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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Self-assembly of Benzenesulfonate Amphiphiles and Synthesis of Membranes Containing Self-assembled Supramolecular Transport Channels

Song, Enfeng 07 January 2014 (has links)
Six series of cunitic amphiphiles based on benzene sulfonates were synthesized. The molecular characterization was performed by IR and NMR spectroscopy and the purity was determined by elemental analysis and thin layer chromatography. The thermotropic properties of these cunitic sulfonate amphiphiles were subsequently investigated by means of a combination of DSC, polarized microscopy and X-ray scattering. Most of the synthesized sulfonates were found to exhibit hexagonal columnar mesophases, some of them exhibited a complex polymorphism. The polymorphism depended upon variation of the molecular structure. The Six series of cunitic amphiphiles based on benzene sulfonates were synthesized. The molecular characterization was performed by IR and NMR spectroscopy and the purity was determined by elemental analysis and thin layer chromatography. The thermotropic properties of these cunitic sulfonate amphiphiles were subsequently investigated by means of a combination of DSC, polarized microscopy and X-ray scattering. Most of the synthesized sulfonates were found to exhibit hexagonal columnar mesophases, some of them exhibited a complex polymorphism. The polymorphism depended upon variation of the molecular structure. The phase behavior was determined by the nature of headgroup cation Mn+ (n=1, 2), and for the same Mn+ by the carbon number at the hydrophobic tail and by temperature as well. The lyotropic properties of these cunitic sulfonate amphiphiles were also studied by investigating their gelation behavior and gelling capability. A number of the amphiphiles were found to be favorable organogelators that gel various organic solvents of either high or low polarity upon self-aggregation driven by the Coulomb interaction. The morphological results by means of SEM and TEM demonstrate that the organogelators are able to form fibrous network microstructures by self-organization and self-aggregation. The cylindrical aggregates with sulfonated headgroup in the center as well embody the potential to construct ion-selective transport membranes. The cunitic amphiphiles containing polar sulfonate units at their focal point and polymerizable olefin group on their periphery were exploited to prepare functional membranes that contain ion-active transport channels. The ion-selectivity of the formed membranes was investigated by means of ion transport experiments with LiCl, NaCl, KCl solutions of different concentration. By comparison of the ion transport rates across the membranes the ionic permselectivity was demonstrated.
2

Ionisation par faisceau d'électrons de solutions aqueuses de benzènesulfonate et naphthalènesulfonate et sous-produits / Ionization by electron beam of aqueous solutions of naphthalenesulfonate, benzenesulfonate and by-products

Alkhuraiji, Turki 17 April 2013 (has links)
Ce sujet entre dans le cadre de l'étude d'un procédé d'oxydation avancé innovant dans le domaine de la dépollution des eaux, à savoir l'ionisation par faisceau d'électrons. Le radical hydroxyle (•OH) et l'électron hydraté (e−aq) sont les deux espèces majoritaires issues de l'ionisation de solutions aqueuses par un faisceau d'électrons d'intense énergie. Il a été démontré que la génération des radicaux supplémentaires tels que le radical sulfate (SO4•−) et le radical hydroxyle par les réactions radicalaires entre l'ion persulfate, le peroxyde d'hydrogène et l'électron hydraté respectivement, améliore l'efficacité de ce procédé pour la dégradation de polluants organiques en solution aqueuse. Dans le présent travail, la dégradation et la minéralisation de benzènesulfonate et naphthalènesulfonate de sodium, et d'acide gallique ont été obtenues par irradiation par faisceau d'électrons seul et couplé avec un oxydant (S2O8−−, H2O2). En absence d'oxydant une dose absorbée de 1,5 kGy a été suffisante pour l'élimination totale de ces composés. La présence d'oxydant permet généralement de réduire les doses d'irradiation nécessaires. Par ailleurs, l'augmentation de la concentration en oxydant ou de la dose appliquée a un effet bénéfique vis-à-vis de l'élimination du carbone organique. Cependant, le couplage S2O8−−/faisceau d'électrons est plus adapté que le couplage H2O2/faisceau d'électrons même en présence de constituants inorganiques. Les résultats obtenus soulignent l'importance du rôle du dioxygène dissous lors de l'étape de la minéralisation en vue de favoriser la formation des radicaux organiques (ROO•). Pour chaque une des molécules étudiées, des sous-produits d'oxydation... / This research belongs to the study of the ionization of aqueous solutions by electron beam (E.B.) as an advanced oxidation process for water treatment. The hydroxyl radical (•OH) and hydrated electron(eaq¯) are the two major active species produced from the ionization of aqueous solutions by high energy electron beam. It has been shown that the generation of additional radicals such as the sulphate radical (SO4•¯) and hydroxyl radical from the reaction of persulfate ion (S2O8¯) or hydrogen peroxide (H2O2) with the hydrated electron, improved the efficiency of this process towards the degradation and mineralization of organic pollutants in aquaeous solution. In the présent work, the degradation and mineralization of naphthalenesulfonate, benzenesulfonate and gallic acid were studied by electron beam irradiation alone and coupled with oxidants (S2O8¯, H2O2).In the absence of oxidant, an absorbed dose of 1,5 kGy leads to total elimnation of these pollutants. The presence of added oxidants usually reduces the radiation dose required. In addition, increasing oxidant concentration or applied dose had a beneficial effect towards the organic carbon removal. It was found that coupling E.B./S2O8¯ has more suitable than E.B./ H2O2 even in the presence of inorganic constituents. The results also highlighted the importance of dissolved oxygen in the system when mineralization is aimed. For each of the molecules studied, oxidation by-products resulting from hydroxylation and aromatic ring opening were identified.

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