Journal of Photochemistry and Photobiology A-chemistry, 2021
The aim of this work is to evaluate the use of phenalenone (PN) grafted to sand in the photodegra... more The aim of this work is to evaluate the use of phenalenone (PN) grafted to sand in the photodegradation of tebuconazole (TEB). PN was covalently attached to sand via click reactions between functionalized sand and PN derivatives. The photodegradation study was conducted in an annular reactor equipped with immersed UV and visible lamps. In the first step the photodegradation of TEB was studied in presence of free PN. The influence of the molar ratio = PN/TEB was investigated; a maximal effect was observed with R close to 769; beyond this value a shielding effect appeared. The use and the lifetime of the sand-bound PN were studied and the photodegradation mechanism was investigated. Covalent binding of photosensitizer to sand resulted in a 80 nm red shift of the PN absorption band in the visible region along with an important increase in degradative efficiency. PN-Sand was more stable under visible irradiation. The main mechanism was the type II with some contribution of type I.
Adsorption of the herbicide diuron and its three degradation products: 3-(3,4-dichlorophenyl)- 1-... more Adsorption of the herbicide diuron and its three degradation products: 3-(3,4-dichlorophenyl)- 1-methylurea, 1-(3,4-dichlorophenyl) urea and 2,4-dichloroanilin on three organoinorgano-clay minerals, was investigated. These surfactant-modified pillared ...
Filtration of polluted aqueous solutions is performed by activated carbon membranes. The adsorpti... more Filtration of polluted aqueous solutions is performed by activated carbon membranes. The adsorption capacities are determined in batch reactors. Classic models are applied and kinetic constants are calculated. A comparison with grains and powders of activated carbon is made. The performances of the membranes in continously fed reactors are also studied. The breakthrough curves are plotted for different concentrations of organic compounds and fluid velocities. A simple model of mass transfer into the porous volume of the membrane is put forward and used to predict the outlet concentrations as a function of time. The model parameters are correlated to the fluid velocities and the inlet concentrations.
La production d'eau potable nécessite parfois une filtration sur charbon actif en vue d'é... more La production d'eau potable nécessite parfois une filtration sur charbon actif en vue d'éliminer des micropolluants organiques. Afin de développer un modèle prévisionnel de la durée de vie de ces filtres, il est nécessaire de bien connaître les caractéristiques des charbons influençant l'adsorption. Des caractéristiques de la structure physique (porosité et surface) et chimiques (fonction de surface), le potentiel zêta et les constantes thermodynamiques de neuf charbons actifs ont été déterminées et des essais de corrélation ont indiqué une certaine ligne de conduite pour l'utilisation de charbons de différentes origines. Des cinétiques et des isothermes d'adsorption de l'atrazine et du phénol ont été réalisées, ceci afin de mieux comprendre l'influence de la structure et des caractéristiques physico-chimiques des charbons sur les mécanismes d'adsorption. L'étude a mis en évidence les points suivants : (i) le nombre de sites primaires polaires d&#...
This research reports on phosphate removal from aqueous solution using ZVI/sand packed columns. T... more This research reports on phosphate removal from aqueous solution using ZVI/sand packed columns. The influence of column preconditioning, consisting of ZVI pre-oxidation before feeding the columns with phosphate solution, revealed that a column aged for 1 day was more efficient than un-conditioned column, 5-days and 10-days preconditioned columns. The distribution of phosphate trapped inside the columns was evaluated by measuring phosphate concentration in the solids at different levels (P1, P2 and P3) along the depth of the columns. The distribution of phosphate inside the columns was determined for a time period up to 46 days, corresponding to column saturation. Results showed heterogeneous trapping along the column before saturation and homogeneous distribution upon saturation. The maximum cumulative trapped phosphate after column dismantling was determined before saturation (after 17 days running) at 130, 68 and 31 mgP/gFe at the inlet-P1, P1-P2 and P2-P3 layers, respectively, wh...
Ordered mesoporous silica with hexagonal and cubic structure, type MCM-41 and MCM-48 respectively... more Ordered mesoporous silica with hexagonal and cubic structure, type MCM-41 and MCM-48 respectively, were synthesized under basic media using pure silica, cetyltrimethylammonium bromide and tetramethylammonium hydroxide, for MCM-41 and tetraethylorthosilica, cetyltrimethylammonium and NaOH for MCM-48. The expanded materials were prepared by post-synthesis method with N-N dimethyldodecylamine (DMDDA) and dodecylamine (DDA). Small angle X-ray diffraction, nitrogen adsorption-desorption measurements, FT-IR and thermogravimetry were used to characterize the samples. The expanded materials were tested for adsorption of Cd(2+), Co(2+), Cu(2+) and Pb(2+) in aqueous solution. Aminated materials were found to be fast adsorbents for metallic ions cation with affinity for Cu(2+), Pb(2+), than for Cd(2+) and Co(2+) from single solution. In mixed metallic ions cation solutions, competition by the adsorption sites is likely to occur, the adsorption preference is for Cu(2+)and Pb(2+). The kinetic of the reaction is very rapid and follow pseudo-second order and clearly indicated that Langmuir model describe better the for metal ions adsorption on aminated mesoporous material than Freundlich model.
Phosphorus (P) release from sediment in 96 hours Batch pH stat experiments were carried out in di... more Phosphorus (P) release from sediment in 96 hours Batch pH stat experiments were carried out in different pH values (from 5 to 10) on fresh lake sediment samples treated in situ (TAl) or not (To) with alum. According to phosphorus fractionation, Fe-bound-P, Al-bound-P and Organic-bound-P represent the largest phosphorus pool (80 % of Total Phosphorus). At pH 10, phosphorus was mainly release from the Fe-P, Al-P and organic fractions. These represent 35 % of the total phosphorus content. At circumneutral pH, in oxic conditions, a much lower quantity of P was released (roughly 4 % of total P sediment content) than at pH 10. The addition of alum was shown to reduce the release of soluble reactive phosphorus (SRP) at circumneutral pH, in contrast, no influence had been noticed at alkaline pH.
Re sume ÐL'objectif de ce travail est d'e tudier un re acteur nitri®ant adapte aux systeÁ me... more Re sume ÐL'objectif de ce travail est d'e tudier un re acteur nitri®ant adapte aux systeÁ mes d'assainissement autonome. Le re acteur utilise est un lit ®ltrant garni fonctionnant en e coulement insatureÂ. Le comportement hydrodynamique est de crit par un modeÁ le d'e coulement aÁ deux phases (stagnante et dynamique) avec e change de matieÁ re entre les deux phases, e labore pour des conditions initiales et limites d'un re acteur clos. Ce modeÁ le repre sente par sa fonction de transfert est utilise pour simuler un e coulement en re gime permanent et pour un e coulement adapte aux conditions re elles en re gime pulse pe riodique. Les parameÁ tres sont optimise s en fonction de re sultats expe rimentaux. L'e tude cine tique de la nitri®cation montre que la re action d'e limination des ions ammonium est repre sente e par une re action d'ordre 0 alors que celle de la matieÁ re carbone e est repre sente e par une re action d'ordre 1. Des e quations globales du bilan de matieÁ re sont e tablies et les parameÁ tres cine tiques de termine s. La valeur de la constante cine tique de nitri®cation est de l'ordre 4 aÁ 4,5 mg xy À Q ÁL À1 h À1 .
The 2,3-dichloropropionanilide is a position isomer of propanil, a weed-killer widely used nowada... more The 2,3-dichloropropionanilide is a position isomer of propanil, a weed-killer widely used nowadays in agriculture across the Sahellian countries. We report here the effect of 2,3-dichloropropionanilide on five soil samples collected in the Mauritanian delta of the Senegal River. Methodology: A bit of how soils were sampled and determined using the reactor must be provided to permit repeatability. The results obtained showed that the physical and chemical compositions of the five soils studied were different. The adsorption in discontinuous reactor revealed a specific effect of 2, 3dichloropropionanilide with respect to each of the five soils taken individually. The study of the synthetic product adsorption in dynamic reactor confirmed the affinity of the molecule for the organic matter and clay fraction as demonstrated by the effect of the product on a soil from Limoges (France) different from the five Mauritanian soils. The affinity of the 2, 3-dichloropropionanilide is physical for the organic matter and the clay fraction and chemical for the metal compounds such as Aluminium, Iron and Manganese.
Colloids and Surfaces a Physicochemical and Engineering Aspects, Aug 1, 2010
As a result of the cross-linking process between sodium alginate, Aluminium pillared clay (Al-Mon... more As a result of the cross-linking process between sodium alginate, Aluminium pillared clay (Al-Mont-PILC) or surfactant-modified pillared clay (CTAB-Al-Mont-PILC) and divalent cation (Ca 2+), gel-like beads were obtained under different ratios of PILCs vs. alginate. Experimental ratios (pillared clay/alginate; w/w) increased to a maximum of 3.5 to 4. The results of SEM analysis revealed that surface morphology changes by introducing Al-Mont-PILC and CTAB-Al-Mont-PILC. Structural modifications were evaluated using FTIR and thermal analysis. In agreement with previous works the pseudo-second order model equation fit well with the kinetics data. Diffusion coefficients were calculated using the Linear Adsorption Model; the D eff obtained in this study (3-7 10 −6 cm 2 /s) are within the ranges reported in other works on inorganic pollutants or phenol diffusion in biopolymers. Adsorption isotherms of pentachlorophenol and safranine were analyzed using non-linear regression technique. Langmuir isotherms fit well with the results obtained for the sorption of safranine whereas the Freundlich isotherms was more in accordance with the pentachlorophenol sorption. A decrease of 35 to 40% in sorption capacity was observed for pentachlorophenol when the initial pH increased from 5.3 to 8. Modification of the biopolymers by introduction of pillared clays resulted in an enhancement of the adsorption capacity.
Lake Courtille is a shallow eutrophic polymictic lake treated with copper sulphate for four years... more Lake Courtille is a shallow eutrophic polymictic lake treated with copper sulphate for four years. Water column monitoring and laboratory experiments have shown that dissolved copper (CuD) behaviour correlates well with Dissolved Organic Carbon (DOC). Sequential extraction indicates that a significant fraction of the sediment-borne Cu is associated with the organic fraction (50% to 88% of total copper). This fraction of copper could be released into the water column depending on environmental conditions. Laboratory resuspension experiments have shown that significant short term release of Cu was not possible under circumneutral pH and the oxygenated conditions of the lake (less than 3% of the total copper sediment was released). Nevertheless over the long term, a fraction of the copper bound to the sediment could be released depending on the organic matter mineralization which could explain the presence of copper in the water column one year after the last copper addition.
The efficiency of eight extracellular polymeric substances (EPS) extraction methods was compared ... more The efficiency of eight extracellular polymeric substances (EPS) extraction methods was compared on two different activated sludges. Three chemical methods (EDTA, formaldehyde + NaOH, glutaraldehyde), four physical methods (sonication, cation exchange resin, sonication + cation exchange resin, heating) and a control method (centrifugation alone) were tested. EPS quantities extracted were more greater for chemical methods than those for physical methods. For the chemical methods used EPS contamination due to extracting reagents was pointed out by infra-red analysis. The EPS extracted by physical methods can show a different qualitative composition with protein and carbohydrate as predominant compounds. This study therefore underlines that the choice of EPS extraction method should not only be limited to extraction yield and nucleic acid content but should also consider that the EPS solution may be contaminated by extracting reagents and/or be greatly modified by the extraction protocol.
... l'appliquer aux SBR et simuler les systèmes discontinus afin d'optimiser les perfor... more ... l'appliquer aux SBR et simuler les systèmes discontinus afin d'optimiser les performances ... Lamodélisation de la mortalité englobe les phénomènes de métabolisme endogène, de ... que le procédé présenté aboutit à des rendements moyens d'épuration extrêmement satisfaisants ...
Journal of Shanghai University (English Edition), 2010
In this paper, the characteristics of fluid mixing time in a novel extra-loop fluidized bed were ... more In this paper, the characteristics of fluid mixing time in a novel extra-loop fluidized bed were studied. The results showed that the mixing time was shortened with the increase of fluid velocity. All the discrete numbers of the reactor were above 0.2. The serial number n was 2.5-3.0. It was judged accordingly that the reactor fluid state was continous stirred tank reactor (CSTR) mainly. When the inspiratory capacity increased the mixing time of the reactor was shortened. Thus the air input was beneficial for the fluid mixing. During the three phases mixing process, the mixing time of the reactor could be decreased by the n increase of carrier and air loading together, but the change was not significant. The parameters affecting the reactor fluid state were fluid velocity, inspiratory capacity and carrier. KLa could be increased with the air loading increase, and at the same gas/liquid ratio when the pressure drop was high, KLa value was increased. The amount of carrier complex influence on KLa. As the carrier loading continued to increase, its value had been dropped but the changes was not significant, and optimization condition was found at above 800-1 000 g carrier loading (pouzzolane) or 600 g PVC. Under gas/liquid ratio of 0.8%-5.2%, KLa was (0.62-1.37)×10 −2 s −1. Keywords extra-loop fluidized bed, mixing time, oxygen transfer, fluid velocity, Venturi aero-ejector, carrier Nomenclature D UL : Discrete number θ: Residence time of each reactor (s) C: Concentration of the reactor (V) C0: Original concentration of the reactor (V) Cn: Concentration of the nth reactor (V) H: Height of the tube (mm) KLa: Volumetric mass transfer coefficient (h −1) n: Serial number Qc: Circulation flow (liquid) (m 3 /s) Qg: Inspratory capacity (gas) (L/h) s: Thickness of the tube (mm) S1: Area of the circle pipe (m 2) S2: Area of Venturi aero-ejector pipe t: Average mixing time (s) u1: Liquid velocity in the circle pipe (m/s) ΔP : Pressure drop of the Venturi aero-ejector (Pa) ρ: Liquid density (kg/m 3)
Journal of Photochemistry and Photobiology A-chemistry, 2021
The aim of this work is to evaluate the use of phenalenone (PN) grafted to sand in the photodegra... more The aim of this work is to evaluate the use of phenalenone (PN) grafted to sand in the photodegradation of tebuconazole (TEB). PN was covalently attached to sand via click reactions between functionalized sand and PN derivatives. The photodegradation study was conducted in an annular reactor equipped with immersed UV and visible lamps. In the first step the photodegradation of TEB was studied in presence of free PN. The influence of the molar ratio = PN/TEB was investigated; a maximal effect was observed with R close to 769; beyond this value a shielding effect appeared. The use and the lifetime of the sand-bound PN were studied and the photodegradation mechanism was investigated. Covalent binding of photosensitizer to sand resulted in a 80 nm red shift of the PN absorption band in the visible region along with an important increase in degradative efficiency. PN-Sand was more stable under visible irradiation. The main mechanism was the type II with some contribution of type I.
Adsorption of the herbicide diuron and its three degradation products: 3-(3,4-dichlorophenyl)- 1-... more Adsorption of the herbicide diuron and its three degradation products: 3-(3,4-dichlorophenyl)- 1-methylurea, 1-(3,4-dichlorophenyl) urea and 2,4-dichloroanilin on three organoinorgano-clay minerals, was investigated. These surfactant-modified pillared ...
Filtration of polluted aqueous solutions is performed by activated carbon membranes. The adsorpti... more Filtration of polluted aqueous solutions is performed by activated carbon membranes. The adsorption capacities are determined in batch reactors. Classic models are applied and kinetic constants are calculated. A comparison with grains and powders of activated carbon is made. The performances of the membranes in continously fed reactors are also studied. The breakthrough curves are plotted for different concentrations of organic compounds and fluid velocities. A simple model of mass transfer into the porous volume of the membrane is put forward and used to predict the outlet concentrations as a function of time. The model parameters are correlated to the fluid velocities and the inlet concentrations.
La production d'eau potable nécessite parfois une filtration sur charbon actif en vue d'é... more La production d'eau potable nécessite parfois une filtration sur charbon actif en vue d'éliminer des micropolluants organiques. Afin de développer un modèle prévisionnel de la durée de vie de ces filtres, il est nécessaire de bien connaître les caractéristiques des charbons influençant l'adsorption. Des caractéristiques de la structure physique (porosité et surface) et chimiques (fonction de surface), le potentiel zêta et les constantes thermodynamiques de neuf charbons actifs ont été déterminées et des essais de corrélation ont indiqué une certaine ligne de conduite pour l'utilisation de charbons de différentes origines. Des cinétiques et des isothermes d'adsorption de l'atrazine et du phénol ont été réalisées, ceci afin de mieux comprendre l'influence de la structure et des caractéristiques physico-chimiques des charbons sur les mécanismes d'adsorption. L'étude a mis en évidence les points suivants : (i) le nombre de sites primaires polaires d&#...
This research reports on phosphate removal from aqueous solution using ZVI/sand packed columns. T... more This research reports on phosphate removal from aqueous solution using ZVI/sand packed columns. The influence of column preconditioning, consisting of ZVI pre-oxidation before feeding the columns with phosphate solution, revealed that a column aged for 1 day was more efficient than un-conditioned column, 5-days and 10-days preconditioned columns. The distribution of phosphate trapped inside the columns was evaluated by measuring phosphate concentration in the solids at different levels (P1, P2 and P3) along the depth of the columns. The distribution of phosphate inside the columns was determined for a time period up to 46 days, corresponding to column saturation. Results showed heterogeneous trapping along the column before saturation and homogeneous distribution upon saturation. The maximum cumulative trapped phosphate after column dismantling was determined before saturation (after 17 days running) at 130, 68 and 31 mgP/gFe at the inlet-P1, P1-P2 and P2-P3 layers, respectively, wh...
Ordered mesoporous silica with hexagonal and cubic structure, type MCM-41 and MCM-48 respectively... more Ordered mesoporous silica with hexagonal and cubic structure, type MCM-41 and MCM-48 respectively, were synthesized under basic media using pure silica, cetyltrimethylammonium bromide and tetramethylammonium hydroxide, for MCM-41 and tetraethylorthosilica, cetyltrimethylammonium and NaOH for MCM-48. The expanded materials were prepared by post-synthesis method with N-N dimethyldodecylamine (DMDDA) and dodecylamine (DDA). Small angle X-ray diffraction, nitrogen adsorption-desorption measurements, FT-IR and thermogravimetry were used to characterize the samples. The expanded materials were tested for adsorption of Cd(2+), Co(2+), Cu(2+) and Pb(2+) in aqueous solution. Aminated materials were found to be fast adsorbents for metallic ions cation with affinity for Cu(2+), Pb(2+), than for Cd(2+) and Co(2+) from single solution. In mixed metallic ions cation solutions, competition by the adsorption sites is likely to occur, the adsorption preference is for Cu(2+)and Pb(2+). The kinetic of the reaction is very rapid and follow pseudo-second order and clearly indicated that Langmuir model describe better the for metal ions adsorption on aminated mesoporous material than Freundlich model.
Phosphorus (P) release from sediment in 96 hours Batch pH stat experiments were carried out in di... more Phosphorus (P) release from sediment in 96 hours Batch pH stat experiments were carried out in different pH values (from 5 to 10) on fresh lake sediment samples treated in situ (TAl) or not (To) with alum. According to phosphorus fractionation, Fe-bound-P, Al-bound-P and Organic-bound-P represent the largest phosphorus pool (80 % of Total Phosphorus). At pH 10, phosphorus was mainly release from the Fe-P, Al-P and organic fractions. These represent 35 % of the total phosphorus content. At circumneutral pH, in oxic conditions, a much lower quantity of P was released (roughly 4 % of total P sediment content) than at pH 10. The addition of alum was shown to reduce the release of soluble reactive phosphorus (SRP) at circumneutral pH, in contrast, no influence had been noticed at alkaline pH.
Re sume ÐL'objectif de ce travail est d'e tudier un re acteur nitri®ant adapte aux systeÁ me... more Re sume ÐL'objectif de ce travail est d'e tudier un re acteur nitri®ant adapte aux systeÁ mes d'assainissement autonome. Le re acteur utilise est un lit ®ltrant garni fonctionnant en e coulement insatureÂ. Le comportement hydrodynamique est de crit par un modeÁ le d'e coulement aÁ deux phases (stagnante et dynamique) avec e change de matieÁ re entre les deux phases, e labore pour des conditions initiales et limites d'un re acteur clos. Ce modeÁ le repre sente par sa fonction de transfert est utilise pour simuler un e coulement en re gime permanent et pour un e coulement adapte aux conditions re elles en re gime pulse pe riodique. Les parameÁ tres sont optimise s en fonction de re sultats expe rimentaux. L'e tude cine tique de la nitri®cation montre que la re action d'e limination des ions ammonium est repre sente e par une re action d'ordre 0 alors que celle de la matieÁ re carbone e est repre sente e par une re action d'ordre 1. Des e quations globales du bilan de matieÁ re sont e tablies et les parameÁ tres cine tiques de termine s. La valeur de la constante cine tique de nitri®cation est de l'ordre 4 aÁ 4,5 mg xy À Q ÁL À1 h À1 .
The 2,3-dichloropropionanilide is a position isomer of propanil, a weed-killer widely used nowada... more The 2,3-dichloropropionanilide is a position isomer of propanil, a weed-killer widely used nowadays in agriculture across the Sahellian countries. We report here the effect of 2,3-dichloropropionanilide on five soil samples collected in the Mauritanian delta of the Senegal River. Methodology: A bit of how soils were sampled and determined using the reactor must be provided to permit repeatability. The results obtained showed that the physical and chemical compositions of the five soils studied were different. The adsorption in discontinuous reactor revealed a specific effect of 2, 3dichloropropionanilide with respect to each of the five soils taken individually. The study of the synthetic product adsorption in dynamic reactor confirmed the affinity of the molecule for the organic matter and clay fraction as demonstrated by the effect of the product on a soil from Limoges (France) different from the five Mauritanian soils. The affinity of the 2, 3-dichloropropionanilide is physical for the organic matter and the clay fraction and chemical for the metal compounds such as Aluminium, Iron and Manganese.
Colloids and Surfaces a Physicochemical and Engineering Aspects, Aug 1, 2010
As a result of the cross-linking process between sodium alginate, Aluminium pillared clay (Al-Mon... more As a result of the cross-linking process between sodium alginate, Aluminium pillared clay (Al-Mont-PILC) or surfactant-modified pillared clay (CTAB-Al-Mont-PILC) and divalent cation (Ca 2+), gel-like beads were obtained under different ratios of PILCs vs. alginate. Experimental ratios (pillared clay/alginate; w/w) increased to a maximum of 3.5 to 4. The results of SEM analysis revealed that surface morphology changes by introducing Al-Mont-PILC and CTAB-Al-Mont-PILC. Structural modifications were evaluated using FTIR and thermal analysis. In agreement with previous works the pseudo-second order model equation fit well with the kinetics data. Diffusion coefficients were calculated using the Linear Adsorption Model; the D eff obtained in this study (3-7 10 −6 cm 2 /s) are within the ranges reported in other works on inorganic pollutants or phenol diffusion in biopolymers. Adsorption isotherms of pentachlorophenol and safranine were analyzed using non-linear regression technique. Langmuir isotherms fit well with the results obtained for the sorption of safranine whereas the Freundlich isotherms was more in accordance with the pentachlorophenol sorption. A decrease of 35 to 40% in sorption capacity was observed for pentachlorophenol when the initial pH increased from 5.3 to 8. Modification of the biopolymers by introduction of pillared clays resulted in an enhancement of the adsorption capacity.
Lake Courtille is a shallow eutrophic polymictic lake treated with copper sulphate for four years... more Lake Courtille is a shallow eutrophic polymictic lake treated with copper sulphate for four years. Water column monitoring and laboratory experiments have shown that dissolved copper (CuD) behaviour correlates well with Dissolved Organic Carbon (DOC). Sequential extraction indicates that a significant fraction of the sediment-borne Cu is associated with the organic fraction (50% to 88% of total copper). This fraction of copper could be released into the water column depending on environmental conditions. Laboratory resuspension experiments have shown that significant short term release of Cu was not possible under circumneutral pH and the oxygenated conditions of the lake (less than 3% of the total copper sediment was released). Nevertheless over the long term, a fraction of the copper bound to the sediment could be released depending on the organic matter mineralization which could explain the presence of copper in the water column one year after the last copper addition.
The efficiency of eight extracellular polymeric substances (EPS) extraction methods was compared ... more The efficiency of eight extracellular polymeric substances (EPS) extraction methods was compared on two different activated sludges. Three chemical methods (EDTA, formaldehyde + NaOH, glutaraldehyde), four physical methods (sonication, cation exchange resin, sonication + cation exchange resin, heating) and a control method (centrifugation alone) were tested. EPS quantities extracted were more greater for chemical methods than those for physical methods. For the chemical methods used EPS contamination due to extracting reagents was pointed out by infra-red analysis. The EPS extracted by physical methods can show a different qualitative composition with protein and carbohydrate as predominant compounds. This study therefore underlines that the choice of EPS extraction method should not only be limited to extraction yield and nucleic acid content but should also consider that the EPS solution may be contaminated by extracting reagents and/or be greatly modified by the extraction protocol.
... l'appliquer aux SBR et simuler les systèmes discontinus afin d'optimiser les perfor... more ... l'appliquer aux SBR et simuler les systèmes discontinus afin d'optimiser les performances ... Lamodélisation de la mortalité englobe les phénomènes de métabolisme endogène, de ... que le procédé présenté aboutit à des rendements moyens d'épuration extrêmement satisfaisants ...
Journal of Shanghai University (English Edition), 2010
In this paper, the characteristics of fluid mixing time in a novel extra-loop fluidized bed were ... more In this paper, the characteristics of fluid mixing time in a novel extra-loop fluidized bed were studied. The results showed that the mixing time was shortened with the increase of fluid velocity. All the discrete numbers of the reactor were above 0.2. The serial number n was 2.5-3.0. It was judged accordingly that the reactor fluid state was continous stirred tank reactor (CSTR) mainly. When the inspiratory capacity increased the mixing time of the reactor was shortened. Thus the air input was beneficial for the fluid mixing. During the three phases mixing process, the mixing time of the reactor could be decreased by the n increase of carrier and air loading together, but the change was not significant. The parameters affecting the reactor fluid state were fluid velocity, inspiratory capacity and carrier. KLa could be increased with the air loading increase, and at the same gas/liquid ratio when the pressure drop was high, KLa value was increased. The amount of carrier complex influence on KLa. As the carrier loading continued to increase, its value had been dropped but the changes was not significant, and optimization condition was found at above 800-1 000 g carrier loading (pouzzolane) or 600 g PVC. Under gas/liquid ratio of 0.8%-5.2%, KLa was (0.62-1.37)×10 −2 s −1. Keywords extra-loop fluidized bed, mixing time, oxygen transfer, fluid velocity, Venturi aero-ejector, carrier Nomenclature D UL : Discrete number θ: Residence time of each reactor (s) C: Concentration of the reactor (V) C0: Original concentration of the reactor (V) Cn: Concentration of the nth reactor (V) H: Height of the tube (mm) KLa: Volumetric mass transfer coefficient (h −1) n: Serial number Qc: Circulation flow (liquid) (m 3 /s) Qg: Inspratory capacity (gas) (L/h) s: Thickness of the tube (mm) S1: Area of the circle pipe (m 2) S2: Area of Venturi aero-ejector pipe t: Average mixing time (s) u1: Liquid velocity in the circle pipe (m/s) ΔP : Pressure drop of the Venturi aero-ejector (Pa) ρ: Liquid density (kg/m 3)
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Papers by Michel BAUDU