Academic literature on the topic 'Phosphates – Absorption et adsorption'
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Journal articles on the topic "Phosphates – Absorption et adsorption"
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Suzuki, M., A. Fujishima, T. Miyazaki, H. Hisamitsu, H. Ando, M. Nakahara, M. Yamamoto, and K. Itoh. "A study on adsorption structures of methacryloyloxyalkyl dihydrogen phosphates on silver substrates by infrared reflection absorption spectroscopy." Journal of Biomedical Materials Research 37, no. 2 (November 1997): 252–60. http://dx.doi.org/10.1002/(sici)1097-4636(199711)37:2<252::aid-jbm15>3.0.co;2-g.
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Shin, Euisup S., Ill Yong Kim, Sung Baek Cho, and Chikara Ohtsuki. "Inhibitory Effects of Doped Aluminum and Silicon on HAp-Forming Ability of Titania in Simulated Body Fluid." Key Engineering Materials 529-530 (November 2012): 641–45. http://dx.doi.org/10.4028/www.scientific.net/kem.529-530.641.
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Chemical modification of titanium substrate provides ability of hydroxyapatite (HAp) formation that is important property for bone-bonding capability after implantation in bony defects. Potential of the HAp-formation is occasionally reduced. In the present study, we investigated potential of the HAp-formation on titanium oxide (titania) with doped silicon or aluminum in simulated body fluid (SBF). Sol-gel processing was applied to prepare titania with doped silicon (TSx) or aluminum (TAx), in its nominal composition ranging from 0 to 10 mol%. Specific surface area of the prepared samples was gradually increased with increasing the amounts of silicon or aluminum. Zeta potential of TAx was definite changed from negative charge to positive charge with increasing aluminum amounts, but TSx slightly changed to be positive with increasing silicon amounts. The pure titania sample free from doping of silicon or aluminum showed formation of calcium phosphate precipitates, that is HAp-formation, after soaking in SBF for 14 d. In contrast, all the titania samples with doped silicon or aluminum hardly showed evidence of precipitates of calcium phosphates, although absorption of calcium and phosphate ions were detected. Especially, TAx showed remarkable adsorption of phosphate ions. Aluminum-doping in titania enhances the adsorption of phosphate ion on the surface, but reduce nucleation rate of calcium phosphates in body environment.
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Gray-Wannell, Nia, Peter J. Holliman, H. Christopher Greenwell, Evelyne Delbos, and Stephen Hillier. "Adsorption of phosphate by halloysite (7 Å) nanotubes (HNTs)." Clay Minerals 55, no. 2 (June 2020): 184–93. http://dx.doi.org/10.1180/clm.2020.24.
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AbstractThe adsorption and retention of phosphates in soil systems is of wide environmental importance, and understanding the surface chemistry of halloysite (a common soil clay mineral) is also of prime importance in many emerging technological applications of halloysite nanotubes (HNTs). The adsorption of phosphate anions on tubular halloysite (7 Å) has been studied to gain a greater understanding of the mechanism and kinetics of adsorption on the surface of HNTs. Two well-characterized tubular halloysites with differing morphologies have been studied: one polygonal prismatic and one cylindrical, where the cylindrical form has a greater surface area and shorter tube length. Greater phosphate adsorption of up to 42 μmol g–1 is observed on the cylindrical halloysite when compared to the polygonal prismatic sample, where adsorption reached a maximum of just 15 μmol g–1 compared to a value for platy kaolinite (KGa-2) of 8 μmol g–1. Phosphate adsorption shows strong pH dependence, and the differences in phosphate sorption between the prismatic and cylindrical morphologies suggest that phosphate absorption does not occur at the same pH-dependent alumina edge sites and that the lumen may have a greater influence on uptake for the cylindrical form.
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BOUTALEB, F., N. BOUTALEB, B. BAHLAOUAN, and S. EL ANTRI. "Valorisation du stérile d’exploitation des phosphates au Maroc dans la fabrication de carreaux céramiques." Techniques Sciences Méthodes, no. 3 (March 20, 2020): 37–43. http://dx.doi.org/10.36904/tsm/202003037.
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L’objectif de ce travail est d’étudier une voie de valorisation du stérile d’exploitation des phosphates comme matière première alternative dans l’industrie céramique. Cinq formulations sont étudiées pour produire par pressage à sec des carreaux céramiques. Ces formulations sont réalisées en mélangeant le stérile avec des argiles locales abondantes selon des pourcentages qui varient de 0 à 100 %. Les carreaux céramiques produits sont caractérisés par leurs propriétés physiques (absorption d’eau, retrait de cuisson), mécaniques (résistance à la flexion) et de surface (observation en microscopie électronique à balayage). Les résultats de cette étude montrent que l’intégration du stérile des mines de phosphates permet d’améliorer les propriétés mécaniques des carreaux céramiques. Une utilisation industrielle de ce déchet minier entre 20 et 50 % dans des formules à base d’argile pourrait donc être envisageable pour concevoir des produits de faïence, conformes aux exigences mécaniques et techniques applicables. Cette voie de valorisation permet de gérer les grandes quantités des rejets miniers et donc leur impact environnemental ainsi que de préserver les ressources naturelles non renouvelables.
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Kukulka, Wojciech, Krzysztof Cendrowski, Beata Michalkiewicz, and Ewa Mijowska. "Correction: MOF-5 derived carbon as material for CO2 adsorption." RSC Advances 9, no. 59 (2019): 34349. http://dx.doi.org/10.1039/c9ra90077b.
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Li, Yu, Chong Meng, Meng Wang, Bing Chuan Cheng, and Chang Zhi Zhou. "Regulation of the Absorption of Cu with Various of Pollutants in Sediment through Fractional Factorial Design." Advanced Materials Research 742 (August 2013): 363–66. http://dx.doi.org/10.4028/www.scientific.net/amr.742.363.
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The resolution IV fractional factorial design was used to study the adsorption regularity of Cu coexisted with various pollutions (Zn, Pb, Cd, Ni, atrazine, malathine, et al.) onto the sediment. The study found that the main effect and the second-order interaction effect of ten pollutions concentration had significant influence on the adsorption of Cu on the sediment. The concentration of Cu was the critical factor to the promotion of the absorption capacity of Cu in sediment, the second-order effect played the critical role in restraining the absorption of Cu. The main effect of Cd, and the second-order interaction effect include Cd, had greatly inhibited the absorption of Cu in sediment, and the contribution was over 30%, which meant there was prominent antagonism between Cu and Cd. Fractional factorial design can provide a theoretical basis for the reveal of the adsorption mechanism between the different contaminants in the water environment pollution.
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El Rhilassi, A., H. El Boujaady, M. Bennani-Ziatni, R. El Hamri, and A. Taitai. "Adsorption de la L-lysine et de la DL-leucine sur des phosphates de calcium précipités analogues à la partie minérale du tissu osseux." Annales de chimie Science des Matériaux 36, no. 1 (February 28, 2011): 45–57. http://dx.doi.org/10.3166/acsm.36.45-57.
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Sadeghi, A. A., A. Nikkhah, and P. Shawrang. "The effect of thermally activated natural zeolite on colostral IgGl, IgM and Aga absorption in newborn Holstein calves." Proceedings of the British Society of Animal Science 2005 (2005): 210. http://dx.doi.org/10.1017/s1752756200011212.
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Neonatal calves are born with no immunoglobulins (Igs) in the blood stream and rely on Ig from colostrum through passive immunity transfer. Unfortunately, transfer of passive immunity to neonatal calves is too often inadequate, resulting in excessive rates of morbidity and mortality. Natural zeolite is characterized by framework of linked tetra hydration enclosing open cavities in the form of channels, and cages with ion exchanger and adsorption capacity. In literature, there were reported that thermally activated natural zeolite (T-zeolite) could increase colostral IgG absorption and decrease susceptibility of neonates to infections (Sadeghi et al., 2004; Stojic et al., 1995). To our knowledge, little information is available concerning the effect of thermally activated natural zeolite on colostral IgG1, IgM and IgA absorption in neonates. Our experiment was designed to investigate the effect of thermally activated natural zeolite on colostral IgG1, IgM and IgA absorption in newborn Holstein calves.
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Motakef kazemi, Negar. "Zinc based metal–organic framework for nickel adsorption in water and wastewater samples by ultrasound assisted-dispersive-micro solid phase extraction coupled to electrothermal atomic absorption spectrometry." Analytical Methods in Environmental Chemistry Journal 3, no. 04 (December 29, 2020): 5–16. http://dx.doi.org/10.24200/amecj.v3.i04.123.
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In this research, Zn2(BDC)2(DABCO) metal–organic framework (MOF) as a solid phase was used for separation and preconcentration toxic nickel ions (Ni) from water samples by ultrasound assisted-dispersive-micro solid phase extraction coupled to electrothermal atomic absorption spectrometry (USA-D-μ-SPE/ET-AAS). The MOF nanostructure was characterized by field emission-scanning electron microscope (FE-SEM) and transmission electron microscopey (TEM) for presentation of morphology and size of MOF synthesis. By procedure, 25 mg of Zn2(BDC)2(DABCO) as MOF adsorbent was added to 25 mL of water samples and then, Ni ions chemically adsorbed based on dative bonding of nitrogen in DABCO (1,4-diazabicyclo [2.2. 2]octane); N2(C2H4)3) at pH=8. The adsorbent was separated from liquid phase by syringe cellulose acetate filters (SCAF, 0.2 μm) and Ni ions back extracted from MOF adsorbent before determined by ET-AAS. The maximum recovery of MOF for nickel ions as a physically and chemically adsorption was obtained 34.6% and 98.8% at pH=3 and 8, respectively.
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Schmid, O., P. Artaxo, W. P. Arnott, D. Chand, L. V. Gatti, G. P. Frank, A. Hoffer, M. Schnaiter, and M. O. Andreae. "Spectral light absorption by ambient aerosols influenced by biomass burning in the Amazon Basin. I: Comparison and field calibration of absorption measurement techniques." Atmospheric Chemistry and Physics 6, no. 11 (August 21, 2006): 3443–62. http://dx.doi.org/10.5194/acp-6-3443-2006.
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Abstract. Spectral aerosol light absorption is an important parameter for the assessment of the radiation budget of the atmosphere. Although on-line measurement techniques for aerosol light absorption, such as the Aethalometer and the Particle Soot Absorption Photometer (PSAP), have been available for two decades, they are limited in accuracy and spectral resolution because of the need to deposit the aerosol on a filter substrate before measurement. Recently, a 7-wavelength (λ) Aethalometer became commercially available, which covers the visible (VIS) to near-infrared (NIR) spectral range (λ=450–950 nm), and laboratory calibration studies improved the degree of confidence in these measurement techniques. However, the applicability of the laboratory calibration factors to ambient conditions has not been investigated thoroughly yet. As part of the LBA-SMOCC (Large scale Biosphere atmosphere experiment in Amazonia – SMOke aerosols, Clouds, rainfall and Climate) campaign from September to November 2002 in the Amazon basin we performed an extensive field calibration of a 1-λ PSAP and a 7-λ Aethalometer utilizing a photoacoustic spectrometer (PAS, 532 nm) as reference device. Especially during the dry period of the campaign, the aerosol population was dominated by pyrogenic emissions. The most pronounced artifact of integrating-plate type attenuation techniques (e.g. Aethalometer, PSAP) is due to multiple scattering effects within the filter matrix. For the PSAP, we essentially confirmed the laboratory calibration factor by Bond et al. (1999). On the other hand, for the Aethalometer we found a multiple scattering enhancement of 5.23 (or 4.55, if corrected for aerosol scattering), which is significantly larger than the factors previously reported (~2) for laboratory calibrations. While the exact reason for this discrepancy is unknown, the available data from the present and previous studies suggest aerosol mixing (internal versus external) as a likely cause. For Amazonian aerosol, we found no absorption enhancement due to hygroscopic particle growth in the relative humidity (RH) range between 40% and 80%. However, a substantial bias in PSAP sensitivity that correlated with both RH and temperature (T) was observed for 20%<RH<30% and 24°C<T<26°C, respectively. In addition, both PSAP and Aethalometer demonstrated no sensitivity to gaseous adsorption. Although very similar in measurement principle, the PSAP and Aethalometer require markedly different correction factors, which is probably due to the different filter media used. Although on-site calibration of the PSAP and Aethalometer is advisable for best data quality, we recommend a set of "best practice" correction factors for ambient sampling based on the data from the present and previous studies. For this study, the estimated accuracies of the absorption coefficients determined by the PAS, PSAP and Aethalometer were 10, 15 and 20% (95% confidence level), respectively.
Dissertations / Theses on the topic "Phosphates – Absorption et adsorption"
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Saad, Rabih. "Adsorption et désorption d'ions phosphate et nitrate par des matériaux mésoporeux à base de silice fonctionnalisés avec des groupements ammonium." Thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25747/25747.pdf.
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Barthelemy, Kévin. "Adsorption des anions phosphate par des composés ferriques en vue du traitement des eaux usées : approche en réacteur homogène et en mode hydrodynamique contrôlé." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0237.
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Les travaux présentés dans ce mémoire sont consacrés à l'étude des processus d'adsorption des anions phosphate par la rouille verte ferrique carbonatée et la ferrihydrite. L'objectif final vise une application au traitement des eaux usées en milieu rural. La synthèse des deux oxydes de fer a été réalisée et leurs propriétés physico-chimiques caractérisées. Un intérêt particulier a été consacré à comparer les propriétés structurales de la rouille verte ferrique en fonction de différents paramètres de synthèse. Une étude approfondie des propriétés physico-chimiques de surface de la ferrihydrite par spectroscopie de photoélectrons X a quant à elle été réalisée. La réactivité de ces deux oxydes a ensuite été abordée en mode discontinu où l'équation cinétique du pseudo-second ordre et le modèle d'isotherme de Freundlich offrent les meilleurs ajustements. L'influence de divers paramètres a été prise en compte comme le pH, la force ionique, etc. Le mode continu a été envisagé sur un matériau de filtration constitué de l'oxyde de fer déposé sur de la pouzzolane. La méthode de fabrication ainsi que les conditions optimales de préparation du matériau de filtration ont été déterminées. Les mécanismes d'adsorption en condition de flux hydrodynamique ont alors mis en évidence des phénomènes advectifs, diffusifs et une régionalisation de l'eau régissant l'adsorption au sein de la colonne. Des informations telles que les capacités d'adsorption ou l'influence du débit sur le processus d'adsorption ont pu être également obtenues. Une expérience préliminaire sur une eau usée prétraitée met finalement en évidence une quantité adsorbée particulièrement intéressante pour une application industrielle potentielleThe Ph.D. work, presented in this manuscript, is devoted to evaluating phosphate adsorption process on carbonate ferric green rust and ferrihydrite. The main objective concerns an application for the treatment of waste water in rural areas. Both iron oxides are first synthesized and their physico-chemical properties characterized. The ferric green rust structural properties differences as a function of synthesis parameters such as aging period and addition of hydrogen peroxide solution is of particular interest. A detailed study of surface physico-chemical properties by X Photoelectron Spectroscopy is carried out in the case of ferrihydrite. The reactivity of these two iron oxides is then evaluated in batch experiments. Adsorption process follows the pseudo-second order kinetic equation and Freundlich isotherm model which give the best adjustments of experimental data. The influence of various parameters such as pH, ionic strength, etc on phosphate adsorption is also taken into account. Column experiments are afterwards carried out by using filtration material constituted of iron oxide deposited onto pozzolana. The optimal conditions to prepare this filtration material are naturally predetermined. Phosphate adsorption in hydrodynamic mode is characterized by advective and diffusive mechanisms and water regionalization which govern the adsorption process in the column. Moreover, phosphate adsorption capacity and flow rate influence on adsorption process are obtained. Finally, a preliminary experiment on a pre-treated waste water finally shows that the filtration material is potentially interesting for an industrial application
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Babana, Amadou Hamadoun. "Mise au point d'un inoculant biologique pour le blé irrigué du Mali." Thesis, Université Laval, 2003. http://www.theses.ulaval.ca/2003/21179/21179.pdf.
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A cause du prix élevé des engrais importés au Mali, le phosphate naturel de Tilemsi (PNT) constitue une source de phosphore, locale, peu coûteuse pour les paysans. Dans plusieurs zones, malgré ses bonnes caractéristiques physiques et chimiques, les plantes cultivées, particulièrement le blé, ont faiblement répondu à l’application du PNT. À cause du besoin croissant d’améliorer biologiquement l’absorption du P par le blé, nous présentons dans ce travail les résultats de l’utilisation de microorganismes solubilisant le phosphore (MSP) dans un essai d’inoculation au champ. Dans la rhizosphère (Zone d’interactions intenses entre les racines et les microorganismes) et le rhizoplan (les microorganismes du rhizoplan ont ceux qui sont directement liés à la surface externe des racines) de trois cultivars de blé du Mali, 7 à 12% des microorganismes étaient capables de solubiliser le PNT. Six bactéries et deux champignons ont été sélectionnés, pour leur fort pouvoir de solubilisation du PNT en milieu liquide et sur milieu solide, et testés au champ à Koygour (Diré) en 2000-2001. Deux champignons Aspergillus amovari (C1), Penicillium chrysogenum (C13) et une bactérie Pseudomonas sp. (BR2) ont significativement amélioré la taille du blé (cv. Tétra) après 6 semaines, ainsi que, le poids et le contenu en P de la matière sèche (paille et graines) après 90 jours de croissance. Des essais au champ ont été réalisés à Koygour (Diré) en 2001-2002. Les traitements d’inoculation incluent C1, C13, BR2, C1+BR2, C13+BR2 et un contrôle en présence et à l’absence de Glomus intraradices (Gi). Les traitements de phosphore incluent le PNT, le phosphate biammoniacal (DAP) et un contrôle non fertilisé. La colonisation des racines de blé par les mycorhizes à vésicules et arbuscules (MVA) a été significativement améliorée avec Glomus intraradices quand la source de P utilisée est le PNT. La présence de BR2 améliore encore plus la colonisation des racines par les MVA. En général, les quantités de graines et paille récoltées ont été significativement améliorées après inoculation avec les microorganismes solubilisant le PNT et Glomus intraradices. La plus forte concentration de P dans les graines a été obtenue avec la co-inoculation avec C1+BR2 et Gi en présence de PNT, tandis que, les plantes inoculées avec BR2+Gi présentaient les plus fortes quantités de P dans la paille en présence du DAP.Because of the high price of imported P-fertilizers in Mali, the Tilemsi rock phosphate (TRP) is a cheaper locally available P source alternative for farmers. In many areas regardless of its good physical and chemical characteristics, crops and particularly wheat showed very slow response to TRP. With the broad aim of biologically improving P uptake by wheat, in this work we describe the use of TRP solubilizing microorganisms in field inoculation trials. In 3 different Malian wheat cultivars, 4 to 12% of the rhizosphere microorganisms were able to dissolve TRP. Six bacterial and two fungal isolates were selected for their high P-solubilizing activity in solid and liquid media, and were tested in a field in Koygour (Diré) in 2000-2001. Two fungal isolates Aspergillus niger (C1) and Penicillium chrysogenum (C13) and Pseudomonas sp. (BR2) significantly increased plant heights after 60 days, and the fresh and dry matter yields and P-uptake after 90 days of growth. Field assays were performed in Koygour (Diré) in 2001-2002. Inoculation treatments included C1, C13, BR2, C1+BR2, C13BR2, and a control in the presence or absence of the AM fungus Glomus intraradices. P treatments included Tilemsi rock phosphate (TRP), phosphate biammoniacal (DAP) and an unfertilized control. The colonization of wheat root with AM was significantly higher following inoculation with G. intraradices, and when TRP was the P source used. The presence of Pseudomonas strain (BR2) improved root colonization by the AM fungus. In general, straw and grain yield improved significantly following inoculation with AM and phosphate solubilizing microorganisms. The highest P concentration in wheat grain and straw was recorded in treatment including a combinaison of AM, BR2 and C1 in the presence of TRP.
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Kpannieu, Dan Eude Baudouin. "Traitement de la pollution phosphorée des effluents résiduaires urbains par des matériaux de Côte d’Ivoire constitués de schiste ardoisier, grès et latérite : approches en réacteur homogène, en mode hydrodynamique contrôlé et en réacteur micro-pilote de terrain." Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0133.
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Les travaux présentés dans ce mémoire sont principalement consacrés à l’étude des processus d’adsorption des ions phosphate par des matériaux naturels de Côte d’Ivoire : le schiste ardoisier; le grès et la latérite. L’objectif final est une application de ces matériaux comme massifs filtrants de marais artificiels pour la déphosphatation des ERU (Eaux Résiduaires Urbaines (ERU)). Dans un premier temps, la réactivité des ions phosphate a été abordée vis-à-vis du schiste en réacteurs « batch » et colonne. L’influence de différents paramètres physicochimiques a été caractérisée. La capacité d’adsorption diminue avec la dose de schiste qui augmente. Elle dépend du pH et diminue lorsque celui-ci augmente dans la gamme 2-11 puis ré-augmente au-delà. Une corrélation entre concentration aqueuse en ions calcium, magnésium, aluminium et fer issus de la dissolution du schiste et concentration en ions phosphate en solution a été établie. Une cinétique de pseudo-second ordre a été mise en évidence et les isothermes ont été décrites à partir du modèle de Langmuir. Les expériences réalisées en réacteur colonne, pour une concentration initiale en ions phosphate de 25 mg L-1 et à un débit de 0,23 ml min-1 présentent une percée à V/Vp = 17 correspondant à une capacité de sorption de 0,2 mg g-1en accord avec les expériences en réacteur « batch ». Un réacteur micro-pilote de type marais artificiel à écoulement vertical saturé garni de schiste ardoisier a été développé et les performances vis-à-vis des ions phosphates, de l’azote, des MES (Matières En Suspension) et de la matière organique ont été évaluées. L’influence de la granulométrie du massif filtrant et de la densité de culture du panicum maximum sur la performance de ce micro-pilote a été établie. Le filtre de schiste de granulométrie la plus fine présente une performance épuratoire légèrement supérieure. Le débit d’infiltration dans les filtres diminue après traitement de l’ERU et le taux de colmatage est moins élevé pour les filtres plantés. La densité de culture la plus élevée conduit à une performance épuratoire légèrement plus favorable. La capacité d’adsorption des ions phosphates liée aux plantes seules est faible, confirmant l’importance du choix du massif filtrant. La réactivité des ions phosphate a été finalement étudiée vis-à-vis du grès et de la latérite en réacteurs « batch » et colonne. Le statut du fer, en substitution dans des argiles pour le schiste et sous forme d’hématite et goethite dans la latérite et le grès influence la réactivité du matériau. L’ordre d’efficacité des adsorbants a été établi comme suit : latérite ≥ grès ≥ schiste. Ces trois matériaux offrent des perspectives intéressantes en tant que massifs filtrants de marais à flux vertical saturéThis thesis is devoted to the study of phosphate ions adsorption processes by natural minerals of Ivory Coast, i.e. shale, sandstone and laterite mainly. Phosphate sorption by shale was first investigated in batch and column experiments. Batch experiments allowed the assessment of the influence of initial phosphate concentration, sorbent dosage, contact time, and pH on phosphate removal. The phosphate removal efficiency increased with increasing shale dosage while phosphate uptake decreased. Phosphate uptake strongly depended on pH, decreasing first with increasing pH in the range of 2-11 and then increasing at the highest pH value of 12. A correlation between aqueous Ca, Mg, Al, and Fe concentrations and phosphate uptake was observed. The kinetics was well described using the pseudo-second order model and isotherms with Langmuir sorption model. Column experiments with a flow rate of 1 ml min-1 and 25 mg L-1 initial phosphate concentration showed a breakthrough point at V/Vp of ~17 corresponding to a phosphate uptake of 0.2 mg g-1 in agreement with batch experiments. The performance of shale was evaluated as filter material in (Vertical Flow Constructed Wetland) VFCW in removal of phosphate ions, nitrogen, suspended solids, and organic compounds, using municipal wastewater. The influence of both shale granulometry and plants density was evaluated. The shale with the finest particle size offers a slightly higher efficiency. The flow rate decreased after wastewater treatment and the fooling is less pronounced for planted VFCW. The filter with the highest plant density offers only slightly higher efficiency towards phosphate and nitrate removal. The phosphate sorption capacity of the plants is negligible confirming the importance in the choice of the filter medium. Finally, phosphate removal by shale was compared to sandstone and laterite in both batch and column experiments. The different chemical compositions of the materials influence strongly the reactivity towards phosphate ions. It is supposed that the status of iron in the material, i.e. in substitution in clays in shale and occurring as hematite and goethite in laterite and sandstone, explained the differences of reactivity. Both batch and column experiments revealed that phosphate uptake decreased in the following ranking order laterite > sandstone > shale. These three materials appear as promising filter materials in VFCW
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Grimal, Jean-Yves. "Influence de l'exsudation racinaire de Zea mays L. Sur mobilisation de formes de phosphore difficilement biodisponibles." Vandoeuvre-les-Nancy, INPL, 1994. http://www.theses.fr/1994INPL058N.
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L’influence de l'exsudation racinaire de Zea mays sur la mobilisation de formes de phosphore difficilement disponibles a été étudiée suivant trois niveaux d'approche. L’étude de l'adsorption d'un modèle d'exsudats (apg) et de mucilages racinaires sur une goethite a montré que l'apg et les mucilages diminuent l'adsorption des ions phosphate. L’effet le plus marqué est constaté lorsque les ions phosphate sont apportés sur le complexe mucilages-goethite. Dans ce cas, le mécanisme mis en jeu est de nature physique. L’enrobage de la goethite a probablement diminué le nombre de sites d'adsorption des ions phosphate. Des cultures en conditions hydroponiques stériles ont permis d'examiner le comportement du maïs en présence d'ions phosphate adsorbés sur une goethite. Dans ces conditions expérimentales, la plante est capable de prélever jusqu'à 23% du phosphore initialement adsorbé. La réponse du maïs à cette contrainte se traduit aussi par une modification des flux de phosphore à l'intérieur de la plante. Le rôle des phosphatases racinaires dans l'acquisition du phosphore a été étudié en mettant à la disposition du maïs le glucose-1-phosphate et le myoinositol hexaphosphate. Les activités phosphatasiques ont été détectées à la surface des racines, dans la solution nutritive ainsi qu’à la surface de la goethite. Les possibilités d'action des phosphatases sont liées à l'accessibilité des phosphates organiques et des enzymes, adsorption sur les colloïdes ou précipitation. Ces résultats montrent que les composés diffusibles (mucilages) par leur action physique et les composés carbonés diffusibles (phosphohydrolases notamment) contribuent à augmenter la mobilité du phosphore à partir de sources peu accessibles pour la plante dans la rhizosphère
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Fu, Yong 1948. "Solid activity coefficients of phosphate adsorbed by soil." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276722.
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The data of 14 soils were used to compute the ion activity product (IAP), the ratio of the ion activity product and to the solubility product (Ksp) of the pure minerals (IAP/Ksp) and to estimate the solid activity coefficients (SAC) of the soil components. The value of IAP and SAC of AlPO4 differs from soil to soil and increases with increasing P added to soil in acid soils and for calcium phosphate in basic soils. Magnesium apparently did not cause P adsorption or precipitation in the soils studied. The SAC of aluminum phosphate ranged from 10 to 10000 in acid soils. The mole fraction of the total phosphate in soil seemed to be a more satisfactory basis for calculating the concentration of the solid phase than was measurements of the available phosphate.
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Mohd, Ali. "Adsorption et électrosorption d'herbicides et de tensioactifs sur charbons actifs en grains." Pau, 1996. http://www.theses.fr/1996PAUU3028.
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Ce travail relatif a l'adsorption et l'electrosorption (adsorption sous potentiel impose) de polluants sur charbons actifs en grains comporte trois parties : la premiere partie a pour but d'etudier l'influence sur l'interaction adsorbat-adsorbant de la nature physique et chimique du charbon actif. Les resultats obtenus, par les methodes de titrage de boehm, de chromatographie gazeuse inverse et d'une combination de ces deux methodes, ont permis d'identifier separement l'effet sur les forces d'interaction de la porosite et des groupements fonctionnels. La deuxieme partie est consacree a l'etude de l'adsorption d'herbicides et de tensioactifs sur charbon actif en grains (cag) en regime dynamique. Les resultats obtenus montrent que la capacite et la cinetique d'adsorption en flux continu sont influencees par les proprietes de l'adsorbat et celles de l'adsorbant. Les parametres utilises sont la solubilite, la charge et la concentration pour les solutes, la porosite et les proprietes acido-basiques pour l'adsorbant. La capacite d'adsorption varie lineairement avec ln t. La derniere partie s'interesse a l'etude de l'electrosorption de deux herbicides et de trois tensioactifs. Les resultats montrent, pour les herbicides atrazine et simazine, que l'application d'un potentiel negatif au cag augmente legerement l'adsorption tandis qu'un potentiel positif diminue nettement la quantite retenue. Pour les tensioactifs anionique (abs) ou non-ionique (triton n-101), l'effet d'un potentiel applique est relativement faible et difficile a interpreter. Pour le cdbac, tensioactif cationique, l'alternance de cycles positifs et negatifs donne lieu a une electrosorption reversible et comprise entre 10 et 15%.
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Sandhu, Harjinder. "Sorption of lead and arsenic on soil components and effectiveness of phosphates for remediating lead and arsenic contaminated soils." Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=1923.
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Thesis (Ph. D.)--West Virginia University, 2001.Title from document title page. Document formatted into pages; contains xii, 170 p. : ill. (some col.). Includes abstract. Includes bibliographical references.
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Paul, Kristian W. "Molecular modeling study of sulfate and phosphate adsorption at the mineral-water interface." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 223 p, 2009. http://proquest.umi.com/pqdweb?did=1654487581&sid=3&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Caja, Monique. "Adsorption du gaz naturel sur les charbons en conditions anhydres et saturées en eau : Etude des quantités adsorbées et du fractionnement isotopique." Aix-Marseille 2, 2000. http://www.theses.fr/2000AIX22019.
Full textBooks on the topic "Phosphates – Absorption et adsorption"
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Vandenberg, A. Modèle physique de l'infiltration, du drainage et du ruissellement dans des sols à couches multiples. [s.l: s.n.], 1989.
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Westall, John C. The use of cationic surfactants to modify aquifer materials to reduce the mobility of hydrophobic organic compounds / John C. Westall ... [et al.]. Ada, OK: U.S. Environmental Protection Agency, Robert S. Kerr Environmental Research Laboratory, 1994.
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Westall, John C. The use of cationic surfactants to modify aquifer materials to reduce the mobility of hydrophobic organic compounds / John C. Westall ... [et al.]. Ada, OK: U.S. Environmental Protection Agency, Robert S. Kerr Environmental Research Laboratory, 1994.
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International Institute of Refrigeration. Commission A3. Comparaison avec la cryogénie des procédés PSA et membranes pour la séparation des gaz industriels: Compte rendu de la réunion de la Commission A3 = Comparison between cryogenics and PSA and membrane processes for industrial gas separation : proceedings of the meeting of Commission A3, October 24-25, 1989. Paris, France: Institut international du froid, 1989.
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Adsorption Analysis: Equilibria and Kinetics (Chemical Engineer Series, Volume 2). Imperial College Press, 1998.
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Adsorption Analysis: Equilibria and Kinetics (Series on Chemical Engineering, Vol 2). World Scientific Publishing Company, 1998.
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1947-, Ghebre-Sellassie Isaac, ed. Multiparticulate oral drug delivery. New York: M. Dekker, 1994.
Find full textConference papers on the topic "Phosphates – Absorption et adsorption"
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von Felten, A. "DETECTION OF LUPUS ANTICOAGULANTS BY THE “INSIDE-OUT MEMBRANE ADSORPTION TEST”: aPTT IS SHORTENED AFTER INCUBATION OF THE PLASMA WITH THE ADSORBENT." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644238.
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Prolongation of the aPTT in a mixture of a patient’s plasma with normal plasma is characteristic for the presence of a coagulation inhibitor. Since inhibitors directed against individual blood coagulation factors differ in their clinical significance from a lupus anticoagulant (LA), a fast and reliable distinction from each-other would be highly desirable. The test presented which is based on the absorption of antiphospholipid antibodies by use of a stable phospholipid adsorbent largely fullfills this demand.Method 1. Preparation of the LA-adsorbent (modified acc. to Steck et al., Science 168:255, 1970): Fresh human RBC (bl. gr. 0, in 0.5% EDTA) are washed (NaCl, 0.15m / phosphate buffer,0.005m, pH8.0) and lysed in phosphate buffer alone. The membranes are washed with the same buffer (centrifugations: 40’000g, lOmin, 4°C) and incubated 60 min on ice in phosphate buffer, 0.0005m. After centrifugation, the sediment is resuspended in an equal volume of buffer (0.0005m, with merthiolate 0.1%), homogenized and centrifuged in portions of lml; the supernatant is carefully removed. The adsorbent, stored at 4°C in capped tubes, is stable for at least three months.2. Performance of test: To 600ul of patient’s plasma mixed with 600ul normal plasma (citrated), 12ul of heparin (501U/ml) are added. 600ul of the mixture are given to the LA-adsorbent, vorte-xed, incubated (room temp., 30min) and centrifuged (40’000g). From the supernatant as well as the not adsorbed portion of the plasma mixture, heparin is eliminated by adding ECTEOLA-cellulose. After centrifugation, aPTT is determined in both supernatant samples. Results The test is positive, i.e. LA is present, if aPTT is shortened by at least 5 sec after treatment with LA-adsorbent. *not diluted; other samples are mixed 1:1 with normal plasma
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Suciu, Claudiu Valentin. "Thermal Effects on Nano-Energy Absorption Systems (Nano-EAS)." In 2008 Second International Conference on Integration and Commercialization of Micro and Nanosystems. ASMEDC, 2008. http://dx.doi.org/10.1115/micronano2008-70039.
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Development of intelligent and ecological energy absorption systems (EAS) is important to various fields such as automotive (vehicle suspensions, bumpers, engine mounts), construction (protections against seismic and wind-induced vibrations), and defense (parachuted objects, armors). Usual EAS use composites, shape-memory alloys and foams. Recently, liquid adsorption/desorption in/from nanoporous solids was employed to develop high-performance nano-EAS. Energy loss is based on the well-known capillary phenomenon: external work must be done to spread a non-wetting liquid on a solid surface. Nano-EAS provide considerably higher dissipated energies, about 1–10J/g at deformability of 30–70%, compared with the energy absorption of Ti-Ni alloys, about 0.01–0.05J/g at deformability of 5–8%. For water against hydrophobic nanoporous silica gel (artificial sand), the nano-EAS become ecological; they can be also made intelligent by thermo-electrical control. Relative to thermal effects, Qiao et al. have investigated, for nanoporous silica gel with insufficient coverage of the alkyl-based hydrophobic coating, the problem of hysteresis recovery by increasing the temperature in the range 20∼80°C. Energy loss capacity reduced severely after the first loading-unloading cycle, so, the hysteresis was found as irreversible. Shape of the first hysteresis, the accessible specific pore volume and the desorption pressure were almost unaffected by the temperature change. At temperature augmentation the second hysteresis was partially recovered and when the temperature exceeded 50°C the system became almost fully reusable. Water inflow was found as governed by Laplace-Washburn equation but the outflow process was perceived as thermally aided. On the other hand, Eroshenko et al. have contradictorily obtained for nanoporous silica gel with full coverage of the alkyl-based hydrophobic coating, a stable hysteresis at repeated working cycles. Adsorption pressure decreased and desorption pressure increased at temperature augmentation, this producing a reduction of the hysteresis area and damping. However, the accessible specific pore volume was found as thermally unaffected. Oppositely, both the in- and out-flows were found as governed by Laplace-Washburn equation. In this work, for nanoporous silica gels with partial and full coverage of the alkyl and fluorocarbon based hydrophobic coatings, the thermal effects on the hysteresis and damping performances are studied. Test rig used is a compression-decompression chamber introduced inside of an incubator that allows temperature adjustment in the range of −10∼50°C. Results reveal that, depending on the hydrophobic coating coverage, findings reported by Qiao et al. and Eroshenko et al. are in fact not contradictory but complementary. However, as expected, the accessible specific pore volume was found to decrease at temperature reduction. In order to explain all these apparently opposite experimental findings, a model based on the water cluster size distribution versus temperature, the pore size distribution of silica gel and the ability of water molecules to form hydrogen bonds with the uncovered hydroxyl groups on the solid surface is proposed.
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Seniūnaitė, Jurgita, Rasa Vaiškūnaitė, and Kristina Bazienė. "Mathematical Modelling for Copper and Lead Adsorption on Coffee Grounds." In Environmental Engineering. VGTU Technika, 2017. http://dx.doi.org/10.3846/enviro.2017.007.
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Research studies on the adsorption kinetics are conducted in order to determine the absorption time of heavy metals on coffee grounds from liquid. The models of adsorption kinetics and adsorption diffusion are based on mathe-matical models (Cho et al. 2005). The adsorption kinetics can provide information on the mechanisms occurring be-tween adsorbates and adsorbents and give an understanding of the adsorption process. In the mathematical modelling of processes, Lagergren’s pseudo-first- and pseudo-second-order kinetics and the intra-particle diffusion models are usually applied. The mathematical modelling has shown that the kinetics of the adsorption process of heavy metals (copper (Cu) and lead (Pb)) is more appropriately described by the Lagergren’s pseudo-second-order kinetic model. The kinetic constants (k2Cu = 0.117; k2Pb = 0,037 min−1) and the sorption process speed (k2qeCu = 0.0058–0.4975; k2qePb = 0.021–0.1661 mg/g per min) were calculated. After completing the mathematical modelling it was calculated that the Langmuir isotherm better reflects the sorption processes of copper (Cu) (R2 = 0.950), whilst the Freundlich isotherm – the sorption processes of lead (Pb) (R2 = 0.925). The difference between the mathematically modelled and experimen-tally obtained sorption capacities for removal of heavy metals on coffee grounds from aqueous solutions is 0.059–0.164 mg/l for copper and 0.004–0.285 mg/l for lead. Residual concentrations of metals in a solution showed difference of 1.01 and 0.96 mg/l, respectively.
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Li, Shidong, and Ole Torsæter. "The Impact of Nanoparticles Adsorption and Transport on Wettability Alteration of Intermediate Wet Berea Sandstone." In SPE Middle East Unconventional Resources Conference and Exhibition. SPE, 2015. http://dx.doi.org/10.2118/spe-172943-ms.
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AbstractNanoparticles as part of nanotechnology have drawn the attention for its great potential of increasing oil recovery. From authors' previous studies (Li et al., 2013a), wettability alteration was proposed as one of the main Enhanced Oil Recovery (EOR) mechanisms for nanoparticles fluid, as adsorption of nanoparticles on pore walls leads to wettability alteration of reservoir. We conducted a series of wettability measurement experiments for aged intermediate-wet Berea sandstone, where the core plugs were treated by different concentration and type of nanoparticles fluid. Nanoparticles transport experiments also were performed for core plugs with injection of varying concentration and type of nanoparticles fluid. Pressure drop across the core plug during injection was recorded to evaluate nanoparticles adsorption and retention inside core, as well as desorption during brine postflush. Both hydrophilic silica nano-structure particles and hydrophilic silica colloidal nanoparticles were utilized in above two experiments.The results of wettability alteration experiments indicated that hydrophilic nanoparticles have ability of making intermediate-wet Berea sandstone to be more water wet, and basically the higher concentration the more water wet will be. And different type of nanoparticles has different effect on the wettability alteration process. For nanoparticles transport experiments, the results showed that the nanoparticles undergo both adsorption and desorption as well as retention during injection. Pressure drop curves showed that absorption and retention of nano-structure particles inside core was significant while colloidal nanoparticles did not adsorb much. Permeability impairment was observed during nano-structure particles fluid injection, but on the contrary colloidal nanoparticles dispersion injection made core more permeable.
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Li, Jinwei, Shiyou Xu, and Yong Shi. "TiO2 Nanofibers Based Dye-Sensitized Solar Cells." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-13027.
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Dye sensitized solar cells (DSSCs) are promising photovoltaic devices as they offer advantages such as low cost and easy for fabrication et al. The key part of the original DSSC is a sintered film of nanoparticles which has a large surface area for the absorption of dyes. It has been reported that boundaries of nanoparticles diminish the efficiency of charge transport in the nanoparticle network, and lead to charge–carrier recombination. The one dimensional morphology of the nanofiber is believed to improve electron transport efficiency without sacrificing the high specific surface area for the adsorption of dyes. In this paper, TiO2 nanofibers are used to replace TiO2 nanoparticles in the DSSC. The film of nanofibers was synthesized by electrospinning process and collected on the transparent conductive glass substrate. The precursor used for the electrospinning of the nanofiber consists of titanium (IV) isopropoxide, acetate acid, ethanol and polyvinylpyrrolidone(PVP). After the electrospinning process, nanofibers were pretreated at 120°C for 2 hours and annealed at 500°C in atmosphere for another 2 hours. Then DSSC with the film of TiO2 nanofibers were assembled and characterized through electrical measurements. Open circuit voltage of 0.7V and short circuit current densities of 0.45mA/cm2 were achieved.