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Utilization and development of liquid brewer’s yeast mixed with cassava pulp for cattle feed / キャッサバデンプン粕と混合した液状ビール酵母の牛用飼料としての利用と開発に関する研究Sukanya, Kamphayae 23 March 2017 (has links)
京都大学 / 0048 / 新制・論文博士 / 博士(農学) / 乙第13101号 / 論農博第2847号 / 新制||農||1051(附属図書館) / 学位論文||H29||N5033(農学部図書室) / (主査)教授 廣岡 博之, 教授 松井 徹, 准教授 熊谷 元 / 学位規則第4条第2項該当 / Doctor of Agricultural Science / Kyoto University / DFAM
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Development of Adsorbents from Brewer’s Spent Grain for Uranyl Ion Removal from WastewaterSu, Yi 10 October 2022 (has links)
Unwanted uranium released in the aquatic environment from uranium mining and nuclear fuel industry has become a growing threat to human health and environment safety due to its radiological and chemical toxicity. Biosorbents from agro-industrial waste are the most preferred materials for the removal of uranium from the wastewater due to their good cost-to-performance ratio. Brewer’s spent grain (BSG), a widely produced by-product from the beer brewery industry, is an inexpensive and readily available feedstock for the production of uranium biosorbents. In the current work, the use of BSG as a promising starting feedstock for low-cost and efficient adsorbents with high adsorption capacity, fast kinetics, selectivity, and reusability, is investigated. Functionalization methods such as thermal treatment, chemical modification (oxidation), and polymer grafting were explored, and the selectivity was tuned using surface ion-imprinting technology. The adsorption performance of adsorbents prepared from BSG was tested under various conditions for practical application, and structure affinity principles were derived from the characterization, data modeling and experimental results (Fig. 1).
In the first part of this work, BSG is successfully converted into altered BSG (ABSG), an effective biosorbent, by mild hydrothermal treatment approach (150 ℃, 16 h). Compared with the conventional hydrothermal carbonation method (up to 250 ℃), the current method is carried out at a significantly lower temperature without any additional activation process, which minimizes the energy consumption and environmental impact during the treatment. Maillard reaction plays an important role in increasing the adsorption capacity by forming various Maillard reaction products (methylglyoxal-derived hydroimidazolone-1 with the highest content) and melanoidins with a large number of functional groups. In addition, other pathways such as dehydration, decarboxylation, aromatization and oxidation also contribute to the increased adsorption capacity. Therefore, the content of carboxyl groups in ABSG increases up to 1.46 mmol/g with maximum adsorption capacities for La(Ⅲ), Eu(Ⅲ), Yb(Ⅲ) (pH = 5.7), and U(Ⅵ) (pH = 4.7) of 38, 68, 46 and 221 mg/g, respectively (estimated by the Langmuir model). Moreover, FT-IR spectra show that both O- and N-containing functional groups are involved in the adsorption of studied ions.
The second part of this work demonstrates for the first time the successful oxidization of BSG using 85 wt% H3PO4 and NaNO2, increasing the carboxyl groups content from 0.15 mmol/g for BSG to 1.3 mmol/g for oxidized BSG (OBSG). OBSG exhibits fast adsorption kinetics in 1 h and an adsorption capacity for U(Ⅵ) of 297.3 mg/g (c0(U) = 900 mg/L, pH = 4.7), which is superior to other biosorbents reported in the literature. Possible adsorption mechanisms are based on ion-exchange between UO22+ and H+ released from carboxyl groups, and the complexation of UO22+ with the two oxygen atoms of carboxyl groups. For practical application, adsorption/desorption studies show that OBSG retains 60% of original adsorption capacity (167 mg/g) with a desorption ratio of 89% after 5 adsorption/desorption cycles. Evaluation of OBSG performance in simulated seawater (10.8 mg/g, c0(U) = 10 mg/L, 193 mg/L NaHCO3 and 25.6 g/L NaCl, pH0 = 7.7) indicates a potential usage at low concentration, high salinity, and in the presence of carbonate.
In the third part of this work, brewer’s spent grain supported superabsorbent polymers (BSG-SAP) with various cross-linking density are prepared for the first time via one-pot swelling and graft polymerization of acrylic acid (AA) and acrylamide as low-cost and environmentally friendly adsorbents. A 7 wt% NaOH solution was used as a swelling agent for BSG and as a neutralization agent for AA without generating alkaline effluents. The use of BSG and graft polymerization can significantly increase the available hydroxyl, carboxyl and amide groups, resulting in a highly cross-linked and highly hydrophilic three-dimensional polymer network of BSG-SAP. The BSG-SAP (BSG-SAP-H) prepared with high cross-linking density exhibits better properties with exceptional adsorption capacity for U(VI) of 1465 mg/g (estimated by the Toth model) at pH0 = 4.6 within 45 min. It also shows good selectivity for U(VI) in the presence of several metal ions (V(V), K(I), Na(I), Mg(II), Zn(II), Co(II), Ni(II), and Cu(II)) with selectivity coefficients (SU) higher than 72%. In simulated seawater, BSG-SAP-H showed higher adsorption capacity (17.6 mg/g for c0(U) = 8 mg/L, pH0 = 8) compared to the currently reported adsorbents based on natural polymers. In the experiments with the fixed bed column (c0(U) = 30 mg/L), the uranyl ions could be concentrated up to 15 folders in U(VI)-spiked water and up to 13 folds in simulated seawater. Moreover, after four cycles, BSG-SAP-H was able to maintain 80% of adsorption capacity in U(VI)-spiked water (254.4 mg/g) and 90% in simulated seawater (37.4 mg/g). FT-IR and 13C solid-state NMR spectra show the function of amide groups for U(VI) adsorption, the bidentate binding structure between UO22+ and the carboxyl groups, and the cation exchange between Na+ in BSG-SAP and UO22+.
The fourth part of this work describes a new strategy for the preparation of surface ion imprinted brewer’s spent grain (IIP-BSG) using binary functional monomers (2-hydroxyethyl methacrylate and diethyl vinylphosphonate) for selective removal of U(VI). A high monomer/template molar ratio of 500:1 is used to ensure high site accessibility and easy template removal. IIP-BSG exhibits a maximum U(VI) adsorption capacity of 165.7 mg/g (pH0 = 4.6, estimated by the Sips model), a high selectivity (SU > 80%) for U(VI) in the presence of an excess amount of Eu(III) (Eu/U molar ratio = 20), and good tolerance to salinity (47.4 mg/g for U(VI) at ionic strength = 1 mol/L and c0(U) = 0.5 mM = 120 mg/L). After 5 adsorption and desorption cycles, IIP-BSG retains 90% of its adsorption capacity (36.9 mg/g) and high selectivity (SU > 92%) in binary U(VI)/Eu(III) solution (c0 = 0.5 mM = 120 mg/L). In addition, FT-IR spectra show the electrostatic interaction and a coordination of uranyl ions by carboxyl and phosphoryl groups, the site energy distribution theory shows the predominant contribution of high-energy (specific) sites during selective adsorption, and the kinetic model shows that the internal mass transfer is the rate-determining step of U(VI) adsorption.
In the last part of this work, the additional tests were performed for BSG and its derived adsorbents to evaluate their potential for practical application. BSG and most of its derived adsorbents retain 90% of their adsorption capacity after aging in water for 6 days, except for ABSG (60% decrease in adsorption capacity). IIP-BSG shows efficient separation of U(VI)/Ln(Ⅲ) (e.g. La(III), and Nd(III), Sm(III)) in weakly acidic nuclear wastewater (pH0 = 3.5) and U(VI) concentration in carbonate-rich-mine water (e.g. Schlema mine water, pH0 = 7.1) and tailings water (e.g. Helmsdorf tailings water, pH0 = 9.8), demonstrating a high potential for practical use. Selectivity of IIP-BSG is also given for acidic mine water (e.g. Königstein mine water, pH0 = 2.6). In addition, the unmodified BSG and BSG-SAP-H could effectively remove uranyl ions from acidic mine water with high selectivity. In particular, the cost efficiency and the availability of unmodified BSG make it of great interests for the remediation of uranium containing acidic mine water (Table 1).
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Integrated processing of brewer's spent grain into value-added protein feedstuff and cellulose adsorbentHe, Yanhong 16 September 2021 (has links)
Brewer's spent grain (BSG) is the major byproduct generated by the brewing industry, which contains 14–30% protein and 50–70% of fiber. Currently, BSG is predominantly used as low-value cattle feed or buried in landfills, which is a considerable loss of valuable resources, leading to economic loss and environmental problems. Although research has been done on BSG valorization, the studies are limited to producing a single product (e.g., polyphenols, ethanol, or active carbon) and without further utilization of the produced products. Besides, the economic information available about the production of value-added products from BSG is insufficient. The overall goal of this research is to develop an integrated process to convert BSG into value-added protein-rich feedstuff and cellulose absorbent. The objectives of the research detailed here were to 1) develop a process to simultaneously produce protein-rich (PP) and fiber-rich products (FP) from BSG, 2) assess the replacement of fishmeal with PP in shrimp feed, 3) evaluate the economics of the overall process of PP production at a commercial scale, and 4) explore the potential use of cellulose adsorbent obtained from the FP in removing heavy metals from contaminated water.
To attain these objectives, BSG was first subjected to a wet fractionation process to produce PP and FP using different chemical/biological treatments, where the effects of sodium hydroxide, sodium bisulfite, and a protease (Alcalase) at different concentrations were investigated. Under the optimized conditions, the produced PP contained 46% protein and less than 1% fiber. The effectiveness of using PP to replace fishmeal at increasing levels (10–70%) was then evaluated by performing shrimp feeding trials. The results showed that up to 50% of fishmeal in shrimp feed can be replaced by PP without affecting shrimp growth and feed utilization. Moving forward, a techno-economic analysis was conducted to evaluate the economic feasibility of the production of PP. The experimental conditions and results were input into the process simulation model for determining the mass and energy flows. For a processing plant with a capacity of 590 t wet BSG per day, the minimum selling price of PP to achieve a 5% return was determined to be $1044/t, lower than the price of fishmeal, indicating that the use of PP to replace fishmeal in shrimp feed could potentially reduce shrimp farming cost. The utilization of FP will further improve the economic feasibility of the fractionation process. FP was sequentially treated by dilute acid, alkali, and bleach to produce purified cellulose fibers, which were then modified by 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) oxidation to produce a cellulose adsorbent. The feasibility of the adsorbent in removing heavy metals (especially lead and manganese) from contaminated water was then investigated. Based on the results, the produced cellulose adsorbent showed high adsorption capacities for lead (272.5 mg/g) and manganese (52.9 mg/g). Overall, this study demonstrated that BSG can be upcycled into multiple value-added products via an integrated process. The outcomes of this study not only provide a low-cost and sustainable protein source to the aquaculture industry, and provide a novel adsorbent for the water treatment industry, but also offer alternative ways for the brewing industry to manage BSG. / Doctor of Philosophy / Brewer's spent grain (BSG) is the major byproduct generated by the brewing industry. Currently, BSG is predominantly used as low-value cattle feed or buried in landfills due to its high fiber and low protein contents, which is a considerable loss of valuable resources. Besides, raw BSG contains other nutrients and high water content, the inappropriate management of BSG may introduce environmental concerns. Though technologies have been investigated to valorize BSG by extracting protein from it, the process scaled-up is limited by the high drying costs of wet BSG, heavy chemical consumptions, and a large amount of fiber residue. The overall goal of this research is to develop an integrated process to convert BSG into value-added protein-rich feedstuff and cellulose absorbent.
In this study, we developed and optimized a process to produce protein and fiber products from wet BSG. The protein content of the produced protein product was doubled and the fiber content was reduced significantly compared with the raw BSG, which lighted the use of the protein product as an alternative to fishmeal. Fishmeal is an expensive aquafeed ingredient, the aquaculture industry is looking for alternatives to replace it. Herein, we investigated the effectiveness of the protein product as an alternative to fishmeal by conducting shrimp trials. A further economic analysis was conducted to evaluate the economic feasibility of the proposed process for protein and fiber production from BSG. In addition, the fiber product was used for producing a cellulose adsorbent to remove heavy metals from contaminated water.
Overall, this study demonstrated that BSG can be upcycled into multiple value-added products via an integrated process. The outcomes of this study not only provide a low-cost and sustainable protein source to the aquaculture industry, and provide a novel adsorbent for the water treatment industry, but also provide alternative ways for the brewing industry to manage BSG.
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Produção de cerveja com baixo teor alcoólico / Low-alcohol beer productionRicardo Henrik Kinouti Costa 19 October 2016 (has links)
Atualmente observa-se um aumento significativo no consumo de cervejas com baixo teor alcoólico e cervejas sem álcool. Existe um crescente interesse por este tipo de produto tanto por parte das indústrias cervejeiras como por parte dos consumidores. Este aumento é principalmente devido a questões de saúde e a razões de segurança no trabalho e nas estradas. Além disso, há países onde o consumo de álcool é proibido por lei. Tendo em vista que o consumidor está em busca de novos produtos com características mais próximas possíveis de uma cerveja convencional, o presente trabalho visa analisar uma nova abordagem para a produção de cerveja lager com baixo teor alcoólico, reutilizando o bagaço de malte, um subproduto da indústria cervejeira, como substituinte de parte do malte. Foram obtidas cervejas com as seguintes proporções de bagaço/malte: 0:100, 25/75, 50/50 e 75/25. Nas cervejas com 50 e 75% de bagaço de malte, observou-se uma redução no tempo de fermentação quando comparadas com a cerveja puro malte. A atenuação real de fermentação das cervejas produzidas também foi menor devido a menor fermentabilidade dos mostos. O teor alcoólico das cervejas obtidas em escala de bancada apresentou valores entre 0,665 e 1,615 % (v/v), o que as caracterizam como cervejas de baixo teor alcoólico A cerveja com 25% de bagaço recebeu as maiores notas na análise sensorial, tendo boa aceitação entre os provadores, e foi escolhida para a produção em escala piloto. O perfil de fermentação da cerveja produzida em escala piloto foi similar ao perfil de fermentação da cerveja produzida em escala de bancada. Também foi realizada uma análise sensorial, comparando a cerveja produzida em escala piloto com duas cervejas comercias. A utilização do bagaço de malte como substituinte do malte na fabricação de cervejas com baixo teor alcoólico é uma estratégia viável, produzindo uma bebida com aceitação sensorial semelhante ao de uma cerveja de baixo teor alcoólico comercial. / Nowadays there has been a significant increase in the consumption of beer with low alcohol content and non-alcoholic beers. There is a growing interest on this type of product by both brewers industries and consumers. This increase is mainly due to health issues and safety reasons at work and on the roads. In addition, there are countries where the consumption of alcohol is prohibited by law. Given that the consumer is looking for new products with characteristics as similar as possible of conventional beer, this study aims to analyze a new approach for the production of lager beer with low alcohol content, by reusing brewer\'s spent grain, a by-product of brewing industry, as a substitute of part of the malt. Beers were obtained with the following proportions of bagasse/malt: 0/100, 25/75, 50/50 and 75/25. In beers with 50 and 75% of bagasse, it was observed a reduction in the fermentation time compared with all-malt beer. The Real Attenuation Fermentation of Beer produced was also lower due to lower fermentability of wort. The beers\' alcohol content obtained in laboratory scale showed values between 0.665 and 1.615% (v/v), which characterize them as low-alcohol beers. Beer with 25% of bagasse received the highest scores in sensory analysis, having a good acceptance among the tasters, therefore it was chosen for the production on a pilot scale. The beer\'s fermentation profile produced on pilot scale was similar to the beer\'s fermentation profile produced in laboratory scale. Sensory analysis was also performed, comparing the beer produced in pilot scale with two commercial beers. The use of brewer\'s spent grain as a substitute in the manufacture of beers with low alcohol content is a viable strategy, producing a beverage with sensory acceptance similar to a commercial low-alcohol beer.
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Produção de cerveja com baixo teor alcoólico / Low-alcohol beer productionCosta, Ricardo Henrik Kinouti 19 October 2016 (has links)
Atualmente observa-se um aumento significativo no consumo de cervejas com baixo teor alcoólico e cervejas sem álcool. Existe um crescente interesse por este tipo de produto tanto por parte das indústrias cervejeiras como por parte dos consumidores. Este aumento é principalmente devido a questões de saúde e a razões de segurança no trabalho e nas estradas. Além disso, há países onde o consumo de álcool é proibido por lei. Tendo em vista que o consumidor está em busca de novos produtos com características mais próximas possíveis de uma cerveja convencional, o presente trabalho visa analisar uma nova abordagem para a produção de cerveja lager com baixo teor alcoólico, reutilizando o bagaço de malte, um subproduto da indústria cervejeira, como substituinte de parte do malte. Foram obtidas cervejas com as seguintes proporções de bagaço/malte: 0:100, 25/75, 50/50 e 75/25. Nas cervejas com 50 e 75% de bagaço de malte, observou-se uma redução no tempo de fermentação quando comparadas com a cerveja puro malte. A atenuação real de fermentação das cervejas produzidas também foi menor devido a menor fermentabilidade dos mostos. O teor alcoólico das cervejas obtidas em escala de bancada apresentou valores entre 0,665 e 1,615 % (v/v), o que as caracterizam como cervejas de baixo teor alcoólico A cerveja com 25% de bagaço recebeu as maiores notas na análise sensorial, tendo boa aceitação entre os provadores, e foi escolhida para a produção em escala piloto. O perfil de fermentação da cerveja produzida em escala piloto foi similar ao perfil de fermentação da cerveja produzida em escala de bancada. Também foi realizada uma análise sensorial, comparando a cerveja produzida em escala piloto com duas cervejas comercias. A utilização do bagaço de malte como substituinte do malte na fabricação de cervejas com baixo teor alcoólico é uma estratégia viável, produzindo uma bebida com aceitação sensorial semelhante ao de uma cerveja de baixo teor alcoólico comercial. / Nowadays there has been a significant increase in the consumption of beer with low alcohol content and non-alcoholic beers. There is a growing interest on this type of product by both brewers industries and consumers. This increase is mainly due to health issues and safety reasons at work and on the roads. In addition, there are countries where the consumption of alcohol is prohibited by law. Given that the consumer is looking for new products with characteristics as similar as possible of conventional beer, this study aims to analyze a new approach for the production of lager beer with low alcohol content, by reusing brewer\'s spent grain, a by-product of brewing industry, as a substitute of part of the malt. Beers were obtained with the following proportions of bagasse/malt: 0/100, 25/75, 50/50 and 75/25. In beers with 50 and 75% of bagasse, it was observed a reduction in the fermentation time compared with all-malt beer. The Real Attenuation Fermentation of Beer produced was also lower due to lower fermentability of wort. The beers\' alcohol content obtained in laboratory scale showed values between 0.665 and 1.615% (v/v), which characterize them as low-alcohol beers. Beer with 25% of bagasse received the highest scores in sensory analysis, having a good acceptance among the tasters, therefore it was chosen for the production on a pilot scale. The beer\'s fermentation profile produced on pilot scale was similar to the beer\'s fermentation profile produced in laboratory scale. Sensory analysis was also performed, comparing the beer produced in pilot scale with two commercial beers. The use of brewer\'s spent grain as a substitute in the manufacture of beers with low alcohol content is a viable strategy, producing a beverage with sensory acceptance similar to a commercial low-alcohol beer.
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Valorizacija nutritivnog profila keksa proizvedenog sa dodatkom sporednih proizvoda prehrambene industrije / Valorization of the nutritional profile of cookies produced with the addition of food industry by-productsPetrović Jovana 22 May 2018 (has links)
<p>Zadatak ove teze je da se ispita uticaj zamene dela pšeničnog brašna ekstrudiranim snek proizvodima obogaćenim dodatkom pšenične klice, pivskog tropa i tropa jabuke na svojstva testa (boja, fizička, reološka) kao i na karakteristike čajnog peciva (fizičke, senzorske, nutritivne, trajnost, mikrobiološke). U toku preliminarnih ispitivanja (prva faza eksperimentalnog rada) ispitan je uticaj obezmašćene pšenične klice na kvalitet testa i čajnog peciva u cilju definisanja optimalnog nivoa zamene pšeničnog brašna ekstrudatima kukuruzne krupice sa dodatkom sporednih proizvoda prehrambene industrije i optimalnog sadržaja vlage testa. Pšenično brašno je u količini od 5, 10 i 15 % zamenjeno obezmašćenom pšeničnom klicom. Pored uticaja nivoa zamene pšeničnog brašna pšeničnom klicom, ispitan je i uticaj veličine čestica pšenične klice (<150 μm, 150-1000 μm i 800-2000 μm), kao i vlage testa pri zamesu (20, 22 i 24 %). U toku druge faze eksperimentalnog rada ove doktorske disertacije, pripremljeni su ekstrudati kukuruzne krupice sa dodatkom sporednih proizvoda prehrambene industrije i to: pšenične klice, pivskog tropa i tropa jabuke u udelima 15, 30 i 45 % (odnos kukuruzna krupica:sporedni proizvod bio je 85:15, 70:30 i 55:45). Dobijeni ekstrudati su samleveni i prosejani na sitima u cilju dobijanja tri frakcije sa različitim veličinama čestica (< 250 μm, 250 - 1000 μm i 1000 - 2000 μm). Izvršena je karakterizacija ekstrudata u smislu određivanja hemijskog sastava, raspodele veličine čestica, boje i mikrobiološke analize. Ovako dobijeni ekstrudati su zatim korišćeni u proizvodnji čajnog peciva kao zamena pšeničnog brašna u količinama od 5, 10 i 15 % računato na masu brašna. Za procenu uticaja veličine čestica ekstrudata, udela sporednog proizvoda u ekstrudatu i udela ekstrudata u čajnom pecivu na osobine testa i čajnog peciva takođe je korišćen Box-Behnken eksperimentalni dizajn. Rezultati su pokazali da je moguća proizvodnja funkcionalnog čajnog peciva sa dodatkom ekstrudata kukuruzne krupice obogaćene sporednim proizvodima prehrambene industrije, pri čemu se poboljšava nutritivni profil čajnog peciva, bez negativnih efekata na fizičke i senzorske karakteristike gotovog proizvoda.</p> / <p>The aim of this study is to examine the effect of replacing a portion of wheat flour with extruded snack products enriched with the addition of wheat germ, brewer's spent grain and apple pomace on the rheological and textural properties of dough and on characteristics of cookies (physical, sensory, nutritive, microbiological). During the preliminary analysis (the first phase of the experimental work), the influence of defatted wheat germ particle size, wheat germ content and dough moisture content on the quality of the dough and the cookies was investigated using the Box-Behnken experimental design. During the second phase of the experimental work, the extruded corn meal with the addition of by-products of the food industry (wheat germ, brewer's spent grain and apple pomace) were prepared (the ratio of corn meal: by-product was 85:15, 70:30 and 55:45). The obtained snack products are milled and sieved to obtain 3 fractions with different particle sizes (<250 μm, 250-1000 μm and 1000-2000 μm). Characterization of the extrudates in terms of determining the chemical composition, particle size distribution, color and microbiological analysis was performed. The obtained extrudates were then used in the production of cookies for the replacement of wheat flour in quantities of 5, 10 and 15%. The Box-Behnken experimental design was used to evaluate the influence of the extrudate particle size, the share of the by-product in the extrudate, and the share of extrudates in the cookies, on the dough properties and cookies characteristics.<br />The results showed that the corn snack products enriched with food industry by-products (brewer's spent grain, wheat germ and apple pomace) can be used for production of functional cookies. These additives in an amount up to 15% improving the nutritional profile of the cookies, without adverse effects on the physical and sensory characteristics of the final product.</p>
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Voltametrijske metode zasnovane na ugljeničnim elektrodama modifikovane kompozitima na bazi višezidnih ugljeničnih nanocevi i čestica bizmuta ili antimona za određivanje odabranih ciljnih analita / Voltammetric methods based on carbon electrodes modified with multi walled carbon nanotubes and bismuth and antimony particles based composites for determination of selected target analytesPetrović Sandra 12 September 2019 (has links)
<p>Cilj ove doktorske disertacija bio je razvoj novih, osetljivih, selektivnih i ekonomski<br />isplativih voltametrijskih radnih elektroda za praćenje odabranih analita kako u<br />laboratorijskim tako i pri terenskim uslovima. Ispitivana je mogućnost primene ovih radnih elektroda primenom voltametrijskih metoda kako u model rastvorima tako i u pojedinim realnim sistemima. SW-ASV zasnovana na elektrodama od staklastog ugljenika površinski modifikovanim Bi-MWCNT i BiOCl-MWCNT je primenjena za određivanje jona Pb(II) i Cd(II) pri optimizovanim uslovima merenja. Određivanje ciljnih jona vršeno je pri radnom potencijalu od -1,2 V (izmeren u odnosu na zasićenu kalomelovu elektrodu) i vremenu<br />elektrodepozicije jona od 120 s. Sva merenja su izvršena u rastvoru acetatnog pufera čija je pH-vrednost iznosila 4,0. Primenjeni koncentracioni opseg ciljnih analita iznosio je od 5 do 50 μg dm <sup>-3</sup> . Primenom ovog tipa elektrode dobijene su vrednosti granice detekcije za jone Pb(II) i Cd(II) 0,57 μg dm <sup>-3 </sup>i 1,2 μg dm<sup>-3</sup> , redom. Dobijena RSD iznosila je manje od 10% za oba jona. Ova metoda je primenjena i za određivanje ciljnih jona u realnom uzorku porne vode sedimenta a rezultati dobijeni optimizovanom voltametrijskom metodom su u dobroj saglasnosti sa rezultatima koji su dobijeni primenom komparativne GFAAS metode. Bizmut oksihlorid-višezidne ugljenične nanocevi kompozitni materijal je primenjen za površinsko modifikovanje elektrode od staklastog ugljenika za brzo i jednostavno voltametrijsko određivanje tragova Zn(II)-jona primenom SW-ASV metode. BiOClMWCNT/GCE je pokazala linearan analitički odgovor u osegu koncentracija od 2,50 do 80,0 μg dm <sup>-3 </sup>sa dobijenom vrednošću GD 0,75 μg dm<sup>-3 </sup>pri akumulacionom vremenu od 120 s i potencijalu elektrodepozicije -1,40 V u odnosu na ZKE. Merenja su vršena u acetatnom puferu pH 4,5. Dobijena RSD iznosila je 4,8 %. Upoređene su performanse novodizajnirane BiOCl-MWCNT/GCE elektrode i tradicionalne elektrode na bazi bizmut filma (BiF/GCE), MWCNT/GCE, BiF-MWCNT/GCE i nemodifikovane GC elektrode. Novodizajnirana elektroda je primenjena za detekciju i određivanje Zn(II)-jona u realnim uzorcima kao što su<br />dijetetski suplement i pekarski kvasac. Dobijeni rezultati su uporedivi sa deklarisanom vrednošću u slučaju dijetetskog suplementa a u slučaju pekarskog kvasca sa rezultatima dobijenih komparativnom FAAS .<br />Elektroda od ugljenične paste je površinski modifikovana pripremljenim kompozitom<br />koji je izgrađen od višezidnih ugljeničnih nanocevi i čestica Sb<sub>2</sub>O<sub>3.</sub> Kompozitni materijal je okarakterisan primenom TEM, EDS i XRD mernih tehnika. Sb<sub>2</sub>O<sub>3</sub>-MWCNT/CPE je okarakterisana primenom ciklične voltametrije a merenja su vršena u rastvoru hlorovodonične kiseline (pH 2,0). Primenom SW-ASV metode ova radna elektroda je upotrebljena za određivanje jona Pb(II) i Cd(II) u koncentracionom opsegu 2,0-40,0 μg dm <sup>-3 </sup>za Pb(II)-jon i 2,0-40,0 μg dm <sup>-3</sup> za Cd(II)-jon pri čemu su dobijene dobre linearne zavisnosti za oba ciljna jona. Optimalna procedura uključuje primenu Sb2O3-MWCNT/CPE u 0,01 mol dm <sup>-3</sup><br />hlorovodoničnoj kiselini uz vreme elektrodepozicije jona iz rastvora od 120 s na potencijaluod -1,2 V, pri čemu su dobijene vrednosti za GD 1,1 μg dm <sup>-3</sup> Cd(II) i 1,6 μg dm <sup>-3</sup> Pb(II). Optimizovana metoda zasnovana na ovom tipu voltametrijskog senzora je uspešno primenjena za određivanje jona Cd(II) u obogaćenom uzorku česmenske vode, gde su se dobijene vrednosti u saglasnosti sa očekivanom. Elektroda od ugljenične paste površinski je modifikovana primenom Sb<sub>2</sub>O<sub>3</sub>-MWCNT nanokompozitnog materijala i primenjena za direktno voltametrijsko određivanje imidakloprida u model rastvorima. U cilju postizanja što boljih analitičkih performansi optimizovani su eksperimentalni uslovi merenja kao što su pH-vrednost rastvora pomoćnog elektrolita i kondicioniranje površine voltametrijskog senzora. Kao optimalna pH-vrednost pomoćnog elektolita (Britton-Robinsonovog pufera) odabrana je pH 7,0, a ponavljanje ciklusa cikliranja najmanje 4 puta povoljno utiče na stabilnost voltametrijskih signala. Optimizovana metoda primenjena je za SW direktno katodno određivanje imidakloprida u koncentracionom intervalu od 1,41 do 32,77 μg cm <sup>-3</sup> uz dobijeni korelacioni faktor od 0,9995. Na osnovu dobijenih rezultata može se zaključiti da su razvijene analitičke metode pre svega osetljive, selektivne, reproduktivne i jednostavne što omogućava njihovu primenu za veliki broj uzoraka. Merenjima u model i realnim rastvorima dokazana je mogućnost njihove primene u komplikovanim matriksima, pri različitim pH vredostima pri čemu su dobijeni<br />rezultati koji su u saglasnosti sa rezultatima primenjenih komparativnih metoda. Naravno, za dobijanje reprezentativnih rezultata neohodno je izvršiti optimizaciju uslova merenja što podrazumeva sam odabir supstrat-elektrode, odabir površinskog modifikatora i optimizaciju eksperimentalnih uslova merenja.</p> / <p>The aim of this Ph.D. thesis was the development of new, sensitive, selective and economically viable voltametric working electrode for continuous monitoring of different target analytes. The use of these advantaged working electrodes was investigated using voltametric methods both in model solutions and in certain real systems.SW-ASV based on glassy carbon electrode surface modified with Bi- MWCNT and BiOCl-MWCNT were applied for determination of Pb(II) and Cd(II) ions. Voltametric determination of Pb(II) and Cd(II) ions was performed at working potential of -1.2 V (measured against the saturated calomel electrode) and time of electrodeposition of 120 s. All measurements were performed in acetate buffer solution pH 4.0. Concentration range of targetanalites were 5-50 μg dm -3 . Using this type of electrode, obtained detection limits for Pb(II) and Cd(II) ions were 0.57 μg dm -3 and 1.2 μg dm -3 , respectively, with RSD lower than 10%.This method was applied for target ions determination in sediment pore water sample, and obtained results are comparable with those who are obtained using GFAAS method. Bismuth oxychloride-multiwalled carbon nanotubes composite material was applied for surface modification of the glass-carbon electrode for quick and simple voltametric determination of Zn(II) ions using the SW-ASV method. BiOCl-MWCNT/GCE showed a linear analytical response in a concentration from 2.50 to 80.0 μg dm -3 with a value of detection limit 0.75 μg dm -3 at a acumulation time of 120 s and an electrodeposition potential of -1.40 V vs. saturated calomel electrode. Measurements were carried out in acetate buffer pH 4.5. The obtained value of the RSD was 4.8%. The performance of the newly designed BiOCl-MWCNT/GCE electrode, traditional bismuth-based electrode (BiF/GCE), MWCNT/GCE, BiF-MWCNT/GCE and unmodified GC electrodes were compared. The applied electrode shows very good electroanalytic properties when determining this target ion. Obtained results are in good agreement with declared value in case of dietetic suplement, and in the brewer’s yeast sample results were comparable with FAAS results. Carbon paste electrode surface modified with new composite material based on multiwalled carbon nanotubes and Sb2O3 particles. The composite is characterized by TEM, EDS and XRD measurment. Sb2O3- MWCNT/CPE was characterized by cyclic voltammetry and measurements were carried out in a hydrochloric acid solution (pH 2.0). Using the SWASV method, this working electrode was used to determine Pb(II), Cd(II) ions in the concentration range from 2.0 to 40.0 μg dm -3 for Pb(II) and 2.0-40.0 μg dm -3 for Cd(II) ions. Newly designed sensor showed good linear dependences for both target ions. The most optimal procedure involving application of Sb2O3-MWCNT/CPE in .01 mol dm -3 hydrochloric acid, with electroposition time of target ions 120 s at a electrodeposition potential of -1.2 V. Obtained values of LOD 1,1 μg dm -3 for Cd(II) and for 1,6 μg dm -3 Pb(II) ions. An optimized method based on this type of voltametric sensor has been successfully applied for determination of Cd(II) ion in a spiked tap water sample. Results obtained during this measurment were in tune with expected results. CPE was surface modified using Sb2O3-MWCNT nanocomposite material and tested for direct voltametric determination of imidacloprid in model solutions. In order to achieve the best analytical performance, experimental conditions of measurement such as the pH value of the supporting electrolyte and conditioning of the voltametric sensor surface havebeen optimized. As an optimum pH value of the supporting electrolyte (Britton-Robinson buffer), a pH 7.0 was selected, and the repeating cycles of the cycling process at least 4 times favorably influenced the stability of the voltametric signals. The optimized method was applied for the SW direct cathodic determination of imidacloprid in the concentration range from 1.41 to 32.77 μg cm -3 with obtained correlation factor of 0.9995. Based on results it can be concluded that developed analytical methods are sensitive, selective, reproducibile and simple, which can enable their application for various number of samples. Measurements in the model and real solutions have demonstrated the possibility of their application in complicated matrices, at different pH, whereby obtained results are in accordance with the results of the applied comparative methods. For obtainig of representative results it is necessary to optimize conditions of measurment which include: selection of substrat electrode, surface modifier and optimization of experimental condition.</p>
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