Ocean salinity is a renewable energy source that has not been recognized and could provide an opportunity to capture significant amount of clean energy when it mixes with river water. One of the processes emerging as a sustainable method for capturing energy from seawater is reverse electrodialysis (RED), which generates power via the transport of the positive and negative ions in the water through selective ion exchange membranes (IEMs). RED power generation is relatively close to commercialization, but its application is often limited by system power efficiency in natural water conditions. Although various types of salt ions exist in environmental saline water, most efforts have been focused on sodium chloride as a single ionic source in the water and the effects of other common multivalent ions (e.g., magnesium and sulfate) on power generation remain unexplored. Moreover, the commercial feasibility of RED is highly challenged by the absence of specialized RED membranes. Currently available IEMs are not optimized for RED power conversion systems, but successful operation is highly dependent on the membranes used. Major advances in manufacturing of proper IEMs will be a critical pathway to accelerate large-scale energy conversion by RED. Therefore, this study aimed at advancing our understanding of the RED power system for efficient and stable salinity gradient energy generation. Specifically, it is comprised of three parts. First, a mathematical model is developed for three different monovalent and multivalent ion combinations to determine the effect of different ionic compositions of the feed solution on the power density. Efforts are further made to optimize the RED system with respect to improving power density by investigating the sensitivity of key response parameters such as flow rate ratios and intermembrane distance ratios. Second, novel organic-inorganic nanocomposite cation exchange membranes (CEMs) are synthesized for RED application by introducing functionalized inorganic materials into an organic polymer matrix. The effect of inorganic particle filler loading within the organic polymer matrix on physico- and electrochemical performance is investigated. The results revealed that the increase of functionalized nanoparticle loading controls the effective ion transport in the membrane structure and there exists an optimum amount of nanoparticles (i.e., charged groups), which performs the best in selectively exchanging counter-ions, while excluding co-ionic species. Third, the membrane structure modification is demonstrated to enhance ion transport while maintaining large surface-charged functional groups in the polymer matrix. We have synthesized custom nanocomposite CEMs to tailor porous membrane structures of various thicknesses, aging (evaporation) time, and inorganic nanoparticle loadings. We have further tailored the membrane structure by incorporating different inorganic particle filler sizes. These engineered design approaches are found to be highly effective in obtaining desired physico- and electrochemical properties, which allowed higher ionic current flow throughout the system. Furthermore, for the first time we showed the successful application of tailor-made nanocomposite CEMs in a RED stack and achieved superb power density, which exceeds the power output obtained with the commercially available membranes. In summary, this dissertation has advanced our understanding of salinity gradient energy generation using RED technique. Specifically, computational modeling and simulation study investigates the development and optimization approaches of the RED process for practical application of RED using natural water conditions. Furthermore, the RED membranes developed in this dissertation focuses on fabrication, characterization, and optimization of cation exchange membranes. Overall, the results of this study are anticipated to benefit the future optimization of energy-capturing mechanisms in RED and provide the better pathway for the sustainable salinity gradient power generation.

Reverse electrodialysis (RED) is a technique that can capture electrical potential from mixing two water streams of different salt concentration through permselective ion exchange membranes. Effective design of ion exchange membranes through structure optimization is critical to increase the feasibility of salinity gradient power production by RED. In this work, we present the preparation of organic-inorganic nanocomposite cation exchange membranes containing sulfonated polymer, poly (2,6-dimethyl-1,4-phenylene oxide), and sulfonated silica (SiO2-SO3H). The effect of silica filler size at various loading concentrations on membrane structures, electrochemical properties, and the RED power performance is investigated. The membranes containing bigger-sized fillers (70 nm) at 0.5 wt% SiO2-SO3H exhibited a relatively favorable electrochemical characteristic for power performance: an area resistance of 0.85 Ω cm2, which is around 9.3% lower than the resistance of the membranes with smaller filler particles. The power performance of this nanocomposite cation exchange membrane in a RED stack showed 10% higher power output compared with the membranes containing small particle size and achieved the highest gross power density of 1.3 W m-2. Thus, further optimized combination of material properties and membrane structure is a viable option for the development of effective ion exchange membrane design, which could provide desirable electrochemical performance and greater power production by RED.

<p>As the number of water stressed regions around the world continues to growth due to a steadily increasing demand and climate change; the use of unconventional water sources, such as, brackish or seawater, through the implementation of desalination technologies has increased significantly. Reverse osmosis has established itself as the most widespread and energy efficient desalination technology, thanks to the development of high permeability membranes, high efficient pumps, and the integration of energy recovery devices; but, it still faces important challenges, such as, high specific energy consumption compared with traditional water treatment technologies, and poses environmental threats due to its significant CO₂emissions and the need of disposal of high salinity brine.</p> <p> </p> <p>The aim of this research is to address and provide solutions for two of the major challenge areas in reverse osmosis: reduction of the energy consumption and strategies to facilitate its integration with renewable energy sources to decrease its environmental impact. </p> <p> </p> <p>In chapter 2, the modeling and design of a double-acting batch reverse osmosis system is presented. A reduced specific energy consumption compared with previously proposed configurations was found. Moreover, the new design presents solutions to practical concerns that have limited the implementation of Batch reverse osmosis processes such as high start time and downtime, and permeate contamination. On the other hand, a novel hydraulic modeling is introduced to calculate the evolution of the pressure and other important parameters during the cycle.</p> <p> </p> <p>Chapter 3 presents a novel method which allows reverse osmosis plants to vary their power usage according to the energy availability, therefore, providing demand response capabilities. The effects on the energy consumption and performance of the reverse osmosis desalination facility due to the implementation of this technique are also studied. The split-salinity demand response reverse osmosis process proposed here poses as the first approach to grant demand response capabilities to reverse osmosis plants that provides energy gains and can be applied to existing plants. </p>

No description available.

Submitted by Leticia Schettini (leticia@ufrrj.br) on 2016-09-19T13:26:00Z No. of bitstreams: 1 2009 - Leonardo Mitrano Neves.pdf: 932793 bytes, checksum: 1e42ee61916afbed6020d0c2430fa7a4 (MD5) / Made available in DSpace on 2016-09-19T13:26:00Z (GMT). No. of bitstreams: 1 2009 - Leonardo Mitrano Neves.pdf: 932793 bytes, checksum: 1e42ee61916afbed6020d0c2430fa7a4 (MD5) Previous issue date: 2009-03-05 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPQ / The estuarine systems influence fish assemblages, throughout their longitudinal gradients and remarkable salinity changes. Such assemblages adapt to different habitat constraints and change in spatial and temporal scales. The aim of this study was to assess the ichthyofauna composition and structure in three zones of the Mambucaba estuary (CZ ? coastal zone; MZ ? mixture zone and RZ ? river zone) and their relationship with environmental variables and habitat characteristics. Systematic fish collections (2 months in each seasons) were performed between October 2007 and August 2008, by using otter trawl at two sites in CZ (C1 e C2), beach seine at three sites in MZ (M1, M2, M3) and mesh trays at two sites in RZ (R1 e R2). At each fish sampling occasion, both surface and depth environmental variables of temperature, salinity, conductivity, turbidity and dissolved oxygen were taken and depth was measured. A total of 14,320 individuals, in 111 species (RZ ? 18; MZ ? 50, and CZ - 66) were collected. Distinct fish assemblages were found for each zone, as indicated by low number of common species (14 - MZ and CZ; 8 - MZ and RZ; and 2 - CZ and RZ), and only one abundant species (> 1% of the total number of fish within the zone) being common in more than one zone (Eucinostomus argenteus in CZ and MZ). Such pattern can be related to high salinity variation in MZ and narrow (20 m) channel width connecting the estuary with the sea, which can limit fish movement (into/out of the estuary). In CZ, the three more abundant species were Paralonchurus brasiliensis, Ctenosciaena gracillicirrhus, Anchoa lyolepis, Larimus breviceps and Stellifer brasiliensis, with large contribution of fish from the Scieanidae family in this zone (18 species). Spatial changes inf fish species were not consistent in CZ, probably due to lack of spatio-temporal estuarine plume influence on depth environmental variables (ANOVA, p>0.05). Depth was the main factor to influence spatial changes for Diapterus rhombeus (negative association) more abundant in C1 (average depth = 10 m; ANOVA, p<0.05) and Micropogonias furnieri, P. brasiliensis and Pellona harroweri (positive association) more abundant in C2 (average depth = 17 m; ANOVA, p<0.00). Diapterus rhombeus and Etropus crossotus occured mainly in Spring and Summer, and Eucinosomus gula in Spring. The most abundant species in CZ, typical of high salinty influence, is a indication that this zone have characteristics to inner continental shelf. In MZ, most abundant species (Eugerres brasilianus, Eucinostomus melanopterus, Trinectes paulistanus, Gobionellus shufeldti, G. oceanicus, Geophagus brasiliensis, Centropomus parallelus and Citharichthys arenaceus) have higher number and weight of individuals in M1 (ANOVA, p<0.01), an adjacent lagoon connected to the main channel. In spite of the significant negative correlation between this species and salinity (r-Spearman>0.32, p<0.01), the more sheltered areas in M1 seem to be more important to determine this pattern than salinity itself. The site M1 also have more number of individuals and species (ANOVA, p<0.01), and larger number of fish of smaller size (CT median = 58mm) compared to M2 and M3, located in the main channel (median = 106mm) according to Median and Kruskall-Wallis tests (p<0.01; 2 = 1167.5), indicating the importance of this area for species recruitment. Low average similarity (SIMPER) for sites M2 (38.7%) and M3 (17.8%) indicate larger variability of assemblage in these sites, probably due to lesser habitat structure e higher dynamism. In RZ, the fish assemblage have few species (5) with abundance higher than 1% of the total number of fishes, being dominated by Dormitator maculatus, Astyanax sp and ix Microphis brachyurus lineatus, species typical of upper estuaries and lower river reaches. Spatial variation was detected for D. maculatus only, more abundant at R2, a site with abundant riparian vegetation, mainly grass. Dormitator maculatus was more abundant in Summer and Autumn, M. brachyurus lineatus, in Spring, Autumn and Winter and Astyanax sp was absent in Spring only. Patterns in fish assemblage structure were at large scale, primarily species-specific responses to dominant environmental gradient, while at small scale, results of association with the habitat. / Os sistemas estuarinos influenciam as assembl?ias de peixes, ao longo de seus gradientes longitudinais e das marcadas varia??es da salinidade. Estas assembl?ias se adaptam ?s diferentes condicionantes do habitat e variam em escalas espaciais e temporais. O objetivo do presente estudo foi avaliar a composi??o e estrutura da ictiofauna em tr?s zonas do estu?rio do rio Mambucaba (ZC ? zona costeira; ZM ? zona de mistura e ZR ? zona de rio) e suas rela??es com as vari?veis ambientais e caracter?sticas do habitat destas zonas. Coletas sistem?ticas de peixes (2 meses por esta??o do ano) foram realizadas entre outubro de 2007 e agosto de 2008, com arrastos de fundo em dois locais da ZC (C1 e C2), arrasto de praia em 3 locais da ZM (M1, M2, M3) e peneira em 2 locais da ZR (R1 e R2). Em cada amostragem de peixes, foram tomadas, para a superf?cie e fundo, as vari?veis ambientais de temperatura, salinidade, condutividade, turbidez e oxig?nio dissolvido, bem como medida a profundidade. Um total de 14320 indiv?duos, constitu?dos por 111 esp?cies (ZR ? 18; ZM ? 50 e ZC - 66) foram coletados. Assembl?ias de peixes distintas foram identificadas para cada zona, indicadas pelo baixo n?mero de esp?cies comuns (14 - ZM e ZC; 8 - ZM e ZR; e 2 - ZC e ZR), e com apenas uma esp?cie abundante (> 1% do numero total de peixes na zona) comum em mais de uma zona (Eucinostomus argenteus na ZC e ZM). Tal padr?o pode estar relacionado ? maior variabilidade da salinidade existente na ZM e a estreita (20 m) largura do canal de conex?o com o mar, fatores que podem ser limitantes aos movimentos (entrada/sa?da) de peixes. Na ZC, as tr?s esp?cies mais abundantes foram Paralonchurus brasiliensis, Ctenosciaena gracillicirrhus, Anchoa lyolepis, Larimus breviceps e Stellifer brasiliensis, com a maior participa??o de peixes da fam?lia Sciaenidae nesta zona (18 esp?cies). As varia??es espaciais das esp?cies foram pouco consistentes na ZC, provavelmente relacionado a influencia da pluma estuarina n?o ter provocado mudan?as espa?o-temporais nas vari?veis ambientais de fundo (ANOVA, p>0,05). A profundidade foi o principal fator respons?vel pela separa??o espacial encontrada para Diapterus rhombeus (associa??es negativas) mais abundante em C1 (profundidade m?dia = 10 m; ANOVA, p<0,05) e Micropogonias furnieri, P. brasiliensis e Pellona harroweri (associa??es positivas) mais abundantes em C2 (profundidade m?dia = 17 m; ANOVA, p<0,00). Diapterus rhombeus e Etropus crossotus ocorreram principalmente na primavera e ver?o, e Eucinosomus gula na primavera. As esp?cies mais abundantes da ZC, t?picas de ?guas com maior influencia salina, ? um indicativo de que esta zona tem caracter?sticas mais associadas ? plataforma continental interna. Na ZM, a maioria das esp?cies mais abundantes (Eugerres brasilianus, Eucinostomus melanopterus, Trinectes paulistanus, Gobionellus shufeldti, G. oceanicus, Geophagus brasiliensis, Centropomus parallelus e Citharichthys arenaceus) apresentou maior n?mero e peso de indiv?duos em M1 (ANOVA, p<0,01), uma lagoa adjacente conectada ao canal principal. Apesar das correla??es negativas significativas observadas entre estas esp?cies e a salinidade (r-Spearman>0.32, p<0,01), as ?reas mais abrigadas em M1 parecem ser mais determinantes neste padr?o do que a salinidade em si. O local M1 tamb?m apresentou o maior n?mero de indiv?duos e de esp?cies (ANOVA, p<0,01), com maior n?mero de peixes de menor tamanho (CT mediana = 58mm) do que dos locais M2 e M3, situados no canal principal (mediana = 106mm) de acordo com o Teste das Medianas e Teste de Kruskallvii Wallis (p<0,01; 2 = 1167,5), indicando a import?ncia desta ?rea para o recrutamento das esp?cies. A baixa similaridade m?dia (SIMPER) para os locais M2 (38,7%) e M3 (17,8%) indicam uma maior variabilidade na assembl?ia destes locais, possivelmente devido a menor estrutura??o do habitat e maior dinamismo. Na ZR, a assembl?ia de peixes apresentou poucas esp?cies (5) com abund?ncia maior que 1% do n?mero total de peixes, sendo dominada por Dormitator maculatus, Astyanax sp e Microphis brachyurus lineatus, esp?cies t?picas de ?reas lim?trofes entre a zona superior do estu?rio e a zona baixa de rio. Varia??es espaciais foram detectadas apenas para D. maculatus, mais abundantes em R2, um local com abundante vegeta??o marginal composta principalmente por gram?neas. D. maculatus foi mais abundante no ver?o e outono, M. brachyurus lineatus, na primavera, outono e inverno e Astyanax sp foi ausente somente na primavera. Os padr?es na estrutura da assembl?ia de peixes s?o, em maior escala, primariamente resultado das respostas individuais das esp?cies ao gradiente ambiental dominante, enquanto em menor escala, resultado das associa??es com o habitat.

<p>Benthic diatoms are valuable tools for biological monitoring and paleo-ecological reconstruction of past environmental conditions. This thesis aims at describing size-related properties of benthic diatoms and suggests that data assessment for community analysis can be improved by considering the importance of scale. It investigates which environmental factors structure epilithic diatom communities on the coast of the Gulf of Bothnia and identifies environmental factors correlated with phytobenthic biomass. It also contributes to the floristic knowledge of the Baltic Sea. </p><p>Diatom species show large variation in size. The responses of large species (≥1000 μm3) in diatom communities to environmental factors are underestimated if solely measured as relative abundance, as is the common practice. However, relative abundance gives the best gradient resolution, as compared to surface area and biovolume, if species are counted separately in two biovolume classes. Small and large species in the same community may respond differently to the same environmental factors. </p><p>To assess the principal environmental factors structuring diatom communities in the Gulf of Bothnia, 270 quantitative samples were collected from submerged stones. Sampling was carried out in spring in four areas of the Bothnian Bay, characterized by a stable north-south salinity gradient (0.4-3.3 psu), and in three areas of the Bothnian Sea which has a rather uniform salinity of ca. 5 psu. Canonical correspondence analysis (CCA) identified salinity and exposure to wave action as the principal factors structuring the diatom communities of the Bothnian Bay, whereas exposure to wave action was the principal factor in the Bothnian Sea. Measurements of relative ignition loss suggested that the cover of macroalgae, and thereby the higher abundance of epiphytic diatoms in the epilithic samples, was positively correlated with salinity in the Bothnian Bay and with water movement in the Bothnian Sea. </p><p>Two new brackish water species are described, <i>Navicula sjoersii</i> S. Busse & Snoeijs and <i>N. bossvikensis</i> S. Busse & Snoeijs. The new species are compared with <i>N. perminuta</i> Grunow, a common brackish-water species.</p>

Benthic diatoms are valuable tools for biological monitoring and paleo-ecological reconstruction of past environmental conditions. This thesis aims at describing size-related properties of benthic diatoms and suggests that data assessment for community analysis can be improved by considering the importance of scale. It investigates which environmental factors structure epilithic diatom communities on the coast of the Gulf of Bothnia and identifies environmental factors correlated with phytobenthic biomass. It also contributes to the floristic knowledge of the Baltic Sea. Diatom species show large variation in size. The responses of large species (≥1000 μm3) in diatom communities to environmental factors are underestimated if solely measured as relative abundance, as is the common practice. However, relative abundance gives the best gradient resolution, as compared to surface area and biovolume, if species are counted separately in two biovolume classes. Small and large species in the same community may respond differently to the same environmental factors. To assess the principal environmental factors structuring diatom communities in the Gulf of Bothnia, 270 quantitative samples were collected from submerged stones. Sampling was carried out in spring in four areas of the Bothnian Bay, characterized by a stable north-south salinity gradient (0.4-3.3 psu), and in three areas of the Bothnian Sea which has a rather uniform salinity of ca. 5 psu. Canonical correspondence analysis (CCA) identified salinity and exposure to wave action as the principal factors structuring the diatom communities of the Bothnian Bay, whereas exposure to wave action was the principal factor in the Bothnian Sea. Measurements of relative ignition loss suggested that the cover of macroalgae, and thereby the higher abundance of epiphytic diatoms in the epilithic samples, was positively correlated with salinity in the Bothnian Bay and with water movement in the Bothnian Sea. Two new brackish water species are described, Navicula sjoersii S. Busse &amp; Snoeijs and N. bossvikensis S. Busse &amp; Snoeijs. The new species are compared with N. perminuta Grunow, a common brackish-water species.

Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós–Graduação em Oceanografia Biológica, Instituto de Oceanografia, 2011. / Submitted by Cristiane Gomides (cristiane_gomides@hotmail.com) on 2013-12-16T03:31:29Z No. of bitstreams: 1 Priscila Martins de Moura.pdf: 499869 bytes, checksum: 89e9bd15d4cf51cf14c19da5f5c8c309 (MD5) / Approved for entry into archive by Sabrina Andrade (sabrinabeatriz@ibest.com.br) on 2013-12-18T17:58:11Z (GMT) No. of bitstreams: 1 Priscila Martins de Moura.pdf: 499869 bytes, checksum: 89e9bd15d4cf51cf14c19da5f5c8c309 (MD5) / Made available in DSpace on 2013-12-18T17:58:11Z (GMT). No. of bitstreams: 1 Priscila Martins de Moura.pdf: 499869 bytes, checksum: 89e9bd15d4cf51cf14c19da5f5c8c309 (MD5) Previous issue date: 2011 / A presente dissertação é composta de um capítulo (em Português) sintetizando os principais resultados obtidos, os quais são apresentados na forma de um manuscrito (em inglês) no apêndice. O principal objetivo foi analisar o padrão de distribuição das assembléias de peixes e a influência de algumas variáveis ambientais na abundância relativa das espécies dominantes ao longo de um amplo eixo espacial (~300 km), englobando o estuário da Lagoa dos Patos, canal São Gonçalo e Lagoa Mirim. No total, sete locais foram amostrados mensalmente entre 03/2004 e 02/2005 com uma rede de arrasto em zonas rasas (< 2 m). Foram capturadas 63 espécies e 45.929 indivíduos. As análises de escalonamento multidimensional (MDS) evidenciaram a presença de dois grupos principais espacialmente distintos: um formado pelas amostras do estuário e outro formado pelo Canal São Gonçalo e Lagoa Mirim. Os peixes foram agrupados em guildas ecológicas e, através da análise de composição e abundância relativa, verificou-se uma marcada substituição dessas guildas entre a zona estuarina (estuário e norte do canal) e zona límnica (sul do canal e Lagoa Mirim). Essa substituição foi mais pronunciada em termos de abundância do que em termos de frequência de ocorrência, sendo que a segregação entre as guildas foi intensificada pela presença de uma barragem-eclusa, posicionada na porção mediana do gradiente. Variáveis físico-químicas (e.g., salinidade e transparência da água) e outras relacionadas às características estruturais dos habitats (e.g., declividade e percentual de silte e argila no sedimento) foram os principais fatores, dentre os investigados, que melhor explicaram a variabilidade na abundância e distribuição da ictiofauna ao longo do gradiente. / This dissertation is comprised of a chapter (in Portuguese) summarizing our main findings, which are shown in a manuscript (in English) in the annex. Our main goal was to analyze the distribution pattern of fish assemblages and the influence of some environmental variables on the relative abundance of dominant species along a broad spatial axes (~300 km), including the Patos Lagoon estuary, São Gonçalo channel and Mirim Lake. A total of seven sites were sampled monthly between 03/2004 and 02/2005 with a beach seine in shallow areas (<2 m). A total of 63 fish species and 45.929 individuals were caught. The multidimensional scaling (MDS) analyses revealed two main groups spatially distinct: one formed by the estuarine samples and other by freshwater samples from the channel and the Mirim. Fish species were grouped into ecological guilds and the analyses of their composition and relative abundance revealed a marked substitution of ecological guilds between the estuarine zone (estuary and northern portion of the channel) and the limnetic zone (southern portion of the channel and Mirim). This substitution was more pronounced in terms of abundance than in terms of frequency of occurrence. Guilds segregation was intensified by the presence of a dam lock positioned in the middle portion of the gradient. Physico-chemical variables (e.g., salinity and water transparency) and others related to the structural characteristics of habitats (e.g., slope and percentage of silt and clay in the sediment) were the main factors, among those investigated, that better explained the variability in the distribution and abundance of fish fauna along the gradient.