced photoactivity in mesoporous In-doped TiO2 nanoparticles can be attributed to interfacial transfer of photogenerated charges, which led to effective charge separation and inhibited recombination of photogenerated electron-hole (e-/h+) pairs. Langmuir-Hinshelwood model, developed to investigate reaction rate parameters, fitted well with the experimental data.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, 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, Ammoniac, Ammonia, Amoníaco, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Cinétique, Kinetics, Cinética, Condition hydrothermale, Hydrothermal condition, Condición hidrotermal, Modèle cinétique, Kinetic model, Modelo cinético, Modélisation, Modeling, Modelización, Protection environnement, Environmental protection, Protección medio ambiente, Zéolite, Zeolite, Zeolita, Ammonia SCR, Cu zeolites, Cu/BEA, and Hydrothermal aging

In this study, a kinetic model describing the effect of hydrothermal aging (at 500, 600, 700, 800 and 900 °C) on Cu-zeolites is developed. The model accounts for the impact of hydrothermal aging on key reactions such as ammonia adsorption/desorption, NH3 oxidation, NO oxidation, standard SCR, rapid SCR, and NO2 SCR. In addition, a mechanism for the complex N2O formation were developed. The effect of aging on ammonia adsorption and desorption were established using micro-calorimeter data. Thereafter, an aging factor model was developed containing two aging factors, one related to over-exchanged copper sites and the other to under-exchanged copper sites. This approach worked well for ammonia and NO oxidation up to an aging temperature of 800 °C, whereas for the SCR reactions only to 700 °C. According to UV-vis, fresh and mildly aged catalysts are dominated by copper hydroxyls, while after aging at high temperature copper oxides are observed. We therefore introduce one SCR reaction associated with copper oxides, simultaneously with one SCR reaction associated with ion-exchanged Cu sites and the updated model could describe the experimental findings well. The results from the model also suggest that the standard SCR reaction is more deactivated during aging compared to SCR with NO2 present in the feed. After the 900 °C aging the BEA structure had collapsed, resulting in that several parameters in the model needed to be retuned. The results from this modeling study clearly show how complex the hydro thermal aging is over copper zeolites.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, 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, Composé de métal de transition, Transition element compounds, Cétone, Ketone, Cetona, Acétone, Acetone, Acetona, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Cinétique, Kinetics, Cinética, Haute fréquence, High frequency, Alta frecuencia, Oxydation, Oxidation, Oxidación, Oxyde de titane, Titanium oxide, Titanio óxido, Photocatalyse, Photocatalysis, Fotocatálisis, Protection environnement, Environmental protection, Protección medio ambiente, Simulation, Simulación, Vapeur, Vapor, Controlled periodic illumination, Reaction kinetics simulation, Titanium dioxide, and UV LED

We investigated the effect of controlled periodic illumination on quantum efficiency of acetone vapor photocatalytic oxidation. It was demonstrated that quantum efficiency increases with the increase of light pulses frequency and decrease of the duty cycle and at some point reaches its maximum value which is equal to the quantum efficiency obtained under the same average photon flux. Several kinetic models were applied to the experimental data. The general conclusion was made that there are only two kinetically distinguishable active species on TiO2 surface with the lifetimes in 10-3-101 s range.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, 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, Accepteur électron, Electron acceptor, Aceptor electrón, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Cinétique, Kinetics, Cinética, Dégradation photochimique, Photochemical degradation, Degradación fotoquímica, Mécanisme, Mechanism, Mecanismo, Oxydant, Oxidant, Oxidante, Oxydation, Oxidation, Oxidación, Oxyde de tungstène, Tungsten oxide, Wolframio óxido, Photocatalyse, Photocatalysis, Fotocatálisis, Protection environnement, Environmental protection, Protección medio ambiente, Séparation charge, Charge separation, Separación carga, WO3, Alternative electron acceptor, Inorganic oxidant, Photocatalytic oxidation, and Visible light activity

This study evaluates the capacity of various inorganic oxidants (IO4-, HSO5-, S2O82-, H2O2, and BrO3-) to act as alternative electron acceptors for WO3-mediated photocatalytic oxidation. Combination with IO4- drastically increased the rate of photocatalytic degradation of 4-chlorophenol by WO3, while the other oxyanions only negligibly improved the photocatalytic activity. The extent of the photocatalytic performance enhancement in the presence of inorganic oxidants correlated well with the efficiencies for: (1) hydroxylation of benzoic acid as an OH• probe, (2) dechlorination of dichloroaceate as a hole scavenger, and (3) water oxidation with O2 evolution. The results suggest that the promoted charge separation primarily causes kinetic enhancement in photocatalytic degradation using the WO3/IO4- system. In marked contrast to the substrate-dependent activity of the photochemically activated IO4- (generating selective IO3•), the efficiency of the WO3/IO4- system for photocatalytic degradation did not sensitively depend on the type of target organic compound, which implies the existence of a minor contribution of the photocatalytic reduction pathway associated with the production of IO3• as a secondary oxidant. On the other hand, the insignificant inhibitory effect of methanol as an OH• quencher may reveal the possible involvement of SO4•- in the improved photocatalytic activity of the WO3/HSO5- system. The alternative use of platinized WO3, where the interfacial electron transfer occurs in a concerted step, achieved a highly accelerated photocatalytic oxidation in the presence of HSO5- and polyoxometalates as electron scavengers. In particular, the surface loading of nanoscale platinum appeared to retard the reaction route for SO4•- generation associated with a one-electron transfer.

Electrical engineering, Electrotechnique, Energy, Énergie, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Electrotechnique. Electroenergetique, Electrical engineering. Electrical power engineering, Electroénergétique, Electrical power engineering, Conversion directe et accumulation d'énergie, Direct energy conversion and energy accumulation, Conversion électrochimique: piles et accumulateurs électrochimiques, piles à combustibles, Electrochemical conversion: primary and secondary batteries, fuel cells, Energie, Energy, Energie. Utilisation thermique des combustibles, Energy. Thermal use of fuels, Appareils de production et de conversion d'énergie: énergie thermique, énergie électrique, énergie mécanique, etc, Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc, Piles à combustible, Fuel cells, Metaux. Metallurgie, Metals. Metallurgy, Corrosion, Mécanismes fondamentaux et formes de la corrosion, Corrosion mechanisms, Electrolyte polymère, Polymer electrolytes, Acier inoxydable 316, Stainless steel-316, Acier inoxydable 316L, Stainless steel-316L, Acier inoxydable, Stainless steel, Acero inoxidable, Nichtrostender Stahl, Cinétique, Kinetics, Cinética, Kinetik, Défaut ponctuel, Point defect, Defecto puntual, Punktfehler, Dégradation, Degradation, Degradación, Electrolyte solide polymère, Polymer solid electrolyte, Electrólito sólido polímero, Endommagement, Damaging, Deterioración, Environnement, Environment, Medio ambiente, Umgebung, Formation film, Film formation, Formación película, Modèle, Models, Modelo, Pile combustible membrane échangeuse proton, Proton exchange membrane fuel cells, Pile combustible électrolyte solide, Solid electrolyte fuel cells, Pile combustible, Fuel cell, Pila combustión, Brennstoffzelle, Résistance contact, Contact resistance, Resistencia contacto, Kontaktwiderstand, Vitesse corrosion, Corrosion rate, Velocidad corrosión, Korrosionsgeschwindigkeit, Plaque bipolaire, Bipolar plate, Bipolar plates, Corrosion rates, PEFC, and Point defect model

A potentiostatic polarization method is used to evaluate the corrosion behavior of SS316L in simulated anode and cathode environments of polymer electrolyte fuel cells. A passive barrier oxide film is observed to form and reach steady state within ~10 h of polarization, after which time the total ion release rates are low and nearly constant at ~0.4 μg cm-2 h-1 for all potentials investigated. The equilibrium film thickness, however, is a function of the applied potential. The main ionic species dissolved in the liquid are predominately Fe followed by Ni, that account for >90% of the steady-state corrosion current. The dissolution rate of Cr is low but increases systematically at potentials higher than 0.8 V. The experimental ion release rates can be correlated with a point defect model using a single set of parameters over a broad range of potentials (0.2―1 V) on the cathode side. The interfacial contact resistance measured after 48 h of polarization is observed to increase with increase in applied potential and can be empirically correlated with applied load and oxide film thickness. The oxide film is substantially thicker at 1.5 V possibly because of alteration in film composition to Fe-rich as indicated by XPS data.

Biomass, bioproducts, Biomasse, bioproduits, Biotechnology, Biotechnologies, Wastes, Déchets, Energy, Énergie, Environment, Environnement, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Biotechnologie, Biotechnology, Absorption, Absorción, Biosorption, Biosorción, Cinétique, Kinetics, Cinética, Eau douce, Fresh water, Agua dulce, Etude comparative, Comparative study, Estudio comparativo, Lanthane, Lanthanum, Lantano, Microorganisme, Microorganism, Microorganismo, Modélisation, Modeling, Modelización, Paroi cellulaire, Cell wall, Pared celular, Algue, Alga, Cell wall properties, Micro algae, and Modelling

In this study, the adsorption and desorption kinetics of lanthanum (La) on micro algal cells was investigated. The internal transcribed spacer (ITS) and 18S ribosomal RNA gene (rRNA) were used for molecular identification of the species. The algal species were found to have 95-98% identities to Desmodesmus multivariabilis, Scenedesmus acuminutus, Chloroidium saccharophilum and Stichococcus bacillaris. The species were cultured and tested independently. D. multivariabilis was found to be the most efficient at adsorbing lanthanum with a maximum sorption capacity (qmax) of 100mg/g and a high affinity (b) of 4.55 L/g. Desorption of La was also highest in D. multivariabilis with recovery up to 99.63% at initial concentration as high as 100 mg/L. Desorption data fitted best to the modified pseudo second-order with a better correlation coefficient (R2) of ≤0.98 than first order model. The results showed feasibility of lanthanum recovery using algal sorbents, a cost effective method.

Environment, Environnement, Pollution, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Pollution, Déchets, Wastes, Déchets divers et constituants particuliers des déchets, Other wastes and particular components of wastes, Azote, Nitrogen, Nitrógeno, Cinétique, Kinetics, Cinética, Dioxyde de carbone, Carbon dioxide, Carbono dióxido, Hydrocarbure, Hydrocarbon, Hidrocarburo, Mécanisme réaction, Reaction mechanism, Mecanismo reacción, Polychlorobiphényles, Polychlorobiphenyls, Polichlorobifenilos, Pyrolyse, Pyrolysis, Pirólisis, Thermogravimétrie, Thermogravimetry, and Termogravimetría

Thermogravimetric (TG) analysis and infrared spectroscopy were used to analyze the pyrolysis characteristics of printed circuit board scraps (PCBs), coal powder and their mixtures under nitrogen atmosphere. The experimental results show that there is a large difference between waste PCBs and coal powder in pyrolysis processing. The pyrolysis properties of the mixing samples are the result of interaction of the PCBs and coal powder, which is influenced by the content of mixture. The degree of pyrolysis and pyrolysis properties of the mixture are much better than that of the single component. The TG and the differential thermogravimetric (DTG) curves of the PCBs mixed with coal powder move towards the high-temperature zone with increasing amount of coal powder and subsequently the DTG peak also becomes wider. The Coats-Redfern integral method was used to determine the kinetic parameters of pyrolysis reaction mechanism with the different proportion of mixture. The gas of pyrolysis mainly composes of CO2, CO, H2O and some hydrocarbon. The bromide characteristic absorption peak has been detected obviously in the pyrolysis gas of PCBs. On the contrary, the absorption peak of the bromide is not obvious in pyrolysis gas of the PCBs samples adding 40% coal powder.

Plant biology and physiology, Biologie et physiologie végétales, Ecology, Ecologie, Environment, Environnement, Toxicology, Toxicologie, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Cytologie, morphologie, systematique, floristique et evolution des vegetaux, Plant cytology, morphology, systematics, chorology and evolution, Thallophyta, Algae, Protozoaires, Protozoa, Ecologie animale, vegetale et microbienne, Animal, plant and microbial ecology, Ecologie animale et végétale, Animal and plant ecology, Autoécologie, Autoecology, Végétaux et champignons, Plants and fungi, Algae, Protozoa, Algue nuisible, Harmful alga, Alga nociva, Aminoacide, Aminoacid, Aminoácido, Ammonium, Amonio, Azote, Nitrogen, Nitrógeno, Captation, Uptake, Captación, Cinétique, Kinetics, Cinética, Nitrate, Nitrates, Nitrato, Population naturelle, Natural population, Población natural, Urée, Urea, Urées, Ureas, Alveolata, Dinozoa, Karenia brevis, Protiste, Amino acids, and Uptake kinetics

This study represents the most comprehensive assessment of kinetic parameters for Karenia brevis to date as it encompasses natural populations sampled during three different bloom years in addition to cultured strains under controlled conditions. Nitrogen (N) uptake kinetics for ammonium (NH4+), nitrate (NO3-), urea, an amino acid mixture, individual amino acids (glutamate and alanine), and humic substrates were examined for the toxic red tide dinoflagellate, K. brevis, during short term incubations (0.5-1 h) using 15N tracer techniques. Experiments were conducted using natural populations collected during extensive blooms along the West Florida Shelf in October 2001, 2002, and 2007, and in cultured strains (CCFWC 251 and CCFWC 267) obtained from the Florida Fish and Wildlife Institute culture collection. Kinetic parameters for the maximum uptake velocity (Vmax), half-saturation concentration (Ks), and the affinity constant (α) were determined. The affinity constant is considered a more accurate indicator of substrate affinity at low concentrations. K. brevis took up all organic substrates tested, including N derived from humic substances. Uptake rates of the amino acid mixture and some NO3- incubations did not saturate even at the highest substrate additions (50-200 μmol N L-1). Based upon the calculated α values, the greatest substrate preference was for NH4+ followed by NO3- > urea, humic compounds and amino acids. The ability of K. brevis to utilize a variety of inorganic and organic substrates likely helps it flourish under a wide range of nutrient conditions from bloom initiation in oligotrophic waters offshore to bloom maintenance near shore where ambient nutrient concentrations may be orders of magnitude greater.

Sustainable development, Développement durable, Environment, Environnement, Management economics, Gestion, économie, management, Pollution, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Pollution, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Ecologie animale, vegetale et microbienne, Animal, plant and microbial ecology, Ecologie appliquée, Applied ecology, Conservation, protection, gestion de l'environnement, de la flore et de la faune, Conservation, protection and management of environment and wildlife, Environnement et développement durable, Environment and sustainable development, Chromate, Chromates, Cromato, Chrome, Chromium, Cromo, Cinétique, Kinetics, Cinética, Développement durable, Sustainable development, Desarrollo sostenible, Lessivage, Leaching, Lavado, Protection environnement, Environmental protection, Protección medio ambiente, Prévention pollution, Pollution prevention, Prevención polución, Sulfate, Sulfates, Sulfato, Chromium sulfate, Cr―Fe alloy, and Leaching kinetics

In the traditional leaching process for producing chromate from chromite ore, large quantities of chromium-containing residues and dusts are discharged, creating serious environmental pollution. In order to solve this serious environmental problem and realize a clean production process for chromate, a new cleaning process using a Cr―Fe alloy as a raw material has been developed, in which the pollution problem of chromium-containing residues caused by the leaching process is resolved. The effects of leaching temperature, reaction time, particle size, stirring rate, and liquid-to-solid ratio in the leaching process have been investigated in this study. The experiment results show that the leaching ratio of the Cr and Fe in the alloy can be greater than 97% at a leaching temperature of 90 °C, a liquid-to-solid ratio of 3:1, an alloy powder particle size of 200 mesh, a stirring rate of 300 rpm and a leaching time of 6 h. Kinetic analysis was carried out, and the calculated activation energy for chromium leaching was 43.94 kJ/mol, indicating control of this process by a chemical reaction on the particle surface. In the proposed process for producing chromate from a Cr―Fe alloy, chromium is present in the form of Cr3+, so the pollution problem of hexavalent chromium residues can be resolved and clean production can be realized.

Biomass, bioproducts, Biomasse, bioproduits, Biotechnology, Biotechnologies, Wastes, Déchets, Energy, Énergie, Environment, Environnement, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Chitosane, Chitosan, Quitosano, Cinétique, Kinetics, Cinética, Dérivé du chitosane, Chitosan derivatives, Quitosano derivado, Ion, Ions, Ión, Résine, Resins, Resina, Solution aqueuse, Aqueous solution, Solución acuosa, Sorbant, Sorbent, Sorbente, Thermodynamique, Thermodynamics, Termodinámica, Uranium, Uranio, Chitosan derivative, Ferromagnetic sorbent, and Uranyl ion removal

Chitosan was cross-linked using glutaraldehyde in the presence of magnetite. The resin was chemically modified through the reaction with tetraethylenepentamine (TEPA) to produce amine bearing chitosan. The resin showed a higher affinity towards the uptake of UO22 ions from aqueous medium: maximum sorption capacity reached 1.8 mmol g-1 at pH 4 and 25 °C. The nature of interaction of UO22 ions with the resin was identified. Kinetics were carried out at different temperatures and thermodynamic parameters were evaluated. Breakthrough curves for the removal of UO22 were studied at different flow rates, bed heights and after 3 regeneration cycles. Hydrochloric acid (0.5 M) was used for desorbing UO22 from loaded resin: desorption yield as high as 98% was obtained.

Biotechnology, Biotechnologies, Ecology, Ecologie, Energy, Énergie, Environment, Environnement, Pollution, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, 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 du sol et des sédiments, Soil and sediments pollution, Propriétés biologiques et physicochimiques des polluants. Interaction dans le sol, Biological and physicochemical properties of pollutants. Interaction in the soil, Terre, ocean, espace, Earth, ocean, space, Sciences de la terre, Earth sciences, Géologie de l'ingénieur et de l'environnement. Géothermie, Engineering and environment geology. Geothermics, Pollution, géologie de l'environnement, Pollution, environment geology, Composé organique, Organic compounds, Compuesto orgánico, Polluant organique persistant, Persistent organic pollutant, Contaminante organico persistente, Activité microbienne, Microbial activity, Actividad microbiana, Aérobie, Aerobe, Aerobio, Bactérie Gram négatif, Gram negative bacteria, Bacteria Gram negativa, Biodisponibilité, Bioavailability, Biodisponibilidad, Carcinogène, Carcinogen, Carcinógeno, Cinétique, Kinetics, Cinética, Composé aromatique polycyclique, Polycyclic aromatic compound, Compuesto aromático policíclico, Composé hydrophobe, Hydrophobic compound, Compuesto hidrofobo, Devenir polluant, Pollutant behavior, Evolución contaminante, Dissolution, Disolución, Dégradation biologique, Biodegradation, Degradación biológica, Environnement, Environment, Medio ambiente, Hydrocarbure, Hydrocarbon, Hidrocarburo, Mutagène, Mutagen, Mutágeno, Phénanthrène, Phenanthrene, Fenantreno, Pollution, and Polución

Metabolism of a low-solubility substrate is limited by dissolution and availability and can hardly be determined. We developed a numerical model for simultaneously calculating dissolution kinetics of such substrates and their metabolism and microbial growth (Monod kinetics with decay) and tested it with three aerobic phenanthrene (PHE) degraders: Novosphingobium pentaromativorans US6-1, Sphingomonas sp. EPA505, and Sphingobium yanoikuyae B1. PHE was present as microcrystals, providing non-limiting conditions for growth. Total PHE and protein concentration were tracked over 6―12 days. The model was fitted to the test results for the rates of dissolution, metabolism, and growth. The strains showed similar efifciency, with vmax values of 12―18 g dw g―1 d―1, yields of 0.21 g g―1, maximum growth rates of 2.5―3.8 d―1, and decay rates of 0.04―0.05 d―1. Sensitivity analysis with the model shows that (i) retention in crystals or NAPLs or by sequestration competes with biodegradation, (ii) bacterial growth conditions (dissolution flux and resulting chemical activity of substrate) are more relevant for the final state of the system than the initial biomass, and (iii) the desorption flux regulates the turnover in the presence of solid-state, sequestered (aged), or NAPL substrate sources.

Sustainable development, Développement durable, Environment, Environnement, Management economics, Gestion, économie, management, Pollution, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Pollution, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Ecologie animale, vegetale et microbienne, Animal, plant and microbial ecology, Ecologie appliquée, Applied ecology, Conservation, protection, gestion de l'environnement, de la flore et de la faune, Conservation, protection and management of environment and wildlife, Environnement et développement durable, Environment and sustainable development, Biotechnologie, Biotechnology, Algae, Biosorption, Biosorción, Cinétique, Kinetics, Cinética, Développement durable, Sustainable development, Desarrollo sostenible, Modèle, Models, Modelo, Modélisation, Modeling, Modelización, Phosphate, Phosphates, Fosfato, Protection environnement, Environmental protection, Protección medio ambiente, Prévention pollution, Pollution prevention, Prevención polución, Rhodophyta, Solution aqueuse, Aqueous solution, Solución acuosa, Thermodynamique, Thermodynamics, Termodinámica, Diffusion models, and Kappaphycus alverezii

In the present study, dead biomass of marine macro algae, Kappaphycus alverezii (K. alverezii) was used for the removal of phosphate from water. The effect of different parameters such as contact time, adsorbate concentration, biosorbent dose and temperature was investigated. The biosorption kinetics data were best described by the pseudo-second order rate equation, and equilibrium was achieved after 80 min. The phosphate biosorption was governed by film diffusion process. The maximum phosphate biosorption on K. alverezii was 59.77 mg/g at 25 °C and it followed the Redlich-Peterson model. The biosorption on K. alverezii increased with increasing temperature and was the highest at pH 6.0. The calculated thermodynamic parameters (ΔG°, ΔH° and ΔS°) showed that the biosorption of phosphate onto K. alverezii biomass was feasible, spontaneous and endothermic at 15-45 °C. Results suggest that the prepared biomass of K. alverezii has potential in remediation of phosphate contaminated waters.

Biomass, bioproducts, Biomasse, bioproduits, Biotechnology, Biotechnologies, Wastes, Déchets, Energy, Énergie, Environment, Environnement, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Pollution, Déchets, Wastes, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Biotechnologie, Biotechnology, Agronomie. Sciences du sol et productions vegetales, Agronomy. Soil science and plant productions, Agronomie générale. Phytotechnie, General agronomy. Plant production, Utilisation de déchets et sous-produits agricoles et forestiers. Exploitation de la biomasse, bioconversion, Use of agricultural and forest wastes. Biomass use, bioconversion, Biosorption, Biosorción, Cinétique, Kinetics, Cinética, Déchet agricole, Agricultural waste, Desperdicio agrícola, Déchet industriel, Industrial waste, Desperdicio industrial, Industrie agricole, Agricultural industry, Industria agrícola, Isotherme, Isotherm, Isoterma, Métal lourd, Heavy metal, Metal pesado, Agro industrial waste, and Kinetic study

A novel multi-metal binding biosorbent (MMBB) was developed by combining a group of three from the selective natural lignocellulosic agro-industrial wastes for effectively eliminating lead, cadmium, copper and zinc from aqueous solutions. Four MMBBs with different combinations (MMBB1: tea waste, corncob, sugarcane bagasse; MMBB2: tea waste, corncob and sawdust; MMBB3: tea waste, corncob and apple peel; MMBB4: tea waste, corncob and grape stalk) were evaluated. FTIR analysis for characterizing the MMBB2 explored that the MMBB2 contains more functional groups available for multi-metals binding. Comparing among the MMBBs as well as the single group biosorbents, MMBB2 was the best biosorbent with the maximum biosorption capacities of 41.48, 39.48, 94.00 and 27.23 mg/g for Cd(II), Cu(II), Pb(II) and Zn(II), respectively. After 5 times of desorption with CaCl2, CH3COOH and NaCl as eluent, the MMBB2 still remained excellent biosorptive capacity, so as it could be well regenerated for reuse and possible recovery of metals.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, 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, Alcool, Alcohol, Composé benzénique, Benzenic compound, Compuesto bencénico, Acide, Acids, Acido, Air humide, Wet air, Aire húmedo, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Catalyseur, Catalyst, Catalizador, Cinétique, Kinetics, Cinética, Eau usée, Waste water, Agua residual, Mécanisme, Mechanism, Mecanismo, Oxydation, Oxidation, Oxidación, Phénol, Phenol, Fenol, Phénols, Phenols, Fenoles, Polluant, Pollutant, Contaminante, Protection environnement, Environmental protection, Protección medio ambiente, Réaction catalytique, Catalytic reaction, Reacción catalítica, Réfractaire, Refractory, Refractario, C1-C2 acids, Catalytic wet air oxidation (CWAO), Industrial wastewater, and Mechanism-Kinetics

The reactivity pattern of a model MnCeOx catalyst (Mnat:Ceat, 1) in the wet air oxidation (CWAO) of toxic (phenol) and refractory (acetic, oxalic and formic acids) organic pollutants has been probed, using a stirred batch reactor with continuous oxygen feeding (PO2, 0,9 MPa). In the range of 110―150°C the MnCeOx catalyst (wcat/wsub, 5) shows high abatement and mineralization efficiency toward all the substrates. Parallel trends of substrate and total organic carbon (TOC) conversion prove that adsorption is the primary reaction step, while slower mineralization rates signal that surface oxidation is rate determiningstep (r.d.s.). Activity data in the pH range of 3―10 and straight relationships between conversion and dissociation constant (Ka) signal that acids adsorption is driven by electrostatic interactions with acid sites (EAds ≈ 80 kJ/mol), while a low energetic barrier (EAds ≈ 16 kJ/mol) discloses the physical nature of phenol adsorption. A kinetic analysis of conversion-selectivity data, based on a dual-site Langmuir―Hinshelwood (L―H) mechanism, sheds light into the CWAO pattern of MnCeOx catalyst toward different classes of organic pollutants.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, 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, Electrochimie, Electrochemistry, Cinétique et mécanisme des réactions, Kinetics and mechanism of reactions, Composé binaire, Binary compound, Compuesto binario, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Cinétique, Kinetics, Cinética, Electrocatalyse, Electrocatalysis, Electrocatálisis, Electrochimie, Electrochemistry, Electroquímica, Electrode, Electrodes, Electrodo, Oxydation, Oxidation, Oxidación, Oxyde d'étain, Tin oxide, Estaño óxido, Phosphate, Phosphates, Fosfato, Protection environnement, Environmental protection, Protección medio ambiente, O Sn, SnO2, Advanced oxidation process, Dichlorvos (2,2-dichlorovinyl dimethyl phosphate), Langmuir-Hinshelwood kinetics, and Metal oxide electrode

The effects of electrode potential and the initial concentration of 2,2-dichlorovinyl dimethyl phosphate (dichlorvos, DDVP) on its oxidation/mineralization reaction kinetics, using an electrochemical oxidation system based on SnO2—Sb2O5 anodes, have been studied. Electrochemical degradation followed the Langmuir―Hinshelwood mechanism, with adsorption equilibrium constant K = 0.082 L mg―1 of dichlorvos on the electrode material surface, and reaction rate constant K = 0.021 mg L―1 s―1 of the organic compound-electrocatalyst adduct. Chemical oxygen demand and CO2 measurements in neutral media suggest that the rate limiting step for mineralization is the same as for the electrochemical oxidation. The results show that the electrochemical mineralization of dichlorvos was readily possible at potentials more positive than 2.5 V vs. SCE, with lower reaction half-lives than obtained with other advanced oxidation process. The fastest overall degradation rate constants were obtained at limiting low concentrations of dichlorvos in aqueous solution, kobs = kK = 0.0017 s―1.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, 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, Caractérisation, Characterization, Caracterización, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Cinétique, Kinetics, Cinética, Hydrodésulfuration, Hydrodesulfurization, Hidrodesulfuración, Protection environnement, Environmental protection, Protección medio ambiente, Simulation, Simulación, Soufre, Sulfur, Azufre, Dibenzothiophène, 5 days of HDS runs, Adsorbed sulfur species, DBT HDS, Two kinds of sites, and W2C

The stability of unsupported W2C tungsten carbide and its sulfur resistance during hydrodesulfurization (HDS) of dibenzothiophene (DBT) are a specificity of W2C. This material was characterized by X-ray diffraction, specific surface area measurements, HRTEM associated with EDS, lattice images, direct and reverse Fast Fourier Transforms, direct lattice fringes profiles, dynamic CO chemisorptions and elemental analysis of S, C and W. The absence of surface crystallographic layer of tungsten sulfide and the presence of a surface monolayer of adsorbed sulfur species (post-sulfur passivation by H2S by the end of HDS runs), after 5 days of HDS runs on unsupported W2C, are established. The repeatability of both W2C synthesis and catalytic activity with chemical stability are shown. The HDS of DBT was investigated using a fixed-bed reactor. The reaction was carried out at 613 K, under a 6 MPa total pressure of H2. The global reaction follows two parallel routes. Under the experimental conditions, DBT has a single final product along each route, leading either to biphenyl through the direct desulfurization (DDS) pathway, or to cyclohexylbenzene through the hydrogenation (HYD) pathway. Accordingly, the HDS of DBT over W2C presents a true zero order reaction to DBT along the DDS route, and a true first order reaction along the HYD route. The resulting global apparent first order rate with respect to DBT is linked to the selectivity towards these two routes. The kinetically true zero order rate along the DDS route corresponds to the saturation by DBT of all its active sites and, consequently, means that the HYD route is occurring on a second kind of sites. The presence of two kinds of sites is thus kinetically demonstrated and discussed in term of Coordinatively Unsaturated Sites (CUS).