Zugl.: Aachen, Techn. Hochsch., Diss., 2008.

Techn. Hochsch., Diss., 2000--Aachen.

Universiẗat, Diss., 1999--Essen.

Submitted in part fulfillment of the requirements for the Degree of Masters in Technology in Chemical Engineering, ML Sultan Technikon, 2003. / Whilst microfiltration (MF) has numerous uses and advantages over conventional separation processes it does have certain limitations. MF membrane process can effectively remove turbidity but cannot sufficiently remove low molecular organics. For a sufficient removal of such particles adaptations and modifications to the membrane has to be made or additional removal processes (e.g. nanofiltration or reverse osmosis) has to be added. This project makes an attempt at addressing the former issue. In MF, a membrane on a support performs the filtration. There are various types of materials used as supports e.g. ceramics, porous steel tubes, polymers etc. These materials are usually rigid or semi-rigid and thus offer the advantage of maintaining their shape thus enabling operation at high pressures. This project will concentrate exclusively on woven fibre microfiltration (WFMF). This is a tubular cloth-like filter, which becomes rigid when feed flows into it. / M

Orientador: Luiz Antonio Viotto / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-17T12:07:03Z (GMT). No. of bitstreams: 1 Eca_KalianaSitonio_M.pdf: 2250029 bytes, checksum: e8379ef16c1d5fd8ddcf0ec85028e915 (MD5) Previous issue date: 2011 / Resumo: O uso da vinhaça, como fonte de nutrientes, matéria orgânica e água, foi uma das grandes revoluções no manejo da cultura da cana-de-açúcar. Ela é o principal efluente das destilarias de álcool e sua importância está também relacionada à economia de fertilizantes. A normativa P4.231 fez com que o setor sucroalcooleiro se preparasse para aplicar a vinhaça em distâncias maiores sendo que uma das soluções para o transporte de grandes volumes de vinhaça é o seu uso na forma concentrada nestas áreas. Em conseqüência do contexto estabelecido, o objetivo desse trabalho foi concentrar vinhaça por microfiltração (MF) seguido de ultrafiltração (UF) e nanofiltração (NF) direta. Os ensaios foram conduzidos em uma unidade laboratorial a 60ºC e 500 rpm. O desempenho dos processos foi avaliado através da retenção de sólidos totais e fluxo de permeado. Para MF, as membranas poliméricas de celulose (CEL) de 100 kDa e polietersulfona (PES) de 0,05 µm, foram submetidas às pressões de 1,8 e 2,6 até fator de concentração (FC) igual a 4, sendo o permeado direcionado para a UF, com membranas de CEL de 10kDa e 30kDa e PES de 10kDa, 30kDa e 50kDa, nas pressões de 3, 4 e 5 bar até FC igual a 2. Para NF direta, foram utilizadas as membranas de PES de 300 Da, 500 Da e 1000 Da, nas pressões de 15, 25 e 35 bar até FC igual a 4. Os resultados da MF mostraram retenções de 34% a 41% e fluxos de permeado estabilizados por volta de 34 kg/h.m² para a celulose de 100kDa e 17 kg/h.m² para a PES de 0,05 µm, a FC=4. O processo selecionado na MF e submetidos à UF foi a celulose 100 kDa a 1,8 bar. Os resultados mostraram que a concentração por MF seguida de UF teve baixa retenção mas foi efetivo para o preparo do permeado resultando em altos fluxos na UF. Maiores retenções de sólidos totais foram obtidas na NF direta, de 75 a 85%, que também apresentou retenções satisfatórias de minerais. Os fluxos na NF se estabilizaram por volta de 45 kg/h.m², com FC=4. Concluiu-se que os processos de NF direta apresentaram os melhores desempenhos quando utilizada a pressão de 35 bar. Tanto concentrados finais obtidos pela MF seguida de UF como o da NF direta podem ser utilizados para aplicação em áreas mais distantes das usinas visto que apresentaram concentrações de 3,2 e 7,8% de sólidos totais, respectivamente. Além disso, todos os permeados estéreis formados poderão ser concentrados posteriormente ou utilizados em outros processos / Abstract: The use of vinasse as a source of nutrients, organic matter and water, was one of the greatest revolutions in the management of sugar cane crop. It is the main effluent from alcohol distilleries and its importance is also related to the economy with fertilizer. The technical guidelines P4.231 made the sugar cane sector to carry the vinasse to long-distance areas and a solution to reduce transportation costs is its use in concentrated form. Inside this context, the objective of this work was to study the concentration of vinasse by microfiltration (MF) followed by ultrafiltration (UF) and nanofiltration (NF) directly. The process was carried out in a laboratory unit at 60ºC and 500 rpm. The process effectiveness was evaluated by the permeate flux and total solids concentration. For MF, the polymeric membranes used were cellulose 100 kDa (CEL) and PES 0.05 µm, at 1.8 and 2.6 bar until concentration factors (CF) of 4. Selected permeate from the MF was subjected to UF, for which 10 kDa, 30 kDa e 50 kDa molecular weight cut off PES and CEL membranes were evaluated, under three pressure conditions ( 3, 4 and 5 bar) until CF of 2. For NF directly, the membranes used were PES of 300 Da, 500 Da and 1000 Da, at 15, 25 and 35 bar until CF=4. Results of MF showed retention coefficients in the range of 34-41% and permeate flux stabilized around 34 kg/m².h for CEL and 17 kg/m².h for PES at CF=4. The selected MF process was cellulose 100 kDa at 1.8 bar. Results showed that the concentration by MF followed by UF had little changes on total solids retention, but was quite effective to prepare the permeate for concentration by UF, resulting in higher flux. Highest solids retentions were obtained in NF directly, 75-85%, and also satisfactory minerals retentions. The permeate flux stabilized around 45 kg/m².h at CF=4 for the NF. It was concluded that the best performance was with NF directly can allow its transportation to long-distance areas from distilleries with reduced costs, in which showed total solids concentrations of 3,2 and 7,8%, respectively. Also all sterile permeate may be concentrated and further used in other processes / Mestrado / Engenharia de Alimentos / Mestre em Engenharia de Alimentos

Orientador: Luiz Antonio Viotto / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-17T20:45:49Z (GMT). No. of bitstreams: 1 Rosa_MariaTherezadeMoraesGomes_M.pdf: 1538423 bytes, checksum: cedbaaa02603373443d0a6b048ba55ca (MD5) Previous issue date: 2011 / Resumo: A aplicação de vinhaça na lavoura, como fertirrigação, é prática adotada e muito difundida entre as destilarias brasileiras, existindo inúmeros estudos que comprovam os resultados positivos na produtividade agrícola. Mas devido à normativa CETESB P4.231 o setor sucroalcooleiro se prepara para transportar a vinhaça para distâncias maiores e uma das soluções para o transporte de grandes volumes de vinhaça é o seu uso na forma concentrada nestas áreas. Dentro deste contexto, o objetivo deste trabalho foi concentrar vinhaça utilizando microfiltração (MF) seguida de nanofiltração (NF). Os ensaios foram conduzidos em uma unidade laboratorial à 60ºC e 500 rpm. Para MF, as membranas poliméricas de Celulose (CEL) de 100 kDa e de Polifluoreto de Vinilideno (PVDF) de 0,2 µm, foram submetidas às pressões de 1,0; 1,8; 2,6 e 3,4 bar até fator de concentração (FC) igual a 4, sendo o permeado selecionado direcionado para a NF, usando membranas de Polietersulfona (PES) de 300 Da, 500 Da e 1000 Da e pressões de 15, 25 e 35 bar, até FC igual a 2. O desempenho das membranas foi avaliado através da retenção de sólidos totais e fluxo de permeado. Os resultados da MF mostraram retenções de sólidos totais de 35 a 40% e fluxos de permeado estabilizados por volta de 35 kg/m².h a FC=4. Os permeados selecionados na MF foram com membranas de CEL de 100 kDa a 1,8 bar e de PVDF de 0,2 µm a 1 bar sendo submetidos à NF. As retenções de sólidos totais obtidas na NF foram de 47-75%, sendo as maiores observadas para a membrana de PES de 500 Da. O fluxo de permeado variou de 28,9 a 183,2 kg/m².h a FC=2, no qual o aumento da pressão transmembrana ocasionou o aumento do fluxo e os melhores resultados foram observados para membrana de PES 1000 Da a 35 bar. Os fluxos de permeado obtidos na MF apresentaram curvas típicas de permeação e na NF fluxos paradoxais. Concluiu-se que os processos que apresentaram melhor desempenho global foram com a membrana de CEL 100 kDa a 1,8 bar seguida de PES 1000 Da a 35 bar e PVDF 0,2 µm a 1 bar seguida de PES 1000 Da a 35 bar. O concentrado final apresentou por volta de 3,9% de sólidos totais aumentado a sua concentração para aplicação em áreas mais distantes das usinas e todos os permeados estéreis formados poderão ser concentrados posteriormente ou utilizados em outros processos / Abstract: The application of vinasse on sugar cane plantations as fertirrigation is a practice widespread among alcohol distilleries in Brazil, supported by numerous studies that prove the effectiveness in agricultural productivity. Due to technical guidelines CETESB P4.231 the sugar cane sector has been prepared to carry the vinasse to long-distance areas and a solution to reduce transportation costs is its use in concentrated form on these areas. Inside this context, this study aimed to concentrate vinasse by microfiltration (MF) followed by nanofiltration (NF). The process was carried out in a laboratory unit at 60ºC and 500 rpm. For MF, the polymeric membranes used were Cellulose (CEL) 100 kDa and Polyvinylidene Fluoride (PVDF) 0.2 µm, at 1.0; 1.8; 2.6 and 3.4 bar until concentration factors (CF) of 4. Selected permeate from the MF was subjected to NF, for which 300 Da, 500 Da and 1000 Da molecular weight cut off Polyethersulfone (PES) membranes were evaluated, under three pressure conditions, 15, 25 and 35 bar until CF of 2. The process effectiveness was evaluated by the permeate flux and total solids concentration. Results of MF showed retention coefficients in the range of 35-40% and permeate flux stabilized around 35 kg/m².h at CF=4. The selected MF processes were CEL 100 kDa at 1.8 bar and PVDF 0.2 µm at 1 bar. Retentions in NF around 47-75% and the highest retentions were observed for PES 500 Da. Highest flux ranged from 28.9 to 183.2 kg/m².h at CF=2, at which the increase of transmembrane pressure resulted in higher fluxes and the best results were observed for PES 1000 Da at 35 bar. Permeate fluxes obtained through MF showed typical permeation and for NF flux-paradox was observed. It was concluded that the best overall performance was with CEL 100 kDa at 1.8 bar followed by PES 1000 Da at 35 bar and PVDF 0.2 µm at 1 bar followed by PES 1000 Da at 35 bar. The final retentates had about 3.9% of total solids, the increase in the vinasse concentration may allow its transportation to long-distance areas from distilleries with reduced costs. Also all sterile permeate may be concentrated and further used in other processes / Mestrado / Engenharia de Alimentos / Mestre em Engenharia de Alimentos

Orientador: Francisco Maugeri Filho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-18T02:03:49Z (GMT). No. of bitstreams: 1 Carvalho_AndreaLimoeiro_D.pdf: 2076758 bytes, checksum: 0190971971b90ab3f96544e50f0d9933 (MD5) Previous issue date: 2011 / Resumo: A nanofiltração é um processo com membrana por diferença de pressão, enolvendo também mecanismos de sorção e difusão, que pode ser aplicado na etapa de concentração do caldo clarificado na produção de ácido clavulânico. No presente trabalho, o ácido clavulânico foi concentrado, avaliou-se a eficiência do processo e estudaram-se os parâmetros envolvidos na transferência de massa e aplicados ao modelo matemático SEDE-VCh, assim como avaliou-se a ampliação de escala do processo. Esse estudo foi dividido nas seguintes etapas: seleção e caracterização das membranas; aplicação do modelo matemático, nos quais foram realizados experimentos para avaliar o desempenho das membranas NF e NF90 (ambas da FilmtecTM), e NP010 e NP030 (ambas da Microdyn Nadir®); ampliação de escala do processo, na qual a membrana que apresentou os melhores resultados nas etapas anteriores foi utilizada. Quanto à seleção da membrana, as respostas avaliadas foram o coeficiente de retenção, a produtividade e o fator de purificação. Na etapa de caracterização da membrana, foi avaliada a morfologia de superfície das quatro membranas, obtendo-se o tamanho e a distribuição de poros, a rugosidade, a dimensão fractal e a permeabilidade das mesmas, além de estudos que forneceram dados referentes aos efeitos estéricos e elétricos sobre o transporte através das membranas, como suas densidades superficiais e volumétricas de carga, a concentração do soluto nas suas superfícies externas e o coeficiente de transferência de massa do processo. A partir desses dados foi gerado um modelo para explicar o transporte através das membranas. Por fim foram feitos experimentos para verificar o comportamento do processo em uma escala piloto. Os resultados obtidos demonstram que a membrana NF é a melhor para o processo de concentração de ácido clavulânico com coeficiente de retenção médio de 0,988 em escala de bancada e aproximadamente 1,0 em escala piloto. As quatro membranas apresentaram raios de poro inferiores a 1 nm e ponto isoelétrico em pH entre 5 e 6. A membrana NP010 apresentou maior permeabilidade à água, e as demais na seguinte ordem: NP010 > NP030 > NF > NF90. Esse parâmetro se relaciona de forma linear com o diâmetro médio de poros e sua redução aumenta com a diferença entre a dimensão fractal antes e depois do uso das membranas. Foi possível verificar também que em altas adsorções a rugosidade das membranas tendem a ser similares. A membrana NF90 apresentou um maior coeficiente de transferência de massa, seguido da NF, NP010 e NP030, nessa ordem, sendo que a rejeição variou com o pH para as membranas NF e NF90. A constante dielétrica dentro dos poros aumenta inversamente ao tamanho médio dos poros das membranas até quando a mesma atinge o valor da água livre. A seletividade da membrana ao KCl e ácido clavulânico apresenta a mesma tendência da densidade volumétrica de cargas: NF > NF90 > NP030 _ NP010. Com os estudos de ampliação de escala foi possível determinar que o sistema convencional que simula o processo de fluxo tangencial pode ser usado em outros estudos de avaliação de processos e de seleção de membranas visando à aplicação industrial, e que peptídeos e aminoácidos podem atuar melhorando o processo de concentração de ácido clavulânico por nanofiltração. A produtividade final obtida foi de até 6.4 [CA]RET/[CA]0.L.h. / Abstract: Nanofiltration is a pressure driven membrane process, with desorption and diffusion, which is also applied to the concentration of clavulanic acid from a clarified juice. In this study, clavulanic acid was concentrated, and the process had its efficiency evaluated and its mass transfer parameters studied and applied to the mathematical model SEDE-VCh, and in addition scale up was also evaluated. This study was divided into the following stages: selection and characterization of the membranes, and the application of the model, in which experiments were performed to evaluate the performance of the NF and NF90 membranes (both FilmtecTM), and NP010 and NP030 (both Microdyne Nadir®), and the scale up of the process, in which the membrane that showed the best results in the previous steps was used. Concerning the selection of the membrane, the evaluated responses were the retention coefficient, productivity and purification factor. In the characterization of the membrane step, we evaluated the surface morphology of the four membranes, targeting the pore size and pore size distribution, roughness, fractal dimension and permeability, in addition to studies that provided data on the electrical and steric effects over the transport through the membranes, as their surface and volumetric density charges, the concentration of solute in its external surfaces and the mass transfer coefficient of the process. From these data a model was created to explain the transport through the membranes. Finally experiments were carried out to verify the behavior of the process in a pilot scale. The results showed that the NF membrane is best for the process of concentration of clavulanic acid with retention coefficient average of 0.988 in bench scale and almost 1.0 in the pilot plant. All the four membranes had pore radii below 1 nm and an isoelectric point between pH 5 and 6. The NP010 membrane showed the higher water permeability, in the following order: NP010 > NP030 > NF > NF90. This parameter is related linearly with the average pore size and its reduction increases with the difference between the fractal dimension before and after the use of the membranes. It was also verified that at high adsorption the roughness of the membranes tends to be similar. The NF90 membrane showed a higher mass transfer coefficient, followed by NF, NP010 and NP030, in that order and the rejection varied with the pH for the NF and NF90 membranes. The dielectric constant inside the pores increases inversely with pore size of the membranes even when it reaches the value of free water. The selectivity of the membrane to KCl and clavulanic acid shows the same trend as the volumetric density charge: NF > NF90 > NP030 _ NP010. By means of the studies of scale up it was determined that the conventional system with a stirrer that promotes the convection movement in the process can be used in other studies of process evaluation and selection of membranes in view of industrial application, and also that peptide and mino acid substances improve the process concentration of clavulanic acid by nanofiltration. The final productivity was about 6.4 [CA]RET/[CA]0.L.h. / Doutorado / Engenharia de Alimentos / Doutor em Engenharia de Alimentos

M.Sc. (Nanoscience) / Polychlorinated biphenyls (PCBs) are endocrine disrupting compounds (EDCs) and are harmful to humans and the environment. These PCBs are grouped under chlorinated organic compounds (COCs). The PCBs find their way to the environment through human activity such as industrialization and farming. Such activity produces wastes and runoffs that eventually end up in the water we use for drinking, farming and sanitation. It has then become necessary for researchers to find viable methods to remove these compounds from the environment. This is because current water treatment methods are not effective in the removal of the PCBs from water. The stages in the conventional treatment methods may include sand filtration, advanced oxidative processes and coagulation among others. These methods need to be energetically eco-friendly to drive the PCB dechlorination processes. Researchers have used a variety of metallic nanoparticles including bimetallic nanoparticles for the removal of COCs from water. However, nanoparticles tend to agglomerate when not supported - leading to a decrease in their activity. Hence it has become necessary to stabilize or immobilize these nanoparticles on suitable support materials, such as, polymer solutions or solid substrates. Solid substrates including metal oxides, carbon and membranes, are currently being explored. Poly(vinylidene difluoride) microfiltration membranes are especially suitable for this function given the high porosity, chemical inertness and other outstanding physical properties. In this work, the objective was to modify commercially hydrophilized poly(vinylidine)difluoride (PVDF) membranes with poly(ethylene glycol) (PEG). PEG is a bidentate polymer with two –OH groups found on either side of the molecule. The -OH groups allows PEG binding to the PVDF polymer backbone and hence high ability to capture or chelate the metal ions followed by their reduction. Nano-zerovalent metal nanoparticles were formed from these metal ions and chelated into the PEG grafted PVDF membrane to give the composite PVDF-PEG-Fe0. Post addition of the secondary metal was then followed by the introduction of the precomposite to a Pd solution to give the final catalytic membrane (PVDF-PEG-Fe0/Pd0). The use of PEG in this system allows for an even dispersion of the nanoparticles in the composite. The resulting nanocomposite membrane was used for the dechlorination of a polychlorinated biphenyl (PCB 77). Attenuated total reflection- Fourier transform infra red spectroscopy (ATR-FTIR) showed that PEG was successfully grafted onto the PVDF backbone. Optical contact angle measurements (OCA) were taken to determine the change in hydrophilicity of the membrane upon modification. X-ray diffraction spectroscopy (XRD) proved that the Pd and Fe nanoparticles immobilized on the system were indeed zerovalent. Scanning electron microscopy (SEM) images and contact angle measurements suggested a less porous membrane and slightly decreased hydrophilicity after modification. On the SEM micrographs the nanoparticles were observed to be quite evenly distributed in the membrane. Transmission electron microscopy (TEM) showed that the nanoparticles were in the range 20-30 nm in diameter, confirming the particle size values as determined by SEM. For the preliminary dechlorination studies done under ambient conditions, two dimensional column gas chromatography- time of flight- mass spectrometry (GCxGC-TOF-MS) results showed a complete dechlorination of PCB 77. A comparative study of the bare PVDF and catalytic membranes showed a slight difference in adsorption of the total PCB 77 concentrations. The catalytic membrane maintained its activity towards the dechlorination of PCB 77 after multiple regeneration cycles.

Recently a large amount of interest has developed around separating out impurities of small size; pertinent examples are found within fuel and solvent processing. For such applications a leading candidate process is nanofiltration. This thesis focuses on SRNF (solvent resistant nanofiltration) composite membranes consisting of a dense polymer active layer bonded to a stronger, but ultimately more porous, support layer. The composite membranes that have been produced during the course of this work consist of a PDMS (polymdimethylsiloxane) active layer bonded to a commercially available support layer of PAN (polyacrylonitrile). To create the membrane a monomer was spread over the support layer and then polymerised to form the matrix which was responsible for separation. Commercially, either heat or radiation is often applied to cause polymerisation, however the membranes in the current work have been formed by the used of a homogeneous catalyst. This thesis investigates the transport and separation dynamics of the produced membranes for a series of fuel simulants composed of organometallics and poly-nuclear aromatic solutes dissolved in aromatic and alkane solvents. Membrane composition and the extent of polymer swelling were found to be the two key factors which had the greatest influence on solvent flux and solute rejection. By increasing catalyst concentration it was found that the dual effects of increased rejection and reduced flux occurred, with the converse also being true. The effective pore size of the membrane could also be controlled by varying the catalyst amount during manufacture as this directly affected the limit of crosslinking which formed. Polymer swelling was the most pronounced using solvents with a solubility parameter close to that of the polymer. The membrane transport mechanism was most accurately forecast by the solution diffusion model for flux predictions and the convection diffusion model for rejection predictions, however all the models tried were in close agreement. This was postulated to be due to the swelled polymer matrix which allows for both convective and diffusive transport to occur.

Submitted in fulfilment of the academic requirements for the Degree of Masters in Technology: Chemical Engineering, M.L. Sultan Technikon, 2002. / Crossflow microfiltration (CFMF) using a fabric support has been successfully used to treat a range of problematic waters. Experimental evidence indicates that the formation of a dynamic membrane or precoat on a woven-fibre microfilter can significantly increase the performance of the filter, that is, the production rate and rejection. The use of precoats in filtration applications is based on the precoat's unique microstructure that is able to trap sub-micron particles while maintaining a permeable filter cake. However, to date the precoating step has been more of an art than a science. Very little knowledge exists on the best type of precoat to use, or the the optimal velocity, pressure and concentration to form a stable precoat. Further, although various models have been proposed for CFMF, their still exists a lack of knowledge of the mechanisms by which precoats improve performance. / M