In this research, the adsorptive capacities of kenaf, peat moss, hay, and peanut hulls were evaluated for the removal of TNT and 2,4-DCP from aqueous solutions. Adsorbent loading capacities determined by batch studies were verified by continuous column experiments. It was found that the adsorption capacity of the candidate adsorbents were significantly lower than granular activated carbon (GAC). The impact of surface modification techniques, such as surface oxidation, were evaluated to study the effect on adsorption capacity. At lower equilibrium concentrations of the adsorbate (less than 10 ppb), surface oxidation by ozone showed an increase in the adsorption capacity. The same trend was not observed with peroxone and ultrasound pretreatment. The adsorbent requirement for treating water contaminated with TNT and 2,4-DCP were calculated based on the adsorptive capacity of the adsorbents. Though the adsorbent requirements for the candidate adsorbents were considerably higher than granular activated carbon, the adsorbent requirement costs for most of the candidate adsorbents tested were competitive when compared to GAC costs.

No description available.

No description available.

No description available.

In this research, the adsorptive capacities of kenaf in the forms of chopped whole stalk, chopped core, and bast materials were evaluated for the removal of lead, zinc, and toluene from contaminated synthetic waste streams using traditional adsorption isotherm techniques. The effect of surface oxidation using ozone was observed with respect to the adsorption of metals. Hydraulic conductivity experiments were conducted to evaluate the head loss associated with packing a column with kenaf fibers and to determine the suitability of its use in dynamic packed column systems. B.E.T. surface areas were determined as well. Under increasingly stringent regulatory requirements, even low level organic and inorganic contamination (under 100 ppm) in surface and ground waters must be treated. This study is part of an ongoing multi-year research effort aiming to develop a kenaf-based biosorptive process to improve treatment of contaminated aqueous streams at reduced costs and technical complexity.

Atualmente a Engenharia supera novas fronteiras, principalmente devido à redução das dimensões dos equipamentos, e um exemplo desses impactos é o atual estágio de desenvolvimento da nanotecnologia. Ademais, não só as questões ambientais inerentes à contaminação do meio físico como também seu monitoramento devem ser continuamente abordadas para garantir que o profissional possa atuar nessa nova condição. O objetivo deste trabalho foi determinar como um grupo de estruturas miniaturizadas pode ser usado na remoção de partículas de um meio líquido ou gasoso e a separação de componentes de uma mistura. Também objetivou-se desenvolver uma metodologia simples de testes voltada para o estudo do comportamento dos fluidos no interior de estruturas onde material particulado e pequenas dimensões dificultam a passagem deste fluido. A utilização de canais preenchidos com material particulado ocorre tanto na Engenharia Química, para produção de compostos, como na Química, para a análise de substâncias. Os testes utilizaram equipamentos comuns em laboratório de química, uma estrutura para produção de spray, duas estruturas impactadoras distintas para remoção de partículas, e duas estruturas, denominadas como canais tridimensionais e de separação preliminar, para separação de compostos orgânicos voláteis. As substâncias puras permitem avaliar o tempo de residência e compará-lo com as misturas. As estruturas apresentaram comportamento muito semelhante quando comparadas as filmagens com o auxílio de traçadores e as simulações usando FEMLABÒ. O conjunto proposto de estruturas permite produzir spray com gotas de até 10 mm e obter uma impressão digital de compostos orgânicos em uma mistura, pois os resultados permitem montar tabelas qualitativas e semi-quantitativas que descrevem vários fenômenos, tais como, difusão, separação de compostos, perda de carga, etc. Estas estruturas apresentaram uma série de vantagens, tais como, mesodimensionamento, que facilita sua produção e manuseio, e possibilidade de uso em demonstrações de como ocorrem os fenômenos internos à estrutura. / Nowadays, mainly due to products miniaturization, engineering faces new horizons, which can be easily exemplified by the enhancement on nanotechnology development. Furthermore, not only environmental contamination but also environmental monitoring must be addressed in order to produce a systemic knowledge. Therefore, the aim of this work was to determine how a group of miniaturized structures could be used on particle removal and component separation on a mixture. Also a secondary target was to develop a simple methodology in order to determine the fluid behavior inside the structures where particle material and small dimensions hinder flow passage. The use of packed channels is common not only in Chemical Engineering, on synthesis production, but also in Chemistry, for chemical analysis. Tests were carried out using equipment normally present in Chemistry to evaluate a set of structures composed by: one spray, two different impactors and other two different structures (one of them with five different outlets) for separation of volatile organic compounds. Tests were performed in liquid and gaseous phases and used several reactants (kerosene, gasoline, acetone, 2-propanol and ethanol) and their mixtures; pure reactants allow evaluation of the resident time and comparison with mixtures behavior. Simulations were also performed and the structure behavior evaluated by tracers shows good agreement with simulations data. The whole group of structures allows the production of spray with up to 10mm droplet dimension and the footprint of components in a mixture, i.e., the obtained data can be disposed as qualitative and quantitative tables, which describe several phenomena, such as diffusion, separation of compounds, load loss, etc. These structures present several advantages since dimensions on mesorange not only facilitate their production and manipulation bur also allow to unravel phenomena occurring inside the structures.

Regulações ambientais cada vez mais rigorosas em relação ao gerenciamento dos resíduos orgânicos estão impelindo a indústria para uma maior sustentabilidade no sentido de melhorar a relação beneficio/custo e também atender a demanda dos clientes. A valorização dos resíduos orgânicos é uma das áreas de investigação atuais que tem atraído grande atenção nos últimos anos como uma alternativa potencial à eliminação de uma vasta gama de resíduos em aterros sanitários. Os resíduos orgânicos como o lodo de esgoto têm sido encarados como um recurso com um potencial significativo para ser empregado como matéria-prima para a produção de vários tipos de produtos, materiais e combustíveis. Este estudo tem como objetivo fornecer subsídios sobre o potencial de uso de lodo de esgoto para produzir carvões ativados e novos materiais adsorventes misturando com diferentes materiais polissiloxanos para adsorção de poluentes orgânicos a partir de soluções aquosas. Os materiais adsorventes foram caracterizados por varias técnicas analíticas e funcionais e utilizados na adsorção de diclofenaco (DCF) , nimesulida (NM) e alguns compostos fenólicos a partir de soluções aquosas Esta tese visa contribuir em (i) comparar os métodos de pirólise (pirólise convencional e aquecimento assistido por micro-ondas) na preparação de carvões ativados a partir de lodo de esgoto. Para isso foi aplicado um planejamento experimental e metodologia de superfície de resposta no sentido de determinar quais as variáveis dos dois processos são as que influenciam na qualidade do carvão produzido; (ii) a combinação de lodo de esgoto com polissiloxanos para preparar adsorventes para adsorção de fármacos a partir de soluções aquosas por processos de adsorção. Os achados gerais desta tese mostraram (i) que ambos os métodos de pirólise produzem carvões ativados com elevadas porosidades e áreas superficiais; (ii) demonstrou-se também que lodo de esgoto pode ser um excelente precursor para a preparação de carvões ativados e que pode com sucesso ser combinado com outros precursores (como polissiloxanos) a fim de se obter novos materiais com diferentes funcionalidades e características; (iii) foi demonstrado que os carvões ativados, híbridos e materiais compósitos desenvolvidos durante o presente estudo são ótimos adsorventes, especialmente para a remoção de diclofenaco DCF e NM a partir de solução aquosa e; (iv) tanto por microondas ou por pirólise convencional, é possível desenvolver CAs de lodo de esgoto com alta eficiência para a remoção de compostos fenólicos em comparação com outros tipos de CAs relatados na literatura. Estes resultados indicam que o lodo de esgoto e polissiloxanos têm grande potencial como precursores para a preparação de materiais adsorventes para o tratamento de água poluída por compostos orgânicos. / Increasingly tighter regulations regarding organic waste are pushing the manufacturing industry toward higher sustainability to improve cost-effectiveness and meet customers’ demand. Organic waste valorisation is one of the current research areas that have attracted a great deal of attention over the past few years as a potential alternative to the disposal of a wide range of residues in landfill sites. Bio-waste like sewage sludge emerged as a resource with a significant potential to be employed as a raw material for the production of chemicals, materials and fuels given its abundant volumes generated globally. This study aims at providing insights into the potential of the use of the sewage sludge to produce activated carbons (ACs) and novel adsorbent materials mixing with different polysiloxanes materials for adsorption of organic pollutants from aqueous solutions. The characterization of adsorbents were achieved by several analytical and functional techniques and used for adsorption of diclofenac (DCF) and nimesulide (NM) from aqueous solutions. The novelties of the present study are (i) to compare both pyrolysis methods (conventional pyrolysis and microwave assisted heating) for preparation of activated carbons from sewage sludge for that It was applied an experimental design and response surface methodology were used for the preparation and comparison of activated carbon produced by both methods, conventional furnace and microwave; (ii) the combination of sewage sludge with polysiloxanes to prepare adsorbents to uptake pharmaceuticals and phenolic compounds from aqueous solutions by adsorption processes. The general findings of this thesis showed (i) that both methods of pyrolysis produce very good activated carbons from sewage sludge with high specific surface areas and high developed porosities; (ii) It was also shown that the sewage sludge can be an excellent precursor to prepare activated carbons and novels materials by mixing it with other precursors such polysiloxanes; (iii) It was shown that the activated carbons, hybrids and composites materials developed during the present study are good adsorbents, especially for the removal of a model diclofenac (DCF) and nimesulide (NM) from aqueous solution and; (iv) that by microwave and conventional pyrolysis it is possible to develop sludge-ACs with very high efficiency for phenolic compounds compared with others kind of ACs reported in literature. These results indicate that sewage sludge and polysiloxanes have great potential as precursors for preparation of adsorbent materials for water treatment polluted by organic pollutants compounds.

Atualmente a Engenharia supera novas fronteiras, principalmente devido à redução das dimensões dos equipamentos, e um exemplo desses impactos é o atual estágio de desenvolvimento da nanotecnologia. Ademais, não só as questões ambientais inerentes à contaminação do meio físico como também seu monitoramento devem ser continuamente abordadas para garantir que o profissional possa atuar nessa nova condição. O objetivo deste trabalho foi determinar como um grupo de estruturas miniaturizadas pode ser usado na remoção de partículas de um meio líquido ou gasoso e a separação de componentes de uma mistura. Também objetivou-se desenvolver uma metodologia simples de testes voltada para o estudo do comportamento dos fluidos no interior de estruturas onde material particulado e pequenas dimensões dificultam a passagem deste fluido. A utilização de canais preenchidos com material particulado ocorre tanto na Engenharia Química, para produção de compostos, como na Química, para a análise de substâncias. Os testes utilizaram equipamentos comuns em laboratório de química, uma estrutura para produção de spray, duas estruturas impactadoras distintas para remoção de partículas, e duas estruturas, denominadas como canais tridimensionais e de separação preliminar, para separação de compostos orgânicos voláteis. As substâncias puras permitem avaliar o tempo de residência e compará-lo com as misturas. As estruturas apresentaram comportamento muito semelhante quando comparadas as filmagens com o auxílio de traçadores e as simulações usando FEMLABÒ. O conjunto proposto de estruturas permite produzir spray com gotas de até 10 mm e obter uma impressão digital de compostos orgânicos em uma mistura, pois os resultados permitem montar tabelas qualitativas e semi-quantitativas que descrevem vários fenômenos, tais como, difusão, separação de compostos, perda de carga, etc. Estas estruturas apresentaram uma série de vantagens, tais como, mesodimensionamento, que facilita sua produção e manuseio, e possibilidade de uso em demonstrações de como ocorrem os fenômenos internos à estrutura. / Nowadays, mainly due to products miniaturization, engineering faces new horizons, which can be easily exemplified by the enhancement on nanotechnology development. Furthermore, not only environmental contamination but also environmental monitoring must be addressed in order to produce a systemic knowledge. Therefore, the aim of this work was to determine how a group of miniaturized structures could be used on particle removal and component separation on a mixture. Also a secondary target was to develop a simple methodology in order to determine the fluid behavior inside the structures where particle material and small dimensions hinder flow passage. The use of packed channels is common not only in Chemical Engineering, on synthesis production, but also in Chemistry, for chemical analysis. Tests were carried out using equipment normally present in Chemistry to evaluate a set of structures composed by: one spray, two different impactors and other two different structures (one of them with five different outlets) for separation of volatile organic compounds. Tests were performed in liquid and gaseous phases and used several reactants (kerosene, gasoline, acetone, 2-propanol and ethanol) and their mixtures; pure reactants allow evaluation of the resident time and comparison with mixtures behavior. Simulations were also performed and the structure behavior evaluated by tracers shows good agreement with simulations data. The whole group of structures allows the production of spray with up to 10mm droplet dimension and the footprint of components in a mixture, i.e., the obtained data can be disposed as qualitative and quantitative tables, which describe several phenomena, such as diffusion, separation of compounds, load loss, etc. These structures present several advantages since dimensions on mesorange not only facilitate their production and manipulation bur also allow to unravel phenomena occurring inside the structures.

Equipamentos de plasma são muito utilizados para polimerização de filmes finos, orgânicos e inorgânicos. Filmes finos têm uma vasta gama de aplicações no desenvolvimento de dispositivos MEMS (MicroElectroMechanical Systems), tais como sensores, detectores, pré-concentradores, etc. Portanto, neste trabalho é apresentado um equipamento de polimerização por plasma com características distintas, o que permite seu uso para obtenção de novos filmes finos e/ou compósitos em uma única etapa de fabricação. Os filmes obtidos são formados por partes orgânicas distintas, ou mesmo por regiões adsorventes ou repelentes. Alguns filmes possuem partículas orgânicas em mistura com o filme fino, o que facilita o controle da rugosidade e da área superficial, permitindo seu uso em sistemas de retenção. O projeto do reator permite deposições por plasma introduzindo, simultaneamente e sem interrupção do processo, reagentes incompatíveis em plasma ou mesmo a formação seqüencial de camadas, sem a necessidade de abertura do reator entre as etapas do processo (etapa única). O projeto da câmara de plasma foi simulado usando FEMLAB 3.2® e caracterizado utilizando traçadores. Simularam-se fluxo de gás e partículas além de campo elétrico e magnético. As simulações e resultados experimentais mostraram boa coerência. O fluxo permaneceu sem grande vorticidade em toda a faixa de trabalho e o campo magnético foi adequado para o confinamento do plasma. Foram depositados filmes úteis para desenvolvimento de sensores e adsorventes, resistentes a corrosão ou compósitos. Foram polimerizados por plasma: hexametildisilazana (HMDS) com produção de filme hidrofóbico e adsorvente; metil-nonafluoro(iso)butil-éter (HFE 7100®), obtendo-se filmes com características adsorventes, mas oleofóbicos e medianamente hidrofílicos e 2,3-dihidrodecafluoropentano (Vertrel®) com formação de filmes com boa resistência à corrosão além de facilidade de adsorção. Partículas de amido foram recobertas com filme a base de HMDS e de HFE 7100 e mostraram boas propriedades para retenção de moléculas orgânicas de tamanho médio. Neste equipamento, filmes à base de HMDS mostraram-se úteis para retenção de compostos orgânicos, em fase líquida ou gasosa. Espectroscopia de infravermelho, da produção simultânea de filme a base de HMDS e de Vertrel, mostrou espécies de flúor e silício e eventualmente CO, porém CHn é a espécie em menor intensidade. Microscopia óptica dos filmes revela boa aderência em metais e acrílico e, para os fluorados, resistência a solventes orgânicos e à exposição a solução aquosa ácida ou básica. Intermixing e dupla camada só são obtidas em condições muito estreitas, entretanto, existe a possibilidade de formação de ilhas. Microbalança de quartzo mostrou que 2-propanol permeia no filme formado por intermixing de HFE7100 e HMDS, porém não existe nenhuma sensibilidade a n-hexano. Um microreator fabricado, com microcanais de 73 cm de comprimento, pôde reter aproximadamente 9.10-4 g/cm2 de 2-propanol em fase gasosa, usando-se o filme obtido por intermixing. Portanto, o filme é um bom candidato a preconcentração de compostos orgânicos voláteis em ambiente corrosivo. Uma microestrutura produzida com as partículas de amido recobertas foi proposta para avaliar em fluxo contínuo a contaminação de soluções aquosas. Foi possível determinar a contaminação na proporção de 1:200 em vol. de 2-propanol, com saturação em 25% em vol. / Plasma equipment is quite useful for polymerization of organic/inorganic thin films. Thin films have a vast range of applications as sensor, detectors, preconcentrators and so on. In this work plasma polymerization equipment is presented with innovative characteristics that it should allow the obtaining of new fine films and composites. These films can be formed not only with different organic parts but also with areas adsorbents and repellents. Some films will present particles, ceramic or metallic, in mixture with the organic thin film, which will facilitate the control of the roughness and of the superficial area, allowing its use in retention systems. The design of the reactor allows plasma depositions introducing more than one reactant simultaneously and without process interruption, or even sequential formation of layers, without the need of chamber opening among process steps, i. e., in a single step. It was simulated and characterized parts of the equipment, such as: gas flow and particles admission; electric and magnetic fields profiles. Therefore, a new plasma chamber with atypical geometry was simulated and projected and manufactured to obtain multiple layers and/or composites. The simulation and experimental results showed good coherence. The gas flow stayed without great vorticity in the all range of the work and the magnetic field was adequate for plasma confinement. As the main objective of this work is the production and characterization of news materials, thin films were deposited with purpose of being adsorbent; corrosion resistant; and composite, all useful for development of sensor. It was plasma polymerized: hexamethyldisilazane (HMDS), a well known organic silicon compound, methyl nonafluoro (iso) butyl ether: should have good resistance to the corrosion besides easiness of adsorption; and 2,3-dihydrodecafluoropentane: adsorbent, hydrophobic and oleophobic. Particles (starch 5mm), were recovered with HMDS and HFE 7100 and showed good properties for retention of medium size organic molecules, such as dye. The results were useful for retention of organic compounds, in liquid or gaseous phase. Not only, HMDS is possible in any configuration of electrodes and the obtained films are hydrophobic but also, fluorinated compounds polymerized, however, intermixing and couple layer is only obtained in very narrow conditions, but the possibility of formation of islands exists. The chemical characterization was determined for infrared spectroscopy, it showed species composed by fluorocompounds, and eventually CO, however CHn is the smallest species. The hydrophobic character, organophylic and oleophobic were obtained through contact angle measurements. Optical Microscopy not only reveals good adherence in metals and acrylic but also resistance to organic solvents, acid and exhibition of basic aqueous solution. A manufactured micro-reactor, with micro channels of 73 cm of length, can keep approximately 9.10-4 g/cm2 of 2-propanol in gaseous phase. Therefore, the film is a good candidate in organic preconcentration of volatile organic compounds even on corrosive environment.

Nanoporous materials for gas purification and thermal insulation have been studied and developed for application in many areas. It is known that a single adsorbent may not adequately control multiple contaminants. Further the utilization of nanoporous material as thermal insulator in building applications is limited due to high cost. Moreover, in view of the global environmental movement for clean air and reduction of heating energy consumption in built environment, the development of new and better nanoporous materials will not only facilitate major advances in gas adsorption and thermal insulation technology, but also meet the new challenges that cannot be met with the nanoporous materials that are currently available. This thesis presents a synthesis of new nanoporous silica based materials, and the characterization and application of these materials for molecular filtration and thermal insulation. Commercial nanoporous materials have been used for benchmarking for the pore properties, the applicability, and the performance of these new materials. First a double metal-silica adsorbent has been synthesized. The preparation procedure is based on the use of sodium silicate coagulated with various ratios of magnesium and calcium salts which yields micro-meso porous structures in the resulting material. The results show that molar ratios of Mg/Ca influence the pore parameters as well as the structure and morphology. The bimodal pore size can be tailored by controlling the Mg/Ca ratio. In the second synthesis, pure mesoporous silica, SNP has been prepared using glycerol as pore forming agent and monovalent salts as coagulant. This leads to material with large surface area and uniformed pore size centred at 43 or 47 nm.  The materials further exhibits a low bulk density in the range of 0.077 to 0.122 g/ml and possess a high porosity in the range of 95-97%. The influence of acid type (organic or inorganic) on the pore parameters and on the tapped density has also been investigated.   A synthesis method has also been developed for the preparation of carbon-silica composites. The method involves a number of routes, which can be summarised as addition of activated carbon particles to (I) the paste, (II) the salt solution, or (III) with the sodium silicate solution. In route II and III the activated carbon is present before coagulation. The routes presented here leads to carbon-silica composites possessing high micro porosity, meso porosity as well as large surface areas. The results further shows that pore size distribution may be tailored based on the route of addition of the carbon particles. Following route I and III a wide pore size (1-30 nm) was obtained whereas by route II a narrow pore size (1-4 nm) was observed.     MgCa-silica chemisorbents were also developed using either potassium hydroxide or potassium permanganate as impregnate chemicals. A direct or post-impregnation procedure was employed. The results revealed that the impregnate route and amount cause a reduction in both specific surface area and pore volume. Finally the thermal conductivity and dynamic adsorption of H2S, SO2 andtoluene were measured. Results show that at room temperature and atmospheric pressure, a thermal conductivity of 28.4 and 29.6 mW/m.K were obtained for the SNP mesoporous silicas. The dynamic adsorption behaviour of the chemisorbents and composites indicate their ability to absorbed H2S, SO2 andtoluene respectively. The highest H2S uptake corresponds to chemisorbents with 11.2-13.6 wt% KMnO4. The effect of impregnation route, amount of KMnO4 and its location in the pore system are likely the key factors in achieving a large H2S uptake. For SO2 adsorption, the highest uptake capacity was observed for MgCa-68/32-KOH. The results further suggest that the key to large SO2 uptake is as a result of the synergetic effect between large mesopore diameter and extensive mesopore volumes. Carbon-silica composites with carbon content 45 wt % exhibits high toluene adsorption with composite via route I having the highest toluene adsorption capacity (27.6 wt % relative to carbon content). The large uptake capacity of this composite was attributed to the presence of high microporosity volume and a wide (1-30 nm) bimodal pore system consisting of extensive mesopore channels (2-30 nm) as well as large surface area. These capacity values of carbon-silica composites are competitive to results obtained for commercial coconut based carbon (31 wt %), and better than commercial alumina-carbon composite (9.5 wt %). / <p>QC 20130408</p>