No description available.

In this work polymeric materials were developed to be used as a solvent and heat resistance membrane for different applications. In ultrafiltration, poly (ether imide sulfone) membranes were manufactured by combining phase inversion and functionalization reaction between epoxy groups and amine modified polyether oligomers (Jeffamine®). Polysilsesquioxanes or oligo silsesquioxanes containing epoxy functionalities were in-situ grown in the casting solution and made available for further reaction with amines in the coagulation/annealing baths. Water permeances up to 1500 l m-2 h-1 bar-1 were obtained with sharp pore size distribution and a pore diameter peak at 66 nm, confirmed by porosimetry, allowing 99.2 % rejection of γ-globulin. The membranes were stable in 50:50 dimethylformamide/water, 50:50 N-methyl pyrrolidone/water and 100 % tetrahydrofuran. In pervaporation, Novel hydrophobic Hyflon®/Extem® and Hyflon®/PVDF were developed and investigated for ethylene glycol dehydration and n-butanol dehydration respectively. For ethylene glycol different Extem® concentrations were evaluated with regard to both flux and amount of water in the permeate side. Eighteen (18) wt% gave more than 90 wt% water in the permeate. Increasing feed temperature from 25 to 85°C increased the water flux from 31 to 91 g m-2 h-1 when using 5 wt% water in ethylene glycol as feed. The water flux of 40 wt% water:ethylene glycol at 45°C was found to be 350 g m-2 h-1. And for n-butanol dehydration the coating protocols for thin defect-free Hyflon® selective layer on the PVDF support was optimized. Water and n-butanol transport was measured, analyzing the effect of operating conditions. The water flux through the newly developed membranes was higher than 150 g m-2 h-1 with selectivity for water higher than 99 wt%. The membrane application can be extended to other solvents, supporting an effective and simple method for dehydration with hydrophobic membranes. In membrane distillation, PVDF and Extem® membranes before and after coating with Hyflon® were examined for ionic liquid dehydration on 23.6 mS cm-1 feed concentration. Different feed temperatures and flow rates were evaluated for flux as well as rejection. High flux was obtained at 70°C and increased at high flow rate from 2 Kg m2 h to 10 Kg m2 h.

Orientadores: Luiz Antonio Viotto, Lireny Aparecida Guaraldo Gonçalves / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-11T18:16:01Z (GMT). No. of bitstreams: 1 Araki_MarciadeSouza_D.pdf: 6998301 bytes, checksum: 53d26f26895e51aecda264fc78f2e301 (MD5) Previous issue date: 2008 / Resumo: A aplicação da tecnologia de membranas em óleos vegetais ainda não está totalmente estabelecida, entretanto esta tecnologia mostra-se com grande potencial neste segmento, sendo que as principais vantagens em relação ao refino convencional são o uso de condições térmicas mais brandas de processamento, menor consumo energético e, maior retenção de compostos nutricionalmente desejáveis. Desta forma, a utilização de membranas permite a produção de óleos vegetais de qualidade superior, indo ao encontro dos anseios do mercado, de forma ecologicamente correta, com diminuição do impacto ambiental pela menor produção de efluentes e racionalização do uso da água, um recurso natural cada vez mais escasso. O presente trabalho teve como objetivo analisar o comportamento de seis membranas planas poliméricas comerciais (PVDF 30 e 50 kDa, CME 0,025 e 0,05 mm, PC 0,05 mm e PES 10 kDa) frente à permeação de três diferentes solventes (água, etanol e hexano), assim como avaliar a estabilidade estrutural e química das mesmas face à exposição e filtração com hexano. Os resultados mostraram que todas as membranas foram resistentes ao hexano. Foi selecionada uma membrana (PVDF 50kDa) para experimentos de degomagem de miscela de óleo bruto de milho em escala laboratorial, variando-se a pressão (1 a 3 bar) e temperatura (20 a 40 ºC), verificando-se o desempenho da referida membrana em relação à retenção de fosfolipídios e ao fluxo de permeado. O aumento da temperatura e da pressão exerceram efeito positivo sobre os fluxos de permeado, e negativo sobre a retenção de fósforo. Adicionalmente, esta membrana foi testada em escala piloto, onde verificou-se os efeitos da pressão (1 a 3 bar) e velocidade tangencial (1 a 6 m/s) sobre o fluxo de permeado e a retenção de fosfolipídios. A retenção de fosfolipídios manteve-se entre 84,7 e 97,1 %, com níveis residuais de fósforo dos produtos permeados, a 40ºC, permanecendo na faixa de 5¿ 28 mg.kg-1. O fluxo de permeado variou entre 20 a 130 kg.h-1m-2. A análise das resistências demonstrou que a camada polarizada controlou o processo de ultrafiltração. A maior eficiência na degomagem foi obtida através da filtração tangencial em módulo piloto de ultrafiltração, e os fluxos de permeado aumentaram significativamente com o aumento da pressão operacional e velocidade, sem prejuízo aos níveis de retenção de fósforo. O melhor ajuste para os dados em escala laboratorial e piloto foi com o modelo desenvolvido por Field et al. (1995) / Abstract: Membrane technology application in vegetable oils is still not completely developed, however, this technology shows a high potential in this segment, which main advantages in comparison to conventional refining are the usage of low temperature processing conditions, lower energetic consumption and higher desired nutritional value compounds retention. The utilization of membranes allows the production of a superior quality vegetable oil, going towards market trends in an environmental friendly way, since it produces less efluents and conscious usage of water, a resource that gets shorter day after day. This work had as its main purpose the analysis of six flat polimeric commercial membranes¿ behavior (PVDF 30 e 50 kDa, CME 0.025 e 0.05 mm, PC 0.05 mm e PES 10 kDa) regarding their permeation with three different solvents, water, ethanol and hexane, and the evaluation of their resistance through exposure and filtration with hexane. Results show that all membranes are resistant to hexane. One of them was selected (PVDF 50 kDa) to run crude corn oil miscella degumming experiments in laboratorial scale, changing pressure (1 a 3 bar) and temperature (20 a 40 ºC), observing the membrane performance regarding phospholipids retention and permeate flux. Temperature and pressure increase presented a positive effect over permeate flux and negative over phospholipids retention. In addition to that, the membrane was tested in a pilot scale skid, where it has been noticed pressure (from 1 to 3 bar) and tangential flow (from 1 to 6 m/s) effects over permeate flux and phospholipids retention. Residual phospholipids levels of permeate products at 40°C stayed in the range of 5-28 mg.kg -1 with 20-130 kg.h-1.m-2 flux. The resistance analysis showed that the polarized layer controlled the ultrafiltration process. The highest efficiency in degumming was obtained through tangential filtration in an ultrafiltration pilot scale skid and permeate flux increased significantly with the increase of operational pressure and tangential flow, without prejudicing phosphorus retention level. The best fit to the experiments data examined in laboratorial and pilot scale was obtained with the model developed previously by Field et al. (1995) / Doutorado / Doutor em Engenharia de Alimentos

No description available.

High energy consumption is a crucial challenge in gas separation processes. With current energy intensive separation methods, there is a real need for more energy-efficient alternative technologies. Membrane technology demonstrates potential uses in industrial separation processes due to its potential energy efficiency, environmental friendliness, and small footprint. The continuous developments in material science contributed directly in enhancing the membrane performance through several engineering modifications such as thermal annealing, which presented visible improvements in gas permeation properties. The objective of this project was to investigate the thermal annealing of three fluorinated polymers (PAE1, PAE2, and TFMPD), aiming for favorable changes in gas permeation properties. In particular, each polymer was annealed for 3 h at various temperature values, targeting the intermediate stage, which is the zone where degradation started but a pure carbon structure stage was not formed yet. Overall, the thermal annealing study revealed that TFMPD had highest pure-gas separation performance among other polymers, in which the Robeson plots displayed that treated sample at 500 ºC surpassed the 2015 H2/CH4 upper bound, whereas the treated sample at 550 ºC surpassed 2019 upper bound of both CO2/CH4 and CO2/N2. Therefore, TFMPD can be a potential candidate polymer for membrane-based gas separation, especially for CO2 and H2 applications. This performance could be attributed to the internal structural changes in the polymer that occurred during thermal annealing. Hence, several characterization techniques were performed to detect these changes. For instance, it was realized that all polymers started crosslinking upon the thermal treatment at 350 ºC. Moreover, FTIR analysis indicated the release of several functional groups from treated polymers at high temperature values. Raman spectroscopy also confirmed that the observed substantial enhancement in gas permeation of annealed TFMPD at 550 ºC was due an early-stage carbon structure formation. Furthermore, several recommendations are proposed to continue the work in this project, which could lead to potential success of the thermally annealed polymers tested in this study in membrane-based gas separations applications.

Separation of CO2, the main global warming causing greenhouse gas, from other flue gases and from biogas has become of great interest due to the predicted effects of global warming that the world is already starting to experience. This research focuses on the separation of CO2 from CH4 and N2 gases using polymeric and mixed matrix membranes. Amine-based poly vinyl alcohol (PVA) polymeric membranes that had previously shown good gas separation results were adapted for use in this research. The physical aging of the adapted membrane was initially analyzed for 37 days and it was observed that the membrane stabilized after 21 days. The adapted membrane was then optimized using a 26 factorial design to improve the membranes’ performance with respect to CO2/N2 and CO2/CH4 selectivity when tested using single gas permeation experiments at near atmospheric conditions. This was done with the membrane components: PVA, formaldehyde, poly (allylamine hydroxide), potassium hydroxide, water and 2-aminoisobutyric acid. Zeolite 13X and ZIF-8 powdered adsorbents were incorporated in the optimized membranes to prepare mixed-matrix membranes with the goal of bettering the separation performance of the membranes. Membrane characterization was done on the best performing membranes through spectroscopy, microscopy, and contact angle measurements. This study concluded with feed pressure tests on the overall best performing membranes. The performance of the fabricated membranes was compared to other polymeric and mixed-matrix membranes and Robeson’s upper bound line. Overall, the polymeric optimized membranes seemed to perform better than the filled mixed matrix membranes due to the introduction of agglomerations and cracks with both the filler materials. Also, the separation performance of the membrane improved with a decrease in pressure. At 1.5 absolute pressure, the optimized membrane was able to achieve a CO2/N2 and CO2/CH4 selectivity of 5.94 and 2.13 respectively with a CO2 permeability of 15,813 Barrer.

Orientador: Luiz Antonio Viotto / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-17T07:08:19Z (GMT). No. of bitstreams: 1 Borovik_CarolinaPavanBagagli_M.pdf: 1682432 bytes, checksum: c579964aeeff51f681a76bd49d7236e5 (MD5) Previous issue date: 2011 / Resumo: O açaí é um fruto nativo da região Amazônica de grande interesse nacional e internacional devido não somente ao seu sabor mas, principalmente, por ser um alimento nutricionalmente completo e rico em compostos antioxidantes, entre eles as antocianinas, que estão relacionados à prevenção de doenças. As antocianinas são pigmentos naturais de interesse na indústria de alimentos por sua coloração atraente e funcionalidade, sendo o açaí uma fonte potencial de sua obtenção. A tecnologia de membranas apresenta-se como uma alternativa para a obtenção de compostos bioativos presentes em frutas, uma vez que permite a concentração de compostos sem mudança de fase, a redução do uso de produtos químicos e a proteção de compostos termicamente sensíveis. Neste trabalho, a polpa de açaí foi tratada enzimaticamente para que passasse, em seguida, pelo processo sequencial de micro, ultra e nanofiltração. Foram utilizadas membranas poliméricas planas de diferentes materiais e massa molecular de corte variando entre 0,3 e 150 kDa, e também uma membrana tubular com tamanho de poro igual a 0,2mm. Para o tratamento enzimático foram usadas as enzimas celulase e pectinase e, para que fosse estudada a melhor combinação dos parâmetros de concentração de cada enzima e o tempo de atividade enzimática que resultasse em bom fluxo de permeado na microfiltração em escala de laboratório, realizou-se um planejamento fatorial completo 23. Concluiu-se que o uso de 0,02 % (m/m) das enzimas celulase e pectinase e o tempo de 77,8 minutos de atividade resultou no mais elevado fluxo de permeado, atingindo-se 17,4 kg/m2.h, sendo tal condição aplicada para a realização da microfiltração em escala piloto. Da microfiltração realizada em planta piloto utilizando-se a membrana tubular de polipropileno (0,2mm) obteve-se fluxo de permeado a Fc=1,5 igual a 300 kg/m2.h e coeficiente de retenção de antocianinas igual a 34,5%. O processo de ultrafiltração, que utilizou como alimentação o permeado da microfiltração, resultou em um coeficiente de retenção de antocianinas igual a 94,5%. Nas nanofiltrações foi utilizado como alimentação tanto o permeado do processo de microfiltração como aquele resultante da ultrafiltração, e foram obtidas altas retenções de antocianinas, com valores de coeficientes iguais as 92,2 e 98,6%. Analisando-se os processos sequenciais realizados, concluiu-se que, considerando o objetivo de obter um composto com elevada concentração de antocianinas e com baixo teor de outros compostos, o retentado resultante da ultrafiltração (posterior à microfiltração em escala piloto) foi o que apresentou maior concentração de antocianinas, de aproximadamente 50 mg/100g, e, ao mesmo tempo, houve considerável redução dos demais componentes presentes na polpa, tais como sólidos, proteínas e gordura / Abstract: The açaí fruit is a native fruit from the Amazon region with a great national and international interest due not only to the good and exotic taste, but mainly because it is a nutritionally complete food, rich in antioxidant compounds, including anthocyanins, which are related to the prevention of diseases. Anthocyanins are natural pigments of interest in the food industry for its attractive color and functionality, and the açai fruit is a potential source from we can obtain it. The technology of membrane is presented as an alternative for obtaining bioactive compounds present in fruits, since it allows the concentration of compounds without phase change, reduces the use of chemicals and protects the thermally sensitive compounds. In this study, the açai fruit pulp was enzymatically treated to pass, then, to a sequencial process of micro, ultra and nanofiltration. It was done by using flat membranes of different materials, and molecular weight cut off ranging from 0.3 to 150kDa, and also a tubular membrane with pore size equal to 0.2mm. For the enzymatic treatment were used pectinase and cellulose enzymes, and it was studied the best combination of the parameters enzyme concentration and time of activity of the enzyme that resulted in a high permeate flux in the microfiltration on a laboratory scale using an experimental design 23. It was concluded that the use of 0.02% (w/w) of the cellulose and pectinase enzymes and 77.8 minutes of activity resulted in the higher permeate flux, reaching 17.4 kg/m2.h, for this reason this condition was applied to the pilot-scale microfiltration. In the pilot-scale microfiltration (using a tubular polypropylene membrane with 0,2mm of the pore size) it was obtained a permeate flux at Fc=1.5 equal to 300 kg/m2.h, and retention coefficient of anthocyanins equal to 34,5%. The ultrafiltration process, that used the permeate of the microfiltration as feed, resulted in a retention coefficient of anthocyanins equal to 94.5%. As feed of the nanofiltration processes it was used the permeate of the microfiltration and also the permeate of the ultrafiltration, and it was obtained high retention coefficient of anthocyanins, which values were equal to 92.2 and 98.6%. Analyzing the sequencial processes, it was concluded that, considering the purpose of obtaining a compound with high anthocyanin content and low content of other compounds, the retentate of the ultrafiltration (after pilot-scale microfiltration) was that showed the higher anthocyanin content (approcimately 50mg/100g) and, at the same time, there was a considerable reduction in the other components present in the pulp, such as solids, protein and fat / Mestrado / Engenharia de Alimentos / Mestre em Engenharia de Alimentos

Orientadores: Lireny Aparecida Guaraldo Gonçalves, Luiz Antonio Viotto / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-09T22:21:15Z (GMT). No. of bitstreams: 1 Coutinho_CesardeMorais_D.pdf: 7072281 bytes, checksum: 272165bc7f6a8624d3b02dcebb324f53 (MD5) Previous issue date: 2008 / Resumo: A aplicação da tecnologia de membranas como método de separação, concentração e purificação de componentes está largamente difundida nos processos industriais de um modo geral, incluindo a indústria de alimentos. Em tecnologia de óleos, o uso de membranas como método de separação ainda não está totalmente estabelecido, entretanto esta tecnologia mostra-se com grande potencial no refino de óleos vegetais, cujas principais vantagens em relação ao refino convencional são o uso de condições térmicas mais brandas de processamento, menor consumo energético, maior retenção de compostos nutricionalmente desejáveis e diminuição da geração de efluentes. Desta forma, a utilização de membranas permite a produção de óleos vegetais de qualidade superior, indo de encontro aos anseios do mercado, e de forma ecologicamente correta, com diminuição do impacto ambiental pela menor produção de efluentes e racionalização da água, um recurso natural cada vez mais escasso. O presente trabalho teve como objetivos a análise do comportamento de seis membranas poliméricas planas frente à permeação com três diferentes solventes, água, etanol e hexano, assim como avaliar a resistência das mesmas face à exposição e filtração com hexano. Adicionalmente, foram selecionadas duas membranas para experimentos de degomagem de óleo bruto de girassol e de soja, variando-se a concentração de solutos na alimentação, pressão, temperatura e modo de filtração, verificando-se o desempenho das referidas membranas em relação à retenção de fosfolipídeos e ao fluxo de permeado. Os resultados mostraram que todas as membranas são resistentes ao hexano e que a maior eficiência na degomagem de ambas as matérias-primas foi obtida através da filtração tangencial em módulo piloto de ultrafiltração, e os fluxos de permeado aumentaram significativamente com o aumento da pressão operacional, sem prejuízo nos niveis de retenção de fósforo. Em ultrafiltração frontal de bancada, o aumento da temperatura e da pressão exerceram efeito positivo sobre os fluxos de permeado, sem mudança significativa sobre os níveis de retenção de fósforo / Doutorado / Doutor em Tecnologia de Alimentos

Orientador: Luiz Antonio Viotto / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-18T13:58:39Z (GMT). No. of bitstreams: 1 Paes_Juliana_M.pdf: 2604997 bytes, checksum: d7ef0b20d4fe9e008ad2bf97ee008848 (MD5) Previous issue date: 2011 / Resumo: O licopeno, um dos mais importantes carotenóides, tem sido crescentemente estudado devido a resultados positivos em pesquisas relacionadas à redução de riscos de alguns cânceres e doenças cardíacas. Os processos de separação com membranas destacam-se como uma alternativa aos processos convencionais de tratamento térmico, agindo como uma barreira permeável seletiva para separar um ou mais solutos de um fluido inclusive microrganismos. Dentre estes, a ultrafiltração pode ser um atrativo para a concentração de alguns componentes funcionais. A concentração de licopeno por membranas é um processo viável, pois este carotenóide fica na porção retida mesmo possuindo baixa massa molecular, já que se liga a outras moléculas como as proteínas, pectina e lipídio. Visando a concentração do licopeno, foi avaliado o desempenho de duas membranas de ultrafiltração (UF), polissulfona (PS) 100 kDa e polieterssulfona (PES) 50 kDa em diferentes condições de pressão e velocidade. Foi realizado a comparação dos experimentos com polpa tratada enzimaticamente e in natura e pode-se concluir que os resultados foram semelhantes. O permeado obtido apresentou-se levemente amarelado, límpido e sem a presença de carotenóides, enquanto o retentado mostrou-se opaco e de cor vermelha mais intensa que o produto inicial. A retenção do licopeno foi de quase 100%. Foram observados melhores fluxos de permeado em relação ao tempo de processo na membrana de PES 50 kDa e sob pressão de 1,5 bar e velocidade de escoamento de 6m/s e com esta membrana foram realizados dois experimentos utilizando o processo de diafiltração: diafiltração com posterior concentração e concentração com posterior diafiltração, o que resultou em retentado com 68 µg/g de licopeno. A maior parte dos dados experimentais obtidos nas curvas de fluxo de permeado se ajustaram bem aos modelos de Cheryan (1998) nos quais obteve-se valores de R2 de 0,90 a 0,98 / Abstract: Lycopene, one of the most important carotenoids, has been increasingly studied due to positive results in research related to reduced risk of some cancers and heart disease. The membrane separation processes stand out as an alternative to traditional heat treatment, acting as a selectively permeable barrier to separate one or more solutes from a fluid including microorganisms. Among these, the ultrafiltration can be attractive for the concentration of some functional components. The lycopene concentration on membranes is a viable process, since this carotenoid is retained even in the portion having low molecular weight, since it binds to other molecules such as proteins, lipids and pectin. Aiming at the concentration of lycopene, was evaluated the performance of two membrane ultrafiltration (UF), polysulfone (PS) 100 kDa and polieterssulfona (PES) 50 kDa in different conditions of pressure and speed. Was conducted to compare the experiments with enzymatically treated pulp and pulp in nature and can conclude that the experiment with the enzyme treatment showed similar results to the pulp in natura. The permeate obtained was slightly yellow, clear and without the presence of carotenoids, while the retentate was shown to be opaque and red color more intense than the original. The retention of lycopene was almost 100%. Was observed better flow in relation to the process time in 50 kDa PES membrane and pressure of 1,5 bar and flow rate of 6 m/s, and with this membrane, it was two experiments using the process of diafiltration: diafiltration with subsequent concentration and concentration with subsequent diafiltration, resulting in a retentate of 68 µg / g of lycopene. Most of the experimental data obtained in the permeate flow curves adjusted well to models Cheryan (1998) in which was obtained R2 values from 0,90 to 0,98 / Mestrado / Engenharia de Alimentos / Mestre em Engenharia de Alimentos

Biogas is becoming a more important source of green, renewable energy however, its production results in a liquid wastewater, known as centrate, which must be treated due to its high levels of total dissolved solids (TDS), and chemical oxygen demand (COD). Currently, biogas generation facilities treat centrate using a combination of biological and physical treatments (via a membrane bioreactor (MBR)), which produces a stream known as MBR permeate. While MBR permeate achieves improved quality, MBR usage has several challenges including difficulty of scaling biological processes, and handling capacity limitations. In this study, membrane only treatment of centrate, collected from an operating biogas generation facility, was investigated to determine if similar quality permeates could be obtained without any biological treatments. Single- stage treatment of centrate using either polymeric or ceramic nanofiltration membranes with molecular weight cut offs between 400 and 800 Da, produced a permeate similar to MBR permeate. These membrane types caused average COD rejections of 92% and 90% respectively. However, the permeates from the nanofiltration membranes had very high levels of ammonia, which was not present in the MBR permeate. The ceramic nanofiltration membranes can achieve higher permeate fluxes than the polymeric nanofiltration membranes. Both membrane types experienced significant fouling which was removed using cleaning procedures. Two-stage treatment of centrate using ceramic nanofiltration membranes followed by polymeric reverse osmosis membranes further improved the quality of permeate and achieved COD rejections of 99% overall. While the reverse osmosis membranes did remove some ammonia, the levels were still higher than what was seen in the MBR permeate. The two-stage treatment of centrate can provide the permeate which is closest to the MBR permeate however, further studies are required to address the higher ammonia concentration values. The research shows that only using membranes is a potential treatment pathway for real centrate samples. / Thesis / Master of Applied Science (MASc) / The production of biogas, which is a green, renewable energy source results in a liquid wastewater known as centrate. This wastewater is very dirty and complex and requires treatment as it cannot be dumped and disposed of in its current state. Current treatment methods for centrate use combinations of biological treatment and filtration processes, which has its own challenges due to the complexity of biological treatments. An alternative treatment method for the centrate is nanofiltration membranes which offer the ability to treat large volumes of centrate wastewater without the complexity of relying on biological treatment options. Four different nanofiltration membranes, including two polymeric and two ceramic membranes, were used to treat real industrial wastewater samples of centrate collected from a biogas generation facility. Both types of nanofiltration membranes provided similar quality permeate to the current treatment method of centrate, which uses a combination of biological and physical treatment methods.