No description available.

No description available.

In this research project, adsorption is considered in conjunction with the reverse water gas shift reaction in order to convert CO2 to CO for synthetic fuel production. If the CO2 for this process can be captured from high emitting industries it can be a very good alternative for reduced fossil fuel consumption and GHG emission mitigation. CO as an active gas could be used in Fischer-Tropsch process to produce conventional fuels. Literature review and process simulation were carried out in order to determine the best operating conditions for reverse water gas shift (RWGS) reaction. Increasing CO2 conversion to CO requires CO2/CO separation downstream of the reactor and recycling unreacted CO2 and H2 back into the reactor. Adsorption as a viable and cost effective process for gas separation was chosen for the CO2/CO separation. This was started by a series of adsorbent screening experiments to select the best adsorbent for the application. Screening study was performed by comparing pure gas isotherms for CO2 and CO at different temperatures and pressures. Then experimental isotherm data were modeled by the Temperature-Dependent Toth isotherm model which provided satisfactory fits for these isotherms. Henry law’s constant, isosteric heat of adsorption and binary mixture prediction were determined as well as selectivity for each adsorbent. Finally, the expected working capacity was calculated in order to find the best candidate in terms of adsorption and desorption. Zeolite NaY was selected as the best candidate for CO2/CO separation in adsorption process for this project. In the last step breakthrough experiments were performed to evaluate operating condition and adsorption capacity for real multi component mixture of CO2, CO, H2 in both cases of saturated with water and dry gas basis. In multi components experiments zeolite NaY has shown very good performance to separate CO2/CO at low adsorption pressure and ambient temperature. Also desorption experiment was carried out in order to evaluate the working capacity of the adsorbent for using in industrial scale and eventually temperature swing adsorption (TSA) process worked very well for the regeneration step. Integrated adsorption system downstream of RWGS reactor can enhance the conversion of CO2 to CO in this process significantly resulting to provide synthetic gas for synthetic fuel production as well as GHG emission mitigation.

In this research project, adsorption is considered in conjunction with the reverse water gas shift reaction in order to convert CO2 to CO for synthetic fuel production. If the CO2 for this process can be captured from high emitting industries it can be a very good alternative for reduced fossil fuel consumption and GHG emission mitigation. CO as an active gas could be used in Fischer-Tropsch process to produce conventional fuels. Literature review and process simulation were carried out in order to determine the best operating conditions for reverse water gas shift (RWGS) reaction. Increasing CO2 conversion to CO requires CO2/CO separation downstream of the reactor and recycling unreacted CO2 and H2 back into the reactor. Adsorption as a viable and cost effective process for gas separation was chosen for the CO2/CO separation. This was started by a series of adsorbent screening experiments to select the best adsorbent for the application. Screening study was performed by comparing pure gas isotherms for CO2 and CO at different temperatures and pressures. Then experimental isotherm data were modeled by the Temperature-Dependent Toth isotherm model which provided satisfactory fits for these isotherms. Henry law’s constant, isosteric heat of adsorption and binary mixture prediction were determined as well as selectivity for each adsorbent. Finally, the expected working capacity was calculated in order to find the best candidate in terms of adsorption and desorption. Zeolite NaY was selected as the best candidate for CO2/CO separation in adsorption process for this project. In the last step breakthrough experiments were performed to evaluate operating condition and adsorption capacity for real multi component mixture of CO2, CO, H2 in both cases of saturated with water and dry gas basis. In multi components experiments zeolite NaY has shown very good performance to separate CO2/CO at low adsorption pressure and ambient temperature. Also desorption experiment was carried out in order to evaluate the working capacity of the adsorbent for using in industrial scale and eventually temperature swing adsorption (TSA) process worked very well for the regeneration step. Integrated adsorption system downstream of RWGS reactor can enhance the conversion of CO2 to CO in this process significantly resulting to provide synthetic gas for synthetic fuel production as well as GHG emission mitigation.

nÃo hà / Os altos nÃveis de emissÃo de CO2 neste Ãltimo sÃculo tÃm gerado alerta e preocupaÃÃo Ãs autoridades a nÃvel mundial. Incentivos para desenvolver tecnologias de captura e armazenamento de CO2 ganham destaque nesse cenÃrio. Dentre as alternativas viÃveis para captura do referido gÃs està o processo de adsorÃÃo. A literatura à vasta nos estudos experimentais de adsorÃÃo de CO2 em diversos materiais impregnados, entretanto poucos trabalhos se dedicam ao entendimento dos fenÃmenos em nÃvel atÃmico. O presente estudo objetiva investigar a adsorÃÃo de CO2 em faujasitas do tipo X e carbonos ativados impregnados com monoetanolamina (MEA), mediante o uso de simulaÃÃo molecular. Para isso, modelos de MEA, CO2, faujasita e carbono ativado foram elaborados. Para a faujasita, construiu-se a estrutura com base nos dados cristalogrÃficos reportados na literatura. No carbono ativado, os poros foram representados pelo modelo de placas paralelas de grafeno e realizou-se o estudo em trÃs tamanhos caracterÃsticos (8,9, 18,5, 30,9 Ã) de modo a representar distintas regiÃes de adsorÃÃo e tambÃm permitir correlacionar dados com o carvÃo comercial WV-1050. A molÃcula de CO2 foi construÃda com os modelos de 3 centros (ensaios em faujasitas) e de 1 centro (ensaios em carbonos ativados). Os adsorventes foram carregados com quantidades crescentes de MEA e o impacto desta adiÃÃo foi avaliado atravÃs do levantamento de novas isotermas de CO2 utilizando-se o mÃtodo de Monte Carlo no ensemble Grande CanÃnico (GCMC). Com o modelo proposto faujasita/MEA/CO2, foi possÃvel reproduzir a tendÃncia experimental de reduÃÃo de adsorÃÃo de CO2 com aumento da concentraÃÃo de MEA, em concordÃncia com resultados experimentais apresentados na literatura. Em carbonos ativados, observou-se que os valores de CO2 adsorvidos a alta pressÃo (acima de 4 bar) sempre decaÃam com o carregamento de MEA para ambos os poros, como foi evidenciado experimentalmente em carbonos reais. No entanto, a simulaÃÃo revelou que as quantidades adsorvidas a baixa pressÃo (abaixo de 1 bar) sÃo maiores quando se adiciona monoetanolamina ao material carbonoso. Os resultados, com base nas tÃcnicas aplicadas nesse estudo, indicam que os sistemas NaX e carbono ativado modificados com MEA sÃo pouco viÃveis para captura de CO2 no que diz respeito ao critÃrio isolado de capacidade de adsorÃÃo / The high levels of CO2 emissions over the last century have generated concern and alert worldwide. Incentives to promote technologies for CO2 capture and storage are highlighted in this situation. Among the viable alternatives to capture that gas is the adsorption process. The literature contains many experimental studies of CO2 adsorption in various impregnated materials, despite that, few papers are devoted to the understanding of such phenomena at the atomic level. This study investigates the CO2 adsorption in X-faujasites and activated carbons impregnated with monoethanolamine (MEA) using molecular simulation. Thus, models of MEA, CO2, faujasite and activated carbon were proposed. For faujasite, the structure was modeled based on the crystallographic data reported in the literature. For activated carbon, the pores were represented by the slit pores model of graphene and the study was conducted in three pore sizes (8.9, 18.5, 30.9 Ã) to represent different regions of the adsorption and also allow for data correlation with the commercial activated carbon WV-1050. The CO2 molecule was modeled in the three-centers (faujasites tests) and one-center (carbons tests) models. The adsorbents were loaded with increasing amounts of monoethanolamine and the impact of this addition was evaluated through a set of simulated CO2 isotherms using the Grand Canonical Monte Carlo (GCMC) method. With the model faujasite/MEA/CO2, it was possible to reproduce the decreasing experimental CO2 adsorption with increased MEA concentration. In carbons, it was observed that the values of adsorbed CO2 at high pressure (above 4 bar) always decrease with MEA increasing loadings for both pores, as verified experimentally in real carbons. However, the simulation has shown that the amount adsorbed at low pressures (below 1 bar) is enhanced with monoethanolamine concentration in carbonaceous material. These results, considering the techniques used in this study, indicate that the activated carbon and NaX systems modified with monoethanolamine are unfeasible for capturing CO2 if adsorption capacity is the only criterion to take into account

CO2 adsorption is considered as a promising strategy to decrease the amount of CO2 in the atmosphere and stop global warming. The goal of this project is to prepare a cellulose-based CO2 adsorbent with a good mass transfer. Monolithic adsorbent based on cellulose nanofibrils (CNF) was fabricated via freeze-casting. 0.1g or 0.5g cellulose acetate (CA) or 0.1g acetylated CNC (aCNC) was dipped into the crosslinked aerogel to increase its CO2 capacity. Acetylation of CNC was confirmed by Fourier transformed infrared spectroscopy (FT-IR) and the degree of substitution was determined to be 1.6 through titration. Scanning electron microscopy (SEM) images showed that monolithic structure was formed through freeze-casting and the structure was maintained after dipping. Compression test suggested that the mechanical properties of the aerogel increased with the increasing amount of dipped CA, while the CO2 capacity of the adsorbent decreased. Furthermore, the outstanding reinforcing effect of aCNC was noticed in the compression test, and the aerogel dipped with aCNC has the highest CO2 capacity with a value of 1.49 mmol/g.

In this research project, adsorption is considered in conjunction with the reverse water gas shift reaction in order to convert CO2 to CO for synthetic fuel production. If the CO2 for this process can be captured from high emitting industries it can be a very good alternative for reduced fossil fuel consumption and GHG emission mitigation. CO as an active gas could be used in Fischer-Tropsch process to produce conventional fuels. Literature review and process simulation were carried out in order to determine the best operating conditions for reverse water gas shift (RWGS) reaction. Increasing CO2 conversion to CO requires CO2/CO separation downstream of the reactor and recycling unreacted CO2 and H2 back into the reactor. Adsorption as a viable and cost effective process for gas separation was chosen for the CO2/CO separation. This was started by a series of adsorbent screening experiments to select the best adsorbent for the application. Screening study was performed by comparing pure gas isotherms for CO2 and CO at different temperatures and pressures. Then experimental isotherm data were modeled by the Temperature-Dependent Toth isotherm model which provided satisfactory fits for these isotherms. Henry law’s constant, isosteric heat of adsorption and binary mixture prediction were determined as well as selectivity for each adsorbent. Finally, the expected working capacity was calculated in order to find the best candidate in terms of adsorption and desorption. Zeolite NaY was selected as the best candidate for CO2/CO separation in adsorption process for this project. In the last step breakthrough experiments were performed to evaluate operating condition and adsorption capacity for real multi component mixture of CO2, CO, H2 in both cases of saturated with water and dry gas basis. In multi components experiments zeolite NaY has shown very good performance to separate CO2/CO at low adsorption pressure and ambient temperature. Also desorption experiment was carried out in order to evaluate the working capacity of the adsorbent for using in industrial scale and eventually temperature swing adsorption (TSA) process worked very well for the regeneration step. Integrated adsorption system downstream of RWGS reactor can enhance the conversion of CO2 to CO in this process significantly resulting to provide synthetic gas for synthetic fuel production as well as GHG emission mitigation.

No description available.

No description available.

Alternating copolymers represent a special class of copolymers in which the two comonomers copolymerize in a regular alternating sequence along the polymer chain. Of particular interest in our group are the stilbene-maleic anhydride/maleimide alternating copolymers. These copolymers possess sterically congested backbones and precisely placed functional groups arising from the strictly alternating copolymerization. The research in this dissertation is focused on the synthesis, characterization, and potential application of functionalized copolymers that contain semi-rigid alternating copolymer sequences. The fluorescence properties of a series of non-conjugated, tert-butyl carboxylate functionalized alternating copolymers were investigated. Extraordinarily high fluorescent intensity with excellent linearity was observed for the di-tert-butyl group-containing stilbene and maleic anhydride alternating copolymer in THF. We attributed the origin of the strong fluorescence to the “through space” π – π interactions between the phenyl rings from the stilbene and C=O groups from the anhydride. The fluorescence was maintained when the copolymer was deprotected and hydrolyzed and the resulting carboxylic acid-functionalized copolymer was dissolved in water at neutral pH. The tert-butyl carboxylate functionalized alternating copolymer sequences were incorporated into highly crosslinked polymer networks using suspension polymerization. After removing the tert-butyl groups by acidic hydrolysis, the surface area of the networks increased significantly. Using this facile two-step strategy, we were able to achieve nanoporous polymers with BET surface area up to 817 m2/g and carboxylic acid-functionalized surfaces. The BET surface area of deprotected polymers increased with increasing crosslinking density, and the stilbene-containing polymers showed systematically higher BET surface area than the styrene-containing polymers due to the stiffness of the alternating sequences. The resulting nanoporous polymers have potential to be employed as solid sorbents for CO2. The same tert-butyl carboxylate functionalized alternating copolymer sequences were also incorporated into microgels via miniemulsion polymerization. The miniemulsion technique ensured the successful synthesis of microgels with ~100 nm diameter using solid stilbene and maleimide monomers. The resulting tert-butyl carboxylate-containing microgels were converted into carboxylic acid-containing aqueous microgels by acid hydrolysis. These aqueous microgels showed good and reversible lead and copper ion adsorption capacities. Amine-functionalized nanoporous polymers were synthesized by the post-modification of highly-crosslinked divinylbenzene-maleic anhydride polymers. High amine-contents were achieved by covalently attaching multiamines to the acid-chloride functionalized polymer surface. The resulting polymers showed medium to high BET surface areas (up to 500 m2/g) and high CO2 capture capacities. / PHD / Copolymers are polymers that consist of two or more different monomers in the polymer chain. Research on copolymers can be traced back to the 1930s. Since the early discoveries, the research on copolymers has received considerable attention because of the ease of synthesis and the versatile properties and applications of these materials. Alternating copolymers are one of the most studied types of copolymers. In an alternating copolymer, the two different monomers arrange in a regular alternating sequence along the polymer backbone. Of special interest in our group are the alternating copolymers that contain stilbene (1,2- diphenylethylene). The stilbene-containing alternating copolymers have relatively rigid (semi-rigid) structures, which lead to unusual and interesting properties. The research described in this dissertation is focused on incorporating these semi-rigid alternating copolymers into different types of systems and studying their structure/property relationships. Three different polymeric materials and their properties were explored. Fluorescent materials can glow when irradiated by a certain wavelength of light. This property is very useful in biomedical sensing, imaging and labeling. The semi-rigid stilbene-containing alternating copolymer exhibited fluorescence with extraordinarily high intensity, solely due to the conjugation from the exact juxtaposition of molecular orbitals. This high intensity fluorescence suggests potential application as novel light-emitting materials. The increasing atmospheric CO₂ concentrations due to human activities like transportation and manufacturing have caused public concerns. Currently, liquid amine scrubbing is one of the most well established methods for CO₂ capture in industry. However, due to the solvent evaporation, degradation, and the high energy demand during the solvent regeneration, solid polymeric materials are considered as attractive alternative CO₂ capture materials. We designed two kinds of polymers based on our semi-rigid alternating copolymer sequences, and they both exhibited pores smaller than 2 nm. With the help of different functional groups designed to interact with CO₂, these polymers showed enhancement in CO₂ capture properties, and show the viability as solid sorbents for atmospheric CO₂. Heavy metal contamination in water is a severe environmental and public health problem. The recent Flint water crisis raised the public awareness of this problem. We synthesized a series of hydrogel beads with diameters in the range of 100-200 nm. The incorporation of these functional alternating copolymer sequence into the microgels led to fast and reversible adsorption of the lead and copper ions in water.