Perfluoroalkylated substances (PFASs) are a group of synthetic compounds that have gained growing attention due to their environmental persistence, toxicity and their potential to bioaccumulate. Even though PFASs are not occurring naturally in our environment, they are globally distributed and can be found ubiquitously in air, water, soil, wildlife as well as in humans. PFASs have primarily been used, due to their unique properties of being both hydrophilic and hydrophobic, as surfactants in numerous products such as firefighting foams, paint, leather and textile coating. The occurrence of PFASs in drinking water as well as in wastewater makes it important to develop effective techniques to remove these compounds from drinking water sources and wastewater. To be able to effectively remove PFASs from drinking water and wastewater it is important to understand which treatment process is most efficient and how the removal efficiency is affected by the physicochemical properties of PFASs and characteristics of water. In this study, the removal efficiency of PFASs was investigated using six different water types with varying dissolved organic carbon (DOC) character. Four different treatment techniques were evaluated including anion exchange using MIEX® resins, coagulation with iron (III) chloride (FeCl3), adsorption using powdered activated carbon (PAC) and nanofiltration (NF) membrane. The batch experiments were performed in laboratory-scale for 14 individual PFASs including C3-11, C13 perfluoroalkyl carboxylic acids (PFCAs), C4, C6, C8 perfluoroalkyl sulfonic acids (PFSAs) and perfluorooctane sulfonamide (FOSA). The results showed that the removal efficiency of PFASs was dependent on both perfluorocarbon chain length as well as functional group, with an increase in removal efficiency with increased perfluorocarbon chain length. Short-chained PFASs (C!6) were removed in less extent than the long chained PFASs for all treatment techniques. Amongst the four treatment techniques investigated, NF membrane exhibited the best removal efficiency for both short- and long chained PFASs (on average, 51%). Lower removal efficiencies for PFASs were observed for MIEX (33%) < FeCl3 (16%) < PAC (14%). However, all tested treatment techniques used in this study exhibited generally low removal efficiency (< 78%), in particular for the short-chained PFASs (C!6, < 41%) Results using three different doses of PAC (i.e. 20, 50, 100 mg L-1) showed an increase in removal (i.e. 2.2-41%, 8.0-78% and 12-92% respectively) with increasing dose. No significant trends were found between PFAS removal and DOC removal for any of the treatments (p<0.05, student t-test). However, the removal efficiency was different of the six different water types, which indicates that the DOC characteristics (i.e. Freshness, humification index, pH and absorbance) have an influence on the removal efficiency of PFASs in water. / Perfluoroalkylerade ämnen (PFASer) är en grupp syntetiska ämnen som har fått allt större uppmärksamhet den senaste tiden då de har visat sig vara persistenta, toxiska och bioackumulerande. Även om PFASer inte förekommer naturligt i vår miljö är de globalt fördelade och kan återfinnas i luft, vatten, mark, djur och hos människor. PFASer har främst använts, på grund av sina unika egenskaper att vara både hydrofila och hydrofoba, som tensider i många produkter såsom brandsläckningsskum, färg, läder och textil. Förekomsten av PFASer i dricksvattentäkter och i många reningsverk gör det viktigt att utveckla effektiva metoder för att ta bort dessa föreningar i vattenreningsverk. För att effektivt kunna avlägsna PFASer från dricks- och avloppsvatten är det viktigt att ha kunskap om vilken behandlingsmetod som är effektivast och hur reningseffektiviteten påverkas av ämnenas fysikalisk-kemiska egenskaper och vattnets karaktär.   Syftet med denna studie var att undersökta reningseffektiviteten för PFASer i sex olika vatten innehållande olika typer av löst organiskt kol (DOC). Detta undersöktes för fyra olika behandlingsteknikert; jonbyte med MIEX®, koagulering med järnklorid (FeCl3), adsorption med hjälp av pulveriserat aktivt kol (PAC) och nanofiltrering. Försöken gjordes små skaligt i laboratorie och 14 olika PFASer undersöktes; C3-11,13  perfluoralkyl karboxylsyror (PFCAer), C4, C6, C8, perfluoralkyl sulfonsyror (PFSAer) och perfluoroktan sulfonamid (FOSA). Resultaten visar att reningseffektiviteten för PFASer var beroende av både den perfluorerade kolkedjans längd och funktionell grupp, med en ökning av reningseffektivitet med längre perfluorerad kolkedja. PFASer med kort perfluorerad kolkedja (C≤6) renades i mindre utsträckning än PFASer med lång perfluorerad kolkedjade; detta gällde för alla behandlingstekniker. Bland de fyra behandlingstekniker som undersöktes uppvisade nanofiltreringen den bästa reningseffektiviteten för PFASer med både korta och långa kolkedjor (i genomsnitt, 51%.). Lägre reningseffektivitet för PFASer observerades för MIEX®(33%), < FeCl3(16%) < PAC (14%). Totalt sett erhölls en relativt låg reningseffektivitet (<78%) för samtliga reningstekniker, speciellt för de kortkedjade PFASer (C£6, < 41%). Resultat från försök med tre olika doser PAC (e.g. 20, 50, 100 mg L-1) visade på en ökad reningseffektivitet (2,2-41%, 8,0-78% och 12-92%) med ökad dos PAC. Inga signifikanta trender kunde urskiljas vad gäller reningseffektivitet av PFASer och rening av DOC (p<0.05, student t-test), detta gällde för samtliga behandlingstekniker. Det fanns dock tydliga skillnader i reningseffektivitet mellan de sex olika vattentyperna vilket indikerar på att DOC egenskaperna (Freshnessindex, humifieringsindex, pH, absorbans) har en påverkan på reningseffektiviteten för PFASer i vatten.

La complexité des mécanismes de transport en nanofiltration (NF) nécessite ledéveloppement d'outils de modélisation fiables permettant de comprendre et d'optimiser lesopérations de séparation en NF.La présente étude comprend deux volets. Le premier porte sur la rétention d'un soluténeutre - le poly(éthylène glycol) à 600 g mol-1 (PEG) - seul et en présence d'ions, par unemembrane organique de NF (polyamide). Les résultats obtenus montrent que la rétention dusoluté neutre chute en présence d'ions et ce, d'autant plus que la concentration du sel estélevée. Ce phénomène ne peut être expliqué par le seul phénomène de déshydratation dusoluté neutre par les ions environnants. Un phénomène supplémentaire de gonflement de porea été mis en évidence et corrélé à la densité de charge membranaire. La contribution des deuxphénomènes à la chute du taux de rejet du PEG a été évaluée pour différents sels à plusieursconcentrations.Le deuxième volet du travail est consacré à (i) l'évaluation de la constante diélectrique desolutions à l'intérieur de nanopores (ep) d'une membrane organique de NF (polyamide) àpartir de mesures de potentiel de membrane et (ii) la validation de cette méthode. Les valeursobtenues s'avèrent être inférieures à celle de la solution externe (effet du confinement) etdiminuer avec l'augmentation de la proportion en ions calcium du mélange (effet structurantdes ions). L'accord entre les constantes diélectriques ep déterminées à partir de mesures depotentiel de membrane et de taux de rejet ionique (mélanges ternaires) valide la cohérence dumodèle de transport utilisé (exclusion stérique, électrique et diélectrique aux interfaces) etmontre que les mesures de potentiel de membrane peuvent être envisagées pour l'évaluationcorrecte de la constante diélectrique à l'intérieur de nanopores

Antioxidants are molecules capable of stabilizing and preventing oxidation. Certain peptides, protein hydrolysates, have shown antioxidant capacities, which are obtained once liberated from the native protein structure. Soy protein isolates (SPI) were enzymatically hydrolyzed by pepsin and pancreatin mixtures. The soy protein hydrolysates (SPH) were fractionated with sequential ultrafiltration (UF) and nanofiltration (NF) membrane steps. Heat pre-treatment of SPI at 95 degrees celsius (C) for 5 min prior to enzymatic hydrolysis was investigated for its effect on peptide distribution and antioxidant capacity. SPH were subjected to UF with a 10 kDa molecular weight cut off (MWCO) polysulfone membrane. UF permeate fractions (lower molecular weight than 10 kDa) were fractionated by NF with a thin film composite membrane (2.5 kDa MWCO) at pH 4 and 8. Similar peptide content and antioxidant capacity (α=0.05) were obtained in control and pre-heated SPH when comparing the respective UF and NF permeate and retentate fractions produced. FCR antioxidant capacities of the SPH fractions were significantly lower than their ORAC antioxidant capacities, and the distribution among the UF and NF fractions was generally different. Most UF and NF fractions displayed higher antioxidant capacities when compared to the crude SPI hydrolysates, showing the importance of molecular weight on antioxidant capacity of peptides. The permeate fractions produced by NF at pH 8 displayed the highest antioxidant capacity, expressed in terms of Trolox equivalents (TE) per total solids (TS): 5562 μmol TE/g TS for control SPH, and 5187 μmol TE/g TS for pre-heated SPH. Due to the improvement in antioxidant capacity of peptides by NF at pH 8, the potential for NF as a viable industrial fractionation process was demonstrated. Principal component analysis (PCA) of fluorescence excitation-emission matrix (EEM) data for UF and NF peptide fractions, followed by multi-linear regression analysis, was assessed for its potential to monitor and identify the contributions to ORAC and FCR, two in vitro antioxidant capacity assays, of SPH during membrane fractionation. Two statistically significant principal components (PCs) were obtained for UF and NF peptide fractions. Multi-linear regression models (MLRM) were developed to estimate their fluorescence and PCA-captured ORAC (ORAC-FPCA) and FCR (FCR-FPCA) antioxidant capacities. The ORAC-FPCA and FCR-FPCA antioxidant capacities for NF samples displayed strong, linear relationships at different pH conditions (R-squared>0.99). Such relationships are believed to reflect the individual and relative combined contributions of tryptophan and tyrosine residues present in the SPH fractions to ORAC and FCR antioxidant capacities. Therefore, the proposed method provides a tool for the assessment of fundamental parameters of antioxidant capacities captured by ORAC and FCR assays.

Le couplage de la nanofiltration et de l'oxydation électrochimique est étudié pour le traitement tertiaire des eaux usées de l'hôpital après leur traitement par bioréacteur à membrane. L'efficacité de la nanofiltration est fortement influencée par le colmatage. Afin d'assurer des flux durables et des performances élevées lors de l'étape de nanofiltration, les mécanismes de colmatage sont étudiés. Les flux critique et limite sont déterminés et liés à l'effet combiné du colmatage colloïdal organique et du dépôt inorganique. L'impact de la couche de colmatage et de la présence de matières organiques dans la matrice sur la rétention des produits pharmaceutiques est également évalué. Le rétentat de la nanofiltration est ensuite traité par oxydation électrochimique sur une anode BDD. L'influence des conditions opératoires et la compétition lors de l'oxydation des constituants au sein du réacteur sont évaluées. Au lieu d'être rédhibitoire au bon fonctionnement du procédé, la présence des ions et des composés organiques dans le concentrat peut accélérer la dégradation des produits pharmaceutiques. En particulier, la formation de composés organohalogénés due à la présence de chlorure peut être contrôlée par le choix de conditions opératoires appropriées. Un modèle décrivant la dégradation des produits pharmaceutiques en fonction du temps d'électrooxydation est établi. Un des objectifs est d'accéder au meilleur compromis entre la minéralisation des produits pharmaceutiques et la consommation d'énergie. Après optimisation des conditions opératoires des 2 procédés, il est démontré que leur couplage est efficace pour l'élimination de produits pharmaceutiques et la diminution de la toxicité de l'effluent, permettant d'envisager son rejet dans l'environnement ou sa réutilisation. / The coupling of nanofiltration and electrochemical oxidation is studied for the tertiary treatment of hospital wastewater after membrane bioreactor treatment. The effectiveness of nanofiltration is greatly affected by membrane fouling. In order to ensure sustainable flux and high performances during nanofiltration step, fouling mechanisms are investigated. The critical flux and the limiting flux are determined and associated with the combined effect of the organic colloidal fouling and the scaling. Impact of the fouling layer and of the presence of organic matters in the matrix on pharmaceuticals rejection is also investigated. NF retentate is then treated by electrochemical oxidation on BDD anode. The influence of operating conditions and the competition between components oxidation in the reactor are studied. Rather than a hindering effect, the presence of ions and common organics in the concentrate can accelerate the degradation of pharmaceuticals. In particular, the formation of organohalogens due to the presence of chloride can be controlled thanks to the choice of appropriate operating conditions. A model for the degradation of pharmaceuticals over electrooxidation time is established. One objective is to access to the best compromise between mineralization of pharmaceuticals and energy consumption. After optimization of the operating conditions of both processes, their coupling is confirmed to be efficient for the elimination of pharmaceuticals and the reduction of the toxicity of the effluent, allowing to consider its release into the environment or its reuse.

Os efluentes contendo cádmio podem ser gerados dos por várias indústrias. A aplicação de ambas as tecnologias osmose inversa (OI) e nanofiltração (NF) para o tratamento de efluentes contendo o íon cádmio para reduzir a degradação ambiental foram estudadas no presente trabalho. Amostras sintéticas contendo o íon cádmio em várias concentrações foram preparadas e submetidas aos tratamentos por OI e NF em escala laboratorial. Assim, dividiu-se o processo de remoção em três etapas: 1- analisou-se os processos de osmose inversa e nanofiltração em termos da rejeição do íon cádmio, onde se correlacionou e avaliou os principais parâmetros de processos (concentração da solução alimentação, fluxo de permeado e pressão) e comparou-se os sistemas entre si. Nas etapas 2 e 3 avaliou-se os efeitos da salinidade utilizando os contra-íons zinco e sódio respectivamente, sobre a rejeição do íon cádmio no sistema de osmose inversa em soluções aquosas contendo misturas de sulfato de cádmio e sulfato de zinco, e sulfato de cádmio e sulfato de sódio. Mediu-se as concentrações de cádmio e zinco por espectroscopia de absorção atômica e as concentrações de sulfato e sódio por cromatografia de íons. Os resultados obtidos na primeira etapa dos experimentos mostram que a osmose inversa e nanofiltração são eficientes na remoção de cádmio, onde se obteve as taxas médias de rejeição de 92,4% e 96,6% respectivamente, sendo esses valores iguais em magnitude, tendo em vista os valores da incerteza padrão relativa associada a esses resultados. Em ambos os sitemas, os fluxos de permeado e as rejeições não sofreram influência do aumento da concentração de cádmio na solução alimentação.Na etapa 2, os resultados mostraram a diminuição da rejeição de cádmio com o aumento da concentração de sulfato de zinco na alimentação, sendo esse fenômeno atribuído a semelhança existente entre os íons Cd2+ e Zn2+ associados aos seus raios iônicos de hidratação e as energias de hidratação. Foram observadas as quedas do fluxo de permeado e das rejeições com o aumento da concentração de alimentação provavelmente devido ao efeito da polarização. Na etapa 3, a rejeição do íon cádmio não foi afetada pelo aumento da concentração de sulfato de sódio na alimentação, assim como os fluxos de permeado. Outro aspecto relacionado à rejeição é que a difusão do sódio através da membrana é favorecida frente à difusão do cádmio, sendo atribuído ao menor raio de hidratação do sódio / Effluents containing cadmium may be produced by a variety of industries. The application of the reverse osmosis and nanofiltration technologies for the treatment of effluents containing cadmium, in order to reduce environmental degradation, were studied in the present work. Synthetic samples containing the cadmium ion in different concentrations were prepared and treated by reverse osmosis and nanofiltration. The removal process was divided in three steps: 1- the reverse osmosis and nanofiltration processes were analyzed concerning the rejection of the cadmium ion, correlating and evaluating the main process parameters (feeding solution concentration, permeated flow and pressure), and comparing the systems between themselves. In steps 2 and 3, the effects of salinity in the elimination of the cadmium ion in aqueous solutions, containing a combination of cadmium sulfate and zinc sulfate, or a combination of cadmium sulfate and sodium sulfate, were assessed by the use of zinc and sodium counterions. The concentrations of cadmium and zinc were measured by atomic absorption spectroscopy, and the concentrations of sulfate and sodium were measured by ion chromatography. The results obtained in the first step of the experiments show that the reverse osmosis and the nanofiltration processes are efficient in removing cadmium, with an average rejection rate of 92,4% and 96,6%, respectively. Considering the standard relative incertitude associated to the results, the values obtained are considered of the same magnitude. In both systems, the permeated flow and the rejects were not influenced by a rise in cadmium concentration in the feeding solution. In step 2, the results showed a decrease in cadmium rejection related with a rise in the zinc sulfate concentration in the feeding solution. This phenomenon is due to the similarity between the Cd2+ and Zn2+ ions, associated to their hydration ionic radius and to their hydration energies. A decrease in the permeated flow and of the rejects related to a rise in the feeding concentration was observed and was probably due to the polarization effect. In step 3, the cadmium ion rejection was not affected by a sodium sulphate concentration rise in the feeding, as well as in the permeated flow. Another aspect related to the rejection is that, due to its smaller hydration radius, sodium has a better diffusion rate through the membrane than cadmium

Membrane technology can be utilised for the high purification and desalination of water. However membrane filtration processes are commonly impeded by membrane fouling, which can lead to flux decline and an overall reduction in separation efficiency within the process. Therefore the aim of this research study was a comprehensive investigation of the issue of biofouling on industrial RO membranes through molecular biology techniques, characterisation of surface charge of foulant bacteria and RO membrane surface and AFM imaging and force measurements on clean and fouled membranes for the determination of adhesion force and micromechanical properties. The laboratories within Gwangju Institute of Science and Technology, South Korea and Swansea University, Wales were equipped for the scope of this research work. Research focused on the extraction of microbial DNA obtained from fouling layers on the surface of Reverse Osmosis Membranes obtained from the Fujairah Water and Power Plant, UAE. The use of the culture independent method of the molecular technique based on the 16S rDNA sequence and constructed gene libraries, was then used to determine the bacterial species that caused significant fouling on the RO membrane. Four bacterial species isolated from the fouling layer from the RO membrane were characterised in terms of electrophoretic mobility and zeta potential to determine the cell surface charge within various industrial relevant environments for the elucidation of cell adhesion mechanisms to the membrane surface. AFM images of virgin and fouled membranes were obtained and analysed to reveal the roughness of the surface which could influence fouling and the surface charge of the membranes were measured through the method of streaming potential at various industrial relevant environments to further elucidate the mechanisms of cell adhesion to the membrane surface. Force measurements were performed to reveal the adhesion force and elasticity values of virgin, process fouled and purposely fouled with the four bacterial isolates, to determine process behaviour in various environmental conditions. Through this research and future work, it is hoped that a rational strategy for economic and effective cleaning processes will be developed which will maintain efficient membrane operation and prolong membrane life, thus enabling the reduction of operating costs of such processes.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-03-09T20:44:52Z No. of bitstreams: 1 FRANCISCO RUBENS MACEDO DE QUEIROZ - TESE PPGEQ 2017..pdf: 6491313 bytes, checksum: 6c4f94936ecedff528d64322072a5f31 (MD5) / Made available in DSpace on 2018-03-09T20:44:52Z (GMT). No. of bitstreams: 1 FRANCISCO RUBENS MACEDO DE QUEIROZ - TESE PPGEQ 2017..pdf: 6491313 bytes, checksum: 6c4f94936ecedff528d64322072a5f31 (MD5) Previous issue date: 2016-12-09 / Capes / Um dos grandes desafios da atualidade vem sendo a conservação e manutenção dos corpos de águas do mundo, devido as suas contaminações em função das atividades humana. A diversidade das substâncias toxicas de diferentes naturezas são veiculadas como fontes de doenças de alto risco para todos os seres e vegetações do planeta. Um dos pontos preliminares é o acesso ao saneamento básico que a maioria das cidades brasileiras não possuem e que carreiam seus resíduos para mananciais superficiais e subterrâneas, deixando-os com altos índices de bactérias, inclusive com o aumento da concentração de nitrato nas águas subterrâneas. O presente trabalho visa estudar o desempenho de dois sistemas de membranas para reduzir a concentração de nitrato presente em águas de poços doces e salobros, contendo índices de nitrato acima dos padrões de potabilidade da legislação brasileira. Os desempenhos dos sistemas de membranas de microfiltração/nanofiltração e ultrafiltração/osmose inversa, foram estudados em função de seus limites de pressões de operações para diferentes níveis de concentrações de nitrato presentes nos meios aquosos. Os níveis das pressões de operações para todas as águas estudadas foram obtidos com auxílio de um simulador de processos de membranas (Reverse Osmose System Analysis), o qual contribui para realizar o planejamento experimental em função das pressões de operações versus concentrações nitrato. A primeira fase do trabalho os dois sistemas operaram com uma solução de nitrato na faixa de 0,67 mg.L-1 ≤ [N-N03-] ≤ 23,3 mg.L-1 visando explorar os níveis das taxas rejeição do nitrato em função de suas pressões de operações. Os desempenhos dos dois sistemas de membranas foram estudados com água doce de poço contaminada com nitrato, água de abastecimento da rede do LABDES e água de poço salobra, ambas com adição de 20,8 mg.L-1 de nitrato. Os resultados das taxas de rejeição de nitrato para os dois sistemas foram comparados em função do tipo de água de alimentação e seus níveis de concentrações de nitrato. Observou-se que o sistema de membranas de ultrafiltração/osmose inversa apresentou uma remoção de nitrato superior para todos os casos estudados, quando comparados com os obtidos pelo sistema de microfiltração/nanofiltração. Comparando os resultados para uma pressão de operação comum para os dois sistemas de membranas estudados de 3,2 bar o sistema de membrana de microfiltração/nanofiltração conseguiu uma taxa de remoção de 54,50% e o sistema de ultrafiltração/osmose inversa foi de 86,10% para uma concentração de 20,8 mg.L-1 de nitrato na água doce de poço. Observou-se que uma redução de nitrato e dos sólidos totais dissolvidos em águas doces para os padrões de potabilidade foram significativas para o sistema de ultrafiltração/osmose inversa do que a do sistema de microfiltração/nanofiltração, em função da pressão de operação. Com auxilio do MINITAB Versão 17.0 os modelos foram validados a partir das curvas dos dados experimentais para os dois sistemas de membranas estudados. / One of the great challenges of the present time has been the conservation and maintenance of the bodies of water of the world, due to its contaminations due to human activities. The diversity of toxic substances of different natures are conveyed as sources of high risk diseases for all beings and vegetations of the planet. One of the preliminary points is access to basic sanitation that most Brazilian cities do not have and that carry their waste to surface and underground springs, leaving them with high rates of bacteria, including with increasing nitrate concentration in groundwater. The present work aims to study the performance of two membrane systems to reduce the concentration of nitrate present in waters of sweet and brackish wells, containing nitrate indices above the potability standards of Brazilian legislation. The performances of the microfiltration/nanofiltration and ultrafiltration/reverse osmosis membranes systems were studied as a function of their operating pressure limits for different levels of nitrate concentrations present in the aqueous media. The operating pressure levels for all studied waters were obtained using a Reverse Osmose System Analysis, which contributes to perform the experimental planning as a function of the operating pressures versus nitrate concentrations. In the first phase of the work the two systems operated with a nitrate solution in the range of 0,67 mg.L-1 ≤ [N-N03-] ≤ 23,3 mg.L-1 to explore the levels of nitrate rejection rates as a function of their pressures Operations. The performances of the two membrane systems were studied with fresh water from well contaminated with nitrate, LABDES network water supply and brackish water, both with addition of 20,8 mg.L-1 of nitrate. The results of the nitrate rejection rates for the two systems were compared according to the type of feed water and their levels of nitrate concentrations. It was observed that the ultrafiltration / reverse osmosis membrane system showed superior nitrate removal for all the studied cases when compared to those obtained by the microfiltration / nanofiltration system. Comparing the results to a common operating pressure for the two 3,2 bar membrane systems studied, the microfiltration/nanofiltration membrane system achieved a removal rate of 54,50% and the ultrafiltration/reverse osmosis system was 86,10% for a concentration of 20,8 mg.L-1 nitrate in freshwater well. It was observed that a reduction of nitrate and total solids dissolved in fresh water to the potability standards were significant for the ultrafiltration / reverse osmosis system than that of the microfiltration/nanofiltration system as a function of the operating pressure. With the help of MINITAB Version 17.0 the models were validated from the curves of the experimental data for the two systems of membranes studied.

O objetivo deste trabalho foi estudar a remoção de metais pesados de efluentes sintéticos aquosos através de nanofiltração, com utilização de membrana de poliamida. A membrana utilizada constituída de poliamida apresentou uma boa permeabilidade hidráulica, constatada pela linearidade de fluxo com a variação de pressão de trabalho. Os metais estudados foram cobre, cádmio, zinco, chumbo e níquel com especiação de nitrato e sulfato. O desempenho do sistema foi verificado pela variação dos parâmetros operacionais (pressão e fluxo), associados também com a variação da salinidade e da concentração do metal. Em uma etapa inicial estudou-se a remoção de metais (nitrato e sulfato) isoladamente em uma mesma concentração molar, na pressão de 10 bar, comparando-se as rejeições com e sem agente complexante (EDTA). Em uma segunda etapa, estudou-se o desempenho da membrana, com misturas dos metais (nitrato) e mistura de metais (sulfato), também com e sem agente complexante, os resultados mostraram que a presença de agente complexante melhorou a rejeição dos metais. Nestas misturas estudaram-se os efeitos das concentrações (0,001; 0,0005 e 0,0001mol/L) e das pressões (5; 7; 10 e 12,5 bar) no sistema de remoção, constatou-se que o aumento da concentração e diminuição da pressão afeta a remoção. Em uma terceira etapa, estudou-se a influência da salinidade pela mistura de dois metais de mesma especiação (sulfato), comparando a remoção na pressão de 10 bar. Os resultados atestaram uma rejeição maior que 94 % para todos metais, na pressão de 10 bar, indicando um excelente desempenho e fluxo adequado, daí viabilidade de processo para todas as concentrações testadas. A pertinência do teste se justifica pela adequação do permeado ao atendimento aos padrões ambientais de concentração de metais e confirmam a eficácia do sistema de nanofiltração na remoção de metais pesados / The objective of this work was to study the removal of heavy metals of aqueous synthetic efluentes through nanofiltração, with use of polyamide membrane. The membrane used constituted of polyamide it presented a good hydraulic permeabilidade, verified by the flow linearidade with the variation of work pressure. The studied metals were copper, cadmium, zinc, lead and nickel with speciation of nitrate and sulfate. The performance of the system was verified by the variation of the operational parameters (pressure and flow), also associated with the variation of the salinity and of the concentration of the metal. In an initial stage it was studied the removal of metals (nitrate and sulfate) separately in a same concentration molar, in the pressure of 10 bar, being compared the rejections with and without agent complexante (EDTA). In a second stage, it was studied the performance of the membrane, with mixtures of the metals (nitrate) and mixture of metals (sulfate), also with and without agent complexante, the results showed that the presence of agent complexante improved the rejection of the metals. In these mixtures they were studied the effects of the concentrations (0,001; 0,0005 and 0,0001mol/L) and of the pressures (5; 7; 10 and 12,5 bar) in the removal system, it was verified that the increase of the concentration and decrease of the pressure affects the removal. In a third stage, it was studied the influence of the salinity by the mixture of two metals of same speciation (sulfate), comparing the removal in the pressure of 10 bar. The results attested a larger rejection than 94% for all metals, in the pressure of 10 bar, indicating an excellent acting and appropriate flow, then process viability for all of the tested concentrations. The importance of the test is justified for the adaptation of the permeated to the service to the environmental patterns of concentration of metals and they confirm the effectiveness of the nanofiltração system in the removal of heavy metals

Os efluentes contendo cádmio podem ser gerados dos por várias indústrias. A aplicação de ambas as tecnologias osmose inversa (OI) e nanofiltração (NF) para o tratamento de efluentes contendo o íon cádmio para reduzir a degradação ambiental foram estudadas no presente trabalho. Amostras sintéticas contendo o íon cádmio em várias concentrações foram preparadas e submetidas aos tratamentos por OI e NF em escala laboratorial. Assim, dividiu-se o processo de remoção em três etapas: 1- analisou-se os processos de osmose inversa e nanofiltração em termos da rejeição do íon cádmio, onde se correlacionou e avaliou os principais parâmetros de processos (concentração da solução alimentação, fluxo de permeado e pressão) e comparou-se os sistemas entre si. Nas etapas 2 e 3 avaliou-se os efeitos da salinidade utilizando os contra-íons zinco e sódio respectivamente, sobre a rejeição do íon cádmio no sistema de osmose inversa em soluções aquosas contendo misturas de sulfato de cádmio e sulfato de zinco, e sulfato de cádmio e sulfato de sódio. Mediu-se as concentrações de cádmio e zinco por espectroscopia de absorção atômica e as concentrações de sulfato e sódio por cromatografia de íons. Os resultados obtidos na primeira etapa dos experimentos mostram que a osmose inversa e nanofiltração são eficientes na remoção de cádmio, onde se obteve as taxas médias de rejeição de 92,4% e 96,6% respectivamente, sendo esses valores iguais em magnitude, tendo em vista os valores da incerteza padrão relativa associada a esses resultados. Em ambos os sitemas, os fluxos de permeado e as rejeições não sofreram influência do aumento da concentração de cádmio na solução alimentação.Na etapa 2, os resultados mostraram a diminuição da rejeição de cádmio com o aumento da concentração de sulfato de zinco na alimentação, sendo esse fenômeno atribuído a semelhança existente entre os íons Cd2+ e Zn2+ associados aos seus raios iônicos de hidratação e as energias de hidratação. Foram observadas as quedas do fluxo de permeado e das rejeições com o aumento da concentração de alimentação provavelmente devido ao efeito da polarização. Na etapa 3, a rejeição do íon cádmio não foi afetada pelo aumento da concentração de sulfato de sódio na alimentação, assim como os fluxos de permeado. Outro aspecto relacionado à rejeição é que a difusão do sódio através da membrana é favorecida frente à difusão do cádmio, sendo atribuído ao menor raio de hidratação do sódio / Effluents containing cadmium may be produced by a variety of industries. The application of the reverse osmosis and nanofiltration technologies for the treatment of effluents containing cadmium, in order to reduce environmental degradation, were studied in the present work. Synthetic samples containing the cadmium ion in different concentrations were prepared and treated by reverse osmosis and nanofiltration. The removal process was divided in three steps: 1- the reverse osmosis and nanofiltration processes were analyzed concerning the rejection of the cadmium ion, correlating and evaluating the main process parameters (feeding solution concentration, permeated flow and pressure), and comparing the systems between themselves. In steps 2 and 3, the effects of salinity in the elimination of the cadmium ion in aqueous solutions, containing a combination of cadmium sulfate and zinc sulfate, or a combination of cadmium sulfate and sodium sulfate, were assessed by the use of zinc and sodium counterions. The concentrations of cadmium and zinc were measured by atomic absorption spectroscopy, and the concentrations of sulfate and sodium were measured by ion chromatography. The results obtained in the first step of the experiments show that the reverse osmosis and the nanofiltration processes are efficient in removing cadmium, with an average rejection rate of 92,4% and 96,6%, respectively. Considering the standard relative incertitude associated to the results, the values obtained are considered of the same magnitude. In both systems, the permeated flow and the rejects were not influenced by a rise in cadmium concentration in the feeding solution. In step 2, the results showed a decrease in cadmium rejection related with a rise in the zinc sulfate concentration in the feeding solution. This phenomenon is due to the similarity between the Cd2+ and Zn2+ ions, associated to their hydration ionic radius and to their hydration energies. A decrease in the permeated flow and of the rejects related to a rise in the feeding concentration was observed and was probably due to the polarization effect. In step 3, the cadmium ion rejection was not affected by a sodium sulphate concentration rise in the feeding, as well as in the permeated flow. Another aspect related to the rejection is that, due to its smaller hydration radius, sodium has a better diffusion rate through the membrane than cadmium

Orientador: Francisco Maugeri Filho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-16T16:35:27Z (GMT). No. of bitstreams: 1 Kuhn_RaquelCristine_D.pdf: 4200026 bytes, checksum: e446a4c8621430fcdc142e54faba4194 (MD5) Previous issue date: 2010 / Doutorado / Doutor em Engenharia de Alimentos