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Removal of organic compounds from water by adsorption and photocatalytic oxidation / Elimination de polluants organiques dans l'eau par adsorption et oxydation photocatalytiqueMohamed, Elham Farouk 20 May 2011 (has links)
Les effluents industriels sont constitués de molécules de natures très diverses, plus ou moins réfractaires aux classiques traitements biologiques. Les normes de rejets évoluant régulièrement vers des contraintes de plus en plus sévères, il semble aujourd'hui nécessaire de proposer des solutions complémentaires pour atteindre de hauts rendements d'épuration. Le premier procédé mis en oeuvre dans ce travail est l'adsorption sur charbon actif. Le caractère novateur de cette technique se situe dans l'utilisation de charbons actifs fabriqués à partir de boues de stations d'épuration d'eaux usées. La seconde méthode est un procédé hybride innovant combinant adsorption et photocatalyse avec TiO2. Les eaux industrielles ciblées sont les effluents colorés, représentés par la tartrazine, et les effluents phénolés représentés par le phénol, l'acide p-hydroxybenzoïque, le p-chlorophénol er le p-nitrophénol. Pour traiter par adsorption les eaux chargées en phénols, plusieurs charbons actifs commerciaux et six charbons de boues ont été utilisés. Il ressort de cette première étude que, malgré leurs faibles surfaces spécifiques, certains charbons de boues présentent des performances très satisfaisantes. Le procédé séquentiel combinant adsorption et photocatalyse a été réalisé avec plusieurs matériaux: un tissu Ahlstrom contenant du charbon et du TiO2, un charbon actif avec dépôt de TiO2 par MOCVD puis un mélange de charbon actif et TiO2 en poudre. Des résultats prometteurs ont été obtenus pour dégrader la tartrazine, en particulier avec le TiO2 déposé sur charbon actif montrant que la proximité de sites d'adsorption et photocatalytique améliore les performances de l'oxydation / In order to explore a new sequential process for water treatment its two steps, adsorption on activated carbon and in situ photocatalytic oxidative regeneration, were investigated successively. Several commercial activated carbons (AC) and sewage sludge based activated carbons (SBAC) were tested with several phenols and one dye as pollutants. Despite low BET surface SBAC exhibits convenient adsorption properties. Photocatalysis on TiO2 was carried out with several materials to achieve activated carbon adsorption- egeneration process: a multilayer tissue with fixed granular AC and TiO2 on a sheet, a composite with TiO2, CVD deposited on AC, and AC-TiO2 powder mixture for comparison. Promising results were obtained especially with TiO2 deposited on AC proving the vicinity of adsorption and photocatalytic sites to be beneficial
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Exposition à des perturbateurs endocriniens non-persistants pendant la grossesse : Variabilité intra-individuelle et effets sur la santé respiratoire de l'enfant / Exposure to nonpersistent endocrine disruptors during pregnancy using biomarkers of exposure : Within-subject variability and effects on respiratory health in the offspringVernet, Céline 24 May 2018 (has links)
Les phénols et les phtalates incluent des composés très largement utilisés dans des produits de la vie quotidienne. Une grande partie de la population générale y est donc largement exposée. Ces composés sont suspectés d’être des perturbateurs endocriniens et des effets sur la santé chez l’Homme ont été rapportés, notamment après une exposition périnatale. Les études épidémiologiques sur les effets sur la santé humaine reposent généralement sur un faible nombre de biospécimens pour estimer l’exposition. Cependant, la variabilité intra-individuelle des phénols et des phtalates est potentiellement forte, ce qui peut entraîner une mauvaise classification de l’exposition dans les études sur les effets des phénols et des phtalates et limite leurs conclusions. La variabilité intra-individuelle des phénols et des phtalates au cours de la grossesse n’est pas très bien caractérisée à l’heure actuelle.L’objectif de cette thèse est d’explorer l’exposition aux phénols et aux phtalates et plus précisément : 1) d’étudier les associations entre une telle exposition pendant la grossesse et la santé respiratoire de l’enfant au cours de ses premières années de vie ; 2) de caractériser la variabilité temporelle intra-individuelle de ces composés au cours de la grossesse ; et 3) d’évaluer l’efficacité d’une approche basée sur le pooling intra-sujet d’un nombre réduit d’échantillons journaliers pour estimer l’exposition.Les associations entre l’exposition aux phénols et phtalates et la santé respiratoire reposent sur n = 587 couples mèresenfants de la cohorte prospective française EDEN. Les développements sur l’estimation de l’exposition au cours de la grossesse s’appuient sur n = 16 femmes enceintes ayant participé à l’étude de faisabilité de la cohorte SEPAGES.Les travaux de cette thèse quantifient la variabilité intra-individuelle des concentrations urinaires des biomarqueurs d’exposition aux phénols et des phtalates au cours de la grossesse pour des échelles de temps variées (du jour à plusieurs mois). Ils confirment empiriquement que cette variabilité peut biaiser fortement les fonctions doses-réponses dans les études épidémiologiques explorant les effets de l’exposition fœtale à ces composés chez l’Homme.Les résultats de cette thèse enrichissent la littérature émergente sur les effets des expositions précoces aux phénols et phtalates sur la santé respiratoire de l’Homme. Cependant, notre étude ainsi que la plupart des recherches précédentes sont potentiellement limitées par les problématiques liées à la mesure de l’exposition. Ce travail souligne l’importance de stratégies d’échantillonnage des biomarqueurs d’exposition plus élaborées pour l’étude de ces composés dans de futures études épidémiologiques. Ces résultats sont aussi pertinents en dehors du contexte de la grossesse et pour d’autres composés non-persistants. De nouvelles approches, telles que le pooling répété pour chaque sujet d’un petit nombre de biospécimens journaliers, validé dans cette thèse, sont nécessaires pour caractériser efficacement l’impact des composés non-persistants sur la santé de l’Homme. / Phenols and phthalates include chemicals widely used in daily-life products, resulting in ubiquitous exposure of the general population. There is growing concern regarding the effects on human health of these compounds, suspected to be endocrine disruptors, particularly during early life. Epidemiological research on the health effects of phenols and phthalates in offspring generally rely on a few biospecimens to assess exposure. These studies are limited by the possibly strong within-subject variability, which may result in exposure misclassification. The within-subject variability in the context of pregnancy and its possible impact on dose-response functions are poorly characterized.The aim of this thesis was to study the exposure to several phenols and phthalates during pregnancy by: 1) investigating the possible associations between this exposure and respiratory outcomes in childhood; 2) characterizing the temporal within-subject variability of these compounds during pregnancy; and finally 3) studying the efficiency of a within-subject pooling approach using a small number of daily biospecimens for exposure assessment.Associations between exposure to phenols and phthalates and respiratory health relied on n = 587 mother-child pairs from the French EDEN prospective cohort. Developments about the assessment of exposure during pregnancy relied on n = 16 pregnant participants of the SEPAGES-feasibility study who had collected all their urine samples for three weeks.This work quantified the within-subject variability of phenol and phthalate biomarker concentrations during pregnancy over various time scales (day to months), and confirmed empirically that this variability is likely to strongly bias the doseresponse functions in human-based epidemiological studies exploring the effects of gestational exposure to these chemicals.This thesis adds to the emerging literature on respiratory health impacts of early-life exposure to several phenols and phthalates. However, as for most studies on the human health effects of phenol and phthalate exposure, it is potentially challenged by this exposure assessment issue. Thus, this work emphasizes the relevance of more elaborate sampling strategies for exposure biomarkers in future epidemiological studies. These results have relevance for studies outside the context of pregnancy, and also for other nonpersistent compounds. New designs, such as the within-subject pooling of biospecimens validated in this study, are needed so as to efficiently characterize the health impact of nonpersistent chemicals.
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Nouvelles méthodes de synthèse de benzofuroindolines. Vers la synthèse de la phalarine / New methodologies for the synthesis of benzofuroindolines.Towards the synthesis of phalarineTomakinian, Terry 15 October 2015 (has links)
Les benzofuroindolines forment une famille de composés qui se retrouvent sous deux formes : les benzofuro[2,3-b]indolines ou les benzofuro[3,2-b]indolines. Ce motif se retrouve dans de nombreuses molécules naturelles comme la bipleiophylline, la voacalgine A, le diazonamide A et la phalarine ce qui a mené à de nombreuses recherches pour leur synthèse. La biogénèse postulée est le couplage oxydant d'un indole et d'un phénol. Nous avons développé plusieurs voies d'accès à ces motifs en utilisant le noyau indolique. La première étude a consisté en un couplage oxydant direct entre un N-acétylindole et un phénol en présence de FeCl₃ et de DDQ. La méthodologie a montré sa généralité sur des dérivés d'indoles N-acétylés pour former en une seule étape des benzofuro[3,2-b]indolines. Dans certains cas, la benzofuro[2,3-b]indoline est obtenue si les groupements fonctionnels en position 2 et 3 sur l'indole sont identiques. Dans un but de synthétiser la phalarine, unique molécule naturelle contenant un motif benzofuro[3,2-b]indoline, nous avons réalisé une étape de C2-arylation d'un indole par un phénol à l'aide d'un couplage pallado-catalysé. La cyclisation à l'aide de NIS permet d'obtenir la benzofuro[3,2-b]indoline. L'ajout du carbone manquant de l'un des cycles est en cours d'étude par ajout d'un nucléophile monocarboné possédant un groupement partant. Par ailleurs, une dernière voie d'accès aux benzofuro[3,2-b]indolines a pu été mise au point par une réaction de Fischer interrompue. La réaction entre des benzofuran-3-ones et des arylhydrazines dans des conditions acides conduit aux benzofuroindolines souhaitées sous forme d'hémiacétals. La méthode a montré sa généralité et sa robustesse. Finalement, réaliser l'Umpolung de l'indole est un défi intéressant pour additionner des nucléophiles en position 3 de l'indole. Pour cela, des N-hydroxyindoles ont été synthétisés et l'utilisation de sels de biaryliodonium triflate a permis de réaliser une O-arylation. Le produit formé étant instable, il subit un réarrangement sigmatropique [3,3] pour conduire aux benzofuro[2,3-b]indolines désirées. / Benzofuroindolines are a family of compounds which can be found in two regioisomeric forms: benzofuro[2,3-b]indolines or benzofuro[3,2-b]indolines. This core is present in several natural products such as bipleiophylline, voacalgine A, diazonamide A or phalarine which have been the subject of intensive efforts towards their syntheses. The postulated biogenesis is the oxidative coupling of an indole and a phenol. We developed four pathways to access these structures using the indole nucleus.The first part consisted in a direct oxidative coupling between a N-acetylindole and a phenol in presence of FeCl₃ and DDQ. This strategy showed its generality on N-acetylindoles derivatives to form in only one step the benzofuro[3,2-b]indoline core. In some cases, the benzofuro[2,3-b]indoline is obtained if the substitution in the C-2 and C-3 position is the same. In order to synthesize the phalarine, the unique natural product to possess a benzofuro[3,2-b]indoline core, we designed a C-2 arylation of an indole with a phenol using a palladium-catalyzed coupling. The cyclization steps using NIS led to the benzofuro[3,2-b]indoline core. The insertion of the missing carbon of one of the rings is under study by adding a nucleophile which contains only one carbon and a leaving group. The last strategy to access to benzofuro[3,2-b]indolines has been focused on an interrupted Fischer indolization. The reaction between benzofuran-3-ones and arylhydrazines in acidic conditions led to the desired benzofuro[3,2-b]indolines. This methodology is general and robust. Another part of the project was to achieve the Umpolung of the indole to add nucleophiles in C-3 position of the indole nucleus. N-hydroxyindoles were synthesized and the use of biaryliodonium triflate salts allowed an O-arylation reaction. The product being unstable, a [3,3] sigmatropic rearrangement can take place to afford the desired benzofuro[2,3-b]indolines.
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Phytochemical analysis and biological activities of crude extracts from selected Tulbaghia speciesTakaidza, Samkeliso 12 1900 (has links)
PhD (Department of Biotechnology, Faculty of Applied and Computer Sciences), Vaal Universtiy of Technology / The genus Tulbaghia has been used in traditional medicine to treat various ailments such as fever, earache, tuberculosis and esophageal cancer. However, there is limited scientific evidence to support its use. Therefore the objectives of this study were to perform phytochemical analysis, investigate the antioxidant, antimicrobial, anticancer, immunomodulatory activities and toxicity of crude acetone and water extracts from selected Tulbaghia species.
Standard methods were used for preliminary phytochemical analysis. The total phenolic content of the plant extracts was determined using the folin ciocalteu method whereas the total flavonoids were determined by using the aluminium chloride colorimetric method. DPPH and ABTS assays were used to evaluate the antioxidant activity. The antimicrobial activity was assessed by agar well diffusion, microtiter dilution and time kill assays.
For anticancer studies, the antiproliferative activity of the extracts was evaluated using the MTT assay on Hkesc-1 and KB cells. Morphological changes of the cancer cells treated with extracts were examined using light microscopy. Induction of apoptosis was assessed using fluorescence microscopy and acridine orange/ethidium bromide staining. Flow cytometry analysis was conducted to examine the multicaspase activity and cell cycle arrest. For immunomodulatory activity, the Greiss reagent and Luminex cytokine assays were used to determine the effect of the extracts on NO production and the concentration of the cytokines in the treated cells, respectively.
Toxicity of selected Tulbaghia species was examined by investigating the effect of the extracts on the metabolic activity and cell membrane integrity on the treated RAW264.7 cells using the MTT and LDH assays, respectively. The zebrafish assay was used to evaluate the embryotoxicity and teratogenic effects of crude acetone and water extracts of T. violacea at 24 h intervals for 96 h post fertilisation (hpf). The percentage mortality, hatchability and heart rate were examined.
Phytochemical screening of eight Tulbaghia species demonstrated the presence of flavonoids, glycosides, tannins, terpenoids, saponins and steroids. The amount of total phenol and flavonoid content varied in different plant extracts ranging from 4.50 to 11.10 milligrams gallic acid equivalent per gram (mg GAE/g) of fresh material and 3.04 to 9.65 milligrams quercetin equivalent per gram (mg QE/g) of fresh material respectively. The IC50 values based on DPPH and ABTS for T. alliacea (0.06 and 0.06 mg/mL) and T. violacea (0.08 and 0.03 mg/mL) were generally lower showing potential antioxidant activities. For antimicrobial activity, the acetone extracts of T. acutiloba, T. alliacea, T. leucantha, T. ludwigiana, T. natalensis and T. simmleri showed moderate antimicrobial activity against all test organisms while the water extracts showed moderate to no activity. One species, T. cernua, showed poor activity against all the tested microbes. The acetone and water extracts of T. violacea showed the greatest antibacterial and antifungal activity against all the tested microorganisms with minimum inhibitory concentration ranging from 0.1 mg/mL to 3.13 mg/mL. The acetone extracts of T. violacea also exhibited both bacteriostatic/fungistatic and bactericidal/fungicidal activity depending on the incubation time and concentration of the extract. The bactericidal/fungicidal activity was observed at x2 MIC.
The results for anticancer activity showed that treatment of Hkesc-1 cells with acetone and water crude extracts had anti-proliferative activity with IC50 values of 0.4 mg/mL and 1.625 mg/mL, respectively while KB had 0.2 mg/mL and 1 mg/mL, respectively. Morphological changes such as blebbing, cell shrinkage and rounding were observed in the treated cells suggesting that apoptosis was taking place. AOEB staining showed that the level of apoptosis was dependent on the concentration of the extracts. The activation of multicaspase activity in both Hkesc-1 and KB treated cells was also concentration dependent leading to cell death by apoptosis and the induction of cell cycle arrest at the G2/M phase.
Immunomodulatory activity results indicated that cell viability was above 80% when concentrations of 50 µg/mL or less of both acetone and water crude was used. Treatment with the acetone extract had no significant effect (p>0.05) on the LPS induced NO production in RAW264.7 cells except at 50 µg/mL where significant inhibition was observed. The water extract had no significant effect (p>0.05) on NO production at all the concentrations. Treatment of LPS–induced RAW264.7 cells with acetone extract stimulated the production of IL-1α, IL-6 and TNF-α, but had no significant effect (p > 0.05) on IL-1β. On the other hand, treatment with the water extracts stimulated the production of IL-1α, IL-6 but had no significant effect (p>0.05) on TNF-α and IL-1β. Treatment of LPS-induced RAW264.7 cells with the acetone extract had very little stimulatory effect on IL-4, IL-5 and IL-13 and no significant effect on IL-10 whereas for the water extract a significant stimulatory effect was only observed for IL-4 after 48 h of treatment. High concentrations (>10000 pg/mL) of MCP-1, MIP1-α, MIP1-β, MIP-2, GCSF, GM-CSF, RANTES and IP-10 were also observed in acetone and water extract treated RAW264.7 cells.
For toxicity studies, acetone and aqueous crude leaf extracts from T. alliacea, T. simmleri, and T. violacea had a significant inhibitory (p<0.05) effect on the RAW264.7 cells after 48h treatment. Acetone extracts from T. alliacea, T. simmleri and T. violacea resulted in IC50 values of 0.48 mg/mL, 0.72 mg/mL and 0.1 mg/mL, respectively. Treatment with water extracts showed minimal toxic effect indicated by higher IC50 values of 0.95 mg/mL, 2.49 mg/mL and 0.3 mg/mL for T. alliacea, T. simmleri and T. violacea, respectively. The LDH release by macrophages after 24 h treatment with acetone extracts was observed to be concentration dependent while treatment with water extracts did not induce LDH release. The zebra fish assay showed a lethal dose (LD50) for the T. violacea acetone crude extract of 20 μg/mL whereas that for water extract was 85 μg/mL. The observed teratogenic effects included scoliosis, edema of the pericardial cavity, retarded yolk resorption, hook-like/bent tail and shorter body length.
In conclusion, the results from this study indicate that the extracts from the eight Tulbaghia species examined contain phytochemicals that may have the antioxidant, antimicrobial, anticancer and immunomodulatory properties. Extracts from T. violacea were observed to be the most potent. This study thus supports the use of T. violacea in treating bacterial and fungal infections in traditional medicine. The results of this study also confirm the anticancer potential of T. violacea. The immunomodulatory activity of the acetone and water extracts from T. violacea indicated a dominantly pro-inflammatory activity. Traditional medicine prepared form T. violacea may be of benefit to individuals with weak immune systems. The toxicity of selected Tulbaghia species was observed to be concentration, extract and time dependent. Therefore, traditional medicine prepared from Tulbaghia extracts should be taken with caution preferably in small doses over a short period of time. Future studies will focus on the identification of the bioactive compound(s) responsible for the antimicrobial, anticancer and immunomodulatory activities.
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Uticaj fizičko-hemijskih svojstava mikroplastike i odabranih perzistentnih organskih polutanata na interakcije u vodenom matriksu / Impact of physicochemical properties of microplastics and selected persistent organic pollutants on interactions in the aqueous matrixLončarski Maja 20 October 2020 (has links)
<p>Mikroplastika je sveprisutna u vodenom ekosistemu pri čemu se često<br />ističe značaj ispitivanja njihovog uticaja na ponašanje drugih jedinjenja u vodi.<br />Pod pojmom mikroplastika podrazumevaju se plastične čestice manje od 5 mm.<br />Imajući u vidu potrebu za unapređenjem znanja o štetnom uticaju mikroplastike<br />u životnoj sredini u ovom radu sproveden je set eksperimenata u kom je ispitivan<br />mehanizam interakcija koje se uspostavljaju prilikom adsorpcije hlorovanih<br />fenola, derivata benzena i policikličnih aromatičnih ugljovodonika na mikroplastici u vodenom matriksu. Kako bi se što detaljnije razumeo uticaj mikroplastike i osobina vodenog matriksa na ponašanje organskih polutanata, laboratorijska ispitivanja su sprovedena u sintetičkom i realnom vodenommatriksu. Takođe je sprovedena optimizacija izolovanja i karakterizacije mikroplastike iz kozmetičkih sredstava u cilju procene uticaja osobina primarne mikroplastike na uspostavljanje interakcija sa organskim polutantima. Na osnovu dobijenih rezultata istraživanja može se zaključiti da se optimalna metoda izolovanja mikroplastike iz kozmetičkih sredstava zasniva na dodatnom tretiranju osušenog materijala 30% vodonik-peroksidom, nakon ekstrakcije sredstva u destilovanoj vodi, u cilju dobijanja čistijih uzoraka mikroplastike. Promena brzine mešanja ima znčajan uticaj na promenu stepena adsorpcije ispitivanih grupa organskih jedinjenja. Uticaj se ogleda u povećanju stepena adsorpcije sa porastom brzine mešanja, a maksimalni procenat adsorpcije postignut je pri brzini mešanja od 150 o/min. Dodatno, disperzija praškastih materijala u vodi nema značajan uticaj na promenu stepena adsorpcije hlorovanih fenola, derivata benzena i policikličnih aromatičnih ugljovodonika na mikroplastici.Ravnotežno stanje između koncentracije hlorovanih fenola, derivata<br />benzena i policikličnih aromatičnih ugljovodonika u vodi i odabranih predstavnika mikroplastike (PEp, PE_PCPs_1, PE_PCPs_2, PEg, PET, PP i PLA) uspostavlja se nakon 24 i 48 h kontakta u zavisnosti od vrste jedinjenja. Na promenu adsorpcionog afiniteta hlorovanih fenola, derivata benzena i policikličnih aromatičnih ugljovodonika prema mikroplastici utiču kako fizičkohemijske osobine jedinjenja tako i karakteristike mikroplastike. Na osnovu kinetičkih eksperimenata, najveći adsorpcioni afinitet ka mikroplastici ispoljili su derivati benzena (qt=103-350 µg/g), dok je najmanji uočen kod hlorovanih fenola (qt=25-225 µg/g). Dobijeni rezultati adsorpcije derivata benzena na ispitivanim česticama mikroplastike takođe su ukazali na veći afinitet ovih jedinjenja ka mikroplastici, u poređenju sa jedinjenjima iz grupe policikličnih aromatičnih ugljovodonika i hlorovanih fenola sličnih logKow vrednosti. Dodatno, uticaj vodenog matriksa na adsorpciju hlorovanih fenola, derivata benzena i policikličnih aromatičnih ugljovodonika na mikroplastici zavisi od same grupe jedinjenja kao i od vrste mikroplastike pri čemu je najmanje izražen u slučaju ispitivanih policikličnih aromatičnih ugljovodonika, a najviše kod hlorovanih fenola.Visoke vrednosti koeficijenta determinacije kinetičkog modela pseudodrugog reda za adsorpciju hlorovanih fenola, derivata benzena i policikličnih aromatičnih ugljovodonika na čestice mikroplastike ukazjuju da je hemisorpcija mogući mehanizam. Pored visokih vrednosti koeficijenata determinacije u slučaju svih odabranih organskih jedninjenja dobijena konstanta brzine drugog reda bila je manja od po četne brzine adsorpcije što ukazuje na znatno brže odvijanje adsorpcije pri kraćim vremenima kontakta (12-24 h) nakon čega je<br />dolazilo do usporavanja procesa adsorpcije.Mehanizam adsorpcije hlorovanih fenola, derivata benzena i policikličnih aromatičnih ugljovodonika ispitivan je primenom Freundlich-ovog, Langmuirovog, Redlich-Peterson-ovog i Dubinine-Radusckevich-evog adsorpcionog modela. Vrednosti Freundlich-ovog eksponenta za adsorpciju hlorovanih fenola, derivata benzena i policikličnih aromatičnih ugljovodonika bile su manje od 1,<br />što ukazuje na to da je slobodna energije adsorpcije na mikroplastci opadala sa povećanjem inicijalne koncetracije ispitivanih polutanata. Vrednosti maksimalnog adsorpcionog kapaciteta dobijene za adsorpcione procese PAH na česticama mikroplastike bile su u opsegu od 29,7-2596,5 µg/g. Visoke vrednosti maksimalnih adsorpcionih kapaciteta dobijene su takođe za adsorpciju derivata benzena na ispitivanim vrstama mikroplastike 39,3-2010,1 µg/g. S druge strane, uočeno je različito adsorpciono ponšanje hlorovanih fenola u zavisnosti od vodenog metriksa u kom su eksperimenti sprovedeni pri čemu su qmax vrednosti iznosile 20,00-205,6 µg/g. Značajan uticaj pH vrednosti vodenog matriksa utvrđen je za adsorpciju hlorovanih fenola na mikroplastici, dok u slučaju derivata benzena i PAH promena pH vrednosti vodenog matriksa nije pokazala značajan uticaj. Rezultati dobijeni za adsorpciju hlorovanih fenola na mikroplastici ukazuju na nižu tendenciju ka formiranju interakcija hlorovanih fenola sa česticama mikroplastike pri pH 4 i pH 10, pri čemu se stepen adsorpcije kretao u opsegu od 8-35% i 15-35%, respektivno, u odnosu na pH 7 (55-65%). Najniži adsorpcioni afinitet uočava se pri adsorpciji ispitivanih grupa jedinjenja na PLA. Može se pretpostaviti da će se organski polutanti, ukoliko ova vrsta mikroplastike dospe u vodene sisteme, slabo vezivati na ovaj materijal pri čemu će značajno manje uticati na njihov trasport kroz životnu sredinu, u odnosu<br />na druge ispitivane vrste mikroplastike. Na osnovu dobijenih rezultata istraživanja može se zaključiti da na adsorpciju ispitivanih grupa organskih jedinjenja i mikroplastike značajan uticaj imaju fizičko-hemijske osobine ispitivanih jedinjenja kao što su kiselinska konstanta, veličina molekula, hidrofobnost, stukturni raspored i dr. Pored toga, karakteristike vodenog matriksa, među kojima je najvažnija pH vrednost, imaju značajan uticaj na adsorpcioni afinitet jedinjenja ka mikroplastici. Dodatno,<br />struktura i poreklo polimera ima veliki uticaj na formiranje interakcija sa<br />ispitivanim grupama organskih polutanata. Dobijeni rezultati takođe ukazuju na<br />nemogućnost određivanje unifomnog mehanizma adsorpcije organskih<br />jedinjenja na česticama mikroplastike u vodi.</p> / <p>Microplastics are ubiquitous in aquatic ecosystems, so it is essential to study their impact on the behaviour of other compounds which are commonly present in water. The term microplastics refers to all plastic particles smaller than 5 mm. In order to address knowledge gaps relating to the potential harmful effects of microplastics in the environment, the experiments conducted during this thesis were designed to investigate the adsorption mechanism of chlorinated phenols, benzene derivatives, and polycyclic aromatic hydrocarbons on microplastics in water. To provide a more detailed understanding of the influence of different water matrices on adsorption properties of microplastics, experiments were conducted in both synthetic and real water matrices. In the course of this work, methods were optimised for the isolation and characterization of microplastifrom personal care products, in order to allow investigation of the influence of the properties of primary microplastics on their interactions with organic pollutants.Base on the obtained results, it can be concluded that the optimal method of isolating microplastics from personal care products is based on treating already dried material with 30% hydrogen peroxide, after extraction of the agent in distilled water, in order to obtain cleaner microplastic samples. The mixing rate was found to have a significant effect on the degree of adsorption of the investigated organic compounds. Increasing the mixing speed led to a higher<br />degree of adsorption, with the maximum adsorption percentage reached at a<br />mixing speed of 150 rpm. In addition, the dispersion of powdered materials in the water had no significant effect on the degree of adsorption of chlorinated phenols, benzene derivatives, and polycyclic aromatic hydrocarbons on microplastics.<br />The adsorption equilibrium between the concentration of chlorinated phenols, benzene derivatives and polycyclic aromatic hydrocarbons in water and selected types of microplastics (PEp, PE_PCPs_1, PE_PCPs_2, PEg, PET, PP, and PLA) was established after 24 and 48 h of contact time, depending on the selected group of organic pollutants. The adsorption affinity of chlorinated phenols, benzene derivatives, and polycyclic aromatic hydrocarbons towards microplastics was influenced by both the physicochemical properties of the compounds and the characteristics of the microplastics. Based on the kinetic experiments, the highest adsorption affinity for microplastics was shown by benzene derivatives (qt=103-350 µg/g), while the lowest was observed during the adsorption of chlorinated phenols (qt=25-225 µg/g). Benzene derivatives showed higher adsorption affinities for the selected microplastic particles than the polycyclic aromatic hydrocarbons and chlorinated phenols which had similar logKow values. The influence of the water matrix on adsorption of chlorinated phenols, benzene derivatives, and polycyclic aromatic hydrocarbons on microplastics depended on the specific functional groups of the investigated compounds as well as on the type of microplastics. Water matrix had little impact on the adsorption of polycyclic aromatic hydrocarbons on microplastics but greatly impacted the adsorption of chlorinated phenols. Fitting the pseudo-second order kinetic model to the adsorption data of chlorinated phenols, benzene derivatives, and polycyclic aromatic hydrocarbons on microplastic particles resulted in high correlation coefficients, indicating that chemisorption is the likely adsorption mechanism. In addition to the high correlation coefficients obtained for all the organic pollutants investigated, the pseudo-second order rate constants obtained were lower than the initiaadsorption rate, indicating significantly faster adsorption at shorter contact times (12-24 h), with adsorption slowing down as equilibrium was reached.The adsorption mechanism of chlorinated phenols, benzene derivatives,<br />and polycyclic aromatic hydrocarbons was investigated using Freundlich,Langmuir, Redlich-Peterson, Dubinine-Radusckevich, and Temkin adsorption models. The Freundlich exponent values for the adsorption of chlorinated phenols, benzene derivatives, and polycyclic aromatic hydrocarbons were less than 1 which indicates that the free energy of adsorption of these compounds on microplastics decreases as the initial concentration increases. The maximum adsorption capacities of PAHs on microplastic particles were in the range of 29.7-2596.5 µg/g. High maximum adsorption capacities were also obtained for the adsorption of benzene derivatives on the tested types of microplastics: 39.3-2010.1 µg/g. The chlorinated phenols behaved differently, and were more effected by the water matrix, with qmax values in the range 20.00-205.6 µg/g. The pH of the water matrix was found to have a significant effect on the adsorption of chlorinated phenols on microplastics, whereas in the case of benzene derivatives and polycyclic aromatic hydrocarbons, the degree of<br />adsorption was largely independent of the water pH. For the adsorption of chlorinated phenols on microplastics, neutral pH conditions resulted in the greatest degrees of adsorption (55-65% at pH 7), while adsorption was inhibited under acidic (8-35% at pH 4) and basic (15-35% at pH 10) conditions. The microplastic type with the lowest observed adsorption affinities was PLA. It can be thus be assumed that in the event that this type of microplastic enters water systems, organic pollutants will only adsorb weakly to this material, such that it will have significantly less impact on the transport of the se compounds through the environment, than the other tested types of microplastics. The results obtained in this research demonstrate that the adsorption of the selected groups of organic pollutants on the microplastics investigated is significantly controlled by the physicochemical properties of the tested compounds, such as the dissociation constant, molecule size, hydrophobicity,<br />structural properties, etc. In addition, the characteristics of the water matrix play an important role in controlling adsorption of organic pollutants on microplastic, especially the water pH. In addition, the structure and aging of the polymers had a major influence on their interactions with the selected organic pollutants. The obtained results also demonstrate the difficulty in determining a uniform mechanism of adsorption between the various organic compounds and microplastic particles in water.</p>
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Influence of pH and NOM on Sorption of Phenols onto Aquifer MaterialAmiri, Fariba 10 March 2005 (has links)
Geosorption processes play an important role as retardation mechanism in subsurface transport of organic water constituents. Geosorption behaviour of Ionisable Hydrophobic Organic compounds (IHOCs) especially influence of dissolved natural organic materials on their sorption coefficients is poorly investigated. In this study influence of pH and NOM on the sorption of three different phenols (2-methyl-4,6-dinitrophenol, 2,4,6-trichlorophenol and pentachlorophenol) on a natural sandy aquifer material collected from a bank filtration site was studied in flow through column experiments. In first step the sorption coefficients of investigated phenols from NOM-free solutions with different pH values were determined. Single as well as multi (mixed) solutes experiments confirmed that there was no competition effect among the phenols investigated. An increasing sorption/retardation was observed with decreasing pH. A linear model was used to resolve the apparent sorption coefficient into an ionised species and neutral species component. This model allows a prediction of apparent sorption coefficients for any pH value. Analysis of data also revealed that the anion of 2-M-4,6-DNP show no significant sorption and a simple model based on the neutral form sorption coefficient was useful in predicting the apparent sorption coefficient over the entire pH range investigated. For 2,4,6-TCP and PCP, the anion sorption is much lower than that of the neutral species but cannot be neglected completely. For PCP, the anion sorption is even as high as the sorption of neutral 2,4,6-TCP. Thus for such hydrophobic phenols prediction of sorption based only on the partitioning of non-dissociated species may lead to an error, especially at high pH values (&gt; pKa), where ionised form is present predominantly. On the other hand prediction of sorption based on the partitioning of non-dissociated species is useful at pH &lt; pKa or in cases where the anion sorption can be neglected. The advantage of this prediction is that it allows predicting the pH-dependent sorption only on the basis of LFER correlations. It was shown that the organic carbon normalized sorption coefficients of the neutral forms of the phenols can be predicted better by solubility based regression correlations than by n-octanol-water partition coefficient based correlations. In second step the apparent sorption coefficients of investigated phenols from NOM-containing solutions (mixed solution of phenols dissolved in natural river water) with different pH values were determined; the sorption coefficients obtained from this step were compared with the results of the first step examinations. Analysis of data revealed that binding of 2-M-4,6-DNP by dissolved humic substances (DHS) reduces the sorption coefficient significantly. In contrast to it, the sorption of the more hydrophobic chlorinated phenols was not affected by DHS. A strong reduction of sorption onto aquifer material caused by complex formation with DHS was also observed for a second nitrophenol (2,4-DNP) and seems to be typically for nitrophenols. A combined sorption and complex formation model was proposed which could be used successfully to describe the effect of pH and NOM concentration on sorption reduction and to estimate binding constants. The binding constant found for 2-M-4,6-DNP is much higher than those reported by Ohlenbusch and Frimmel, 2001, for chlorophenols associated with Aldrich humic acid. This can be interpreted as a result of specific interactions between the nitrophenol and DHS. This phenomenon may cause an increase of the amount of nitrophenols, which can be transported with the groundwater flow and has to be considered in transport modelling, especially in cases where pH is lower than pKa. The models developed here are a useful tool to describe the influence of pH and NOM on geosorption processes and to estimate the Kd values which have to be used in transport models.
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Analiza komine grožđa i dijetetskih suplemenata na bazi grožđa i japanskog troskota i ispitivanje uticaja suplementacije kod eksperimentalnih životinja / Analysis of grape pomace and dietary supplements based on grapes and Polygonum cuspidatum and examination of the effect of supplementation in experimental animalsĆućuz Veljko 22 June 2020 (has links)
<p>Doktorsku disertaciju čine tri celine kojima je zajednički element ispitivanje fenola, u pogledu njihovog sadržaja i dostupnosti u dijetetskim suplementima na bazi grožđa i japanskog troskota, ispitivanja uticaja suplementacije kod eksperimentalnih životinja, odnosno mogućnosti ekstrakcije fenolnih jedinjenja iz komine grožđa. Osnovni ciljevi prvog dela bili su ispitivanje bezbednosti i kvaliteta 14 suplemenata na bazi grožđa i japanskog troskota u pogledu ujednačenosti mase, sadržaja i brzine rastvorljivosti. U drugom delu je radi provere terapijske delotvornosti suplementa koji sadrži čist resveratrol ispitan njegov uticaj na glikemiju i lipidni status eksperimentalnih životinja. Treći deo je obuhvatio analizu pet različitih komina grožđa i razvoj metode ekstrakcije fenola iz odabrane komine kako bi se dobili ekstrakti sa što je moguće većim prinosom, koristeći rastvarače koji su bezbedni po ljudsko zdravlje. Rezultati su pokazali da dva od četrnaest suplemenata nisu ispunila zahteve farmakopeje za lekove u pogledu ujednačenosti mase i sadržaja aktivne komponente, dok ni jedan suplement nije ispunio zahteve u pogledu brzine rastvorljivosti aktivne supstance, zbog čega se postavlja pitanje delotvornosti ispitanih suplemenata. Ni kod jednog suplementa nisu kvantifikovani ostaci pesticida ni toksični metali, čime je potvrđena njihova bezbednost. Farmakodinamska ispitivanja na pacovima pokazala su antioksidantna, anti-dijabetska i hipolipidemijska svojstva dijetetskog suplementa na bazi resveratrola, čime je potvrđena njegova delotvornost. Za potvrdu delotvornosti suplementa na ljudima neophodno je sprovesti dobro dizajnirano kliničko ispitivanje na dovoljnom broju ispitanika. Analiza pet različitih komina grožđa pokazala je da ovaj nusprodukt proizvodnje vina sadrži različite fenole, od kojih je samo katehin bio prisutan u značajnoj količini. Kvalitativan i kvantitativan sastav komine značajno varira zavisno od sorte i berbe grožđa, kao i od primenjenog tehnološkog procesa proizvodnje vina. Imajući u vidu sveobuhvatne kriterijume u pogledu efikasnosti ekstrakcije, zaključeno je da su 55% etanol, odnos uzorak / rastvarač 1:40, pH 4,5, T 55°C i vreme od 30 min optimalni eksperimentalni uslovi za ekstrakciju fenola iz komine grožđa. U zavisnosti od osnovnog cilja procesa ekstrakcije ovi parametri se mogu lako modifikovati. Višestruke su mogućnosti za iskorišćenje komine grožđa, a jedan od njih bi mogla biti i da se koristi kao sirovina za izradu dijetetskih suplemenata.</p> / <p>The dissertation consists of three parts with a common element – testing phenols in terms of content and availability in grape and Polygonum cuspidatum-based dietary supplements, testing the supplement’s impact on experimental animals and the possibility to extract phenolic compounds from grape pomace. The primary objectives of the first part were testing safety and quality of fourteen grape and Polygonum cuspidatum-based supplements in terms of uniformity of mass, content and dissolution profile. In the second part, to test the therapeutic efficacy of a supplement containing pure resveratrol, its effect on the glycemia and lipid profile of experimental animals was examined. The third part covers the analysis of five different grape pomaces and the development of a phenol extraction method from the selected grape pomace to obtain extracts with the highest possible yield, using solvents that are safe for human health. The results showed that two out of fourteen supplements have not met the Pharmacopoeia requirements in terms of uniformity of mass and active substance content, while no supplement has met requirements in terms of dissolution test of the active substance, which raises the question of the effectiveness of the tested supplements. No pesticide or heavy metal residues were quantified in any of the supplements which confirms their safety. Pharmacodynamic testing on rats has shown antioxidant, antidiabetic and hypolipidemic properties of the resveratrol-based dietary supplement which confirms its efficacy. In order to confirm the supplement efficacy on people, it is necessary to conduct a well-designed clinical trial on a sufficient number of human participants. The analysis of five different grape pomaces revealed that this byproduct of vine production contains different phenols, and only catechin was present in significant amounts. The qualitative and quantitative composition of grape pomace varies significantly depending on grape variety and harvesting as well as on the technological process that was applied in vine production. Considering the comprehensive criteria in terms of extraction efficacy, it was concluded that optimal experimental conditions for the extraction of phenol from grape pomace include 55% ethanol, sample/solvent ratio 1:40, pH 4.5, T 55°C for 30 minutes. Depending on the primary objective in the extraction process, these parameters can be easily modified. There are multiple possibilities for utilizing grape pomace and one of them could be as raw material in production of dietary supplements.</p>
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Nouveaux polymères de coordination à base de titane et de dérivés phénoliques / New coordination polymers based on titanium and phenolic derivativesAssi, Hala 21 October 2016 (has links)
Les solides hybrides poreux ou les « MOFs » sont l'une des classes les plus récentes de polymères de coordination poreux cristallins. En raison de la variété de leur structure et leur composition, Ils sont actuellement considérés comme des candidats prometteurs dans divers domaines (le stockage de gaz, la séparation des fluides, la catalyse, la biomédecine…). Cependant, la littérature sur l'activité photocatalytique de ces solides n’a commencé à s’exploser que très récemment, bien que l’utilisation de ces matériaux comme photocatalyseurs hétérogènes soit avantageux en comparaison avec les semi-conducteurs classiques. Compte tenu des propriétés photocatalytiques bien établies de TiO2, il semble logique de se concentrer sur le titane(IV) pour la conception de nouveaux MOFs pour de telles applications. Néanmoins, en raison de la difficulté de contrôler la réactivité de cet ion métallique en solution (en particulier hors des conditions très acides), très peu de MOFs à base de titane ont été décrits, parmi les MOFs nombreux connus dans la littérature. Ainsi, l'obtention de solides cristallins à base de titane dans l'eau et en milieu basique reste un défi majeur dans ce domaine. Dans nos travaux, certaines stratégies ont été suivies afin de bénéficier des avantages de l’utilisation des cations Ti4+ et parallèlement confronter leurs limitations en se focalisant sur l'exploration de la chimie de ces cations (alcoxydes de titane, complexes et oxo-clusters) avec divers ligands polytopiques, en particulier les dérivés hydroxycarboxylates et polycatécholates pour la conception de nouveaux solides hybrides poreux stables à base de titane. Ces ligands présentent des avantages importants par rapport aux carboxylates purs, tels que la diversité structurale potentiellement plus élevée, les liaisons Ti-O plus fortes conduisant à une stabilité chimique améliorée en milieu basique, et une large absorption dans le visible assurée par un transfert de charge ligand-métal. D'autre part, l'utilisation des complexes moléculaires ou des oxo-clusters de titane sera une opportunité prometteuse dans le but de contrôler l'hydrolyse spontanée et la réactivité élevée des ions Ti4+. En privilégiant la synthèse solvo- et hydrothermale à l'aide du « système haut-débit », ces stratégies ont conduit à l’obtention de nouveaux solides cristallins (composés moléculaires et polymériques 1D /2D /3D). La synthèse, la caractérisation structurale au travers de la combinaison de différentes techniques (diffraction des rayons X, analyse thermogravimétrique, spectroscopie IR, RMN du solide, mesure de sorption...), l'étude de certaines propriétés et l’étude préliminaire de l’activité photocatalytique (production de dihydrogène de l’eau) de ces nouveaux solides seront ainsi discutées dans ce manuscrit. / Crystalline Metal-Organic Frameworks MOFs are one of the most recent classes of crystalline porous coordination polymers. Due to the variety of their structure and composition, they are currently considered as promising candidates in various domains (gas storage, fluid separation, catalysis, biomedicine…). However, the literature on the photocatalytic activity of these solids has exploded only very recently, although the many advantages of using these materials as heterogeneous photocatalysts in comparison with classical semiconductors. Considering the well-established photocatalytic properties of TiO2, it seems logical to focus on titanium in order to design new MOFs for such applications. Nevertheless, because of the difficulty in controlling the reactivity of these ions in solution (especially out of the very acidic conditions), very few crystalline titanium-based MOFs have been described, among the numerous MOFs known in the literature. Thus, obtaining titanium-based MOFs in water and basic medium remains a big challenge. In our work, some strategies has been followed in order to benefice from the advantages of the titanium ions and at the same time confront their limitations by focusing on the exploration of the chemistry of Ti4+ ions (titanium alkoxides, complexes and oxo-clusters) with various polytopic ligands, especially hydroxycarboxylate and polycatecholate derivatives in order to design new stable titanium-based MOFs. Such ligands provide important advantages in comparison with pure carboxylates, such as a potentially higher structural diversity, stronger Ti-O bonds leading to an enhanced chemical stability in basic medium, and a strong absorption in the visible range ensured by ligand to metal charge transfer. On the other hand, the use of titanium molecular complexes or oxo-clusters will be a promising opportunity in order to control the spontaneous hydrolysis and the high activity of Ti4+ ions. By privileging the solvo- and hydrothermal synthesis using the «high-throughput system», these strategies lead to obtain new crystalline solids (molecular and 1D/2D/3D polymeric compounds). The synthesis, the structural characterization by a combination of different technics (X-ray diffraction, TGA analysis, IR spectroscopy, Solid State NMR, sorption measurement…), the study of some properties and the preliminary photocatalytic experiments (water splitting reaction) of these new solids will be discussed in this manuscript.
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Childhood and adolescent exposure to chemicals found in personal care productsKhan, Nahiyan Saiyara 12 1900 (has links)
Contexte : Les produits de soins personnels contiennent plusieurs substances chimiques dont l'exposition est préoccupante pour les jeunes vu leur plus grande susceptibilité aux expositions chimiques. Aucune revue publiée n’a étudié l'exposition des jeunes aux substances chimiques dans ces produits.
Objectif : Cette revue de la portée vise à synthétiser des études de biosurveillance décrivant les concentrations de parabènes, phénols, phtalates et substances per- et polyfluoroalkylées (PFAS) après l'utilisation de produits de soins personnels chez les jeunes âgés de 5 à 19 ans.
Méthodes : La recherche a été effectuée dans MEDLINE, Embase et Global Health. L’éligibilité des articles a été évaluée. Les résultats des études éligibles ont été résumées et décrites.
Résultats : Trente-sept études ont été incluses, la première étant publiée en 2013. La majorité des études étaient transversales (n=35) et incluaient plus de 100 participants (n=27). Les substances chimiques les plus fréquemment étudiées étaient les phtalates (n=23), suivies des parabènes et des phénols (chacun n=18), puis des PFAS (n=1). La matrice biologique principalement utilisée était l'urine (n=36). Plusieurs études (n=31) ont rapporté au moins une association positive entre les produits de soins personnels et certaines classes chimiques, comme entre le maquillage et les parabènes; la lotion et les phénols; et le parfum et les phtalates.
Conclusion : Plus d'études sur ce sujet sont nécessaires pour documenter l'importance relative de l'utilisation des produits de soins personnels par rapport à l'exposition totale aux substances chimiques. L’uniformisation des questionnaires de collecte de données pourrait aider à réduire l'hétérogénéité des résultats. / Background: Personal care products (PCPs) contain a variety of chemicals including parabens, phenols, phthalates, and per- and polyfluoroalkyl substances (PFAS). Exposure to these chemicals is of concern for children and adolescents, as they are known possess an increased susceptibility to chemical exposures. To date, no published review has explored youth exposure to chemicals found in PCPs.
Objective: This scoping review aimed to provide an overview of biomonitoring studies that describe the concentrations of parabens, phenols, phthalates, and PFAS following PCP use among children and adolescents of any age from 5 to 19 years old.
Methods: The search was conducted in MEDLINE, Embase, and Global Health. Articles were screened and assessed for eligibility. From eligible studies, data were extracted to summarize and describe the findings.
Results: Thirty-seven studies were included, the first of which appeared in 2013. The majority of studies were cross-sectional (n=35) and included more than 100 participants (n=27). The most frequently studied chemicals were phthalates (n=23), followed by parabens and phenols (each n=18), and then PFAS (n=1). The biological matrix mainly used was urine (n=36). Thirty-one studies reported at least one positive association between personal care products and certain chemical classes, such as between makeup and parabens; lotion and phenols; and perfume and phthalates.
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Development of Photochemically Initiated Direct and Indirect Luminescence Detection Methods for Liquid Chromatography (LC) and Study of Aromatic Sulfonates and Phospholipids Using Reversed Phase Ion-Pair LC-Mass SpectrometryZhang, Wei 13 November 2003 (has links)
No description available.
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