A Twyman-Green interferometer was used to study the selective transport of ethanol-water mixtures of various concentration across a nonporous homogeneous silicone rubber membrane at 25°C. The instrument developed enabled the measurement of the transient concentration profiles within the boundary layers bathing the membrane. Measurements as close as 5um from the membrane surface were possible. The majority of the reported interferometric studies of liquid/membrane transport have been limited to the observation of the fringes and stop short of a full theoretical analysis. Such analysis is complicated by the optical effects of light deflection and the computational burden involved in the transient solution of the mathematical models required to describe membrane transport. A rigorous treatment of light deflection was developed on the basis of Fermat's principle of least time. The transient numerical solution of the model equations was accomplished by the application of the method of lines. To decouple the equilibrium and kinetic phenomena in membrane transport requires the independent measurement of the sorption isotherm. Traditional techniques for measuring the extent and composition of the imbibed phase involve removing the membrane from the liquid and are therefore limited by the inherent difficulties of obtaining a 'clean' separation. This was circumvented by measuring the excess (relative) sorption isotherm without removing the membrane from the liquid. The data was analysed in terms of Flory-Huggins thermodynamics which was fitted to the measured excess isotherm across the entire concentration range. For a binary mixture, transport across a homogeneous membrane involves two simultaneous fluxes which can be coupled through kinetic and/or equilibrium interactions. A measure of the extent of coupling was obtained by comparing the results from a simplified 'decoupled' flux model with those based on a 'coupled' flux model allowing for equilibrium interactions. Such interactions were found to have little effect on the flux of ethanol but strongly influenced the flux of water across silicone rubber. In particular, coupling through equilibrium interaction was found to be responsible for as much as 75% of the total flux of water. The diffusion coefficients of both ethanol and water in silicone rubber were shown to decrease strongly with alcohol concentration.

Separation of dissolved metals from aqueous solutions using liquid membrane technology is highly advantageous owing to the degree of separation achieved, efficiency and application potential. In the present investigation four types of liquid membranes - bulk liquid membrane (BLM), emulsion liquid membrane (ELM), electrostatic pseudo liquid membrane (ESPLIM) and unified liquid membrane (ULM) have been extensively studied, for their application in extraction and concentration of dissolved metals from effluents. Experiments were conducted with various metal systems to optimize both system and process conditions and to find out the effect of various parameters on the performance of the process. Different mass transport models were proposed for each type, taking diffusional and kinetic resistances into account. Models were extended for simultaneous extraction systems and were verified by different metal-carrier experiments. Good agreement was found between the concentration profiles obtained from the models and the experimental data, thereby establishing the validity of models for all the four types of liquid membranes. The stirred cell employed in BLM process eliminates emulsification and demulsification processes. It also provides simultaneous contact of the organic liquid membrane phase with aqueous feed and strip phases. Overall rate expressions for extraction and stripping in BLM are based on an assumed kinetic mechanism to explain the process qualitatively. It was found that the magnitude^ of diffusional and kinetic resistances determines the overall mass transfer coefficient. The relative magnitude of mass transfer coefficient, reaction rate constants and equilibrium constants enables to visualize the controlling regime of the process. The problem of low flux rate due to high diffusion resistances, inefficient operation and exorbitant costs encountered in bulk and supported liquid membranes (SLM) are overcome in an ELM. In the ELM process, an emulsion of organic membrane phase and aqueous inner phase, is dispersed in the continuous aqueous feed phase. This gives a highly selective and ultra thin liquid film generating a large mass transfer area for separation. Experimental results on membrane instability and emulsion swelling indicate that volumetric leakage rate depends linearly on the stirring speed and that the nature of surfactant does not have any appreciable effect on emulsion swelling. A general permeation model was developed taking into account the external mass transfer around the emulsion drop, diffusion in the drop, reaction at the aqueous-organic interface, leakage of the internal phase to the external phase due to membrane breakup and emulsion swelling due to osmotic pressure difference. Model equations with appropriate boundary conditions were numerically solved by orthogonal collocation technique for a set of model parameters obtained either from known correlations or from independent experiments. Comparison of the model predictions with experimental data from the batch permeation of chromium and other metals using carrier Alamine 336 or LIX 64N, shows that the model predictions are in very good agreement with the experimental findings. Further this model can be used to simulate the effects of various experimental conditions such as metal and hydrogen ion concentrations, carrier concentration, drop diameters, etc., for similar systems. Studies on ESPLIM were conducted with the aim of demonstrating the effectiveness of this new separation process and to develop a simple transport model for metal permeation. In the ESPLIM process, a high electrical field (3-5 kV A.C.) is used for phase dispersion. This system consists of a rectangular reactor filled with membrane solution divided into extraction and stripping cells by a centrally placed integrated type baffle which also acts as an electrode. Two more electrodes were placed in the extraction and stripping cells, where feed and strip phases are introduced from the top of the reactor. When high electrical field is applied across the electrodes, fine droplets of feed and strip are formed and are dispersed in extraction and stripping cells where simultaneous extraction and stripping occurs. The process can be viewed as simultaneous counter current extraction and stripping. The aqueous drops coalesce in the settlers at the bottom of the reactor and are removed continuously. Steady state mass transport model proposed for ESPLIM system accounts for the vertical counter-current extraction and stripping processes taking place in the extraction and stripping cells, together with the lateral transport process of the metal-complex and carrier across the two cells through the integrated baffle zone. The model equations were solved analytically to obtain concentration profiles as a function of the height of the reactor. The required parameters such as mass transfer coefficients, diffusion coefficients etc. were estimated using different correlations. Model predictions agreed remarkably well with the experimental data under various process conditions. From this investigation, it was found that ESPLIM is a simple, efficient and economical process and can be applied in a variety of situations. Based on a suitable combination of solvent extraction, dispersion and liquid membrane technique, a new type of separation system called " Unified Liquid Membrane " was developed. The ULM unit was designed and fabricated, and experiments were conducted to evaluate its performance. The ULM is basically derived from ESPLIM by changing the reactor, baffle design and dispersion technique. Aqueous feed and strip phases were atomized using compressed air through a fine nozzle and are dispersed on either side of an integrated baffle plate that divides the reactor into extraction and stripping cells. Tapering bottom of the reactor reduces the dead volume of the liquid in the settlers and the baffle plate remarkably reduces the leakage problem as well as the resistance through the baffle. Experiments were conducted using LIX 64N and Alamine 336 as carriers for copper and chromium and / or zinc. Mass transport model proposed considers both chemical and phase equilibria in extraction and stripping cells, vertical and lateral transport of carrier and complex across the extraction and stripping cells through the baffle zone. The model equations were solved using initial conditions at the top of the reactor, and equilibrium data for extraction and stripping cells. Effect of various experimental conditions and process parameters was simulated using this model and the model predictions are found to be in excellent agreement with the experimental data. The ULM system developed in this investigation overcomes the major limitations encountered with the other types of liquid membranes while retaining all the advantages of this technology. The problem of high mass transfer resistance from bulk phase to metal permeation as in the case of BLM was eliminated by good phase dispersion. Additional resistance to mass transport from solid membrane as in the case of SLM was removed by using an integrated baffle which also avoids problems of membrane instability, pore clogging and selectivity. The complex problems of emulsification and demulsification were completely eliminated making the system much simpler and efficient. Very good phase dispersion was obtained by atomization without the need for either stirring the whole system or application of high electrical field in the reactor. The membrane liquid within the integrated baffle elements allows easy transport of different species between extraction and stripping cells while completely preventing the mixing of the two aqueous phases. The problems of leakage, swelling and occlusion were avoided due to very short residence time of the aqueous drops in the reactor. It was found that the new ULM configuration is simple, elegant, highly efficient and superior to the other types of liquid membrane systems.

No description available.

Extraction processes employing emulsion liquid membranes (ELMs), water-in-oil emulsions dispersed in aqueous phase, have been shown to be highly efficient in removing a variety of organic and inorganic contaminants from industrial wastewaters. As a result, they have been considered as alternative technologies to other more common separation processes such as pressure-driven membrane processes. Unfortunately, a widespread use of the ELM process has been limited due to the instability of emulsion globules against fluid shear. Breakup of emulsions and subsequent release of the internal receptor phase to the external donor phase would nullify the extraction process. Numerous studies have been, therefore, made in the past to enhance the stability of ELMs. Examples include adding more surfactants into the membrane phase and increasing the membrane viscosity. However, increased stability has been unfortunately accompanied by loss in extraction efficiency and rate in most reported attempts. The primary objective of this research is to apply the ELMs in a unique contacting device, a Taylor-Couette column, which provides a relatively low and uniform fluid shear that helps maintaining the stability of emulsion without compromising the extraction efficiency of a target compound. The ELM used in this study is made of membrane phase converted into non-Newtonian fluid by polymer addition, which provides additional uncommon remedy for the problem. This innovative ELM process was optimized to treat various types of simulated industrial wastewaters containing selected phenolic compounds and heavy metals. Experiments performed in this study suggested that the newly developed ELM process achieved exceptionally high overall removal efficiencies for the removal of these target compounds in relatively short contact time. Mechanistic predictive models were further developed and verified with the experimental data. Combined with the experimental data and novel mathematical predictive models, this study is expected to have a high impact on immediate practices of emulsion liquid membrane technologies in relevant industries.

近年発酵生産が注目されているコハク酸の抽出分離法についてイオン液体を含む液膜法及び水性２相抽出法を用いて研究した．イオン液体を含む含浸型液膜により，受容相に塩酸水溶液を用いることでコハク酸の上り坂輸送を達成できた．次にイオン液体を含む高分子溶媒膜によるコハク酸の透過を検討した．最適な条件は含浸液膜と異なり，透過にはコハク酸の各化学種が関与していた．最後に水溶性有機溶媒やイオン液体を用いた水性２相抽出法によるコハク酸の抽出を行った．塩および糖を相分離剤とすることで，発酵液で想定されるコハク酸の80％以上の抽出が達成できた． / Succinic acid is widely used in many industrial sectors; pharmacy, textile, food, etc. The bio-production of succinic acid from renewable resource was desired because the petrochemical production of succinic acid became costly. In this study, the extraction and separation techniques of succinic acid by liquid membranes (LMs) and aqueous two-phase system (ATPS) containing ionic liquids (ILs) were exploited. The permeation mechanisms and optical conditions were elucidated. / 博士(工学) / Doctor of Philosophy in Engineering / 同志社大学 / Doshisha University

As the demand on resources is increasing worldwide, the process of recycling material has become more important. The specific recycling of metals used in car batteries, and more specifically in the large batteries used in hybrid electric vehicles, is a rising concern where the industrially implemented recycling processes concerning these batteries that exist today are often highly pollutant and energy consuming. In the present study, an alternative hydrometallurgical recycling process of the previously and to some extent presently widely used battery type for hybrid electric vehicle applications, namely the Nickel Metal Hydride (NiMH) battery, has been investigated. The focus was to evaluate different routes of recovering Ni, Co, Mn, Zn, Al and residual Y from a NiMH battery leach solution as obtained in a priorly conducted leaching study. Three different possible products were chosen for closer investigation, a mixed metal hydroxide where all of the metals would be precipitated together, a new NiMH cathode material where a controlled precipitation of Ni, Co and Zn together would be implemented and last a pure Ni salt product where a selective separation of Ni from the other metals would be required. Two of the three products, the mixed metal hydroxide and the pure Ni salt, were found suitable for the specific system and it was concluded that a pure Ni salt production would be most justifiable. The separation of Ni from the other metals present in the solution was here proposedly achieved by an extraction process using supported liquid membranes. A mathematical model was used in Matlab in order to evaluate the separation efficiency and to determine the optimum process conditions for the extraction process and a hydroxide precipitation experimental study was conducted in order to determine both the process streams in the production of a mixed metal hydroxide and the solution behavior during the pH increase in the Ni salt production extraction process. The results suggested a low loss of valuable metals and due to this, both the process of producing a mixed metal hydroxide and the process of producing a pure Ni salt could be found to be economically justifiable. / I samband med den ökande efterfrågan på råmaterial världen över så har processer för att återvinna material blivit mer och mer viktiga. Den specifika återvinningen av metaller som använts i bilbatterier, och än mer specifikt återvinningen av de stora batterier som används i hybridbilar är just nu en ökande oro då de rådande återvinningsprocesser som används idag ofta är högst energikrävande och har en stor förorenande inverkan på naturen. I denna studie har en alternativ hydrometallurgisk återvinningsprocess granskats i syfte att återvinna de metaller som används i nickelmetallhydridbatterier (NiMH) som brett har använts för just hybridbilsapplikationer. Fokus har legat på att utvärdera olika möjligheter att återvinna Ni, Co, Mn, Zn, Al och överbliven Y från en laklösning som är ett resultat av en tidigare genomförd lakstudie angående NiMH-batterierna. Tre möjliga produkter valdes för närmare granskning, en blandad metallhydroxid där alla metaller samutfälls ur lösningen, en ny NiMH-katod där en kontrollerad samutfällning av Ni, Co och Zn implementeras och sist ett rent nickelsalt där a selektiv separation av Ni från de övriga metallerna är nödvändig. Två av de tre produkterna, den blandade metallhydroxiden och det rena nickelsaltet, befanns vara lämpliga för det specifika systemet och slutsatsen drogs att en nickelsaltsproduktion var mest berättigad. Den föreslagna separationstekniken för att separera Ni från de andra metallerna i lösningen var en extraktionsprocess användandes av en vätskemembranteknik. En matematisk modell användes med hjälp av Matlab för att utvärdera separationseffektiviteten och för att bestämma optimala processförhållanden. En experimentell hydroxidutfällningsstudie genomfördes även för att bestämma både procesströmmarna i en produktion av en blandad metallhydroxid och för att undersöka lösningens beteende under pH-ökningen i den föreslagna produktionsprocessen av ett nickelsalt. Enligt resultaten är förlusten av värdefulla metaller låga i båda processerna och i enlighet med detta kunde både produktionsprocessen av en blandad metallhydroxid och av ett rent nickelsalt befinnas ekonomiskt hållbara.

Heavy metal contamination of soils, sediments and groundwater presents an ongoing source of hazardous and persistent environmental pollution. How best to remediate these contaminants is the impetus of continuing research efforts. Methods include containment, ex situ and in situ techniques. A successful in situ method utilizing a combination of emulsified liquid membranes, ELM, and zero-valent metal, ZVM, and bimetals has demonstrated impressive heavy metal reduction in 100 ppm solutions of Cd, Cu, Ni, Pb, Cr and U. This promising in situ method has been employed by the Industrial Chemistry Laboratory at the University of Central Florida and it has demonstrated considerable success in treating several environmental threats. Contaminated soils, surfaces, sediments and groundwater with offending agents such as trichloroethene, polychorobiphenyls and heavy metals have been treated utilizing emulsified liquid membrane systems containing zero-valent iron or bimetal particles. In vial studies, lead spiked sediments have shown repeatable 60% removal of lead after seven days of treatment. A persistent pattern emerged at ten days whereupon remediation levels began to drop. The current study was established to determine the reason for the decline at ten days and beyond. Questions addressed: Does the formation of an impeding oxide layer diminish the remediation capacity of the iron/magnesium system? Does the emulsion reach a maximum capacity to withdraw the contaminant? Do the soil components or the soil structure interfere with the access to the contaminant? This study has yielded insight into the reasons emulsified liquid membrane systems containing zero-valent metals achieved maximum lead removal at day seven, and thereafter begin to lose their effectiveness. A three part study was implemented to address and to answer the three questions pertaining to the consistent pattern of diminishing remediation levels exhibited at day ten and beyond. Initially, from Study I results it appeared that the formation of an impeding oxide layer on the bi-metal which was inside the emulsion droplet and which plated or precipitated with the lead was not occurring at day ten. Results indicated that the iron/magnesium was still capable of removing lead. Furthermore, from Study II results the emulsion dose injected appeared adequate to remove the lead, meaning that the emulsion had not reached its maximum capacity for remediation. The emulsion dose was not a limiting factor. Lastly, Study III results seemed to indicate that the drop in remediation after day seven pertained to the soil structure. There appeared to be some merit to the idea that with aging of the sediment, the lead was diffusing and migrating to some inaccessible interior sites within the sediment particles. Additionally, indications from day ten and day fourteen delineated that a second emulsion dose injection might restore lead removal levels to approach those first observed at day seven and consequently be a useful field application. In order to explore the effectiveness of injecting a second dose of emulsion, another vial study was implemented. The typical pattern of observing sixty percent maximum lead removal at day seven was observed. In separate groups, a second injection of emulsion was added at day five, and then for another vial series, a second dose was added at day seven. The second emulsion dose treatment for either day five or day seven did not yield any increases in percent lead removal. Another theory emerged after viewing micrographs of recovered iron/magnesium compared with fresh ball-milled bimetal. In addition, scanning electron microscopy appeared to confirm the explanation that the emulsified zero-valent metal system might be compromised after day seven. This would lead to exposure of the iron/magnesium to the air and the elements. Corrosion of the bimetal might be occurring. With time, release of the plated or precipitated lead back into the sediment mixture could follow. The results of Study I had led to the conclusion that an impeding oxide layer had not formed; however, this conclusion may have been premature because the recovered iron/magnesium was exposed to lead solution in the vial study. Perhaps if the recovered iron/magnesium was inserted back into an emulsion and injected into lead spiked sediments the percent lead removed might give a more accurate picture of the iron/magnesium's capability to continue performing remediation. Remediation of sediments contaminated with lead is a complicated task because of the complex nature of sediment components. Emulsified liquid membranes utilizing zero-valent bimetals has repeatedly demonstrated impressive results at day seven; however, this treatment method is not without its limitations. Optimal results appear to be gained at day seven after emulsion injection. The bimetal and plated or precipitated lead must be removed at that point; otherwise the effective remediation of the contaminant is progressively reversed.

The diploma thesis is focused on the development of in-line micro-electromembrane extraction (EME) coupled to capillary electrophoresis (CE) for the analysis of selected drugs in body fluids. Up to now, direct coupling of EME to CE has been demonstrated on diluted river samples only [1]. Although the published set-up has been implemented within a commercial CE it suffers from several drawbacks that can have a negative impact on the analysis of samples with higher complexity. The instrumental arrangement presented in this thesis eliminates these deficiencies. The experimental part is based on the optimization of fundamental extraction and separation conditions for the analysis of model basic drugs (nortriptyline, haloperidol, loperamide) with the use of transient isotachophoresis (tITP) principle. The extraction conditions were optimized for electro-driven transport of basic analytes from complex matrices (urine) through free liquid membrane followed by injection step utilized by electrokinetic supercharging (EKS), which focused target analytes into the CE capillary. Optimized conditions have been applied on blood in the form of dry blood spots, which are highly attractive samples in the current clinical analysis. The repeatability of the measurements was

The diploma thesis deals with the study of the influence of composition and curing of self-leveling cement screeds on their properties in the early stage of maturation. Within this work, various concepts of ensuring the volume stability of cement self-leveling screeds were verified. An anti-shrink additive based on neopentyl glycol and an expansion additive based on hard-burnt lime were used as modifiers. The reduction of plastic and overall shrinkage using various types of liquid membrane-forming compounds was verified on the most volume-stable screed using the optical dilatometry method. The effectiveness of the individual solutions was monitored by continuous measurement of the intensity of evaporation from the screed surface. Subsequently, the effect of membrane-forming compounds on the residual moisture of the cured treated cement self-leveling screed was measured by the carbide method and also the effect of this curing on the adhesion of bonded ceramic tiles.

No description available.