Добірка наукової літератури з теми "Phénols – Purification"
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Статті в журналах з теми "Phénols – Purification":
Nasser, B., S. Poussard, P. Cottin, and M. S. Istab, Laboratoire de biochimie et toxic El Kebbaj. "Purification et caractérisation de la D-bêta-hydroxybutyrate déshydrogenase de mitochondries de foie de chamelon." Revue d’élevage et de médecine vétérinaire des pays tropicaux 53, no. 2 (February 1, 2000): 122. http://dx.doi.org/10.19182/remvt.9735.
Дисертації з теми "Phénols – Purification":
Le, Thi Tuong. "Purification et propriétés anti-inflammatoires et anti-oxydantes des fractions phénoliques issues de coproduits de production d'isolats protéiques d'oleoproteagineux." Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0270.
Rapeseed and sunflower are the most cultivated oilseed plants in Europe in general, and in France in particular. Some industrialists are currently focusing on the development of industrial processes for the extraction/purification of proteins from the oil cakes of these two plants. These processes generate co-products which are saline aqueous effluents rich in phenolic compounds such as cholorgenic acid (CGA, for sunflower) and sinapine (SP, for rapeseed). The capture of these phenolic compounds, which can act as natural antioxidants and/or anti-inflammatory agents in nutrition and health, is therefore a promising way of valorization. The main objectives of this work were: 1) to characterize and identify the phenolic compounds of protein isolate by-products from SFM and RSM; 2) to select the best macroporous resins and to study the adsorption mechanism of phenolic compounds; 3) to optimize the conditions in the phenolic compounds adsorption column; and 4) to evaluate the biological activities of the obtained phenolic fractions, especially the antioxidant and anti-inflammatory properties.By different analytical methods, we determined that the liquid effluents consisted of phenolic compounds, amino acids, carbohydrates, and salt, which have a low molecular weight and can easily pass through a UF/DF membrane. All phenolic compounds were identified by HPLC and HPLC-ESI-MS analysis in comparison with standards. CGA is the main phenolic compound in the sunflower effluent. The main phenolic compound of rapeseed effluents is MS. Unlike sunflower, they also contain many other minor compounds. The adsorption/desorption of sunflower and rapeseed phenolic compounds was evaluated using different macroporous resins including XAD4, XAD7, XAD16, XAD1180 and HP20. We found that all phenolic compounds adsorbed readily onto the resins. XAD7 and XAD16 resins showed the best adsorption/desorption properties in sunflower and rapeseed liquid effluents, respectively. The results showed that the adsorption of all phenolic compounds follows a Langmuir model. According to the determined thermodynamic parameters, the adsorption process, is in all cases physical and is exothermic.The optimal condition for column adsorption was determined on the selected resins by experimental planning and multicriteria optimization. A multicriteria optimization methodology based on design of experiments showed the optimal conditions were adsorption flow rate of 15 BV/h at pH 2.7 for CGA from SFM. Meanwhile, adsorption flow rate of 13.3 BV/h and at pH ranging from 2 to 5 were the optimal conditions for sinapine from RSM. Ethanol solutions 50% (v/v) for chlorogenic acid, 70% (v/v) for sinapine were used for desorption.These approaches successfully produced the phenolic fractions for biological activities such as antioxidation and anti-inflammation. Phenolic fraction showed a higher antioxidant capacity than vitamin C in DPPH and ABTS assays (IC50/phenolic fractions < IC50 vitamin C, p < 0.05. In addition, it was discussed whether the phenolic fractions obtained in this project also showed an inflammatory effect. The sunflower fraction (CGA) effectively inhibited the production of TNF-α, which is a pro-inflammatory marker when a sample is treated with LPS. However, the rapeseed fractions were not effective against proinflammatory mediators. None of the fractions showed cytotoxicity
Lofty, Samia. "Etude des hydroxycinnamoyl-CoA : transférases : purification, spécificité et intervention dans la biosynthèse des esters hydroxycinnamiques chez les végétaux." Montpellier 2, 1991. http://www.theses.fr/1991MON20212.
Cherqui, Anas. "Etude de la prophénoloxydase de "Locusta migratoria" : purification, caractérisation et contrôle de sa transformation en phénoloxydase." Montpellier 2, 1994. http://www.theses.fr/1994MON20263.
Beaufils, Nicolas. "Étude du bioraffinage de bois de feuillus en amont du procédé papetier kraft : influence des conditions d'extraction et de purification sur la production de molécules cibles." Thesis, Toulouse, INPT, 2019. http://www.theses.fr/2019INPT0126.
The pulp production processes, in their optimized form, aim to recover wood by removing all impurities that are attached to cellulose fibres. In recent years, the profitability of these industries has fallen sharply. They are therefore looking for new outlets for their co-products. Until now, noncellulosic fractions have been recovered in energy form by combustion. However, these molecules can find outlets in various sectors, generating a new source of revenue for these companies. It is in this context that Fibre Excellence launched a project to produce high-purity cellulose in association with other molecules that can be obtained from hardwoods, in particular C5 (Xylose) and C6 (glucose) sugars and co-extracted phenolic fractions. The thesis is part of the project and aims to study the extraction and purification of extracted phenolic compounds using subcritical water as an extraction solvent. Following the physico-chemical characterization of the four hardwood species of the Pyrenees (poplar, beech, oak and chestnut), their extraction under subcritical water conditions was optimized according to different operating conditions (time, temperature, L/S ratio) and for different extraction processes ranging from laboratory to pilot scale. It is under the action of pressurized hot water that the extraction of phenolic compounds (e.g. tannins/lignins) and polysaccharides (hemicelluloses) was carried out. It has been shown that extraction yields differ according to the morphology of the treated wood species regardless of the process, with limitations highlighted by mass transfer phenomena depending on the process under study. Furthermore, the possibility of extracting phenolic compounds prior to hemicelluloses has been demonstrated. Finally, the purification of extracts rich in phenolic compounds was studied in ultrafiltration and ion-exchange chromatography, which made it possible to separate different phenolic fractions but also gallic acid and ellagic acid, molecules with high added value
Ehtash, Moamer. "Purification des eaux polluées par du phénol dans un pertracteur à disques tournants." Phd thesis, INSA de Rouen, 2011. http://tel.archives-ouvertes.fr/tel-00635855.
Khalil, Ibrahim. "Elimination par adsorption sélective du phénol pour la purification des biocarburants de 2ème génération." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMC245/document.
This work focuses on the study of the selective adsorption of phenol from hydrocarbon solutions for the purification of 2nd generation biofuels. The objective of this work is to propose, using experimental and theoretical approaches, an adsorbent that can gather a good adsorption capacity of phenol, a selectivity towards phenol even in the presence of other aromatic compounds as well as good regeneration capacity under mild conditions.Several adsorbents were studied: Y and USY zeolites with different cations (H+ and Na+) and different proportions of micro and mesoporous surfaces, silica based solids presenting variable amount of silanol group and charcoal as a reference. The adsorption results show that, in the microporous of zeolites, the "internal" phenol can be adsorb to the number of 2 to 4 molecules per supercage, without being able to enter in the sodalite cages. In the mesoporous surface of the USY zeolites and the silica based solids, the amount of adsorbed "external" phenol depends on the density of the silanol groups. In the presence of toluene in the mixture, the acidic sites show a high selectivity towards phenol adsorption, this selectivity is justified by a higher interaction energy of phenol than toluene over these sites. Whereas, the adsorption of phenol over Na+ cation and over the silanol groups was respectively affected at low and high toluene levels. The study of the regeneration capacity of the adsorbents shows that the strongly bounded phenolic species are formed on the acidic sites of Y zeolites (H+Y, Na+Y and USY).The best compromise in terms of phenol adsorption capacity, selectivity and regeneration ability was obtained over the H+Y zeolite presenting a Si/Al ratio of 2.9
Haddou, Boumediene. "Purification d'effluents par extraction à deux phases aqueuses." Toulouse, INPT, 2003. http://www.theses.fr/2003INPT009G.
Jabraoui, Hicham. "Étude théorique de l'adsorption sélective du phénol par des matériaux zéolithiques pour la purification des biocarburants." Thesis, Université de Lorraine, 2019. http://www.theses.fr/2019LORR0044/document.
Biofuels from the transformation of second-generation biomass (2G) are expected to replace fossil fuels in the transport sector. However, the biofuels obtained after the co-treatment (bio- oil refining) still contain 0.5 to 7.0 wt% oxygenated compounds, in particular phenolic molecules, which leads to form carcinogenic benzene during combustion in the engine. In this context, a new challenge is to use selective adsorption to remove phenolic compounds from liquid fuels. As a first step in our work, we used DFT calculations to design a suitable porous material in the family of faujasites exchanged with monovalent cations (cation = H+, Li+, Na+, Cs+, Ag+, and Cu+) in order to find a zeolitic formulation with a high affinity for phenol in the presence of water and toluene (biofuel model molecule). We have found that increasing the amount of the protonated and Lewis acid sites in the faujasite structure would be an appropriate mean of selectively purifying second-generation biofuels by removing phenol molecules. The second step is to study the removal of phenol from an isooctane solution over a faujasite containing protons that was considered as a good cation in the first step. Herein, we focused on the effect of the Si/Al ratio on the adsorption and regeneration capacities of the studied zeolites. For this deeper investigation, we have used a powerful combination of two types of modeling techniques: i) density functional theory (DFT) was used to determine the binding energies of phenol with several types of faujasite formulations, ii) the Grand Canonical Monte Carlo (GCMC) was used to find the adsorption capacities of each used protonated zeolite. The obtained results are compared with those measured by various experimental tools (infrared spectroscopy, breakthrough curves and desorption experiments). As results, we have found that phenol was selectively removed from isooctane into HY (Si/Al=2.5) and USY (Si/Al=47) zeolites with a maximal adsorption capacity of 2.2 mmol·g−1, which corresponds to 3−4 phenol molecules per supercage of a faujasite structure. The adsorption equilibrium was reached more rapidly in DAY (Si /Al = ∞) compared to faujasites with a large amount of protonated sites, due to the presence of large pores at the expense of micro porosity as well as a low density of acidic sites. We have also shown that USY zeolites have good regenerative capacity compared to faujasites with high amounts of protonated sites. Indeed, after temperature programmed desorption, there is a low amount of residual phenol in the faujasite containing a small amount of protonated sites, in agreement with our low adsorption energy of phenol computed for this formulation
Jabraoui, Albert Hicham. "Étude théorique de l'adsorption sélective du phénol par des matériaux zéolithiques pour la purification des biocarburants." Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0044.
Biofuels from the transformation of second-generation biomass (2G) are expected to replace fossil fuels in the transport sector. However, the biofuels obtained after the co-treatment (bio- oil refining) still contain 0.5 to 7.0 wt% oxygenated compounds, in particular phenolic molecules, which leads to form carcinogenic benzene during combustion in the engine. In this context, a new challenge is to use selective adsorption to remove phenolic compounds from liquid fuels. As a first step in our work, we used DFT calculations to design a suitable porous material in the family of faujasites exchanged with monovalent cations (cation = H+, Li+, Na+, Cs+, Ag+, and Cu+) in order to find a zeolitic formulation with a high affinity for phenol in the presence of water and toluene (biofuel model molecule). We have found that increasing the amount of the protonated and Lewis acid sites in the faujasite structure would be an appropriate mean of selectively purifying second-generation biofuels by removing phenol molecules. The second step is to study the removal of phenol from an isooctane solution over a faujasite containing protons that was considered as a good cation in the first step. Herein, we focused on the effect of the Si/Al ratio on the adsorption and regeneration capacities of the studied zeolites. For this deeper investigation, we have used a powerful combination of two types of modeling techniques: i) density functional theory (DFT) was used to determine the binding energies of phenol with several types of faujasite formulations, ii) the Grand Canonical Monte Carlo (GCMC) was used to find the adsorption capacities of each used protonated zeolite. The obtained results are compared with those measured by various experimental tools (infrared spectroscopy, breakthrough curves and desorption experiments). As results, we have found that phenol was selectively removed from isooctane into HY (Si/Al=2.5) and USY (Si/Al=47) zeolites with a maximal adsorption capacity of 2.2 mmol·g−1, which corresponds to 3−4 phenol molecules per supercage of a faujasite structure. The adsorption equilibrium was reached more rapidly in DAY (Si /Al = ∞) compared to faujasites with a large amount of protonated sites, due to the presence of large pores at the expense of micro porosity as well as a low density of acidic sites. We have also shown that USY zeolites have good regenerative capacity compared to faujasites with high amounts of protonated sites. Indeed, after temperature programmed desorption, there is a low amount of residual phenol in the faujasite containing a small amount of protonated sites, in agreement with our low adsorption energy of phenol computed for this formulation