Dissertations / Theses on the topic 'Membrane d’ultrafiltration en PES'

L’ultrafiltration (UF) du lait écrémé pour la standardisation de la teneur en protéines pour la fabrication des fromages est un procédé membranaire très répandu à l’échelle industrielle. Cependant, le colmatage des membranes par des protéines du lait écrémé provoque une baisse de la productivité et constitue un verrou de ce procédé.Ainsi, l’étape de nettoyage/désinfection bi-quotidienne est indispensable afin de restaurer les performances de la membrane et d’assurer la sécurité sanitaire ainsi que la qualité des produits. Elle est en général réalisée avec des détergents formulés alcalins et acides mais il est également possible d’utiliser des détergents enzymatiques formulés ayant la réputation d’être plus efficaces. Cependant, peu d’études fondamentales existent à ce sujet, ce que cette thèse se propose de contribuer à combler. L’objectif de cette thèse a été de développer de nouveaux détergents enzymatiques efficaces et compatibles avec la membrane en PES/PVP largement utilisée pour l’UF de lait écrémé. La cible du nettoyage est un dépôt de protéines. La démarche s’est appuyée sur une méthodologie d’aide à la formulation de détergents fondée sur la mesure des dépôts résiduels sur la membrane par ATR-FTIR: que ce soit les protéines, les enzymes ou les autres constituants des détergents étudiés. De multiples prototypes ont été formulés en collaboration avec la société Kersia. Leur évaluation a suivi 3 étapes: i) des tests rapides en réacteur fermé (14 cm²) pour sélectionner les détergents prometteurs selon leur efficacité d’élimination du colmatage protéique, leur rinçabilité et le respect de l’intégrité de la membrane à court termes, ii) la transposition des résultats prometteurs en condition de filtration (127 cm²) validant également la filtrabilité des détergents, iii) enfin, la validation de la compatibilité détergent/membrane sur le long terme grâce au vieillissement accéléré sous micro-onde (3 cm²), et au nettoyage d’une membrane spirale (6.8 m²) pendant 52 heures
Ultrafiltration (UF) of skim milk for standardization of the protein content for cheese making is a very common membrane process at industrial scale. However, fouling of the membranes with skim milk proteins causes a drop in productivity and constitutes a barrier to this process. Thus, the twice-daily cleaning/disinfection step is essential to restore the performance of the membrane and ensure health safety and product quality. It is generally carried out with alkaline and acidic formulated detergents, but it is also possible to use formulated enzymatic detergents which enjoy the reputation of being more effective. However, few fundamental studies exist on this subject, which this thesis aims to contribute to fill. The objective of this thesis was to develop new enzymatic detergents that are are effecient and compatible with the PES/PVP membrane widely used for skim milk UF. The target of the cleaning is a protein deposit. The approach was based on a methodology to aid the formulation of detergents based on the measurement of residual deposits on the membrane by ATR-FTIR: whether proteins, enzymes or other constituents of the detergents studied. Mutliple prototypes were formulated in collaboration with Kersia Company. Their evaluation followed 3 steps: i) rapid tests in a batch reactor (14 cm²) to select promising detergents according to their effectiveness in eliminating protein fouling, their cleanability and the integrity of the membrane in the short term, ii) transposition of promissing results under filtration conditions (127 cm²) also validating the filterability detergents, iii) finally, validation of detergent/membrane compatibility over the long term thanks to accelerated aging under microwave (3 cm²) and cleaning of the spiral wound membrane (6.8 cm²) for 52 hours

Many studies focused on the improvement of membrane performance by addition of nanofiller creating the so-called mixed matrix membranes. In this work, the feasibility of producing a multi-layer selective membrane for carbon dioxide separation is analysed. Two different deposition technique, 2-D printing and Mayer bar deposition, were explored. The multi-layer membranes were composed by a support layer of polyethersulfone and a selective layer of polyvinyl amine and graphene. Some consideration about ink formulation for 2-D printing were also developed in this work.

Les protéines solubles du lait de vache ont un intérêt reconnu dans les industries agro-alimentaire en raison de leur valeur nutritionnelle et de leurs propriétés techno-fonctionnelles. A condition de valider que les protéines ne sont pas dénaturées par les procédés membranaires, ceci pourraient être utilisés à l’échelle industrielle pour la préparation de fractions protéiques à fonctions ciblées. Cette thèse propose une première partie sur la mise au point d’une méthodologie pour étudier la possibilité de dénaturation des protéines par des membranes fortement rétentives en comparant avec des expériences modèles de dénaturation mécanique et thermique (mixeur, agitateur magnétique et bain marie). L’analyse par fluorescence intrinsèque et HPLC en phase inverse pour laquelle de nouveaux gradients ont été mis au point pour chaque protéine, s’avèrent être deux outils pertinents pour la mise en évidence de la dénaturation ciblées. Par ailleurs, les procédés à membranes génèrent des volumes d’effluents qui doivent être minimisés pour une production éco-compatible et durable. La deuxième partie de cette thèse propose une démarche pour une valorisation des effluents globaux après traitement par ultrafiltration pour le nettoyage de membranes PES spirales colmatées par du lait écrémé
The soluble proteins of cow milk have an interest recognized in the food industry because of their nutritional values and their techno-functional properties. Provided to validate that the proteins are not denatured by membrane processes, this can be used at industrial scale for preparation of proteins fractions with targeted functions. The first part of this thesis is focused on a methodology to study the possibility of the denaturation of proteins by highly retentive membranes in comparison with model experiments of mechanical and thermal denaturation (blender, magnetic stirrer and Marie bath). The analysis of intrinsic fluorescence and reversed phase HPLC for which new gradients were proposed for each protein, prove to be two relevant tools for highlighting targeted denaturation. Moreover, the membranes processes generates large volumes of effluents that must be minimized for an eco-friendly and sustainable production. The second part for this thesis proposes a step for a valorization of global effluents after ultrafiltration for the cleaning of spiral wounded PES membranes fouled by skim milk

Le nettoyage en place des membranes en industrie agro-alimentaire est une opération cruciale qui, outre les exigences de sécurité sanitaire des installations et des produits traités doit permettre de restaurer les performances de la filtration (sélectivité, flux) en éliminant le colmatage formé pendant l'étape de production. Malheureusement cette étape repose encore sur des bases empiriques et non optimisées. A cause d'un manque de notions fondamentales, elle est encore pressentie comme un frein à l'utilisation massive des procédés membranaires. Une démarche originale a été menée dans le cadre de cette thèse incluant la réflexion sur l'incidence des paramètres hydrodynamiques des conditions de production sur la cohésion du dépôt colmatant et plus particulièrement de sa fraction irréversible, dont la nettoyabilité est étudiée. Pour fonder cette démarche, une étude comparée du colmatage et du nettoyage au flux limite et au flux critique a été réalisée en intégrant le rôle de la physico-chimie et de l'hydrodynamique pendant la phase de production. cette étude s'inscrit dans un cadre d'éco-conception de procédé, avec une analyse de cycle de vie réalisée afin d'estimer l'impact environnemental de l'étape de nettoyage via divers scénarii simplifiés.

Ces travaux portent sur l'étude du vieillissement de membranes d'ultrafiltration en PES / PVP. Ils sont motivés par le constat industriel de l'endommagement des membranes au cours de leur utilisation. Il est démontré que l'hypochlorite de sodium utilisé lors des procédures de lavages sur site de production d'eau potable est le principal responsable du vieillissement des membranes. Cette dégradation chimique conduit à une oxydation radicalaire de la PVP (avec et sans rupture de chaînes), entraînant son élimination partielle de la structure de la membrane. Ce phénomène provoque une augmentation de la perméabilité à l'eau pure, une diminution de la sélectivité et une altération des propriétés mécaniques de la membrane. Une relation directe entre l'évolution de l'allongement à la rupture (déterminé par essais de traction) et la quantité de PVP contenue dans les 40 premiers microns en dessous de la surface de la membrane est notamment établie. Nous mettons également en évidence la relative stabilité de la PES. L'exposition de la PES à l'hypochlorite provoque la formation de phénols ortho-substitués (sans rupture de chaînes), uniquement en présence de PVP. En plus de l'altération de la sélectivité et des propriétés mécaniques, d'un point de vue applicatif, ces modifications chimiques donnent lieu à une augmentation de la sensibilité au colmatage. Les résultats de cette étude de vieillissement accéléré en laboratoire sont supportés par l'analyse de membranes issues de modules ayant opéré durant plusieurs années sur site de production d'eau potable. En effet, les marqueurs macroscopiques et moléculaires de la dégradation présentent, dans les deux cas, les mêmes évolutions. Cependant, l'accent est mis sur l'invalidité du concept de dose, très largement utilisé pour quantifier l'avancement de la dégradation. En effet, nous démontrons que, dans la gamme de concentrations et de temps que nous avons étudié, il existe un effet prépondérant de la concentration par rapport au temps
Motivated by drinking water production plants reporting membrane failure issues, this study investigates the ageing of a commercially available PES / PVP UF hollow fiber. Proof is given that membrane degradation is mainly induced by sodium hypochlorite exposure. The effects on the PES chemical structure are limited, very low extend of chain scission occurs and the formation of an ortho-substituted phenol is observed as the main modification. Experiments show that the presence of PVP and/or PVP degradation products is a required condition for the PES oxidation to occur. On the other hand, PVP appears to be very sensitive to hypochlorite exposure. PVP radical oxidation mechanisms are identified presenting a maximal reaction rate for neutral to slightly basic pH and leading to the partial removal of the PVP degradation products from the membrane structure. Correlation of macroscopic and molecular characterizations demonstrates that PVP degradation is responsible for the membrane integrity loss (impairing selectivity and mechanical performance), while hypochlorite exposure also induces enhanced membrane / solutes interactions, leading to an accentuated fouling. The representativeness of static continuous hypochlorite exposure regarding the actual on-site membrane ageing is confirmed by the analysis of membranes extracted from an industrially operated module. Nevertheless, the hypochlorite dose parameter, widely used in the literature, is demonstrated to be inappropriate to describe the degradation rate: the hypochlorite concentration impact is shown to be dominating the exposure time impact on the degradation rate

Actuellement, les émissions de CO₂, principal responsable du réchauffement climatique, augmentent à un rythme alarmant. Par conséquent, il existe un besoin mondial croissant de technologies de pointe capables de séparer et de capturer efficacement le CO₂. Dans ce travail, une série de membranes composites PSF/IL et PES/IL pour la séparation du CO₂ ont été étudiées. Six IL ([Meim][TFSO₃], [Vim][TFSO₃], [Meim][Tf₂N], [Vim][Tf₂N], Li(DOBA)[Tf₂N] et Li(HDA)[Tf₂N]) ont été synthétisés avec succès et caractérisés par FT-IR, 1H RMN, TGA et DSC. Des membranes composites avec différentes quantités d'IL ont été fabriquées par évaporation de solvent puis étudiées par FT-IR, TGA, DSC, MEB, cartographie du F, énergie de surface, essais de traction et perméation aux gaz (CO₂, N₂ et O₂). A 25°C et 4 bar, la membrane PES/10[Vim][Tf₂N] présente une perméabilité au CO₂ de 1,92 Barrer avec des sélectivités CO₂/N₂ et CO₂/O₂ améliorées de 20,4 et 6,1, respectivement
Currently, the emission of CO₂, which is the primary contributor to global warming, is increasing at an alarming rate. Consequently, there is a growing global need for cutting-edge technologies that can effectively separate and capture CO₂. In the present work, a series of PSF/IL and PES/IL composite membranes for CO₂ separation were investigated. Six ILs ([Meim][TFSO₃], [Vim][TFSO₃], [Meim][Tf₂N], [Vim][Tf₂N], Li(DOBA)[Tf₂N] and Li(HDA)[Tf₂N]) were synthesized successfully and characterized by FT-IR, 1H NMR, TGA and DSC. Composite membranes with different IL loadings were fabricated by solution casting method and exhaustively studied by FT-IR, TGA, DSC, SEM, F-mapping, surface energy, tensile tests, and gas permeation (CO₂, N₂ and O₂). Under 25°C and 4 bar, PES/10[Vim][Tf₂N] membrane showed a CO₂ permeability of 1.92 Barrer with improved CO₂/N₂ and CO₂/O₂ selectivities of 20.4 and 6.1, respectively

Les polymères sont à l’heure actuelle étudiés dans de nombreux domaines comme la chimie, la biochimie, les nanotechnologies, l'électronique, la médecine ou encore les sciences des matériaux et trouvent des applications dans des domaines comme l’industrie automobile, la chimie fine. L’objectif de cette thèse est de réaliser la fonctionnalisation de polymères et de modifier les propriétés de ces matériaux afin d’envisager des nouvelles applications. Nous nous sommes intéressés à des polymères de la famille des poly(aryle éther) et plus particulièrement au poly(éther éther cétone) (PEEK). Ce polymère est connu pour ses propriétés mécaniques, thermiques, électriques ou encore pour sa résistance aux produits chimiques. Dans le premier chapitre, il est question de la fonctionnalisation des différents polymères de départ par des fonctions chlorures de sulfonyle, acides sulfoniques et sulfonamides. Le second chapitre est consacré à la synthèse et à l’étude électrochimique de nouveaux électrolytes polymériques et à de nouvelles membranes pour d’éventuelles applications dans le domaine des batteries au lithium et au sodium, ainsi que dans le domaine des piles à combustible. Dans un troisième chapitre, la préparation de nouveaux catalyseurs métalliques dérivés d’acides sulfoniques polymériques est discutée. Une étude de l’activité catalytique de ces différents catalyseurs a été réalisée sur la réaction d’acylation de Friedel-Crafts. Le quatrième chapitre est consacré à la préparation de nouveaux matériaux ayant des propriétés optiques intéressantes. Enfin dans un cinquième chapitre, la préparation et l’étude de nouveaux matériaux ayant des propriétés antibactériennes sont exposées
Polymers are now being studied in many fields such as chemistry, biochemistry, nanotechnology, electronics, medicine or material science and have applications in areas such as automotive industry, food industry, fine chemistry. The objective of this thesis is to achieve the functionalization of polymers and modify the properties of these materials in order to consider new applications. We were interested in polymers with the poly(aryl ether) motif, more particularly poly(ether ether ketone) (PEEK). This polymer is known for its mechanical, thermal, electrical properties and for its resistance to chemicals. In the first chapter, we present the functionalization of different polymers by sulfonyl chloride, sulfonic acid and sulfonamide functions. The second chapter is devoted to the synthesis and electrochemical study of novel polymeric electrolytes and new membranes for potential applications in the field of lithium and sodium batteries, as well as in the field of fuel cells. In the third chapter, the preparation of new metal catalysts derived from polymeric sulfonic acids is discussed. A study of the catalytic activity of these different polymeric catalysts was carried out on the Friedel-Crafts acylation reaction. The fourth chapter is devoted to the preparation of new materials with interesting optical properties. Finally, in the fifth chapter, the preparation and the study of new materials with antibacterial properties are reported

碩士
淡江大學
化學工程與材料工程學系碩士班
106
In this research, we introduce TiO2 sol (synthesized via the sol-gel procedure) and polyvinylpyrrolidone (PVP) into the casting dope for polyethersulfone (PES)/TiO2 composite membrane formation. The former additive is used to enhance the hydrophilicity, whereas the latter functions as a pore former to engender pore-pore interconnection. Prepared membranes (termed mixed matrix membrane, MMM) can be divided into 3 series: P0, P1.5 and P5, according to the amount of added PVP. Each series consists of several membranes with TiO2 contents. To disperse TiO2 finely (on the scale of 2-3 nm) in the casting dope, the sol-gel process incorporates DMAc as the solvent, same as that used for preparation of the casting dopes. All membranes show the asymmetric structure with a dense surface (skin) and a porous cross section composed of finger-liked macrovoids and large irregular macrovoids. With the increase of added PVP, the pores on the top and bottom surfaces increase, resulting in an increase of the pure water flux, while the irregular large macrovoids gradually transform into finger-liked macrovoids. Changing the amount of added TiO2, the surface pore size of the membrane is found to increase first and then decrease; the pure water flux follows the same trend. The porosity of the membrane is about 80-88%, and the contact angle of the top surface gradually decreases with the addition of TiO2. The tensile strength decreases with the increase of added amount of PVP, which is attributed to the larger pores of the top and bottom surfaces. However, when the added PVP is fixed, the tensile strength increases first and then decreases with the addition of TiO2. The amount of PVP resided in the membrane has been determined by NMR analysis. The results show that about 90% of the PVP is removed during the membrane formation process and the residual amount only accounts for 1-2% of the membrane weight. Thermal properties based on TGA and DSC analysis show that the thermal stability of the membrane increases with the TiO2 content: an increase of 5C on the maximum thermal degradation temperature and 10C of the glass transition temperature. The BSA filtration experiments show that the rejection ratio of the P0 and P1.5 series are both 99% and yet it is only about 93% for the P5 series. As to the pure water flux and the recovery ratio, both increase first and then decrease with the TiO2 content. The reason is that TiO2 can increase the hydrophilicity of the membrane surface and thus reduces the hydrophobic adsorption of BSA on the surface. However, excessive amount of TiO2 can cause agglomeration of TiO2, which in turn lead to decrease of its antifouling efficiency. PEG is used to determine the molecular weight cut-off (MWCO) of the membranes. For the P0 series, the MWCO is about 270-350 kDa, for the P1.5 series, it is about 325-510 kDa, and for the P5 series, it is about 450-850 kDa. These results are consistent with the pure water flux and the pore size data.

Efforts in treatment of acid mine drainage (AMD) have been fraught with limitations for the mining industry. Membrane filtration technology is a new alternative employed to treat AMD in this work. A commercially available polyethersulfone (PES) hollow fibre nanofiltration membrane was investigated for its likelihood for the treatment of AMD. The system was configured in a cross flow set up and effects of pH, feed flowrate and operation time were explored in relation to the membrane performance (rejection and flux). Acid mine collected from site had a very high concentration of Iron (1.055 mg/L), sulphate (3639.301 mg/L) and high levels of hardness due to magnesium ions (523.011 mg/L). Also, heavy metals were in trace amounts. Experimental results showed that the maximum rejection of iron was 96.28 % at a pH of 4.37, maximum feed flowrate of 872ml/min and the iron permeate concentration was within the potable water standards (less than 0.100mg/L) inferring suitability of the membrane for AMD amelioration at the aforementioned pH. Furthermore, maximum rejection of sulphate ions was 97.30% at a pH of 6.55 and maximum feed flowrate. In addition, the membrane was efficient in curbing the hardness (91.99 % rejection) of the AMD to the accepted water standards at the pH of 4.37. The reduction of hardness levels, iron, and sulphate concentrations by the membrane were attributed to steric (size) exclusion and electrostatic interaction mechanisms. Although the membrane had a large surface area (2m2), the flux was not that high (ranged from 3 - 4.5 L/m2hr). Further studies on modification of the polyethersulfone polymer matrix within the realm of enhancing its hydrophilicity henceforth flux are desirable.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2008.
Source: Dissertation Abstracts International, Volume: 69-05, Section: B, page: 3200. Adviser: Mark M. Clark. Includes bibliographical references (leaves 99-108) Available on microfilm from Pro Quest Information and Learning.

A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, in fulfillment of the requirements for the degree of Master of Science in Engineering, 2020
The existence of the petroleum industry is vital to many industries and accounts for a large percentage of the world's energy supply. However, it also poses a serious threat due to the amount of wastewater produced daily, which needs to be treated to meet the EPA regulatory standards before disposal to the environment. In this study, blended Polysulfone (PSF) and Polyethersulfone (PES) polymeric membranes were synthesized for the treatment of phenol-containing wastewater. The main aim was to enhance the quality and separation performance of the membranes by improving its mechanical strength, morphology, and hydrophilicity. This is because polymeric membranes are commonly brittle and foul easily due to their hydrophobic nature, and this limits their commercial application. Polymer blending is one of the modifying techniques currently being explored to develop materials with unique anticipated properties depending on the type of membrane needed. The blended membranes were synthesized at different PSF: PES ratio (100%:0%, 0%:100%, 50%:50%, 80%:20%, 20%:80% and 25%:75%) via the phase inversion method using N-Methyl-2-pyrrolidone (NMP) as the solvent. The thermal property, surface roughness, and mechanical strength of the membranes were checked using Thermogravimetric analysis (TGA), Atomic force microscopy (AFM), and nano-tensile measurement, respectively. The performance of the membrane was tested through pure water permeation and separation of phenol and benzene from synthetic wastewater containing 20 ppm of phenol and 20 ppm of benzene using a dead-end filtration cell at a feed pressure of 100 kPa. AFM images show lower roughness in the pure PSF membrane as compared to the blended membranes. The tensile strength only improved on the 25%:75% membrane while the elasticity increased with an increase in PES concentration in the blended membranes. The flux, % rejection, and porosity as the performance criteria of membranes showed an improvement in the majority of the blended membranes than in pure PES and PSF membranes. The PSF/PES blend of 25:75 wt% produced highly desirable results based on its performance and quality. These results demonstrate the significance of blending polymeric membranes to modify their specific properties for the desired function and highlight the possibility of more commercial applications. Furthermore, the best-performing blended membrane obtained from the previous experiment was then embedded with pure CNTs (pCNTs) to investigate if CNTs will further enhance the quality and separation performance of the membrane due to the unique physicochemical and antifouling properties of pCNTs. The pCNTs were also functionalized using acid treatment to enhance their hydrophilicity, mechanical strength and dispersion capability, and then dispersed into the best-performed blended membrane. The best-performing blended membrane was loaded at different concentrations of pCNT, e.g. 0.5% pCNT, 1% pCNT, 1.5% pCNT and one with 1% functionalized CNTs (fCNTs). The same characterization methods used to evaluate the blended membranes were applied. The performance of these membranes was also tested through pure water permeation and separation of phenol and benzene from synthetic wastewater containing 20 ppm of phenol and 20 ppm of benzene using a dead-end filtration cell at a feed pressure of 100-300 kPa. The results show that embedding CNTs in the blended polymer (PSF/PES) increased both the porosity and water absorption capacity of the membranes, thereby resulting in enhanced water flux up to 309 L/m2h for the 1.5 wt.% pure CNTs loaded membrane and 326 L/m2h for 1 wt.% functionalized CNT-loaded membrane. Infusing the PSF/PES membrane with CNTs enhanced the thermal stability, and mechanical strength as well. Results from AFM indicate enhanced hydrophilicity of the membranes, translating in the enhancement of the anti-fouling property of the membranes. The % rejection of benzene and phenol in membranes with CNTs decreased with an increase in pCNTs concentration and pressure, while it increased in membranes embedded with fCNTs. The % rejection of benzene in pCNTs membrane decreased with 13.5% and 7.55% in fCNT membrane while phenol decreased with 55.6% in pCNT membrane and 42.9% in the FCNT membrane. This can be attributed to poor CNT dispersion resulting in increased pore size observed when CNT concentration increased. Optimization of membrane synthesis might be required to enhance the separation performance of the membranes. loaded membrane. Infusing the PSF/PES membrane with CNTs enhanced the thermal stability, and mechanical strength as well. Results from AFM indicate enhanced hydrophilicity of the membranes, translating in the enhancement of the anti-fouling property of the membranes. The % rejection of benzene and phenol in membranes with CNTs decreased with an increase in pCNTs concentration and pressure, while it increased in membranes embedded with fCNTs. The % rejection of benzene in pCNTs membrane decreased with 13.5% and 7.55% in fCNT membrane while phenol decreased with 55.6% in pCNT membrane and 42.9% in the FCNT membrane. This can be attributed to poor CNT dispersion resulting in increased pore size observed when CNT concentration increased. Optimization of membrane synthesis might be required to enhance the separation performance of the membranes
CK2021

碩士
中原大學
化學工程研究所
98
The purpose of this study is to investigate the effect of the substrate surface morphology on the physical structure of plasma-polymerized films. The wet-phase inversion method was used in fabricating the substrate, and by means of changing the membrane formation path, poly(ether sulfone) (PES) substrates with three different surface types (dense skin layer, porous skin layer, and skin-free layer) were formed. Radio frequency-plasma enhanced chemical vapor deposition (RF-PECVD) was the technique applied to conduct the acetylene gas plasma polymerization to deposit plasma-polymerized layer on a substrate with a high homogeneity and good adhesion properties, resulting in the preparation of an asymmetric membrane with a high flux. Scanning electron microscopy (SEM) was used to observe the change in the structure of the plasma-polymerized membrane, and it was combined with the positron annihilation spectroscopy (PAS) technique to investigate the change in the nano-structure of the different layers of the plasma-polymerized composite membrane and to clarify the effect of the substrate surface morphology on the plasma-polymerized layer physical composition. It can be found from the water vapor permeation results that at similar deposited layer thicknesses, different substrate surface morphologies influenced the characteristic permeation rate in the plasma-polymerized composite membrane. With a substrate surface with a lacy-like skin-free structure, a plasma-polymerized layer with a low permeation resistance could be obtained. On investigating the effect of plasma parameters (plasma power, deposition time, acetylene gas feed flow rate, and argon gas amount) on the plasma-polymerized layer structure of different substrate surface morphologies, substrates with different surface morphologies underwent the same change after the plasma polymerization reaction and their polymerized layer deposits had similar thicknesses; changes in the plasma power, feed gas flow rate, and deposition time produced similar trends of changes in polymer layer deposition rates. When the substrate surface morphology was discontinuous, there was a probability to produce a deposited layer with a pillar-like structure; however, with increasing deposited layer thickness, the pillar-like structure would gradually become not obvious. The composite membrane microstructure was investigated further by means of the positron annihilation spectroscopy technique. Based on the VEPFIT software analysis, the change in S parameter values for different layers was shown from best fittings, and with a PES substrate surface with a dense skin layer (T1) or a porous skin layer, a three-layer model produced best fitting results; with a PES substrate surface with a lacy-like structure (T3), a four-layer model gave best fitting results. The structures of T1 and T2 plasma-polymerized composite membranes had three layers: (I) acetylene plasma-polymerized layer, (III) transition layer, and (IV) PES substrate; however, the T3 substrate whose pores were filled with a polymer due to the plasma polymerization reaction had additional pre-transition layer formed by acetylene plasma polymer and PES polymer coexisting in a mixed layer (II). These results explicitly explain the substrate surface morphology influence on the internal structure of the plasma-polymerized deposited layer, especially in the transition layer region.

碩士
中興大學
化學工程學系所
99
This research was distributed into two different topics and discussed. In first part, PES/montmorillonite (MMT) and PES/TiO2 composite membranes were successfully prepared via phase inversion method. The thicknesse of these composite membranes were about 25 μm. The crystal structure, thermal stability, morphology, permeation performance were characterized in detail. XRD, DSC and TGA results showed that the interaction existed between MMT or TiO2 nanopaticles and PES and the thermal stability of the composite membrane had been improved by the addition of these nanopaticles. The transport of carbon dioxide and methane through these composite membranes has been discussed. The gas permeation measurements were conducted using a semi-open cell which is divided into two parts by the membrane. A constant pressure was maintained at the feed side, while a vacuum was created at the permeate side in the beginning of experiment. The CO2 or CH4 permeability increased in case of PES/MMT membrane with growing different contents, and the selectivity decreased with increasing MMT content. The PES/TiO2 membrane did not show any significant change in permeability. The permeability of both gases increased then decreased with increasing TiO2 content ，the highest value of CO2 and CH4 about 5.7 and 0.33 barrer were obtained at PES/20% TiO2. With growing TiO2 content, the separation factor increased than decreased. The highest value was about 38.5 at PES/4% TiO2. In second part, three different kinds of ionic liquid were prepared into a supported liquid membrane in sandwich form using PES/30% MMT as a support. The gas permeation was determined by using the same instrument with first part. The permeability of carbon dioxide of these three ionic liquid were about 1.5-3.5 barrer, and the permeability of methane were about 0.035-0.091 barrer. It`s very low for comparing with some literature using the same ionic liquid. But the selectivity was almost higher than some reference. It seem`s that the result was led because of the configuration of supported liquid membrane.

MSc. (Applied Chemistry)
Remediation of POPs particularly the chlorinated compounds in water is therefore crucial. This research work describes the modification of polyethersulfone (PES) thin-film membrane composite (TFC) with functionalised carbon nanotubes (f-CNTs) using the phase invasion method. The oxidised CNTs were successfully decorated with Zero-Valent (ZV) Fe/Ni nanoparticles for the adsorption and degradation studies of polychlorinated organic pollutants (in this case the dichlorodiphenyltrichloroethanes (DDTs)). The in situ modification procedure was carried out using different quantities (0.04 wt%, 0.1 wt% and 0.2 wt%) of Fe/Ni-f-CNTs nanohybrids dispersed in a DMAc solution and dipping the polyethersulfone powder into a suspension containing the Fe/Ni-f-CNTs to form a nano-composite membrane. The formed composite membrane characteristics were investigated with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle (CA) and X-ray diffraction spectroscopy (XRD). The incorporation of nanohybrid in the PES membrane was found to increase the surface smoothness and the hydrophilicity of the composites. In addition, there was an increase in the adsorption of DDTs with increase in the nano-hybrid loading as indicated by the adsorption studies using the Langmuir isotherm and Freundlich isotherm studies. The data obtained from the batch studies closely fitted with the Langmuir isotherm based on the characteristic parameter RL found to lie within the standard range 0 < RL < 1 .