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1
Merrifield, John D. "Synthesis and Characterization of Thiol-Grafted Chitosan Beads for Mercury Removal." Fogler Library, University of Maine, 2002. http://www.library.umaine.edu/theses/pdf/MerrifieldJD2002.pdf.
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Pickens, Tara L. L. "Immobilization of Beta-Glycosidase BglX from Escherichia coli on Chitosan Gel Beads." Youngstown State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1535472543349818.
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Havenga, John Botha. "Chitosan beads as a delivery vehicle for the antituberculosis drug pyrazinamide / J.B. Havenga." Thesis, North-West University, 2006. http://hdl.handle.net/10394/1354.
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DeGroot, Andreas R. "Encapsulation of urease in alginate beads and protection from alpha-chymotrypsin with chitosan membrane." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0004/MQ44002.pdf.
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Mohlala, Mangaabane Gorden. "The effect of pharmaceutical excipients on rifampicin release from chitosan beads / Mangaabane Gorden Mohlala." Thesis, North-West University, 2004. http://hdl.handle.net/10394/484.
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Controlled release systems aim at achieving a predictable and reproducible drug
release over a desired time period. These systems allow reduced dosing frequency,
constant drug levels in the blood, increased patient compliance and decreased adverse
effects. In a recent study, Chitosan beads, containing N-trimethyl Chitosan chloride,
have shown a potential in the delivery of rifampicin. However, because of inadequate
amounts of rifampicin released over 24 hours, incorporation of other pharmaceutical
excipients to increase the swelling behaviour of the beads to improve drug release,
was considered in this study.
Chitosan beads were prepared through ionotropic gelation with tripolyphosphate
(TPP) as a crosslinking agent. To increase the porosity if the Chitosan beads
Explotab®, Ac-Di-Sol® and vitamin C were added individually to Chitosan solutions
at concentrations of 0.1, 0.25 and 0.5 % w/v before adding the mixture to the TPP
solution. Swelling and morphology studies were used in the evaluation of the different
formulations. The swelling and morphology results were then used to select a set of
combination and concentrations of two excipients sand then prepare and characterise
beads containing two combinations. The combination formulations and formulations
containing single excipients were then loaded with rifampicin. Pure chitosan beads
exhibited a higher drug loading capacity (67.49 %) compared to the lowest loading
capacity of 41.61 % exhibited by chitosan beads containing a combination of
Explotab®, Ac-Di-Sol®.For all the other formulations the drug loading capacity
ranged within 48 and 63 %.
These formulations were used for dissolution studies over a period of 6 hours at pH
5.60 and 7.40. The dissolution results showed that no chitosan has dissolved at both
pH values. A significant amount of rifampicin was, however, released from the beads,
especially at pH 7.40. chitosan beads containing vitamin C also exhibited high
rifampicin release (48.34 ± 1.00) %) at pH 5.60 compared to the other formulations
and this makes vitamin C a potential excipient for enhanced drug release over a wide
pH range (both acidic and alkalinic). However, further studies are necessary to
optimise the preparation method to minimise drug loss during loading and to improve
the drug loading capacity of the beads.Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2005.
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Van, Rensburg Andries Gideon. "The effect of pharmaceutical excipients on isoniazid release from chitosan beads / Deon van Rensburg." Thesis, North-West University, 2007. http://hdl.handle.net/10394/1248.
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In controlled release applications a drug is molecularly dispersed in a polymer phase. In
the presence of a thermodynamically compatible solvent, swelling occurs and the
polymer releases its content to the surrounding medium. The rate of the drug release can
be controlled by interfering with the swelling rate of the beads or by influencing diffusion
through the viscosity of the polymer.
Beads that contain chitosan were prepared through the ionotropic gelation method where
tripolyphosphate (TPP) was used as the crosslinking agent. Beads that consisted of 3%
w/v isoniazid (lNH) and 5% w/v chitosan were prepared in a 5% w/v TPP solution (pH
8.7) as the primary beads. To improve the drug loading of chitosan isoniazid beads (ClB)
the TPP concentration, pH of the TPP solution and the INH concentrations were altered
for maximum drug loading. To increase the porosity of the beads of chitosan beads
Explotab® (EXPL), Ac-Di-Sol® (ADS) and Vitamin C (VC) were added individually to
chitosan solutions at concentrations of 0.1, 0.25 and 0.5% w/v before adding the mixture
to the TPP solution. Morphology, swelling and drug loading studies were used to
evaluate the different formulations. After these excipients were added individually they
were also added in combinations of two excipients respectively and characterised. From
the results of the drug loading studies the beads that contained only chitosan and
isoniazid showed a percentage drug loading of (43.92%) which is the best of all the beads
that were analyzed. The multi excipient combination of Ac-Di-Sol® and Explotab®
showed the best swelling capability at both pH levels.
Dissolution studies were conducted on all the formu lations over a period of 6 hours (360
minutes) at pH 5.6 and pH 7.4. From the dissolution results it were clear that no chitosan
dissolved at both pH values. The dissolution of single pharmaceutical excipient (SPE)
and multi pharmaceutical excipient (MPE) formulations can be arranged in the following
order: VC/ADS < VC < ADS/EXPL < ADS < VC/EXPL < CIB < EXPL. Explotab® is a
potential excipient for enhanced drug release over a wide pH range.Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2007.
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Havinga, Riana. "The effect of pharmaceutical excipients on the release of indomethacin from chitosan beads / Riana Havinga." Thesis, North-West University, 2006. http://hdl.handle.net/10394/4.
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Contents: Chitosan -- Controlled drug delivery -- Indomethacin -- Inotropic gelation -- Tripolyphosphate (TPP) -- Explotab® -- Ac-Di-Sol® -- Vitamin CThesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2007.
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Osifo, Peter Ogbemudia. "The use of chitosan beads for the adsorption and regeneration of heavy metals / Peter Ogbemudia Osifo." Thesis, North-West University, 2007. http://hdl.handle.net/10394/1635.
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Gündüz, Meltem Harsa Şebnem. "Lactic acid production by lactobacillus casei nrrl b-441 immobilized in chitosan stabilized ca-alginate beads/." [s.l.]: [s.n.], 2005. http://library.iyte.edu.tr/tezler/master/gidamuh/T000427.pdf.
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Bouwer, Carel Petrus. "A comparison on the release modifying behaviour of chitosan and kollidon SR / Carel Petrus Bouwer." Thesis, North-West University, 2007. http://hdl.handle.net/10394/1065.
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Controlled release formulations deliver an active ingredient over an extended period of time. It is an ideal dosage form for an active ingredient with a short elimination half-life. An active ingredient with a short elimination half-life would be released in small portions over an extended period of time and thus less frequent administration is necessary and this improve patient compliance. Other advantages of these formulations include: decreased side effects, constant drug levels in the blood, improvement in treatment efficiency and reduction in cost of administration.
Controlled release beads are formulated in such a way that the active ingredient is embedded in a matrix of insoluble substance like chitosan; the dissolving drug then has to find its way through the pores of the matrix into the surrounding medium. The chitosan matrix swells to form a gel, the drug then has to first dissolve in the matrix and diffuse through the outer surface into the surrounding medium.
Chitosan is a biocompatible, biodegradable polymer of natural origin. It has mucoadhesive properties as well as the ability to manipulate the tight junctions in the epithelium membrane and these properties have qualified chitosan as an effective drug carrier in controlled release dosage forms. The effect of a modern controlled release polymer namely Kollidon® SR in combination with chitosan on drug release was investigated. Ketoprofen was chosen as model drug. Ketoprofen is an anti-inflammatory drug that causes gastrointestinal side effects in conventional dosage forms. Ketoprofen has a short elimination half-life of 2.05 ± 0.58 h and this characteristic makes it an ideal candidate for use in a controlled release formulation. The aim of this study was to achieve controlled release and minimize gastrointestinal effects of ketoprofen with chitosan particles. Kollidon® SR was used as polymer because it exhibits pH independent release characteristics and previous studies have shown potential for this combination.
Chitosan beads and chitosan-Kollidon® SR beads, as well as chitosan granules and chitosan-Kollidon® SR granules, were prepared and investigated as potential controlled release formulations. Chitosan beads were prepared through the inotropic gelation method using tripolyphosphate as a cross linking agent. Granules were prepared through wet granulation using 2% v/v acetic acid as the granulating fluid or by dissolving ketoprofen in ethanol and Kollidon® SR in 2-pyrrolidinone and using the solution as granulating fluid. Kollidon® SR was added in concentrations of 0.25, 0.5 and 1% (w/v) in the bead formulations and concentrations of 1, 5 and 10% (w/w) in the granule formulations. The beads and granules were characterised by evaluating the following properties: morphology, drug loading and drug release. Additionally swelling and friability tests were also conducted on the bead formulations.
The cross linking times of the bead formulations were varied to investigate the effect of cross linking time on the characteristics of the beads. Chitosan-Kollidon® SR beads showed promising results for controlled release formulations and ketoprofen were released over an extended period of time. Drug loading of the plain chitosan beads was 74.65 ± 0.71% and it was noted that the inclusion of Kollidon® SR in the beads resulted in an increase in drug loading and the formulation containing 1% (w/v) Kollidon® SR, cross linked for 30 minutes had a drug loading of 77.38 ± 0.01%. Drug loading of the beads that were cross linked for a longer time were slightly lower which is an indication that some of the drug might have leached out during cross linking. The degree of swelling was promising with some beads swelling to a degree of 2.5 in phosphate buffer solution pH 5.6. Granules had a drug loading between 81.73 ± 1.53% and 93.30 ± 0.50%.
Ketoprofen release from the beads and the granules in PBS pH 7.40 at 37 °C over a period of 6 hours were investigated. The bead formulations were more effective in achieving controlled release and it was noted that the bead formulations that was cross linked for a longer period was more efficient in achieving controlled release. The granules did not form a matrix and were not effective in achieving controlled release. Controlled release of ketoprofen were achieved and the results show potential for chitosan-Kollidon® SR formulations in the future.Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2008.
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MELONI, MARIA CRISTINA. "Preparazione e caratterizzazione di due sistemi carrier: beads a base di chitosano e chitosano/alginato; nanoparticelle di N-trimetilchitosano." Doctoral thesis, Università degli Studi di Cagliari, 2012. http://hdl.handle.net/11584/266151.
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Chitosan is a very attractive polysaccharide and it is known to be a favorable pharmaceutical material because of its low toxicity, biodegradability, biocompatibility,
mucoadhesivity and natural origin. Therefore it forms an ideal hydrophilic carrier system. In this study we described the preparation and characterization of two carrier systems, chitosan and chitosan – alginate beads, and N-Trimethyl Chitosan (TMC) chloride nanoparticles.
We realized spherical beads using different polymeric dispersions, chitosan, alginate and chitosan - alginate mixture, to investigate their effect on the phytoterapic anti- inflammatory agent delivery. The main purpose of the present in vitro study is to have some information about their stability in the gastrointestinal tract and to formulate a drug delivery system for the oral administration of this phytoterapic agent. Alginate
beads were prepared by ionotropic gelation in presence of CaCl2 and BaCl2 solutions; chitosan beads were prepared by using a TPP (tripolyphosphate) solution as an ionic
cross-linking agent and acetone as a coacervating agent; beads of chitosan - alginate mixture were prepared according to the two combined procedures reported above.
The swelling degradation behaviour of the bead samples and drug release were investigated using four different medium solutions (PBS pH 7.4, HCl 0.1N pH 1, buffer pH 5). TMC with different degrees of quaternization were synthesized and characterized by 1 H- NMR spectroscopy, XRD and viscosity. Trimethyl Chitosan chloride nanoparticles (TMC-NPs) were prepared according to the ionotropic gelation process of TMC with TPP. The aim of this study is to characterized TMC-NPs (particle size -Z-average mean-, PDI and zeta potential) and evaluate their potential for brain delivery.
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Verwey, Werner Jaun. "Influence of modified release excipients on ketoprofen release from chitosan particles / W.J. Verwey." Thesis, North-West University, 2005. http://hdl.handle.net/10394/1034.
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Controlled release formulations offer many advantages over conventional dosage forms.
These include reduced plasma fluctuations and improved patient comp1i:nce. Complex
controlled release formulations such as those with enteric release properties, often require
additional steps in the production phase. The costs and economic impact associated with
these complex controlled release dosage formulations often outweigh the immediate
benefits. Thus the development of an economic method to produce controlled release
particles is of great importance especially in third world countries.
In controlled release formulations, the drug is generally dispersed throughout a polymer
matrix. The rate of drug release is often determined by the viscosity or complexity of the
polymer matrix through which the drug needs to diffuse in order to be released. With
enteric release the polymer coating, insoluble in an acidic environment is often applied in
the final phase of production.
Chitosan is a versatile polymer of natural origin with many favourable characteristics.
These include its safety, biocompatibility, and biodegradability. Simple methods can be
applied and modified to produce controlled release particles form chitosan. The effect of
modern controlled release polymers such as Aqoat AS-HF, Eudragit SlOO and
Kollidon SR was investigated.
Chitosan beads and chitosan-polymer beads, as well as chitosan granules and chitosan-polymer
granules, were prepared and investigated as possible controlled release
formulations. Ketoprofen was chosen as the model drug. Chitosan beads and chitosan-polymer
beads were prepared by inotropic gelation in tripolyphosphate. Chitosan
granules and chitosan-polymer matrix granules were prepared by binding chitosan with
an acetic acid solution as a granulating system. The beads and granules appeared differed
in appearance as well as in the results obtained from various experiments. Granules
prepared in the study did not appear to be effective with regards to enteric and controlled
release. Beads prepared form Kollidon SR appeared to be effective with regards to
enteric and controlled release, with Kollidon 1% and 5% w/v chitosan beads achieving
good drug loading of up to 73.13% and releasing less than 15 % of the total drug content
in 0.1 M HCI after 60 minutes. Drug release continued steadily for up to 360 minutes in
pH 7.2. It was concluded that Kollidon SR loaded chitosan beads nay be a viable
controlled release dosage form with enteric release properties, and that future
experiments, possibly with lower polymer concentrations, are worthwhileThesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2006.
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Reynaud, Franceline. "Desenvolvimento de um complexo biopolímero-íon metálico matricial microparticulado para adsorção de substâncias." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2009. http://hdl.handle.net/10183/122308.
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Micropartícula de quitosana complexada com íons metálicos [Fe(II), Fe(III), Zn(II)] foram preparadas e caracterizadas a fim de se obter sistemas microparticulados para a adsorção de substâncias. A técnica de preparo utilizada foi a secagem por aspersão, através da qual se obteve micropartículas esféricas colapsadas e com superfície rugosa. O tamanho de partícula foi influenciado tanto pela reação de reticulação com glutaraldeído como pela presença e tipo do metal utilizado para a formação do complexo. A adsorção do ciprofloxacino pelas micropartículas desenvolvidas foi estudada em meio aquoso, O estado de equilíbrio foi influenciado pelo tipo de metal presente na micropartícula e pela concentração inicial de ciprofloxacino na solução. Com o intuito de descrever o mecanismo de adsorção, foram utilizados modelos matemáticos de isotermas de Langmuir e Freundlich, sendo que os dados apresentaram um melhor ajuste para a isoterma de Freundlich. Através da análise de modelos de cinética de pesudo-primeira-ordem e pseudo-segunda-ordem, verificou-se que os dados melhor se ajustaram ao modelo de pseudo-segunda-ordem, indicando que o mecanismo de adsorção do ciprofloxacino pelas micropartículas é através de quimissorção. A determinação da capacidade de adsorção do ciprofloxacino, conduzido in vitro, demonstrou que as micropartículas de quitosana-Fe(III) e quitosana-Zn(II) apresentam efetividade de adsorção. Com isso as micropartículas de quitosana-Fe(III) foram encapsuladas por uma matriz de pectina, sendo este utilizado para a adsorção de antimicrobianos residuais presentes no cólon. A estabilidade das esferas foi determinada em meios digestivos simulados, onde se verificou uma estabilidade de 1 h e 5 h nos meios gástricos e intestinal, respectivamente. Quando as esferas foram incubadas no meio colônico, observou-se uma degradação dependente da concentração de pectina. Com o intuito de evitar a adsorção do ciprofloxacino no meio intestinal, as esferas foram revestidas com Eudragit RS. Estudos de adsorção em meio colônico simulado demonstrou que a capacidade de adsorção das micropartículas de quitosana-Fe(III) não é afeta pela encapsulação na matriz de pectina. O sistema desenvolvido demonstra ser promissor para a extração do ciprofloxacino presente no meio colônico simulado.The aim of this work was to develop, characterize chitosan- metal ion [Fe(II), Fe(III), Zn(II)] microparticle, and evaluate the adsorption capacities of ciprofloxacin by these complexes. The microparticles were prepared by a spray drying method. They showed good sphericity and a roughness surface morphology. The particle size was influenced by crosslinking reaction and by the kind of metal ion onto the microparticle. A batch adsorption system was applied to study the adsorption of ciprofloxacin from aqueous solution by chitosan-metal ion crosslinked microparticle. The adsorption process was fast, and the equilibrium contact times were influenced by the kind of metal ion onto microparticle. The Langmuir and Freundlich adsorption models were used for mathematical description of the adsorption equilibrium, and it was found that experimental data fitted well to Freundlich model. Adsorption models, based on the assumption of the pseudo-first-order and pseudo-second-order mechanism showed that the pseudo-second-order adsorption mechanism is predominant, and the adsorption process appears to be controlled by the chemical reaction. Chitosan-Fe(III) and chitosan-Zn(II) microparticle demonstrated the highest adsorption of ciprofloxacin. Chitosan-Fe(III) microparticle was encapsulated in a pectin matrix. The system was used for the adsorption of colonic residual antibiotics responsible by the emergence of resistance. The stability of the beads was carried out on simulated digestive media. Beads incubated in simulated gastric and intestinal medium were stable for 1 h and 5 h, respectively. When incubated in simulated colonic medium, beads were then degraded by pectinases contained in the medium. Coating with Eudragit RS was needed to prevent the early adsorption of antibiotics in intestinal medium. Adsorption studies in simulated colonic medium show that the adsorption capacity of chitosan-Fe(III) is not modified after encapsulation within pectin beads making the elimination reaching the colon clinically feasible.
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Costa, Jessica. "Use and characterisation of free or immobilised enzymatic systems for the synthesis and functionalisation of novel materials." Doctoral thesis, Università di Siena, 2021. http://hdl.handle.net/11365/1127196.
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The work reported in this Ph.D. thesis is focused on the use and immobilisation of enzymes to produce new materials, which are important for biotechnological applications.
The use of enzymes in industrial sectors is continuously increasing. Enzymes offer many advantages over traditional chemical processes. The research work of this thesis can be divided into two parts. The first part is focused on the immobilisation of laccase and chitinase. The main object of enzymatic immobilisation is to enhance the economics of biocatalytic processes. Enzymatic immobilisation allows the reuse of enzymes for an extended period of time and enables easier separation of the catalyst from the product. Furthermore, immobilisation improves many properties of enzymes: performance in the organic solvents, pH tolerance and heat stability. The most widely used immobilisation method is the covalent binding of the enzyme to support. Different type of support can be chosen for enzymatic immobilisation. As the material can plays a crucial role in the immobilisation process and the properties of the produced catalytic system. In this thesis we have chosen two different supports: super paramagnetic nanoparticles for both the enzymes used and the chitosan beads as an alternative support for chitinase. Magnetic nanoparticles show interesting properties for enzymatic immobilisation, they can be obtained with small size, increasing the yield of enzymatic immobilisation and above all, the reaction products can be easily recovered applying an external magnetic field. Magnetic nanoparticles were prepared following the traditional method of co-precipitation of Fe2+ and Fe3+ ions. This immobilisation process was successfully used for chitinase, obtaining a high immobilisation yield and increasing enzymatic stability. Different was for laccase, which having a different catalytic mechanism a revision of the synthesis has been attempt. The use of the magnetic nanoparticles obtained with the traditional method hampered the detection of stable radical species formed during the catalytic mechanism as it happens for the oxidation product of 2,2'-azino-bis (3-ethylbenzothiazolin-6-sulfonic acid) (ABTS), the standard compound used to test the enzyme activity. Changing some synthetic parameters, the new magnetic nanoparticles were produced and characterized. In fact nanoparticles with a lower aggregation state and a smaller hydrodynamic diameter were obtained and tested without any interference with the ABTS substrate. Chitinase was also immobilised on chitosan beads/Macro-Spheres (CMS), as this support is completely atoxic and so most suitable for application in food industries.The presence of active amino groups in deacetylated GlcNAc units of chitosan also enables the binding of the linker (glutaraldehyde and genipin) and then of the enzyme. The goal of this part of the thesis was to attempt the immobilisation of Chitinase on different supports, MNPs and CMS, for the efficient production of COS.
The second part of this thesis is focused on the use of enzymes to produce melanin pigments. Melanins have a variety of biological functions, including protection against UV radiation, free radical scavengers and metal ions chelators. Thanks to their properties, melanins found applications in several fields such as cosmetics, optoelectronics, food, and pharmacology. Eumelanin and Pheomelanin have been produced by oxidative enzymatic synthesis using laccase from Trametes versicolor and then characterized by the use of Multifrequency Continuos Wave (CW) and pulse Q-band EPR. Then, as soluble melanin pigments have important technological applications in different fields, like in optoelectonics, soluble pigments mimicking pyomelanin structure have been synthesized starting from Homogentisic Acid and Gentisic Acid monomers and spectroscopically characterized with their antioxidant activities determination.
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Fabbri, Alessandro. "Preparation and Characterization of Polymeric Beads and Membranes for Boron Removal From Water." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20671/.
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Boron is an element essential for various biological processes, nevertheless at high concentration it can cause health issues in both plants and animals, thus making boron a pollutant element. Low cost and effective polymeric adsorbents capable of removing boron in aqueous solution at neutral pH were prepared for this purpose. The adsorbent selectivity towards boron was conferred taking advantage of the interaction between boric acid and the alcoholic groups of N-methyl-D-Glucamine, which are able to form specific complexes. Two different kinds of devices were produced and tested: cross-linked chitosan hydrogel beads (CCBMG) and PVA/chitosan membranes, the latter taking advantage of scCO2-assisted phase inversion technique. The capability of the adsorbents to be regenerated and to allow recovery of boric acid from a solution emulating the concentration of boric acid in seawater were evaluated.
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Albarelli, Juliana Queiroz. "Produção e caracterização de quitosana imobilizada em substratos visando adsorção de ions metalicos." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267118.
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Orientador: Marisa Masumi BeppuDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
Made available in DSpace on 2018-08-15T00:01:01Z (GMT). No. of bitstreams: 1 Albarelli_JulianaQueiroz_M.pdf: 12079656 bytes, checksum: 4883a6fcc74937bc5e4be6b917ed0747 (MD5) Previous issue date: 2009
Resumo: A quitosana é um polímero natural muito estudado devido à sua boa capacidade adsorvente. A aplicação deste biopolímero para remoção de metais pesados tem sido estudada desde o início dos anos 1970 sendo que o número de trabalhos sobre este tema cresceu rapidamente desde então. No entanto, o uso da quitosana como adsorvente em maior escala enfrenta alguns obstáculos, devido à sua baixa resistência mecânica. Uma possível alternativa para melhorar aspectos mecânicos e que também contribui para uma melhor transferência de massa do adsorbato no adsorvente é a imobilização da quitosana em matrizes sólidas utilizando-se técnicas de recobrimento de partículas. Neste contexto, este trabalho visou investigar a imobilização da quitosana em substratos para a aplicação em sistemas de adsorção. Inicialmente foram testados como suporte para imobilização da quitosana vidro, polipropileno, borracha vulcanizada, porcelana e tecido de algodão. O substrato de vidro, utilizado na forma de esferas, apresentou melhor interação com a solução de recobrimento e características adequadas para aplicação em processos de adsorção. As esferas de vidro foram recobertas por diferentes métodos utilizando quitosana 2,5% (m/v) em solução de ácido acético 3% (v/v). O material recoberto foi utilizado em sistemas de adsorção em batelada e contínuo a fim de se analisar a capacidade de remoção de cobre pelo filme de quitosana. Dentre as diferentes técnicas de revestimento estudadas, o processo por "dip coating" obteve um revestimento homogêneo e apresentou boa aderência do filme ao substrato. A natureza da superfície a ser recoberta e a temperatura da solução de recobrimento foram variadas objetivando-se melhorar a fixação da camada de quitosana no suporte, sendo esta ultima variável a mais importante para as condições estudadas. As isotermas de adsorção indicaram um aumento na capacidade de adsorção com o aumento da temperatura na qual ocorre a adsorção. Os dados foram mais bem representados pela isoterma de Langmuir, indicando que o principal fenômeno de adsorção se assemelha a adsorção em monocamada. Observou-se que a capacidade máxima de adsorção encontrada em 25 º C foi semelhante a outros sistemas de adsorção de cobre utilizando quitosana relatados na literatura. Verificou-se um melhor ajuste para o modelo cinético de pseudo-segunda ordem, sugerindo que o fator limitante para a transferência de massa é a reação química. Os estudos de adsorção dinâmica usando as esferas recobertas em sistema de leito fixo demonstraram a possibilidade de seu uso com resultados promissores.
Abstract: Chitosan is a natural polymer largely studied because of its good adsorption capacity. The application of this biosorbent for heavy metal removal has been studied since early 1970s and the number of papers in this subject has grown quickly ever since. However, the use of this material in larger scale faces some barriers due to its low mechanical strength. A possible alternative to improve mechanical resistance and also enhance mass transfer is the immobilization of chitosan onto solid matrices using particle coating techniques. In this context, this study investigates the immobilization of chitosan onto solid supports and its application on adsorption systems. It was tested as support for chitosan immobilization glass, polypropylene, vulcanized rubber, porcelain and cotton. The glass support, used in bead form, has shown the best interaction with the coating solution and good characteristics for application in adsorption processes. Glass beads were coated by different methods using chitosan 2.5% w/v in acetic acid 3% v/v solution. The coated material was used in batch and continuous adsorption systems to analyze the copper removal capacity of the chitosan film. Among the different coating techniques studied, the dip coating procedure formed a homogeneous coating and presented an acceptable film adhesion to the substrate. Variables such as type of surface to be covered and temperature of the coating solution were analyzed on the fixation of the coated material on the substrate. The latter variable affected the most in the studied condition. Adsorption isotherms indicated an increase in the adsorption capacity along with the increase of adsorption temperature. The data were better fitted by Langmuir model, which indicates that the main phenomenon that occurred approaches to a monolayer-type adsorption. The maximum adsorption capacity was found at 25ºC and its value was similar to other copper adsorption systems reported in the literature. The mechanism of sorption showed a better fitting to the second order kinetic model, suggesting that the limiting factor to mass transfer is the chemical reaction. The dynamic adsorption studies using the coated beads in a fixed bed system demonstrated the possibility of its use with promising results.
Mestrado
Engenharia de Processos
Mestre em Engenharia Química
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Čangelová, Katarína. "Studium možných aplikací polymeru kyseliny glutamové." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2019. http://www.nusl.cz/ntk/nusl-401873.
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The subject of the thesis is study of possible applications of isoform of glutamic acid polymer (-PGA). The theoretical part is focused on the properties of this biopolymer and potential applications in various areas. Producers and mechanisms of biosynthesis are also mentioned. In the experimental part, the polymer was firstly characterised by following methods: FT-IR spectroscopy, TGA, DSC and SEC-MALS. Its isoelectric point, antimicrobial activity and solubility in various solvents were also determined. The biopolymer was also precipitated by divalent cations and its interaction with oppositely charged CTAB surfactant was studied. The main experimental study was researching the effect of -PGA on viability of Saccharomyces cerevisiae and Lactobacillus rhamnosus under stress conditions by flow cytometry. The performed stresses included ethanol exposure, high temperature and freezing stress, in which its effects were compared to conventional cryoprotectants. The cells of the mentioned microorganisms were also stressed osmotically and exposed to model gastrointestinal juices - gastric, pancreatic and bile. The protective effects of -PGA on the cells were recorded in ethanol stress on Lactobacillus rhamnosus. Its excellent cryoprotection properties were confirmed and its protective effect of gastric juice exposure on Saccharomyces cerevisiae cells was also observed. At the end of the experimental part, -PGA/alginate beads suitable for encapsulation of probiotic bacteria and -PGA/chitosan nanoparticles for encapsulation of biologically active substances.
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Dogra, Sanjeev. "A Chitosan–Polymer Hydrogel Bead System For A Metformin HCl Controlled Release Oral Dosage Form." University of Toledo Health Science Campus / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=mco1303179716.
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Muhsin, Mohammad Didare Alam. "Preparation and in vitro evaluation of a polymer based controlled release dry powder inhaler formulation for pulmonary delivery." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/71806/1/Mohammad%20Didare%20Alam_Muhsin_Thesis.pdf.
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This thesis described the synthesis of an L-leucine conjugate of the biodegradable polymer, chitosan and its potential application for the development of controlled release nanoparticulate dry powder inhaler (DPI) formulations. The study demonstrated that the physicochemical properties of conjugated chitosan nanoparticles had favourable effects on the dispersibility and controlled release profile of a model drug. The toxicity profile of the nanoparticulate formulation revealed promising outcome for its use in pulmonary delivery. The chitosan conjugate produced in this project would be useful for the application of polymer nanoparticulate systems for efficient lung delivery of drugs.
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Lin, Gu-Huang, and 林谷皇. "IMMOBILIZATION OF β—FRRUCTOFURANOSIDASE ON CHITOSAN BEADS." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/17929655637243163472.
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碩士大同大學
生物工程研究所
91
A β—fructofuranosidase (EC 3. 2. 1. 26) partially purified from Aspergillus japonicus TIT-KJ1 was immobilized on chitosan beads using three crosslinking agents. Both the free enzymes and immobilized enzymes had similar optimum pH and temperature for activity of pH 5.4 and 60℃. Free-enzymes was stable at 30~60℃ and at pH ranged from 3.8 to 5.4. The immobilized enzymes has a pH stability ranged from 3.8~7.4 and sustained a 90% activity at 70℃ for 2 hours. The β—fructofuranosidase was immobilized on chitosan beads on chitosan beads by using a low cellular cytotoxity crosslinking agent THP {tris(hydroxymethyl)phosphine}, an excellent natural coupling reagent-genipin (GP), or glutaraldehyde (GA) as crosslinker. Therefore, the Michaelis constant Km value and the maximum velocities (Vmax) were estimated for free- and immobilized enzymes. Furthermore, the various degree of enzyme activities and the reusability and the thermability of enzyme at various temperature was investigated. In these three crosslinking agents, THP was found to be the best crosslinker for immobilization of β—fructofuranosidase on chitosan beads.
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吳勇毅. "The preparation of chitosan beads, their pH-sensitivity and the controlled release of amoxicillin from the chitosan bead." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/50412184666993994814.
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碩士國立海洋大學
食品科學系
90
Abstract Chitosan is a biodegrabale, biocompatible, non-toxic polysaccharide. It has a potential to become an ingredient for novel drug delivery systems because it can delay the release of drug compounds and enhance drug absorption. The objectives of this study were to prepare chitosan beads using commercial chitosan (with degree of deacetylation of 83.9 % and molecular weight of 202 kDa), to investigate their pH-sensitivity, and to measure the release behavior of amoxicillin from the chitosan beads. Coagulated and glycine-gelled chitosan beads dissolved in acidic environment quickly. On the contrary, the cross-linked samples slowly erosed. Chitosan beads did not dissolve in weak basic environment. The glycine-gelled chitosan bead showed similar behavior to the coagulated samples both in dry state and when they were dissolved in acidic or weak basic environment. Freeze-dried chitosan beads dissolved faster than air-dried samples in acidic environment. That was because freeze-dried chitosan beads had more porous structure that test solution could diffuse into them and resulted in a faster dissolution of the beads. The glutaraldehyde concentration affected the swelling ratio of glutaraldehyde-cross-linked chitosan beads. Higher glutaraldehyde concentration made the chitosan beads hard and brittle, while chitosan beads cross-linked with lower glutaraldehyde concentration had higher swelling ratio. Swelling in acidic environment was higher than swelling in weak basic environment. This might be due to that the amino groups in chitosan molecule became protonated in acidic solution. The cationic chitosan molecules would lead to higher intermolecular repulsive forces between molecules. Consequently, chitosan beads had higher swelling ratio in acidic environment. The swelling ratio in acidic solution of cross-linked and air-dried gel beads were about 2.5 times that of the samples in weak basic solution. Cross-linked and freeze-dried samples swelled about 1.8 times (in acidic solution) as high as those in weak basic solution. In weak basic solution, the swelling ratio of coagulated and glycine-gelled chitosan beads swelled about 3~4 times that of the cross-linked and air-dried samples. The total amount of amoxicillin loaded on coagulated, glycine-gelled, 2.5% and 5.0% glutaraldehyde-cross-linked chitosan beads was 84%, 82%, 76% and 74% respectively. During the 24 hr release test in acidic environment the maximum amount of amoxicillin released from coagulated beads was 100%. That of the cross-linked and freeze-dried samples was 95%, and that of the cross-linked and air-dried samples was about 75%. In weak basic environment, freeze-dried samples released about 95% of loaded amoxicillin, while the air-dried samples released about 44~68%. The swelling ratio and its surface structure would affect amoxicillin release from air-dried chitosan bead.
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陳培欣. "The immobilization of protease A on chitosan beads." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/65995902712470341571.
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Yang, Ming-lian, and 楊銘鎌. "Studies of the immobilized lipase on chitosan Beads." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/49280354749556228683.
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碩士國立雲林科技大學
工業化學與災害防治研究所
91
Lipid metabolism is an important part in biochemistry. Energy is stored as triglyceride in living cells that is to metabolize and to change ester. When needed, organisms produce esterase and lipase enzymes to hydrolyze these esters. It is interesting to know that only lipase is capable of decomposing water-insoluble ester. Lipase can also perform many other functions such as esterification and transterification. Since it can catalyze much different type of substrates, it plays an important role in many industries. This research deals with immobilization of lipase with chitosan having 80﹪ deacetylation, and to understand optimal immobilization condition and effect of immobilization on enzyme activity. Firstly, the optimal support composition is: 3% chitosan and 2% of PEG 2000. Secondly, the optimal immobilization condition is: glutaraldehyde concentration 0.1%; the enzyme coupling time: 240 min; 0.096% enzyme (weight percentage). The enzyme activity of 99.42U was obtained at pH 6. Thirdly, hydrolysis of oil was studied with the free enzyme and the immobilized enzyme reactions using olive oil as substrate. The free enzyme has an optimal pH range of 7.0 ~ 8.0 and an optimal temperature range of 30 ~ 40℃. It shifted to an optimal pH rage of 8.0 ~ 9.0 and an optimal temperature range of 50 ~ 60℃ when the immobilized enzyme was used. With 10 repeated experiments, the enzyme activity still shows 68% of activity. The last, free enzyme and immobilization enzyme kinetics was discassed. Km and Vmax were calculated and founded to be 0.58M and 833.37 μmol/hr for free enzyme , and 3.74M and 462.38μmol/hr for immobilized enzyme, respectively. The thermal stability was increased after immobilization, because immobilized enzyme has higher thermal resistance. The immobilized enzyme has 4 times higher decay kinetics constant kd than free enzyme.
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Lin, Fu-Ming, and 林福明. "Preparation and application of chitosan-oxalic acid and chitosan-tartaric acid gel beads." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/45142740967566788041.
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碩士明志科技大學
化學工程研究所
99
Chitosan-oxalate (CO) and chitosan-tartrate (CT) adsorbents, prepared by freeze-dried and oven-dried, were used for treatment of Cu(II) ion from aqueous solution. The effects of the initial pH value of the solution, contact time, temperature and the initial Cu(II) ion concentration on the adsorption of Cu(II) ion were investigated. The characterization of CO and CT adsorbents were investigated by IR, XRD and TGA. The maximum adsorption amount was observed at pH 5 for both CO and CT adsorbents. The adsorption isotherms were better fitted by the Langmuir equation. The maximum theoretical Cu(II) ion adsorption capacities of CO and CT adsorbents prepared by freeze-dried were 227.27 mg/g and 175.44 mg/g respectively. The adsorption kinetics were well described by the pseudo-second order equation, indicating that chemical adsorption is the rate-limiting step for the CO and CT adsorbents. The negative values of gibbs free energy of adsorption indicated the spontaneous adsorption of Cu(II) ion on the CO and CT adsorbents, while the positive enthalpy change indicated an endothermic adsorption process.
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CHEN, ZHI-RUN, and 陳芝潤. "Preparation and application of chitosan-phytic acid gel beads." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/n32p5e.
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碩士明志科技大學
化學工程系碩士班
107
Chitosan gel was usually chemically modified by crosslinking of its linear chains with bifunctional reagents such as glutaraldehyde (GLA), epichlorohydrine (ECH) or ethylene glycol diglycidyl ether (EGDE) to reduce its solubility in aqueous solvent over a broad pH range. These crosslinking agents were not preferred due to their toxicity. A novel and straightforward synthetic technique for the preparation of chitosan beads with less cytotoxicity is desirable. Chitosan has application in the preparation of nontoxic polyelectrolyte-complex products with polyanions. Phytic acid (inositol hexakisphosphate, or phytate when in salt form) is the principle storage form of phosphorus in many plant tissues. Chitosan can form gels with the nontoxic and multivalent inositol hexakisphosphate counter ion. The polycationic chitosan and polyanionic phytic acid via an ionotropic gelation process to form gels. The ionic interactions between the positively charged amino groups and negatively charged counterion were used to prepare chitosan beads. Crosslinking characteristics of the chitosan-phytic acid gel beads were improved by the modification of in-liquid curing mechanism of the beads. The kinetics of chitosan-phytic acid gel beads prepared by in-liquid curing method using polyanions will be studied. FTIR and EDS were studied to confirm the mechanism transition in various treatment conditions. The present study aims to explore the adsorption capacities and kinetics of metal ions from aqueous solution onto fabricated gel beads. The influence of initial pH of the metal ions solution and initial concentration of metal ions solution on the uptake of metal ions were also studied. The equilibrium adsorption data of Cu(II) ions on the gel beads were correlated well with Langmuir isotherm model with a maximum adsorption capacity of 188.68 mg/g. The adsorption of Cu(II) ions on the gel beads exhibited pseudo-second order kinetics. The adsorption thermodynamic parameters indicated that the involved process should be spontaneous and endothermic. This study includes a comparative study on the adsorption capacity of chitosan-based adsorbent, and the results for the application of chitosan-polyanions beads are evaluated in future wastewater treatments.
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Hsieh, Feng-Ming, and 謝峰銘. "Entrapment of Pseudomonas putida in chitosan beads for phenol degradation." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/74295418444640572874.
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碩士國立成功大學
化學工程學系碩博士班
94
This study was aimed to investigate the efficiency of phenol degradation by Pseudomonas putida CCRC14349 that was entrapped within the gel beads prepared by chitosan crosslinked with sodium tripolyphosphate. In addition, various characteristics of these beads were evaluated as well. The efficiency of phenol degradation for the entrapped cells was optimized by changing various processing parameters, such as the amount of cells used, beads washing medium as well as acclimatization strategy. Based on the batch phenol degradation results, these entrapped cells were found to be superior to the free cells in terms of keeping the solution clear, improving the toleration to the environmental loadings (e.g., high pH, low ionic strength, high phenol concentration), and repeating usage for an extended period. After phenol acclimatization, the structure of cell-entrapped beads showed to be stable under acidic and high ionic strength conditions. Diffusion coefficient calculation has indicated that phenol degradation by the entrapped cells varied from the intraparticle diffusion control to reaction control as the beads were used repeatedly. With the increase of hydraulic retention time and the addition of hydrogen peroxide to increase the dissolved oxygen level for cell metabolism, phenol in the influent was almost completely degraded in the packed-column test.
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Chen, Yung-Chih, and 陳勇志. "Synthesis and application of mangnetic a chitosan-citrate gel beads." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/83895198292313978553.
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碩士明志科技大學
化學工程研究所
100
This study used an in-liquid curing method by the ionotropic crosslinking with nontoxic citric acid to synthesize the chitosan-citrate beads, which are used to fabricate magnetic chitosan beads. The magnetic chitosan-coated iron oxide nanoparticles have been synthesized from carboxymethyl chitosan with covalently bonded on the surface of iron oxide nanoparticles via carbodiimide activation. The magnetic chitosan-coated Fe3O4 nanoparticles (MNPs) were dispersed in chitosan-citrate beads, and were thus able to maintain appropriate dispersion and stability, which greatly improves their applicability. The characterization of magnetic nanoparticles and magnetic chitosan-citrate beads were investigated by means of FTIR, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), superconductive quantum interference devices (SQUID). The present study aims to explore the adsorption capacities, kinetics and thermodynamics of metal ions from aqueous solution onto fabricated magnetic gelled beads. The effects of the initial pH value of the solution, contact time and the initial metal ion concentration on the adsorption of metal ion were investigated. The adsorption data of Cu(II) ion obeyed the Freundlich equation and Hg(II) ion obeyed the Langmuir equation. The adsorption kinetics were well described by the pseudo-second order equation, indicating that chemical adsorption is the rate-limiting step for the adsorbents. The thermodynamic parameters such as enthalpy change(ΔH°), entropy change (ΔS°)and Gibbs free energy change(ΔG°) were computed and the results showed that the adsorption of Cu(II) ion onto chitosan-citrate beads was spontaneous and exothermic and Hg(II) ion onto chitosan-citrate beads was spontaneous and endothermic in nature.
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Jian, Jia-Hau, and 簡家豪. "The Immobilization of Candida rugosa Type Ⅶ Lipase on Chitosan Beads." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/79573590015067365576.
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Lin, Yie-Hsean, and 林業祥. "Preparation and Hemocompatibilty of Water-Soluble Chitosan Co-ionic Complex Beads." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/10076634442976877618.
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碩士國立臺灣科技大學
高分子工程系
92
Co-ionic complex beads were prepared by precipitating chitosan using tripolyphosphate (TPP) and dextran sulfate (DS). Water-soluble chitosan (WSC) of two molecular masses (99 and 181 kD) and common chitosan (CS) were employed in this study. These beads were characterized using elemental analysis (EA), optical microscopy, and scanning electron microscopy (SEM). The swelling kinetics and the distribution coefficients of three compounds were also measured. The hemocompatibility was evaluated based on the protein adsorption, platelet adsorption, activated partial thrombin time (APTT), and prothrombin time (PT). The results showed that beads made from WSC exhibited higher swelling ratio (SR) than from CS. The SR increased with the DS content and depended on the pH. Beads made from WSC also exhibited lower cytotoxicity than beads from CS. The biodegrading rate by lysozyme of WSC beads was faster than that of CS beads. In addition, WSC/TPP/DS beads exhibited less protein and platelet adsorption, and longer APTT and PT. These results indicated that the addition of DS could endow WSC and CS beads with anti-coagulating ability.
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Li, De-Yi, and 李得義. "Synthesis and application of chitosan/γ-poly(glutamic acid) gel beads." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/67m799.
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碩士明志科技大學
化學工程研究所
101
Biopolymers have recently received increased attention because they can be used to produce effective biosorbents for removing heavy metals from water. Chitosan and γ-poly glutamic acid(γ-PGA) are both biodegradable and environmental-friendly biopolymers. In this study, chitosan/γ-PGA complex gel beads were prepared by ionotropic gelation of chitosan/γ-PGA blend droplets with tripolyphosphate counterions. The chemical structure and morphology of chitosan/γ-PGA beads were characterized by Fourier transform infrared spectrometry (FTIR) and scanning electron microscopy (SEM). The prepared chitosan/γ-poly glutamic acid beads were used to investigate the adsorption properties of copper (II) and mercury (II) ions, respectively. Equilibrium studies showed that the data of copper (II) and mercury (II) adsorption respectively followed the Freundlich and Langmuir isotherm model. In addition, the adsorption data fitted the pseudo-second order kinetic model well, indicating that chemical sorption is the rate-limiting step. The thermodynamic parameter such as Gibbs free energy change(ΔG°), enthalpy change(ΔH°), entropy change(ΔS°) estimated from the experimental sorption data suggested that the adsorption of copper (II) and mercury (II) ion onto chitosan/γ-poly glutamic acid beads was occurred through a spontaneous and exothermic adsorption process.
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Ni, Yu-hui, and 倪莠惠. "Application of the Calcium lactate composite chitosan beads for enterovirus adsorption." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/10374828437472739946.
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碩士輔英科技大學
生物技術系碩士班
98
Chitosan has various biologically important properties such as unique antibacterial activities, biocompatibility, biodegradability and no toxicity. Due to the presence of amino groups in the unique structural feature of chitosan providing the possibility of cross-linking and chemical modifications, chitosan has excellent selectivity and adsorption capability. It has been used as a biosorbent for enzyme and cell immobilization as well as cell culture substrate. Recently, chitosan has been used in medical health care. It has been pointed out that chitosan can be used as a vaccine adjuvant and/or as an antigen carrier to enhance the host immune effects in vivo. In this study, an edible calcium lactate chitosan particles were developed for enterovirus adsorption. Our results showed that the calcium lactate composite chitosan particles have a very good enterovirus adsorption and the development of edible vaccine is promising.
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Tzu-Yang, Hsien. "Synthesis of porous, magnetic chitosan beads and application to cadmium ion adsorption." Thesis, 1992. http://hdl.handle.net/1957/36143.
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HUANG, XIAO-TING, and 黃筱婷. "Humic Acid-Immobilized Chitosan Gel Beads as a Hg(II) Ion Adsorbent." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/d5zjx7.
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碩士明志科技大學
化學工程系生化工程碩士班
104
The adsorption of Hg(II) ions using humic acid-immobilized chitosan-tripolyphosphate (HA-CTPP) beads was investigated by ICP-OES. First, chitosan (CTPP) beads were used to adsorb humic acid (HA) and the result showed that the HA adsorption capacity increased with pH value. Batch studies, investigating CTPP bead adsorption capacity and adsorption isotherm for the HA, indicated that the HA adsorption equilibrium correlated well with Freundlich isotherm model. The HA adsorption kinetics were well described by the pseudo-first order equation. Further, the adsorption of Hg(II) ions using HA-CTPP beads was correlated well with Freundlich isotherm model. The maximum adsorption capacity derived from Langmuir isotherm was 209.64 mg/g. The experimental data fitted the pseudo-second order kinetic model well, indicating that chemical sorption is the rate-limiting step. The thermodynamic parameters (ΔH°、ΔS°andΔG°) were also discussed in this study.
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Chang, Jung-Chieh, and 張榮傑. "Synthesis and analysis of citric acid and malic acid modified chitosan beads." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/50423696816153199547.
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碩士明志科技大學
化學工程研究所
99
The chitosan-citrate (CC) and chitosan-malate (CM) beads, prepared by ionotropic cross-linking and freeze-drying method, were used for the adsorption of Cu(II) ion from aqueous solution. The characterization of CC and CM beads were investigated by means of IR, X-ray diffraction (XRD), thermogravimetric analysis (TGA), inductively coupled plasma optical emission spectrometry (ICP-OES). The equilibrium adsorption data of Cu(II) on the CC and CM beads were correlated well with by Langmuir isotherm model. The maximum adsorption capacity for adsorption of Cu(II) ion, has been calculated from Langmuir isothermal, were 238.0mg/g (CC) and 256.4mg/g (CM). The experiment data was provide better fit in pseudo-second order adsorption equation , indicating that the chemical adsorption is rate-limit step in the adsorption of Cu(II) ion onto adsorbent. The thermodynamic parameters such as enthalpy change(△H°), entropy change (△S°)and Gibbs free energy change(△G°) were computed and the results showed that the adsorption of Cu(II) ion onto CC and CM beads was spontaneous and endothermic in nature.
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Chang, Shiao-Ting, and 張曉婷. "Entrapment of Pseudomonas putida in chitosan gel beads for biodegradation of phenol." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/4bv3qa.
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碩士國立成功大學
化學工程學系碩博士班
90
In this study, chitosan is used as an immobilization matrix. Pseudomonas putida is entrapped by physical iontropic gelation with chitosan and the resulting beads are used as a biocatalyst for the biodegradation of phenol. Two important issues were investigated about these beads: 1. The surface and cross-section morphology of the beads: the structure of the beads formed by different iontropic gelation procedures were observed by scanning electron microscopy (SEM). To avoid bacteria leakage and attain an effective immobilization, the high surface porosity and small pore diameter that is less than 0.2μm are sought. In addition, the core of the beads shouldn’t be too dense, so as to provide enough growing space for bacteria. 2. The viable bacteria concentration inside the bead: the quantification of bacteria is difficult since the lysis for the chitosan bead was hard. Thus, the following experiments were performed. One is the concentration of the bacterial loss during entrapment. The other is the viable ratio of the bacteria after contact with the solution used for immobilization. Henceforth, the viable bacteria concentration entrapped inside the bead can be calculated. Chitosan beads formed by using 2% chitosan solution gelation in 1% sodium tripolyphosphate solution is strong enough to bear the aeration and shaking tests. This indicates the stability of the chitosan beads were satisfactory. The surface pore diameter of the beads formed is ranging from 1 to 6 μm. This might result in the leakage of bacteria entrapped. High molecular weight and high degree of deacetylation of the chitosan can lead to a better bead formation in the gelation solution. In addition, the core of the beads will become denser with the increase of the chitosan concentration, and this will limit bacteria growth. Most of all, it was found that the bacteria is denatured after its contact with chitosan solution. This may be attributed to the antibacterial property associated with chitosan as well as the acidic environment of the chitosan solution.
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Hung, Shen-Hsiu, and 洪聖修. "The evaluation of phenol degradation by immobilization of Pseudomonas putida onto chitosan beads." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/jg9ux9.
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碩士國立成功大學
化學工程學系碩博士班
92
In this study, we used chitosan lactic acid solution (CLS) and sodium tripolyphosphate (TPP) to immobilize the Pseudomonas putida by physical iontropic gelation and regarded it as a biocatalyst for the biodegradation of phenol. From the results, our conclusions are as followings： (1)The Pseudomonas putida can be acclimatized by the phenol and have well adaptability. (2)The Pseudomonas putida stays alive in the process of immobilization according to the experimental results of the extended direct contact with CLS and TPP. (3)Owing to the effect of the low temperature, the concentration of chitosan could be reduced in the immobilization process. (4)A greater amount of immobilized Pseudomonas putida and/or a higher concentration of gelling agent can lead to a faster phenol degradation rate. In this study, the immobilized chitosan beads embed by 3×10^9 CFU of the bacterials and gelated with 1 wt% of tripolyphosphate have the highest phenol degradation efficiency. This can be attributed to the residual cells from the washing, the cells fallen from the external surface of the beads due to vibration and the cells immobilized onto the chitosan beads.
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Shao, Huei-Jen, and 邵惠珍. "Equilibrium Modeling of Adsorption of Binary Metals from Aqueous Solution on Chitosan Beads." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/46326633877689407860.
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碩士元智大學
化學工程研究所
88
The adsorption of heavy metals such as copper, nickel and zinc at different pH (2.5~5)and concentration (0.77~17 mol/m3) using chitosan beads at 30 ℃was studied. To predict the amount of adsorption in binary metal systems, an equilibrium model for single-metal adsorption system was developed first. In this model, the adsorption of hydrogen and metal ions were competed, and the hydrolysis of copper ion was also considered. According to the equilibrium constants and mass-balance, pH value and the amount of adsorption were obtained after calculation by the computer program. Comparing the calculated amount of adsorption in binary systems with experimental data, there showed positive deviation in some cases and negative deviation in some cases because of competitive effect, which was increased as increasing the amount of copper. And, the equilibrium constant and coordination number in binary systems were different from those obtained in single systems owing to the appearance of the other species . Selectivity factor of Cu/Ni、Cu/Zn, defined as the ratio of amounts of metal adsorption divided by that of their initial aqueous concentrations, was in a range 5~25 at a pH range 3~6. This represented that the selective separation in these binary systems could be achieved. In the Ni/Zn system, however the value was small (1.2~2.6) at pH range 2~5. Since the selective factor in all three systems were larger than 1, therefore the separation of metals using chitosan beads was forward.
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吳照男. "The Study on Immobilizing Lipase on Chitosan beads of Different Degrees of Acetylation." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/10299763456256848902.
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碩士國立海洋大學
食品科學系
91
Abstract Chitin and chitosan both come from natural organisms. They are nontoxic, biodegradable, and bioreactive. During the past few years, researchers in food process and medical analysis did a lot of studies on immobilization of biocatalysts to cut down the production cost in order to become more competitive for the market. Our experiment involved lipase immobilization on chitosan beads made by different methods, which possessed various degrees of N-acetylation. The effect of immobilized lipase activity on degrees of N-acetylation and preparative methods for chitosan beads were investigated. Chitosan with degrees of N-acetylation (DA) of 25% was treated with hot alkali solution for different time intervals to lower its DA to around 5, 10, 15, and 20%. Chitosan beads were then prepared by means of extrusion and spray drying. Lipase immobilized on extruded beads had lower activity than that immobilized on spray dried counterparts. Moreover, lipase on lyophilized beads had higher activity than that on wet ones. And lipase on wet beads had higher activity than that on oven dried ones. Lyophilized beads, having about the same size as wet beads and a lot of holes on the surface, possessed higher lipase activities. Lowering the DA of chitosan was also found helpful in increasing the activity of the lipase immobilized because of the more amino groups on the beads. Among the three methods employed for lipase immobilization, binary immobilization method was found to have higher activity than the other two methods. However, relative specific activities did not follow the same trend. Part of the enzyme probably denatured while too much enzyme was immobilized. Both thermal and pH stability of the enzyme were elevated after immobilization. Immobilized enzyme retained more than 90% of its original activity after 30 bath reactions. For enzyme dynamic constants, the Km value of the immobilized lipase was close to that of free lipase, while the Vmax value of the immobilized lipase was lower than that of free lipase.
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Chang, Min-Yun, and 張敏雲. "Adsorption Characteristics and Enzyme Immobilization on Complex Beads Prepared from Chitosan and Activated Clay." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/74570393754015267340.
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碩士國立中興大學
食品科學系
90
Chitosan is known as an ideal support material widely used for enzyme immobilization. It has been proved that chitosan beads could conquer steric hindrance and exhibit more activated seats and transported spaces. Though chitosan beads have excellent characterization for enzyme immobility and adsorption, if the beads can be modified to promote mechanical property and specific gravity, the operation and reuse of enzyme immobility engineering will be increased. In this study, activated clay was added in chitosan colloid to prepare complex beads. The adsorption action of the complex beads were analyzed by isotherm equations and kinetic models for two dyes and two organic compounds. The activity of two enzymes immobilized on the complex beads were also determined to evaluate the availability of the product. The following results were obtained. 1.All adsorption isotherms of humic acid, RR222, tannic acid and methylene blue from water onto complex beads could be well fitted by the Freundich equation. 2.Three simplified kinetic models including pseudo-first order equation, pseudo-second order equation and intraparticle diffusion model were selected to follow the adsorption processes. It was shown that the adsorption of larger molecules including RR222 and tannic acid could be best described by the pseudo-first order equation. A comparison of the kinetic parameter of intraparticle diffusion ki (g·kg-1 ·min-0.5) among such adsorbents was also obtained. 3.The immobilization of acid phosphatase andβ-glucosidase onto the complex beads was finished by cross-linking with 5.0 g / L glutaraldehyde. The activity of both immobilized enzymes could be described by reversible Michaelis-Menten mechanism applying the pseudo- steady- state hypothesis. The Michaelis constant (Km) and maximum velocity (Vm) were estimated according to the Lineweaver- Burk plot. The values of Km and Vm of acid phosphatase were obtained to be 1.65 mM and 30.9 µmol·min-1, respectively, and those of Km and Vm ofβ-glucosidase were 5.95 mM and 144.4 µmol·min-1, respectively. After 50 times reuse, the immobilized enzyme can keep stability of its activity. 4.The activated energy of thermal inactivation of the immobilized acid phosphatase, Ea, could be obtained if the inactivation was assumed to the first order, which was equal to 66.4 kJ/mol. It was show that the activity of the immobilized β-glucosidase increased with increasing temperature in the range 15-75 oC. The activity of the immobilized acid phosphatase at 57 oC reached maximum. The activities of both immobilized enzymes remained nearly constant at pH 3.5-5.8. 5.This work provided some basic data for solute adsorption and enzyme immobilization onto complex beads for further design of production process.
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Yu, Ti-kai, and 游帝凱. "Preparation and modification of chitosan beads crosslinked by tripolyphosphate for controlled release of protein drugs." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/57684062486526671093.
Full textAbstract:
碩士國立成功大學
化學工程學系碩博士班
94
As chitosan solution was dropped into tripolyphosphate solution, round beads were formed immediately with the formation of ionic-crosslink between these two components. Alginate may also be added into tripolyphophate solution in order to form polyelectrolyte layer for bead surface modification. In this study, a protein drug controlled release system was investigated by using bovine serum albumin as a model drug and beads aforementioned as the carrier matrix. After a series of experiments, it was noticed that using different concentration ratios of chtosan, tripolyphosphate, and alginate solution would lead to the diffusion differences during the bead formation, and, henceforth, make the bead structures very different from each other. The bead structure is generally consisted of a dense cortex and a porous core. The variation of the bead structure would affect the swelling properties, drug loading efficiencies, and release profiles of these beads. In the alginate-modified beads, the drug loading efficiency was dramatically increased, and the drug release tendency was also amplified. In contrast, the unmodified beads had only about 50% loading efficiency and a very limited release tendency instead.
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Wang, Si-Jie, and 王思傑. "Adsorption of Cr（VI）and As（V）form aqueous solution onto zero-valent copper-chitosan beads." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/22223962343092400051.
Full textAbstract:
碩士明志科技大學
化工與材料工程研究所
98
In this study, spherical chitosan-tripolyphosphate chelating resins were used as a polymeric support to prevent copper nanoparticles from agglomerating, which greatly improved its applicability. The high adsorption capacity and the stability of copper on the chitosan over a wide range of pH value justified the use of this biopolymer for the preparation of zero-valent copper-chitosan nanocomposites. The fabrication process contains two steps: using resin beads to adsorb Cu(II) ion, followed by chemical reduction to reduce Cu(II) ion to zero-valent copper. The main objective of the present study was to investigate a new adsorption process for arsenic and chromate removal from an aqueous solution using zero-valent copper-chitosan nanocomposite. The effects of the initial pH value of the solution, initial metal ion concentration and temperature on the adsorption behavior of the nanocomposites were investigated. The equilibrium adsorption data were fitted to Langmuir and Freundlich model, and the model parameters were calculated. The pseudo first-order, pseudo second-order and intraparticle diffusion model were used to understand the adsorption kinetics and rate limiting step in the adsorption of metal ions onto chitosan-tripolyphosphate beads and nanocomposites. The adsorption kinetics were well described by the pseudo second-order equation, and the adsorption isotherms were better fitted by the Langmuir equation. The maximum adsorption capacity of the nanocomposites, as obtained from the Langmuir isotherm, was 29 and 142 mg/g for As(V) and Cr(VI), respectively. The negative values of Gibbs free energy of adsorption indicated the adsorption process was spontaneous, and positive values of the enthalpy change indicated that the adsorption was endothermic in nature. The use of nanocomposites for adsorbing As(V) and Cr(V) led to better and faster results than that of the chitosan-tripolyphosphate beads.
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Yang, Chin-Yo, and 楊進有. "Use TPP/genipin co-crosslinked chitosan gel beads to adsorb the phytic acid of soybean whey solution." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/97425649245773840739.
Full textAbstract:
碩士國立臺灣海洋大學
食品科學系
98
The object of this study is to investigate the characterization of different type of TPP/genipin co-crosslinked chitosan beads and choose an appropriate kind of chitosan bead to carry out the study of adsorption isotherm for phytic acid. Finally, finding the optimum condition for selectively adsorbed of phytic acid from soybean whey, and improving the utilization of soybean whey. The chitosan-based networks of gel beads were prepared with degree of deacetylation of 80% and molecular weight of 900 kDa chitosan. The characterization of chitosan beads were different with to prepared in different pH (2.0, 3.0, 5.0, 7.0 and 9.0). The crosslinking degree and size of beads were decreased with increasing pH value. The degree of crosslinking and the size of chitosan beads were between 80.14% to 59.22% and 2.38 to 1.94 mm, respectively. The chitosan beads co-crosslinked at pH 7.0 had better breaking force, deformation degree of breaking and gel strength, the each of value was 5.38 g, 1.31 mm and 7.08 g•mm, respectively. The phytic acid was adsorbed with different type of chitosan beads to get equilibrium concentration at 24 hours. The amount of phytic acid was adsorbed by co-crosslinked chitosan beads were increasing with decreasing pH value. The TPP/genipin co-crossliked chitosan bead prepared in pH 7.0 was be the adsorbent to adsorb phytic acid, because its mechanical strength and adsorption capacity was good. The parameters studied include the effects of pH, treatment time and the initial concentrations by batch method. The maximum monolayer adsorption of the chitosan beads was 12.24 mg g-1 at pH 2.0, 35℃ and 24 h. The results obtained from equilibrium adsorption studies were fitted in Langmuir adsorption model but not in Freundlich adsorption model, and the model parameters have been evaluated. The equilibrium parameter (KR) indicated that the process of adsorption was favorable. The dynamical data fit well with the second-order kinetic model. The adsorption capacity increases largely with decreasing solution pH and temperature or with increasing initial phytic acid concentration. The adsorption of phytic acid on the chitosan bead co-crosslinked at pH 7.0 was spontaneous and an exothermic process, and accompany of decreasing randomness. The activation energy of adsorption and desorption were 55.77 kJ mol-1 and 71.51 kJ mol-1, respectively. In order to desorb phytic acid from the surface of co-crosslinked chitosan bead into solution which the solution condition need be changed. At pH 2.0 and 25℃, the chitosan beads co-crosslinked at pH 7.0 could selectively adsorb phytic acid from soybean whey solution, and the adsorption rate was 30.23%. At pH 9.0 and 25℃, the chitosan beads co-crosslinked at pH 7.0 could desorb the absorbed phytic acid efficiently, the desorption rate was 93.98%.
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Hsien, Tzu-Yang. "Removal of cadmium ions by porous chitosan beads : effects of acylation & crosslinking on material properties and adsorption isotherms." Thesis, 1996. http://hdl.handle.net/1957/34672.
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Lin, Ya-shen, and 林雅申. "Characteristics and adsorption kinetics of Kunitz trypsin inhibitor and lectin by using chitosan/TPP/genipin co-crosslinked beads." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/71031526068122148131.
Full textAbstract:
碩士國立臺灣海洋大學
食品科學系
100
Chitosan/tripolyphpsphate/genipin co-crosslinked beads (CTGB 7, CTGB 8, CTGB 9) was prepared in different pH solutions (pH 7.0, 8.0 and 9.0) by ionic and chemical co-crosslinking mechanism. Between characteristics of CTGBs, including color, degree of crosslinking, appearance, interior structure and the adsorption capacity of Kunitz trypsin inhibitor (KTI) and lectin were different. The interactions between CTGBs and KTI and lectin are electrostatic, hydrophobic interaction and hydrogen bond. The adsorption capacity varied with changing pH, and the maximum adsorption ratio of KTI and lectin occurred at pH 4.5 and 5.7, respectively. Both adsorption kinetics and theoretical isotherm models indicated that KTI and lectin could be effectively adsorbed by CTGBs, and the adsorption capacities were influenced by the pH, the initial protein concentration and temperature. The experimental data fitted well to Freundlich model and pseudo-second-order kinetic model. The maximum monolayer adsorption capacities (qm) obtained from the Langmuir model of the CTGBs between KTI and lectin were very different, 7.11 mg/g for KTI and 0.90 mg/g for lectin. The maximum adsorption ratio of KTI from soybean whey was 69.41% by CTGB 7 at pH 4.5. However the maximum adsorption ratio by CTGB 7, CTGB 8, and CTGB 9 for lectin from soybean whey were only 4.03%-16.41%. These results suggested that the different adsorption capacities between KTI and lectin from soybean whey may be caused by competitive adsorption effects and different qm.
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Pao, Hsin-Hung, and 包昕弘. "Humic Acid-Immobilized Chitosan Gel Beads As An Adsorbent For The Removal Of Heavy Metal Pb(II) Ions." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/pm2x35.
Full textAbstract:
碩士明志科技大學
化學工程研究所
101
This study was the adsorption of Pb(II) ions using humic acid-immobilized chitosan-tripolyphosphate (HA-CTPP) beads. The HA adsorption capacity of unseasoned CTPP and freeze-dried CTPP are 228.31 mg/g and 54 mg/g respectively. The results showed that unseasoned CTPP beads have better HA adsorption capacity and the adsorption isothermal data correlated well with Langmuir and Freundlich isothermal models, with a maximum adsorption capacity qmax of 200 mg/g. The adsorption kinetics were well described by the pseudo-first order equation. The thermodynamic parameters analyses were performed to discuss ΔH°、ΔS°和ΔG°. The unseasoned HA-CTPP beads and freeze-dried HA-CTPP beads have same Pb(II) adsorption, therefore freeze-drying method was selected due to its simplicity. FTIR was used to verify functional groups, and SEM was used to observe the surface of the prepared beads. The adsorption isotherms fitted Langmuir isotherm well, with a maximum Pb(II) capacity of qmax= 90.99 mg/g for freeze-dried HA-CTPP beads, and the adsorption kinetics were well described by the pseudo-first order equation.
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Weng, Tsai-Yi, and 翁才懿. "The Preparation of Chitosan/CMC/TPP-Polyelectrolyte Complexation (PECs) Gel Beads its Application on Drug Delivery Controlled Release System." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/06447979235100294158.
Full textAbstract:
碩士嘉南藥理科技大學
生物科技系暨研究所
96
The purpose of this study was the preparation and characterization of drug containing polymer gel beads. Natural and biocompatible chitosan was dissolved with drug in 5 wt% acetic acid solution. Different chitosan gel beads were obtained by polyelectrolyte complexation with sodium salt of carboxymethyl cellulose and tripolyphosphate. The effect of drug entrap ratio, gel particle size, morphology and physical properties on drug released behavior were investigated. The results showed that the drug can sustain 16 hrs and its release rate was consistent with T. Higuchi model.
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Chang, Yu-Lung, and 張祐朧. "Selective adsorption of trypsin inhibitor, lectin and phytic acid from soybean whey by chitosan/tripolyphosphate/genipin co-crosslinked beads." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/74344133820169445068.
Full textAbstract:
碩士國立臺灣海洋大學
食品科學系
100
vii Abstract The purpose of this study is selectively adsorbed trypsin inhibitor, lectin and phytic acid form soybean whey by chitosan/tripolyphosphate (TPP)/genipin co-crosslinked beads. The chitosan beads (CB5, CB7, CB9) were co-crosslinked with TPP/genipin solution at pH 5.0, 7.0 and 9.0, respectively. At 5, 15 and 25℃,these co-crosslinked chitosan beads were adsorbed trypsin inhibitor, lectin and phytic acid from soybean whey solutions in pH 2.0-6.0 solutions, respectively. The results showed that all the co-crosslinked chitosan beads had the maximum adsorption ratio of trypsin inhibitor, lectin and phytic acid at pH 4.4, 5.4 and 2.2, respectively. The maximum adsorption ratios of trypsin inhibitors and lectin for were higher than that of CB7 and CB5. The maximum adsorption ratios of trypsin inhibitors and lectin for these beads adsorbing at 25℃were higher than that of 15℃ and 5℃. In pH 9.0 soltuion, the desorption ratios of phytic, trypsin inhibitors and lectin for adsorbed CB7 under pH 2.2, 4.4 and 5.4 were 43.6%, 73.14% and 65.81%, respectively. In short, the selective adsorption for trypsin inhibitor, lectin and phytic acid from soybean whey could be processed by chitosan/TPP/genipin co-crosslinked beads in appropriate conditions.
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Wang, Chang-I., and 王成一. "(I)Application of chitosan beads combined with SPME for the determination and treatment of organochlorine pesticides in water(II)Using hollow fiber membrane-protected SPME to determine the of organochlorine pesticides in bovine milk." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/19490079243178806957.
Full textAbstract:
碩士淡江大學
化學學系碩士班
97
Part. I A new method for analyzing and treatment of organochlorine pesticides (OCPs) in water by solid-phase microextraction (SPME) combined with crab shell and chitosan as an adsorbent is described. The OCPs can effectively control almost all kinds of pests including insect, fungi, rodent, etc. However, they continue to be detected in both biological and environmental samples worldwide because of their persistent and bioaccumulative properties. The present study is the first to use porous biopolymer crab shell and chitosan as an adsorbent for removal of the 18 kinds of OCPs remaining in the water samples. The OCPs standards in the study, including α-HCH、β-HCH、γ-HCH、δ-HCH、Heptachlor、Aldrin、Heptachlor epoxide isomer B、α-Endosulfan、4,4''-DDE、Dieldrin、Endrin、β-Endosulfan、4,4''-DDD、Endrin aldehyde、Endosulfan sulfate、4,4''- DDT、Endrin ketone and Methoxychlor. We use the 65μm PDMS/DVB fibers and two ways sampling, headspace mode and direct immersion mode, to extract the OCPs from the treatment water samples. Finally, we inject the sample to the GC/ECD for analysis. According to experiments, the water samples after crab shell treatment, we find that seventeen kinds of OCPs can be effectively treatment to 100 % (2.8 ng). The water samples after chitosan treatment, we also find that sixteen kinds of OCPs can be effectively treatment to 100 % (2.8 ng), and the other one is 99.3 %. In this study, we present here the use of crab shell and chitosan have good result and multiplicity concurrently for the removal of OCPs present in water samples. It is easy for the crab shell to obtain and cheap cost, from the environmental protection view, can really use and develop. Part. II A method for analyzing of organochlorine pesticides (OCPs) in bovine milk by hollow fiber membrane-protected solid-phase microextraction (HFM-SPME) is described. Although most of OCPs have been banished from use for many years, they are still detected in organism adipose tissue, blood, urine, feces, sperm and breast milk because of their great chemical stability and lipid solubility. In this study, we use the 65μm PDMS/DVB SPME fibers and hollow fiber membrane-protected mode to extract the OCPs from bovine milk samples. After the sampling, then inject the sample to the GC/ECD for analysis. There are 18 kinds of OCPs standards in the study, including α-HCH、β-HCH、γ-HCH、δ-HCH、Heptachlor、Aldrin、Heptachlor epoxide isomer B、α-Endosulfan、4,4''-DDE、Dieldrin、Endrin、β-Endosulfan、4,4''-DDD、Endrin aldehyde、Endosulfan sulfate、4,4''- DDT、Endrin ketone and Methoxychlor. HFM-SPME experimental parameters such as extraction temperature, extraction time, salt concentration and pH values were investigated and optimized. According to experiments, we choose that 100 ℃extraction temperature, 60 min extraction time, 1 %(w/v) salt concentration and pH 6.6 for the best response in HFM extraction mode. In this optimal parameters, we find that sixteen kinds of OCPs can be effectively extracted in skim milk samples and eleven kinds of OCPs in whole milk samples. We present here that HFM-SPME was an efficient pretreatment method and have good results for complex matrices samples.
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Suryani, Devi, and 蔣香松. "Biodiesel Production by Using Immobilized CaO in Chitosan Bead." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/61444863862062866034.
Full textAbstract:
碩士國立成功大學
化學工程學系碩博士班
97
CaO, immobilized in chitosan beads by physical encapsulation, was employed as an alkali catalyst to catalytically produce biodiesel by transesterification of soybean oil with methanol. The operation conditions for CaO immobilization with high stability were optimized as the CaO loading of this catalyst was obtained around 12% (w/w). The immobilized CaO trapped in chitosan beads was further employed to investigate the transesterification reaction of soybean oil with methanol. The response surface methodology (RSM) was applied to determine the optimal catalytic reaction conditions at temperature of 60oC, molar ratio of oil to methanol of 1:13.4, and catalyst loading of 13.78 wt%. Under the optimal reaction conditions, the equilibrium conversion of soybean oil was up to 97% for 3 hours.
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邱思翰. "The Studies of Urease Immobolized on Sensitive Membrane and Chitosan Bead." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/66206887129778672052.
Full textAbstract:
碩士長庚大學
化學工程研究所
86
Urease was covalently immobilized on glutaraldehyde-pretreated chitosan bead. We also prepared a temperature-sensitive composite membrane by cross-linking N-isopropylacrylamide, N-acryloxysuccinimide on nonwoven support for immobilizing urease. The membrane has the characteristic of volume response to temperature change. We explore the optimum enzyme immobilization conditions, temperature stability, storage stability, reusability and enzyme kinetics of free enzyme, chitosan-immobilized and membrane-immobilized urease. The chitosan-immobilized urease retained 95% of its original activity. The properties of free and immobilized urease were compared. The Michaelis constant was about 4.5 times higher for chitosan-immobilized urease than for the free enzyme, while the maximum reaction rate was higher for the chitosan-immobilized enzyme. The optimum pH was determined to be 7.5 for the free and chitosan-immobilized urease. The optimum temperature was determined to be 70℃ for the free and chitosan-immobilized urease. The chitosan-immobilized urease had good heat, storage and operational stability, properties that offer potential for practical application. The membrane-immobilized urease retained 25% of its original activity. The Michaelis constant was lower for membrane-immobilized urease than for the free enzyme, while the maximum reaction rate was lower for the membrane-immobilized enzyme. The optimum pH was determined to be 7.5 for the free and membrane-immobilized urease. The optimum temperature was determined to be 70℃ for the free and membrane-immobilized urease. The membrane-immobilized urease had good heat stability and good reusability.The membrane-immobilized urease was used in a membrane-reactor to take advantage of its temperature-sensitivity by temperature cycling. The best temperature cycle was between 60 and 20℃ with cyclic time at 5 minutes.