碩士 / 國立清華大學 / 化學工程學系 / 89 / Recently, up-flow anaerobic fluidized bed reactor has been developed as an effective device for wastewater treatment. Up to now, studies in the up-flow fluidization are mostly focused on the biofilm growing on different supports, such as sand, activated carbon and glass beads. However, littile information is available in literatures regarding immobilized growing cells. Since our laboratory has developed a novel PVA-immobilization technology for entrapping cells, the hydrodynamic characteristics including particle densities, terminal velocities, drag coefficient, bed expansion characteristics, and minimum fluidzation velocities for various particle size of PVA beads were studied. From experimental measurements of the single particle terminal settling velocity, the corresponding drag coefficient was found to be large than that of a smooth, rigid sphere at the same Reynolds number. A new simple correlation describing this finding is suggested. According the buoyancy force based on the bulk density of the bed, a correlation for the bed expansion of particulately fluidized spheres based on dynamic equilibrium of individual particles was presented. Other focus of the study was to determine the feasibility of biodegradation of azo dye (Red RBN) using PVA immobilized-cell beads in the up-flow anaerobic fluidized bed reactor. The effect of typical process variables such as hydraulic retention time (HRT), influent dye concentration level, particle number density, particle size, and degree of bed fluidization on removal efficiencies were also studied. Using PVA particle diameter of 2.965 mm and particle number density of 19200 particle l-1, results indicate that nearly complete color removal (94 %) was easily accomplished for Red RBN under hydraulic retention time of 12 hr, bed expansion of 60 %, and influent dye concentration of 200 mg/l. Besides, the overall effectiveness factor ηDf was used to illustrate the mass transfer (pore and film diffusion resistances) in fluidized bed reactor. Taking into account mass fransfer of PVA immobilized-cell beads, biodegradation of azo dye and liquid mixing in the reactor, a general model for the design of fluidized bed reactors operating with immobilized-cell in spherical porous PVA particles is presented.

碩士 / 國立清華大學 / 化學工程學系 / 89 / Nano-particles as particles in the size range of 1 to 100 nm, in which the characteristic length scale falls in between the microscopic and macroscopic worlds. Due to the unusual property falls in the nano-material as compared to the bulk material and that there is no simple theory that can describe the thermodynamic change of physical property well, we choose SiO2 as the system to study the size effect of nano-particles for sintering behavior. We have the particle sizes of 7-10nm, 10-13nm, 50nm and 80nm produced by factory using the method of water-glass and 30nm synthesized by the hydolysis of TEOS. Several characterizations including BET, SEM, DTA, gravimetry, light-scattering, XRD and ESCA are employed to analyze the sintering mechanism effected by the particle size and sintering temperatures at 800℃,900℃ and 1000℃. The 7-10nm was sintered faster than the 10-13nm at 800℃, however, there was no sintering for the 50nm and 80nm. The 7-10nm and 10-13nm may undergo the initial sintering stage with the phenomena of neck growing, disappearance of small pores, and large pores growing. For the 7-10nm and 10-13nm , the sintering was faster at 900℃than 800℃, however, the 50nm and 80nm still did not sinter at 900℃. The 7-10nm and 10-13nm would become the bulk material without pores when sintered above 900℃ and become the one with large pores below 800℃. Besides, the 7-10nm sintered at 850℃ would become the bulk material essentially with a lot of pinholes. As for the phase transition, the morphology would change from amorphous to tridymite when 7-10nm was sintered for 24 hours at 900℃. And the morphology would change to cristobalite when 7-10nm was sintered for 2 hours at 1000℃ and then change to tridymite when sintered for 16 hr. The cristobalite may be present when 10-13nm was sintered for 8 hours at 900℃. The 30nm would undergo the initial stage with the phenomena of neck growing, disappearance of small pores, large pores growing and then would enter the evolution of the intermediate stage with equilibrium shapes and continuous shrinkage. But up to now, we still can not explain the unreasonable phenomena for 30nm sintered at 800℃ compared with the same condition of 7-10nm and 10-13nm.

碩士 / 國立清華大學 / 化學工程學系 / 89 /

碩士 / 國立清華大學 / 化學工程學系 / 89 / Room temperature ionic liquid, which are nonvolatile, inflammable, and good solvation power, has attracted a lot of recent attention as a "green solvent" alternative. In this work, solid-liquid and liquid-liquid equilibria of [emim][PF6]+water and liquid-liquid equilibria of [bmim][PF6]+water are studied. UV was used to measure the solubility of ionic liquid in water phase. Karl-Fischer was used to measure the solubility of water in ionic phase. The solubility of [bmim][PF6] in water phase (2.36+0.08 wt% at 303 K to 3.67+0.2 wt% at 323 K) is less than that of [emim][PF6] and increases with increasing temperatures. The solubility of water in liquid [bmim][PF6] phase changes from about 2.70+0.03 wt% at 303 K to 3.70+0.03wt% at 323 K. While solubilities of ionic liquids in water are small, they are far from negligible. Hence cautions must be taken to prevent lost into environment when these chemicals are used. So we are conducting experiments to measure the partition of ionic liquids between water and biocompatible organic liquids such as 1-octanol and other alcohols. UV and TGA was used to measure the solubility of ionic liquid in water phase. GC was used to measure the solubility of 1-octanol in water phase. Karl-Fischer was used to measure the solubility of water in 1-octanol phase. TGA was also used to measure the solubility of ionic liquid in 1-octanol phase. But the solubility of 1-octanol in water phase and the solubility of ionic liquid in 1-octanol phase remained to be investigated.

碩士 / 國立清華大學 / 化學工程學系 / 89 /

碩士 / 國立清華大學 / 化學工程學系 / 89 /

碩士 / 國立清華大學 / 化學工程學系 / 89 / Nanoparticles of nickel can be synthesized from NiCl26H2O by hydrazine in alkaline solution in the presence of polymers (PVP and PAA) served as protective and stabilizing agents. In addition, palladium ion is added as a nucleator. By adjusting the nickel ion concentration from 0.01 M to 0.02 M, the colloidal size can be adjusted within the range of 14 nm to 21 nm. Other parameters such as reaction temperature and PVP amount showed only negligible effects on particle size. Results also indicated that by increasing temperature to above 80 C and/or reaction time, we can obtain high purity nickel precipitate, otherwise large amount of Ni(OH)2 still exists in the product. Adjusting the pH to below 3.8 can de-stabilize the stable colloidal solution and separate nickel from original solution. On the other hand, the precipitate can be re-dispersed by simply adding de-ionized water. As regards to thick films, our data showed that the film resistivity will decrease with sintering temperature. After sintering at 1000 C, the film made from nanoparticles of nickel exhibits a sheet resistivity of 373 mOhm/square. The SEM picture showed that film from nanoparticles was better sintered than that from micron sized nickel particles. Nevertheless, due to the formation of some oxide in the film, it had a higher resistivity. Further efforts are needed to improve on the process conditions. The Ni film fabricated by interpolymer complex method shows a well and completely sintered surface, but the film is still too thin to measure the electric properties on it. The rate constant of nanosized nickel powder oxidation is about 4E-16 cm2/s at 300 C and 1.3E-15 cm2/s at 350 C.

碩士 / 國立清華大學 / 化學工程學系 / 89 / Abstract We studied the crystallization kinetics and crystalline morphology of poly(ethylene oxide)-block-poly(1,4-butadiene) (PEO-b-PB) exhibiting various mesophase structures in the melt. In order to establish a proper model system in which the crystallization can be effective confined within the nano-scaled microdomains while maintaining high degree of crystallizability of the crystalline blocks, the amorphous PB blocks in PB-b-PEO were crosslinked by a photo-initiated crosslinking reaction so that the crystallization-induced disruption of microdomain structure may be effectively avoided. Small angle X-ray scattering (SAXS) results revealed that the microdomain morphology in the melt effectively preserved upon crystallization of the PEO block after the PB matrix crosslinked. The kinetics of the crystallization confined in the microdomains displayed a parallel transition with the transformation of microdomain morphology. Such a distinct correlation stemmed largely from the homogeneous nucleation controlled crystallizations where the direct proportionality between nucleation rate and microdomain volume rendered the basis for the direct correlation. The homogeneous nucleation controlled crystallizations in the compositions containing cylindrical and spherical PEO microdomains was further verified from the isothermal crystallization study. In spite of the effective confinement imposed by the crosslinked PB phase, crystallization in the lamellar phase still proceeded through a mechanism analogous to the spherulitic crystallization of homopolymer.

碩士 / 國立清華大學 / 化學工程學系 / 89 / Clavulanic acid is a product of the fermentation of Streptomyces clavuligerus. Clavulanic acid is a specific and irreversible inhibitor of a wide range of bacterial β-lactamases. Clavulanic acid has been used in human therapy for several years in combination with amoxicillin. In this study, the effects of different precursors on the biosynthesis of clavulanic acid using S. clavuligerus in batch and fed-batch fermentations were investigated. An intermittent feeding strategy was employed and the amount of feed medium was optimized to improve the production of clavulanic acid. The intermittent feeding of medium containing glycerol was the feeding strategy in shake flask cultures, which resulted in the maximum production of clavulanic acid was 2.3-fold higher than without glycerol feeding culture. Clavulanic acid biosynthesis was doubled by adding ornithine. The optimal initial ornithine concentration for clavulanic acid biosynthesis was 5~10 mM. Simultaneous intermittent feeding glycerol and ornithine in shake flask cultures, which resulted in the maximum production of clavulanic acid was 3.1-fold higher than without glycerol feeding culture. The optimal amount of glycerol and ornithine feeding twice daily with 12 hours interval for clavulanic acid production were 1.0 g-glycerol/100 ml-broth．day and 1.0 mmol-ornithine/100 ml-broth．day. The optimal mode of intermittent feeding strategy was feeding six times daily with 4-hour intervals. Feeding studies demonstrate that glycerol is precursor of the β-lactam moiety(C-5,C-6, and C-7), whereas ornithine is precursor of C5-moiety. Glycerol and ornithine exert a stimulation of the biosynthesis of clavulanic acid and both precursors are most efficiently incorporated into clavulanic acid.

碩士 / 國立清華大學 / 化學工程學系 / 89 /