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This dissertation delves into the theory, design and fabrication, and practical uses of synthetic trees that replicate the transpiration mechanisms of natural trees. The first chapter provides an in-depth explanation of how natural trees utilize hydraulic mechanisms to draw water from the soil, through their roots, and up to their leaves, sustaining hydration through transpiration. This process is reliant on the difference in relative humidity between the leaf and the ambient to promote evaporation, and synthetic trees replicate this cycle by integrating reservoirs and conduits with wetted nanopores, mimicking the negative Laplace pressure seen in natural trees. Chapter 2 presents a detailed theoretical framework for transpiration in synthetic trees. These trees feature a vertical array of tubes connected to a nanoporous synthetic leaf. Our model considers the impact of convective gas flow on the leaf, minimizing the diffusive boundary layer and directly influencing the leaf's negative Laplace pressure. We next analyze how the rate of evaporation and tree morphology affect the required Laplace pressure for mass conservation, in an ambient environment with an appreciable diffusive boundary layer. Our model considers the changing dynamics of the menisci, including their capability to adjust their contact angle and withdraw into nanopores to self-stabilize. We then determine conditions where transpiration is limited by evaporation or constrained by the leaf's maximum Laplace pressure, across various tree geometries and ambient conditions. In Chapter 3, the focus shifts to a practical application, as the insights from the previous chapters guide the creation of a synthetic tree for water harvesting. Solar steam generation employing a porous evaporator, with a 3D design extending beyond the free surface to mitigate heat losses, is used to demonstrate how transpiration, rather than capillarity, can raise water up glass tubes, and improve liquid transport heights over conventional methods. Chapter 4 expands on the synthetic tree concept, proposing a mobile desalination water container driven by transpiration. The container features a ring-shaped fin designed to absorb solar heat, increasing water evaporation from a nanoporous synthetic leaf. This approach combines reverse osmosis and thermal evaporation, offering a promising solution for obtaining fresh water from seawater. In Chapter 5, the study explores transpiration-powered oil-water filtration using synthetic trees. Our approach showcases the potential for natural separation of oil and water in various applications, without the need for a pump and in opposition to gravity. Chapter 6 modifies the synthetic tree design to selectively absorb and retain oil from oil-water emulsions. When water evaporates from the synthetic leaf, enabled by the generated negative suction within, oil is then drawn and contained within the system through oleophilic and hydrophobic membranes. This approach offers a sustainable method for oil spill clean-up, oil extraction and purification. Chapter 7 experimentally investigates how to eliminate the capillary driving force in synthetic trees. By over-filling the synthetic leaf's top surface to remove existing concave menisci, the study hypothesizes gravity as a replacement mechanism for negative pressure, with the water in hydrostatic columns held in tension by the overlying water supported within the porous leaf. In summary, these engineered hydraulic systems offer novel approaches to water harvesting, desalination, oil-water filtration, and the cleanup of oil spills, and the study of synthetic trees opens up a realm of possibilities for sustainable water management and environmental remediation, showcasing the potential of biomimicry in solving pressing global challenges. / Doctor of Philosophy / This dissertation explores the concept of synthetic trees designed to mimic the transpiration cycle of natural trees for various applications. The first chapter provides a detailed explanation on how this is achieved. The second chapter introduces the theoretical model, highlighting the interplay between suction pressure, spontaneous flow, and tree geometry in surface tension powered water flow. In Chapter 3, the findings inform the design of a synthetic tree for water harvesting through solar steam generation. Overcoming constraints of floating evaporators, this tree demonstrates enhanced water condensation compared to traditional reservoirs, and the use of transpiration in the tubes allow for greater height flexibility. Chapter 4 presents a theoretical design for a portable desalinating water bottle powered by transpiration. Inspired by mangrove trees, the bottle utilizes solar heat absorption, a nanoporous synthetic leaf, and reverse osmosis to spontaneously enable desalination. The hybrid approach enhances thermal evaporation and pre-filters salt, potentially producing a daily extraction of one liter of fresh water from seawater. Chapter 5 explores oil-water filtration using surface tension power in synthetic trees. Operating without pumps and against gravity, this spontaneous phase separation demonstrates potential applications in oil spill cleanup, wastewater purification, and oil extraction. In Chapter 6, the synthetic tree is further modified to selectively take up and contain only oil from an oil-water emulsion. Driven by the surface tension mechanism, oil enters the tree through oil loving and water membranes, yielding high-purity oil samples, and offering innovative solutions for various environmental and industrial challenges. Chapter 7 investigates how to stop capillary forces in synthetic trees. When water evaporates from the leaves, it creates suction, pulling water from the soil through the xylem to keep the tree hydrated. We filled the top of the synthetic leaf to remove the curved surfaces that cause capillary tension. Surprisingly, water in the vertical tubes still held against gravity. This led us to consider a new idea: gravity might be replacing surface tension, with columns of water in the tree held in tension by the water above them in the leaf. Overall, this research on synthetic trees suggests exciting new ways to address environmental issues and manage water resources sustainably, underlying the power of nature-inspired solutions.

<div> Here, the quartz crystal microbalance with dissipation monitoring (QCM-D) is employed to explore the interaction of the various free oxidant species with condensed PA model membranes in order to improve our understanding of how the interaction with these species affects rates of membrane chlorination and alter membrane structure. Molecular-scale mass uptake and changes in the dissipative nature of the of the model membranes as measured by the QCM is correlated to performance changes in interfacially polymerized PA reverse osmosis (RO) membranes. Leveraging newly gained insights from these measured interactions, new strategies are explored to improve flux and chlorine resistance using novel membrane structure and chemistry.<br></div>

Synthetic musk compounds (MUSK) or synthetic fragrances are organic substances commonly used as fragrant constituents of perfumes, detergents, cosmetics and personal care products. These compounds are discharged after use via domestic wastewater and sewage treatment plants to the aquatic environment. The result is accumulation in the environment and occurrence in a food chain especially of aquatic and marine ecosystems. Synthetic musk compounds are also found in surface water, fish tissues and also in body fluid (blood, urine, milk) and tissues of human body. Quantitative detection and studying properties of these compounds is an important activity because we have low knowledge about their fate in the environment (persistence, bioaccumulation) and toxicity. This diploma thesis is focused on three commonly used synthetic fragrances – tonalide, musk ketone and musk xylene. The base of this study was to perform a method optimisation for the determination of selected compounds in water and water biota (fish). The aim was determination of selected musk compounds in real samples (water, fish) and evaluation of the results. Pressurized solvent extraction (PSE) for fish samples and solid phase microextraction (SPME) for water samples were used for isolation of analytes from samples. The identification and quantification of analytes was carried out by high resolution gas chromatography – mass spectrometry.

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Orientador: Maria Regina Wolf Maciel / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-07T04:13:19Z (GMT). No. of bitstreams: 1 Afonso_AdilsonPires_D.pdf: 2963967 bytes, checksum: 74c2f52074d8664fff323f72dc8f5730 (MD5) Previous issue date: 2005 / Resumo: O processo de separação de misturas homogêneas e não ideais é um problema comum nas indústrias. A separação de misturas complexas pode ser realizada a baixa pressão, para evitar a degradação de componentes sensíveis ou ainda, com a utilização de destilação com reação química para eliminar azeótropos e/ou aumentar a volatilidade relativa dos componentes a serem separados. A destilação reativa é uma técnica utilizada há muitos anos na indústria, porém, somente, recentemente, é que a modelagem matemática do problema permitiu que se desenvolvessem algorítmos para calcular e simular o processo de destilação onde ocorre simultaneamente o equilíbrio líquido-vapor- e o equilíbrio químico. Neste contexto, a destilação reat!va é uma das aplicações industriais mais efetivas para separar misturas complexas, uma vez que é baseada no conceito de reatores multifuncionais, isto é, na combinação de reações químicas com a destilação fracionada em um mesmo equipamento. Neste trabalho de tese, foram estudados os processos de destilação a baixas pressões para separar mono e diglicerídeos de glicerol, ácidos graxos e água, e o de destilação reativa para eliminar o fenol da mistura azeotrópica com água. Neste último, o reagente utilizado foi o anidrido acético com a formação de ácido acético e acetato de fenila. O esquema proposto demonstrou ser uma eficiente alternativa para a descontam inação de águas residuais. O simulador de processo HysysPlant@ foi utilizado para simular as destilações em estado estacionário e os resultados obtidos são inéditos na literatura publicada, contribuindo, portanto, com os desenvolvimentos na área de separação de misturas complexas. Para permitir a simulação da destilação reativa para separação do azeótropo água- fenol com anidrido acéticoé necessário se ter a cinética da reação. Como não existem na literatura dados experimentais deste sistema, neste trabalho foram apresentados alguns métodos para permitir a estimativa da cinética. Além disso, uma análise das misturas azeotrópicas formadas foi também realizada, para permitir a caracterização termodinâmica do sistema e, com isto, propor a separação física dos vários componentes. Este trabalho foi desenvolvido no I:aboratório de Desenvolvimento de Processos de Separação /DPQ/FEQ/UNICAMP / Abstract: The separation process of homogeneous and non ideal mixtures is a common problem in chemical industries. The complex mixture separations may happen at low pressure to prevent thermal degradation or using reactive distillation to eliminate existing azeotropes and/or in order to increase the rei ative volatility of the components to be separated. Reactive distillation has been used in industrial applications for many years ago, but only recently, with the availability of mathematical models, it is possible to develop algorithms in order to calculate and to simulate the distillation process where the vapor-liquid and the chemical equilibria occur simultaneously. So, in this way, reactive distillation is one. of the most effective industrial applications in order to separate complex mixtures, since it is based on the concept of multifunction reactors or, in other words, on the combination of chemical reactors with fractionating distillation in a single equipment. In this work, two important processes were studied. The first one was the separation of mono and diglycerides from glycerol, fatty acids and water using low pressure distillation. The second one was the proposition of a new reaction scheme to carry out the separation of the diluted system composed by phenol and water, using acetic anhydride as reactant forming acetic acid and phenyl acetate as product. The scheme seems to be a simple and efficient alternative to the decontamination of wastewaters. It was necessary, also, to develop methodologies to calculate the reaction kinetic and characterization of the mixtures being studied in the second case. Computational steady state simulations were performed using Hysys.Plant@ commercial simulator. The results obtained are inedit in the published literature, contributing, so, with the developments in co.mplex mixture separations. This work was developed in the Separation Process Development Laboratory, at the School of Chemical Engineering, at UNICAMP / Doutorado / Desenvolvimento de Processos Químicos / Doutor em Engenharia Química

This diploma thesis is divided into two parts, the theoretical and practical part. The theoretical part is to study of factors influencing the workability and bleeding of concrete. There is mentioned the production of cement and standard requirement. The task of the practical part is to assess the cements produced by the cement works Hranice and Prachovice. These cements test in terms of water separation. In combination with these cements use superplasticizing admixtures from Mapei and Stachema and determine the impact of water separation on cement pastes. Determine rheology on the cement pastes. Define influence of variations in cement composition affect the stability of cement mixtures.

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