Download or read book In situ Infrared Study of Amine Functionalized Polymer Sorbents for CO2 Capture written by Lin Pan and published by . This book was released on 2015 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: The emissions of CO2 act as a major source for global climate change in today's society and it mainly comes from coal-fired power plants. There are several techniques for CO2 capture such as liquid amine process, membrane separation, chemical looping and solid sorbent process. In my study, the solid amine sorbents are used for CO2 capture due to it can reduce the regeneration energy, avoid the corrosion of equipment and increase the CO2 adsorption and desorption rate compared with liquid amine process. The porous polyvinyl alcohol (PVA) support was synthesized by using glutaraldehyde (GA) as a cross-linking agent and phase inversed in acetone. Polyethyleneimine (PEI) and tetraethylenepentamine (TEPA) were impregnated on PVA support respectively for CO2 adsorption. The performance of sorbents were tested by CO2 capture capacity through weight change method and the nature of CO2 adsorption on sorbents with different amine content (N %) were characterized by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), as well as the formation and desorption of CO2 adsorbed species from fresh and degraded sorbents. Besides, the effect of antioxidant in inhibiting the degradation was also studied.

Download or read book In Situ Infrared and Mass Spectroscopic Study on Amine immobilized Silica for CO2 Capture written by Jak Tanthana and published by . This book was released on 2011 with total page 2005 pages. Available in PDF, EPUB and Kindle. Book excerpt: The rapid increase in atmospheric CO2 has become a major environmental concern in recent years. Coal-fired power plants, releasing flue gas containing CO2, account for approximately 30% of total CO2 emissions worldwide. Solid amine sorbents such as amine immobilized on silica (SiO2) has gained significant consideration for capturing CO2 from flue gas due to its lower operation cost and equipment corrosion compared to existing liquid amine process. The -NH2 functional group of these solid amine sorbents binds CO2 through acid-base interactions, allowing CO2 to adsorb and desorb at temperatures in the range of the flue gas operating conditions. Studies have shown that the solid amine sorbents can initially adsorb CO2 at the economical level compared to that of liquid amine processes. The CO2 capture capacity of solid amine sorbents reduce over the period of time due to the thermal instability and contaminant poisoning of the amine. Our current development focuses on improving the sorbent stability and mechanistic study of the interactions between the amine, CO2, and contaminants present in the flue gas. This dissertation presents a study of the use of polyethylene glycol (PEG) to enhance the stability of amine-immobilized silica. Long term stability of tetraethylenepentamine-immobilized on silica (TEPA/SiO2) and PEG-enhanced TEPA/SiO2 (PEG/TEPA/SiO2) were evaluated by performing multiple cycles of CO2 capture on the sorbents under the constant monitoring of in situ infrared and mass spectrometers. PEG/TEPA/SiO2 shows slower degradation than TEPA/SiO2. The IR absorbance spectra reveal that the accumulation of the strongly adsorbed CO2 species as bicarbonates and carboxylates is the cause of sorbent degradation. The IR absorbance spectra further suggested that the presence of PEG decreased the formation of these strongly adsorbed CO2, reducing the degradation of the sorbent. The interactions between the -NH2 groups, CO2, and other electron acceptor species present in the flue gas govern the CO2 capture capacity and long term stability of the sorbent. The flue gas from coal-fired power plants contains 40-250 ppm of SO2 and 5-7 vol% of H2O. Although the presence of these species in the flue gas is expected to influence the performance of the sorbent, the extent of the interaction between the amine groups and these species has not been studied. CO2 capture under the presence of 250 ppm in the CO2 adsorption stream was performed on TPSENa sorbent (29 wt% TEPA, 18 wt% PEG, 49 wt% SiO2, 3.8 wt% EPON, and 0.2 wt% Na2CO3). The initial CO2 capture capacity of TPSENa was 1.195 mmol-CO2/g-sorb. which decreased to 0.532 mmol-CO2/g-sorb. after 24 cycles of CO2 capture under presence of 250 ppm SO2. The CO2 capture capacity of TPSENa showed a slight reduction from 0.869 to 0.764 mmol-CO2/g-sorb. under the absence of SO2. The IR absorbance spectra indicate that formation of both strongly-adsorbed CO2 species and SO2-adsorbed species accelerated the degradation of the sorbent in the presence of SO2. The development of high stability solid amine sorbent requires an in-depth understanding of the interaction between CO2 and the amine groups. The mechanism of CO2 adsorption on amine groups follows acid-base type interaction where the CO2 acts as the acidic species and amine groups are the basic site. The products of the reaction between CO2 and the amine are ammonium ion (NH3+), carbamate, and bicarbonates. The evidence of the formation of carbamate and bicarbonates are commonly available in literatures while that of the ammonium ion is scarce. The in situ injection of HCl on TEPA/SiO2 was performed under constant infrared spectroscopic monitoring to elucidate the acid-base reaction. The IR spectra of TEPA/SiO2 after HCl injection shows similar absorption features to those of TEPA/SiO2 during CO2 adsorption, evidences for the formation of NH3+. IR spectra also suggests that HCl is likely to react with primary amine (-NH2) of TEPA and then further reacts with secondary amine (-NH), resulting in the decrease in the available amine sites for CO2 adsorption. The in situ injection of H2O on TEPA/SiO2 caused the removal of TEPA from SiO2. The results of this study have provided the several key information of which should prove to be helpful in the development of highly stable solid amine sorbent. The study of PEG-enhanced TEPA/SiO2 has shown that the stability can be improved by addition of chemical stabilizers which slows down the formation of the carboxylate species. The SO2 poisoning of the sorbent is caused by (i) accelerating the formation of strongly adsorbed CO2 species and (ii) depositing of SO2-adsorbed species on the amine sites. The further studies should focus on development of the sorbent with high resistance to HCl and SO2. Additional of aromatic amine to the alkyl amine on silica support may reduce the HCl and SO2 poisoning as the aromatic amine has a strong reactivity toward the acidic gaseous species. The addition of these compounds requires optimization to ensure that the sorbent resistance to SO2 while stability and capture capacity are not significantly affected.

Download or read book In Situ Infrared Studies of Carbon Dioxide Capture and Photoelectrocatalytic Reduction written by Jie Yu and published by . This book was released on 2017 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: CO2 capture and sequestration from coal-fired power plant flue gas is an attractive technique to control CO2 emissions. Polyamine-based sorbent is considered as a promising sorbent for CO2 capture due to its low equipment corrosion and regeneration energy penalty. One critical aspect of development of polyamine-based CO2 capture process is to understand the nature of the adsorbed species with amine and their evolution in adsorption / desorption process. Fourier transform infrared (FTIR) spectroscopy is a powerful and versatile tool that can provide the insights from molecular level to address these scientific issues. This dissertation is focusing on using in-situ FTIR spectroscopy to discuss several important topics in CO2 capture and utilization processes, including (i) the structure and binding energy of adsorbed CO2/H2O on solid amine sorbent, (ii) the role of H2O in CO2 adsorption/desorption on liquid amine films, (iii) mechanism of water-enhancement on CO2 capture by amine, and (iv) photoelectrocatalytic reduction of CO2 on polyamine/TiO2 thin film.H2O vapor in flue gas has dramatic effects on polyamine-based sorbent. H2O could affect CO2 capture capacity, regeneration energy, and degradation kinetics of the sorbents. This in situ IR study investigated these various effects on polyamine-based sorbents. The results revealed that CO2 adsorbed on primary amine as ammonium carbamate while H2O adsorbed on secondary amine and promoted the formation of carbamic acid. Adsorbed H2O increases the binding strength of CO2 with amine and protects sorbent from SO2 poisoning. The results of this study clarify the role of H2O in polyamine-based sorbent for CO2 capture and provide a molecular basis for the design and operation of polyamine-based CO2 capture processes. The use of FTIR spectroscopy in the investigation of role of water on CO2 capture by amine has enabled us to verify the reaction processes. The results unraveled that adsorption of CO2 on the 20 μm tetraethylenepentamine (TEPA) film at 50 °C followed a zwitterion-intermediate pathway: zwitterion ¿ ammonium carbamate. H2O in the mixed TEPA/H2O (5:1) film decreased the rate of CO2 adsorption, but increased the amine efficiency. The presence of H2O promotes the formation of carbamic acid and produces a broad IR band centered at 2535 cm-1, which can be assigned to (O-H) of hydronium carbamate, -NCOO-···H-OH2+. The broadness of this 2535 cm-1 band ranging from 2100 cm-1 to 2800 cm-1 persists at 120 °C. These broad components of the band can be ascribed to ¿(N-H) in hydrogen-bonded ammonium carbamate, a R-NH3+/R1R2-NH2+···-NCOO- moiety. The binding strength of adsorbed species on the TEPA film increases in the order: adsorbed H2O

Download or read book In Situ FTIR and Tubular Reactor Studies for CO2 Capture of Immobilized Amine Sorbents and Liquid Amine Films written by Walter Christopher Wilfong and published by . This book was released on 2014 with total page 333 pages. Available in PDF, EPUB and Kindle. Book excerpt: In situ Fourier transform infrared spectroscopy (FTIR) and tubular reactor studies with mass spectrometry (MS) revealed the mechanisms and kinetics of CO2 diffusion and adsorption/desorption for immobilized amine sorbents and liquid amine films. CO2 mass transfer limitations of immobilized tetraethylenepentamine (TEPA)/silica sorbents were studied by a novel in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) technique using benzene as a surrogate CO2 probe molecule. Results showed that (i) adsorbed CO2 creates an interconnected network of ammonium-carbamate ions and carbamic acid that inhibits CO2 diffusion, and (ii) readsorption of desorbed CO2 along the pore wall and at the external surfaces limits the CO2 removal rate from the sorbent. CO2 diffusion and adsorption/desorption for different thicknesses of TEPA films were investigated by attenuated total reflectance (ATR) and DRIFTS. Results showed that CO2 strongly adsorbed to NH and NH2 at the top surface of thicker films and formed a strongly bound, interconnected network that reduced the access of CO2 to the bulk amines. Adsorption/desorption of CO2 onto/from immobilized amine particle and pelletized sorbents was studied in a tubular reactor set-up to investigate the sorbents' performance under different operating conditions. Results showed enhanced CO2 capture on the sorbents in the presence of H2O vapor (wet adsorption), likely resulting from liberation of previously inaccessible amine groups of TEPA. Increasing the CO2 partial pressure by pulsing pure CO2 after wet adsorption, and steam regeneration of the adsorbed species in the CO2 gas environment allows the desorbed CO2 concentration to reach 99+%. A novel, cross-linked porous PVA support (PPc) was synthesized and impregnated with TEPA, polyeythylene glycol 200 (PEG), and other additives for testing as a low cost and stable CO2 capture sorbent. Results showed that PPc exhibited high surface area and pore volume similar to those of silica. Increasing the PEG-OH/TEPA-N ratio of the sorbent enhanced its CO2 capture performance due to dispersion of the NH2 and NH groups by PEG. In situ DRIFTS studies showed a weaker binding strength of CO2 to the amines of the PPc-supported than silica-supported sorbent, suggesting that using PPc sorbents could reduce the cost of sorbent regeneration.

Download or read book Preparation and Modification of Amine functionalized Solid Sorbents for CO2 Adsorption and SO2 Resistance written by Sihan Wang and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Over loading of CO2 emission has been a severe environment problem and the fact of greenhouse issue has become a huge impact to our daily life. The largest and inevitable emission of CO2 gas is the coal-fired power plant, and the most commonly used CO2 capture sorbent is liquid amine. However, there are lots of inconvenience of using liquid amine including equipment corrosion, high regeneration energy and slow diffusion of the CO2 gas, which would cost the capture procedure a huge amount of expense. Nevertheless, the solid sorbent is in face of the issue that the capture capacities and SO2 resistance is really low. So in this research, the modified amine-functionalized solid sorbents for CO2 adsorption and SO2 resistance have been created. The problem of lower CO2 capture capacity was modified by double impregnation, and the issue of lower heat transfer rate was improved by adding heat transfer agent during pelletization. The characterization of the sorbent and pellets capture behavior was done by CO2 capture weight method and in-situ DRIFT spectra, and the SO2 resistance behavior has also been discussed with EDS mapping and quantification.

Download or read book Spectroscopic Evaluation of the CO2 Adsorption Properties on Amine Functionalized Polyvinyl Alcohol and Silica Sorbents written by Yuxin Zhai and published by . This book was released on 2014 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: Porous polyvinyl alcohol (PVA) and silica particles with amine surface functional groups have been prepared for the efficient CO2 capture power plants. The porous PVA membranes or particles were obtained by phase inversion in non-solvent, using glutaraldehyde (GA) as a crosslinking agent. An insoluble amine-PVA or amine-silica network was prepared by immobilizing polyethyleneimine (PEI) on the PVA or silica surface. The performance of the amine functionalized PVA and silica sorbents were tested by CO2 adsorption, and the effect of operational parameters were determined by in-situ IR spectroscopy. The adsorption isotherms for the CO2 adsorbed species formed on amine functionalized silica sorbents were generated at different temperatures. The CO2 adsorbed species were identified by IR spectroscopy and their formation was evaluated at the typical temperature and concentration of CO2 in the flue gas of natural gas-fired power plants. Multiple data points were generated in the low partial pressure region of the isotherms to assess the equilibrium and specify the technical requirements for the sorbents to serve in CO2 capture processes for natural gas-fired power plants.

Download or read book Amine pillared Nanosheet Adsorbents for CO2 Capture Applications written by Hui Jiang and published by . This book was released on 2014 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: Amine-functionalized solid adsorbents have gained attention within the last decade for their application in carbon dioxide capture, due to their many advantages such as low energy cost for regeneration, tunable structure, elimination of corrosion problems, and additional advantages. However, one of the challenges facing this technology is to accomplish both high CO2 capture capacity along with high CO2 diffusion rates concurrently. Current amine-based solid sorbents such as porous materials similar to SBA-15 have large pores diffusion entering molecules; however, the pores become clogged upon amine inclusion. To meet this challenge, our group's solution involves the creation of a new type of material which we are calling-amino-pillared nanosheet (APN) adsorbents which are generated from layered nanosheet precursors. These materials are being proposed because of their unique lamellar structure which exhibits ability to be modified by organic or inorganic pillars through consecutive swelling and pillaring steps to form large mesoporous interlayer spaces. After the expansion of the layer space through swelling and pillaring, the large pore space can be functionalized with amine groups. This selective functionalization is possible by the choice of amine group introduced. Our choice, large amine molecules, do not access the micropore within each layer; however, either physically or chemically immobilized onto the surface of the mesoporous interlayer space between each layer. The final goal of the research is to investigate the ability to prepare APN adsorbents from a model nanoporous layered materials including nanosheets precursor material MCM-22(P) and nanoporous layered silicate material AMH-3. MCM-22(P) contains 2-dimensional porous channels, 6 membered rings (MB) openings perpendicular to the layers and 10 MB channels in the plane of the layers.1 However, the transport limiting openings (6 MB) to the layers is smaller than CO2 gas molecules.2,3 In contrast, AMH-3 has 3D microporous layers with 8 MB openings in the plane of the layers, as well as perpendicular to the layers, which are larger than CO2 molecules. Based on the structure differences between nanosheets precursor material MCM-22(P) and nanoporous layered silicate material AMH-3, the latter might be more suitable for CO2 capturer application as an APN candidate material. However, none of the assumptions above have been approved experimentally. In this study, the influence of the amine loading on adsorption capacity and kinetics of adsorption for the mixed porosity material pillared MCM-22 (P) (also called MCM-36) is studied systematically, in order to determine a potential route to achieve a final material with both high amine loading and high adsorption capacity. We first synthesized MCM-22(P), followed by swelling and pillaring to create MCM-36. Polymeric amines such as polyethylenimine (PEI) are used as an organic component of the supported amine adsorbents, with varying polymer loadings within the adsorbents used. The kinetics and diffusion properties of carbon dioxide capture on a MCM-36 pillared material impregnated with amine containing Polyethylenimine polymers has been investigated. It was determined that the introduction of amine polymer cannot be used to improve the capture capacity of the support over that of the bare material, due to the fact that with the addition of a high loading of amine polymer the large pore diffusion channels become impossible for carbon dioxide molecules to diffuse through. This sets an upper limit to the capture capacity of polymer impregnated MCM-36 for carbon dioxide which does not surpass that for the initial bare material, and greatly reduces the utility of using this sort of amine-solid adsorbent for carbon capture plans in the future.

Download or read book In situ Spectroscopic Investigation of CO2 and SO2 Adsorption Mechanisms on Amine Sorbents written by Uma Tumuluri and published by . This book was released on 2014 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: CO2 capture using amine sorbents is a promising technology for CO2 capture from point sources because of its low energy requirement, low equipment corrosion. Thermal swing adsorption (TSA) using amine sorbents, which operates with CO2 adsorption at 40-55°C and desorption at 100-120°C, could be a cost-effective process for removal of CO2 from coal-fired power plants becasue of the availability of steam for sorbent regeneration. In situ FTIR spectroscopy was used to study the interaction of CO2 with amine sorbents. Adsorbed CO2 on amine sorbents exists in the form of carbamate-ammonium ion pairs, carbamate-ammonium zwitterions and carbamic acid. Carbamate and carbamic acid on sorbents with low amine density desorbed at a faster rate than those on sorbents with high amine density after switching the flow from CO2 to Ar at 55°C. Evaluation of the desorption temperature profiles showed that the temperature required to achieve maximum desorption of CO2 (Tmax. des) increases with the amine density. Flue gas emitted from coal fired power plants after selective catalytic reduction and flue gas desulfurization units contains approximately 3-4% O2, 12-15% CO2, 5-10% H2O, 50-200 ppm SO2, 100-400 ppm NOx. The long term stability of the amine sorbents in flue gas conditions is one of the key operational aspects that the determine the economic viability of the CO2 capture using amine sorbents. The performance of the amine sorbents in the simulated flue gas conditions was evaluated using in situ FTIR spectroscopy. FTIR results revealed that sulfates/sulfites that are formed in presence of SO2 and SO2/H2O bind strongly with amine sites. Evaluation of the break through curves revealed that the competitive adsorption of SO2 and CO2 on the amine sites occurs at low CO2 concentration. The adsorption of CO2 dominates the SO2 at high CO2 concentration. In situ FTIR SO2 capture studies on amine sorbents revealed that SO2 adsorbs in form of ammonium ions and sulfates on the amine sorbents. Analysis of the IR spectra of the adsorbed SO2 revealed that the sorbents containing primary and secondary amine adsorb SO2 irreversibly and tertiary amine sorbents adsorbed SO2 reversibly. The results of these fundamental studies help in designing a suitable sorbent for CO2 capture process, which has high CO2 capture capacity and high SO2 tolerance.

Download or read book Advanced CO2 Capture Technologies written by Shin-ichi Nakao and published by Springer. This book was released on 2019-05-07 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book summarises the advanced CO2 capture technologies that can be used to reduce greenhouse gas emissions, especially those from large-scale sources, such as power-generation and steel-making plants. Focusing on the fundamental chemistry and chemical processes, as well as advanced technologies, including absorption and adsorption, it also discusses other aspects of the major CO2 capture methods: membrane separation; the basic chemistry and process for CO2 capture; the development of materials and processes; and practical applications, based on the authors’ R&D experience. This book serves as a valuable reference resource for researchers, teachers and students interested in CO2 problems, providing essential information on how to capture CO2 from various types of gases efficiently. It is also of interest to practitioners and academics, as it discusses the performance of the latest technologies applied in large-scale emission sources.

Download or read book Handbook of Climate Change Mitigation written by Wei-Yin Chen and published by Springer. This book was released on 2012-02-13 with total page 2130 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is a mounting consensus that human behavior is changing the global climate and its consequence could be catastrophic. Reducing the 24 billion metric tons of carbon dioxide emissions from stationary and mobile sources is a gigantic task involving both technological challenges and monumental financial and societal costs. The pursuit of sustainable energy resources, environment, and economy has become a complex issue of global scale that affects the daily life of every citizen of the world. The present mitigation activities range from energy conservation, carbon-neutral energy conversions, carbon advanced combustion process that produce no greenhouse gases and that enable carbon capture and sequestion, to other advanced technologies. From its causes and impacts to its solutions, the issues surrounding climate change involve multidisciplinary science and technology. This handbook will provide a single source of this information. The book will be divided into the following sections: Scientific Evidence of Climate Change and Societal Issues, Impacts of Climate Change, Energy Conservation, Alternative Energies, Advanced Combustion, Advanced Technologies, and Education and Outreach.

Download or read book CO2 and SO2 Capture by Aromatic and Aliphatic Amine Sorbents written by Ernesto Silva Mojica and published by . This book was released on 2011 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt: The emissions of CO2 to the atmosphere have rapidly increased in the last decades due to the industrialization and the increasing energy demand. Due to the potential effect that CO2 has as global warmer, industrialized and emerging countries are putting efforts on developing technologies to reduce emissions. Coal fired power plants produce 55% of U.S. electricity and more than 33% of global CO2 emissions, representing the largest stationary source of CO2. As a co-product of the combustion process of sulfur-containing coal, SO2 is produced and represents between 0.2 and 0.3 v% of the power plant flue gas composition. SO2 is a serious pollutant, precursor of the acid rain and particulate materials. The release of SO2 to the atmosphere can cause respiratory diseases and destruction of eco-systems. Some existing CO2 capture technologies are inefficient to be applied in power plants due to the large flow rates and high concentration of CO2 in the flue gas. Other technologies such as the liquid amine process are not economically viable because the energy requirements for operation and regeneration are excessive. In addition those processes cause rapid corrosion to the equipment. The adsorption on solid sorbents is potentially the most suitable process for the treatment of flue gas from power plants. The development of solid sorbents by functionalization of solid supports with amine functional groups has been recently studied. The goals during the sorbent development are (i) a high CO2 selectivity and adsorption capacity, (ii) the long term stability and cycle life, (iii) resistivity toward thermal and oxidative degradation, (iv) resistance to SO2 and (iv) low cost. In this thesis, the resistance of aliphatic amine and aromatic anime sorbents towards SO2 was studied by in-situ infrared spectroscopy (IR) and mass spectrometry (MS). An operational condition to improve the CO2 adsorption capacity of an amine sorbent was also studied by introducing H2O in the flue gas. The hypothesis included the use of an aromatic amine to prepare a low basicity sorbent for SO2 capture and to reduce the SO2 poisoning on a CO2 capture sorbent. In addition, it is thought that the presence of H2O in the flue gas improves the adsorption capacity of an amine sorbent due to the formation of different adsorbed species. The IR and MS results showed that the aromatic amine sorbent has a weak adsorption capacity of CO2 and SO2, leading to CO2 capture processes at low temperature. SO2 strongly adsorbs on the aliphatic amine sorbent, causing accumulation of sulfate and sulfite species and reducing the availability of amine sites for CO2 adsorption. The performance of CO2 capture in simulated practical conditions showed the improvement in capture capacity of a sorbent by more than 60% when the flue gas is saturated with H2O.

Download or read book Capture and Utilization of Carbon Dioxide with Polyethylene Glycol written by Zhen-Zhen Yang and published by Springer Science & Business Media. This book was released on 2012-08-10 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this volume, Professor He and his coworkers summarize polyethylene glycol (PEG)-promoted CO2 chemistry on the basis of understanding about phase behavior of PEG/CO2 system and reaction mechanism at molecular level. As PEG could be utilized as a green replacement for organic solvents, phase-transfer catalyst, surfactant, support in various reaction systems, significantly promoting catalytic activity and recovering expensive metal catalysts, particularly regarded as a CO2-philic material, the authors focus on special applications of PEG in CO2 capture and utilization, including PEG-functionalized catalysts for efficient transformation of CO2 and PEG-functionalized absorbents for efficient CO2 capture. Furthermore, they describe carbon capture and utilization strategy as an alternative approach to address the energy penalty problem in carbon capture and storage. Interestingly, the authors also discuss PEG radical chemistry in dense CO2 as rather creative and unusual use of PEG, presumably serves as a reaction medium and a radical initiator for radical chemistry.

Download or read book In situ Infrared Studies of Adsorbed Species in CO2 Capture and Green Chemical Processes written by Long Zhang and published by . This book was released on 2016 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: Clean energy and environment is a 21st-century contemporary challenge we human being faces. Tremendous effort has been paid to explore and develop technologies to produce green energy, to reduce the emissions of wastes, and to utilize these wastes and renewable sources. Catalysis technologies and CO2 capture and utilization technologies are among the most important stepping stones to achieve the challenging goals to secure the environment for human survival and development. The advancement in these technologies requires a molecular-level or quantum-level fundamental understanding of the processes involved. One critical aspect of importance is the nature of the adsorbed species and their evolution in these green chemical processes. Fourier transform infrared (FTIR) spectroscopy is a powerful and versatile tool that can provide the insights to address these scientific issues. This dissertation, with a focus on the applications of in-situ FTIR spectroscopy, discusses about a few important topics in CO2 capture and other green processes, including (i) the catalytic asymmetric hydrogenation of a-amino ester, a potential chemical building block and starting material for biocompatible polymers, (ii) the oxidative and CO2-induced degradation of supported polyethylenimine (PEI) adsorbents for CO2 capture, (iii) the utilization of CO2 by the catalytic conversion of CO2 to carbonates, a precursor for polycarbonates and polyurethanes, (iv) the catalytic conversion of 2,3-butanediol to 1,3-butadiene, the monomer for synthetic rubbers, and (v) the electron-induced IR absorbance in photocatalytic processes on TiO2. A wide array of FTIR techniques, including diffuse reflectance, attenuated total reflectance, and transmission IR has been applied. The FTIR results revealed the vital hydrogen bonding interactions in the catalytic asymmetric hydrogenation of a-amino ester which led to the prochiral structures. The oxidative degradation and CO2-induced degradation pathways were elucidated with the help of various FTIR studies conducted. The mechanism of the oxidative degradation of amines was proposed for the first time that the solid amines underwent the deactivation to imines and further oxidation to amides. The effects of amine loading, temperature, and water vapor on CO2-induced degradation were clarified. The FTIR spectra evidenced the successful conversion of CO2 to dimethyl carbonate and 2,3-butanediol to 1,3-butadiene, and helped the comprehension of the kinetics and the nature of the dehydrating agent in the reactions. In-situ FTIR was also used to differentiate the contributions from the conduction-band electrons and shallow-trapped electrons to the polaronic light absorbance. A modelling method was developed to analyze the IR spectra. The modelling results revealed the correlation of these differently sourced absorbance and the generation of photocurrent and the charge transportation process in photocatalysis.

Download or read book Post combustion Carbon Dioxide Capture Using Amine Functionalized Solid Sorbents written by Nikhil Mittal and published by . This book was released on 2013 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work is divided into two parts: (1) Synthesis of amine functionalized adsorbents using grafting technique for post-combustion CO[subscript 2] capture, (2) Performance evaluation of structured bed configuration with straight gas flow channels using amine impregnated adsorbent for post-combustion CO[subscript 2] capture. Brief description of each part is given below: (1)N-(3-trimethoxysilylpropyl)diethylenetriamine (DAEAPTS) grafted SBA-15 adsorbents were synthesized for CO[subscript 2] capture. The adsorption of CO[subscript 2] on the amine-grafted sorbents was measured by thermogravimetric method over a CO[subscript 2] partial pressure range of 8-101.3 kPa and a temperature range of 25-105 °C under atmospheric pressure. The optimal amine loaded SBA-15 adsorbent was examined for multi-cycle stability and adsorption/desorption kinetics. (2)The performance of structured bed and packed bed configurations for post-combustion CO[subscript 2] capture was evaluated using PEI impregnated SBA-15 adsorbent. The effect of adsorption temperature (25-90 °C), adsorption /desorption kinetics and multi-cycle stability was studied in both structured and packed bed configurations.

Download or read book In Situ Infrared Study of G S L S Adsorption and Photocatalytic Processes written by Duane D. Miller and published by . This book was released on 2009 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Coal fired power plants release large quantities of CO2 and trace amounts of SO2 into the atmosphere, affecting global warming and worldwide climate change. CO2 is a concern as a greenhouse gas in relation to global temperature raise. SO2 is a concern in environmental protection as a precursor for acid rain. The impact of CO2, SO2, and H2S on the environment demonstrate the removal process is a subject of study of great importance. Removal of these gases has been focused on the development of amine based sorbents for sequestration by the adsorption and desorption process. Fourier Transform Infrared spectroscopy (FTIR) is a powerful tool for investigating the adsorption/desorption process and structure of adsorbing molecules. The application of FTIR, coupled with ab initio quantum chemistry, can provide a direct means for understanding the interactions that occur during chemisorption. The removal of CO2 and H2S by an amine based sorbent has been studied. The hypothesis for this study is to investigate the use of polyethylene glycol (PEG) to promote tetraethylenepentamine (TEPA) CO2 and H2S removal capacity. It is thought that the use of PEG may improve the catalytic adsorption capacity through hydrogen bonding. This study used in situ FTIR and ab initio quantum chemistry to investigate the adsorption and desorption processes during CO2 and H2S capture at the molecular level. The FTIR results determine that PEG interacts with the primary amine functional groups of TEPA dispersing the adsorption sites leading to improved adsorption capacity for CO2 and H2S. Ab initio quantum chemistry determined that PEG lowers the binding energy of CO2 and H2S leading to a lower desorption temperature. Removal of the nauseous gas SO2 by an amine based sorbent is studied. The hypothesis investigated the use of 1,3-phenylenediamine low basic property for creating a reusual solid amine based sorbent for SO2 removal. It is thought that the low basic property of the aromatic amine will allow the effective SO2 adsorption and desorption at low temperature. This study used in situ FTIR spectroscopy to investigate the adsorption and desorption processes during SO2 capture. The result of this study determined that 1,3-phenylenediamine basic property allowed SO2 adsorption and desorption at 373 K, however, sorbent deactivation occurs. The in situ UV-Visible spectroscopic technique provided insight that deactivation is the result of agglomeration of 1,3-phenylenediamine. Addition of PEG prevent the agglomeration and improved the adsorption capacity of 1,2-phenylenediamine through hydrogen bonding with the primary amine functional group. Amine based sorbents have proven as an effective and economic process for the removal of CO2 and the hazardous gases H2S and SO2. Advancing knowledge in the area of amine based sorbents will improve our ability for hazardous waste management. Hazardous waste management may also be achieved by the oxidation and reduction (redox) of toxic materials. TiO2 based catalysts have the ability to oxidize a number of hazardous materials to nontoxic products where TiO2 has become the benchmark semiconductor in photo-detoxification of contaminated water. This work also investigates the photocatalytic dehydrogenation process over TiO2 based catalysts. The hypothesis investigated the relationship of the photogenerated electrons and adsorbed species during the photocatalytic dehydrogenation of 2-propanol. It is thought that the interaction of the photogenerated electrons and adsorb species may be elucidated from the reaction mechanism during the photocatalytic dehydrogenation of 2-propanol. 2-propanol is used as a model compound because it provides a simple and standard way to measure the photocatalytic activity during the gas/liquid phase reactions. This study suggest that in the presence of adsorbed H2O, the dehydrogenation process proceeded by a hydroxyl radical species while in the absence of adsorbed H2O the active species is an adsorbed ion. Au/TiO2 unique ability to generate adsorbed oxygen ions resulted in higher catalytic activity in the absence of adsorbed H2O under UV-irradiation. The reaction pathway for the photocatalytic dehydrogenation of 2-propanol is strongly dependent on the coverage of surface H2O."--Abstract.

Download or read book Polymer Based Advanced Functional Materials for Energy and Environmental Applications written by Nithin Kundachira Subramani and published by Springer Nature. This book was released on 2022-01-01 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymer-based advanced functional materials are one of most sought after products of this global high performance material demand as polymer-based materials guarantee both processing ease and mechanical flexibilities. This volume provides a comprehensive and updated review of major innovations in the field of polymer-based advanced functional materials which focuses on constructive knowledge on advanced multifunctional materials and their resultant techno-commercial applications. The contents aim at restricting the coverage to energy and environment related applications as the said two are the most emerging application domains of polymer-based advanced functional materials. It highlights the cutting-edge and recent research findings of polymer based advanced functional materials in energy and environment sectors wherein each chapter focuses on a specific energy and environment related application of polymer-based advanced functional materials, their preparation technique, nature enhancement achieved and allied factors. This volume would be of great interest to researchers, academicians and professionals, involved in polymers, chemistry, energy and environmental research, and other allied domains.

Download or read book In Situ Infrared Study of Adsorbed Species During Catalytic Oxidation and Carbon Dioxide Adsorption written by Rajesh A. Khatri and published by . This book was released on 2005 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: