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Pashaei H, Mashhadimoslem H, Ghaemi A. Modeling and optimization of CO 2 mass transfer flux into Pz-KOH-CO 2 system using RSM and ANN. Sci Rep 2023; 13:4011. [PMID: 36899032 PMCID: PMC10006194 DOI: 10.1038/s41598-023-30856-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 03/02/2023] [Indexed: 03/12/2023] Open
Abstract
In this research, artificial neural networks (ANN) and response surface methodology (RSM) were applied for modeling and optimization of carbon dioxide (CO2) absorption using KOH-Pz-CO2 system. In the RSM approach, the central composite design (CCD) describes the performance condition in accordance with the model using the least-squares technique. The experimental data was placed in second-order equations applying multivariate regressions and appraised applying analysis of variance (ANOVA). The p-value for all dependent variables was obtained to be less than 0.0001, indicating that all models were significant. Furthermore, the experimental values obtained for the mass transfer flux satisfactorily matched the model values. The R2 and Adj-R2 models are 0.9822 and 0.9795, respectively, which, it means that 98.22% of the variations for the NCO2 is explained by the independent variables. Since the RSM does not create any details about the quality of the solution acquired, the ANN method was applied as the global substitute model in optimization problems. The ANNs are versatile utensils that can be utilized to model and anticipate different non-linear and involved processes. This article addresses the validation and improvement of an ANN model and describes the most frequently applied experimental plans, about their restrictions and generic usages. Under different process conditions, the developed ANN weight matrix could successfully forecast the behavior of the CO2 absorption process. In addition, this study provides methods to specify the accuracy and importance of model fitting for both methodologies explained herein. The MSE values for the best integrated MLP and RBF models for the mass transfer flux were 0.00019 and 0.00048 in 100 epochs, respectively.
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Affiliation(s)
- Hassan Pashaei
- School of Chemical, Petroleum and Gas Engineering, Iran University of Science and Technology, Narmak, Tehran, 16846, Iran
| | - Hossein Mashhadimoslem
- School of Chemical, Petroleum and Gas Engineering, Iran University of Science and Technology, Narmak, Tehran, 16846, Iran
| | - Ahad Ghaemi
- School of Chemical, Petroleum and Gas Engineering, Iran University of Science and Technology, Narmak, Tehran, 16846, Iran.
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2
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Aniruddha R, Sreedhar I. Process optimization for enhanced carbon capture and cyclic stability using adsorbents derived from coal fly ash. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:8393-8402. [PMID: 34773588 DOI: 10.1007/s11356-021-17453-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 11/05/2021] [Indexed: 06/13/2023]
Abstract
Zeolites and metal-organic frameworks (MOFs) are popular adsorbents when it comes to capturing CO2 from the gaseous feed stream. In this study, a hybrid of zeolite and ZIF-8 adsorbent was synthesized from coal fly ash via fusion-hydrothermal process and then in-situ aqueous ZIF-8 synthesis technique. This technique of in-situ synthesis is highly cost-effective as it is done at room temperature. The hybrid adsorbent showed an enhanced microporosity as compared to zeolites synthesized from coal fly ash due to the in-situ synthesis of ZIF-8 upon coal fly ash zeolite. It was designated as CFAZ/ZIF-8. At 298 K, a maximum CO2 uptake value of 2.83 mmol/g was observed with a constant decrease with an increase in temperature. BET surface area value of 426 m2/g was obtained for this adsorbent. Kinetics fit for the best uptake value was performed with the Avrami model kinetics, describing the adsorption well at an R2 value of 0.997 for the fit. The adsorbent also showed impressive cyclic stability after five cycles of carbonation and decarbonation. The cyclic stability studies show that the as-synthesized hybrid adsorbent shows promise in CO2 uptake studies.
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Affiliation(s)
- Ramadurgam Aniruddha
- Department of Chemical Engineering, BITS Pilani Hyderabad Campus, Hyderabad, 500078, India
| | - Inkollu Sreedhar
- Department of Chemical Engineering, BITS Pilani Hyderabad Campus, Hyderabad, 500078, India.
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Fonseca R, Vieira R, Sardo M, Marin-Montesinos I, Mafra L. Exploring Molecular Dynamics of Adsorbed CO 2 Species in Amine-Modified Porous Silica by Solid-State NMR Relaxation. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:12582-12591. [PMID: 35968194 PMCID: PMC9358655 DOI: 10.1021/acs.jpcc.2c02656] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Previous studies on CO2 adsorbents have mainly addressed the identification and quantification of adsorbed CO2 species in amine-modified porous materials. Investigation of molecular motion of CO2 species in confinement has not been explored in depth yet. This work entails a comprehensive study of molecular dynamics of the different CO2 species chemi- and physisorbed at amine-modified silica materials through the determination of the rotating frame spin-lattice relaxation times (T 1ρ) by solid-state NMR. Rotational correlation times (τC) were also estimated using spin relaxation models based on the Bloch, Wangsness, and Redfield and the Bloembergen-Purcell-Pound theories. As expected, the τC values for the two physisorbed CO2 species are considerably shorter (32 and 20 μs) than for the three identified chemisorbed CO2 species (162, 62, and 123 μs). The differences in molecular dynamics between the different chemisorbed species correlate well with the structures previously proposed. In the case of the physisorbed CO2 species, the τC values of the CO2 species displaying faster molecular dynamics falls in the range of viscous liquids, whereas the species presenting slower dynamics exhibit T 1ρ and τC values compatible with a CO2 layer of weakly interacting molecules with the silica surface. The values for chemical shift anisotropy (CSA) and 1H-13C heteronuclear dipolar couplings have also been estimated from T 1ρ measurements, for each adsorbed CO2 species. The CSA tensor parameters obtained from fitting the relaxation data agree with the experimentally measured CSA values, thus showing that the theories are well suited to study CO2 dynamics in silica surfaces.
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Affiliation(s)
- Rita Fonseca
- CICECO—Aveiro Institute of Materials,
Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Ricardo Vieira
- CICECO—Aveiro Institute of Materials,
Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Mariana Sardo
- CICECO—Aveiro Institute of Materials,
Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Ildefonso Marin-Montesinos
- CICECO—Aveiro Institute of Materials,
Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Luís Mafra
- CICECO—Aveiro Institute of Materials,
Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
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4
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Dong J, Wang F, Chen G, Wang S, Ji C, Gao F. Fabrication of nickel oxide functionalized zeolite USY composite as a promising adsorbent for CO2 capture. Chin J Chem Eng 2022. [DOI: 10.1016/j.cjche.2021.10.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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5
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Amine-Modified Biochar for the Efficient Adsorption of Carbon Dioxide in Flue Gas. ATMOSPHERE 2022. [DOI: 10.3390/atmos13040579] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Biochar-based carbonaceous adsorbents are gaining interest due to their high availability, ease of modification, and low cost; however, they show limited adsorption of CO2 in flue gas due to common textural properties. In this study, TEPA-modified biochar was used to prepare a solid amine adsorbent for the efficient capture of CO2 in flue gas. First, the porous biochar was prepared with FeCl3, Mg(NO3)2, and H2O (g) as activators and walnut shells as carbon sources. Next, the biochar was modified with TEPA to obtain a solid amine adsorbent. Porous texture properties and sample surface functional groups were characterized, and we measured the adsorption CO2 of the amine-modified biochar in a breakthrough adsorption device. Results showed that biochar has a large specific surface area (744.38 m2 g−1), a total pore volume of 1.41 cm3 g−1, and a high mesoporous volume ratio (82.7%). The high pore volume provided a more efficient support space for loading tetraethylenepentamine (TEPA). The adsorbent had an excellent CO2 adsorption capacity, corresponding to 2.82 mmol g−1, which increased to 3.31 mmol g−1 and kept water resistance at 10% H2O (g) simulated flue gas (SFG). The FTIR analysis showed that H2O (g) inhibited urea production after cyclic adsorption. Therefore, solid amine adsorbent created by amine-modified biochar has potential advantages in its application for capturing CO2 in SFG.
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Estévez-Jácome J, Argáez C, Ramírez-Zamora RM, Alcántar-Vázquez B. CO 2 adsorption on PEHA-functionalized geothermal silica waste: a kinetic study and quantum chemistry approach. REACT CHEM ENG 2022. [DOI: 10.1039/d2re00077f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The use of geothermal silica waste to prepare amine-modified CO2 adsorbent materials was succesfully tested.
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Affiliation(s)
- Jonatan Estévez-Jácome
- Instituto de Ingeniería, Universidad Nacional Autónoma de México, Avenida Universidad 3000, Coyoacán, C.P. 04510, Ciudad de México, Mexico
| | - Carlos Argáez
- Marine and Freshwater Research Institute, Fornubúðir 5, 220 Hafnarfjörður, Iceland
| | - Rosa-María Ramírez-Zamora
- Instituto de Ingeniería, Universidad Nacional Autónoma de México, Avenida Universidad 3000, Coyoacán, C.P. 04510, Ciudad de México, Mexico
| | - Brenda Alcántar-Vázquez
- Instituto de Ingeniería, Universidad Nacional Autónoma de México, Avenida Universidad 3000, Coyoacán, C.P. 04510, Ciudad de México, Mexico
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Sood A, Thakur A, Ahuja SM. Recent advancements in ionic liquid based carbon capture technologies. CHEM ENG COMMUN 2021. [DOI: 10.1080/00986445.2021.1990886] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Akash Sood
- Research Laboratory-III, Department of Chemical Engineering, Sant Longowal Institute of Engineering and Technology, Longowal, Punjab, India
| | - Avinash Thakur
- Research Laboratory-III, Department of Chemical Engineering, Sant Longowal Institute of Engineering and Technology, Longowal, Punjab, India
| | - Sandeep Mohan Ahuja
- Research Laboratory-III, Department of Chemical Engineering, Sant Longowal Institute of Engineering and Technology, Longowal, Punjab, India
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Madugula ACS, Sachde D, Hovorka SD, Meckel TA, Benson TJ. Estimation of CO₂ emissions from petroleum refineries based on the total operable capacity for carbon capture applications. CHEMICAL ENGINEERING JOURNAL ADVANCES 2021. [DOI: 10.1016/j.ceja.2021.100162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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9
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Vieira R, Marin-Montesinos I, Pereira J, Fonseca R, Ilkaeva M, Sardo M, Mafra L. "Hidden" CO 2 in Amine-Modified Porous Silicas Enables Full Quantitative NMR Identification of Physi- and Chemisorbed CO 2 Species. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2021; 125:14797-14806. [PMID: 34567337 PMCID: PMC8456409 DOI: 10.1021/acs.jpcc.1c02871] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 06/17/2021] [Indexed: 06/13/2023]
Abstract
Although spectroscopic investigation of surface chemisorbed CO2 species has been the focus of most studies, identifying different domains of weakly interacting (physisorbed) CO2 molecules in confined spaces is less trivial as they are often indistinguishable resorting to (isotropic) NMR chemical shift or vibrational band analyses. Herein, we undertake for the first time a thorough solid-state NMR analysis of CO2 species physisorbed prior to and after amine-functionalization of silica surfaces; combining 13C NMR chemical shift anisotropy (CSA) and longitudinal relaxation times (T 1). These methods were used to quantitatively distinguish otherwise overlapping physisorbed CO2 signals, which contributed to an empirical model of CO2 speciation for the physi- and chemisorbed fractions. The quantitatively measured T 1 values confirm the presence of CO2 molecular dynamics on the microsecond, millisecond, and second time scales, strongly supporting the existence of up to three physisorbed CO2 species with proportions of about 15%, 15%, and 70%, respectively. Our approach takes advantage from using adsorbed 13C-labeled CO2 as probe molecules and quantitative cross-polarization magic-angle spinning to study both physi- and chemisorbed CO2 species, showing that 45% of chemisorbed CO2 versus 55% of physisorbed CO2 is formed from the overall confined CO2 in amine-modified hybrid silicas. A total of six distinct CO2 environments were identified from which three physisorbed CO2 were discriminated, coined here as "gas, liquid, and solid-like" CO2 species. The complex nature of physisorbed CO2 in the presence and absence of chemisorbed CO2 species is revealed, shedding light on what fractions of weakly interacting CO2 are affected upon pore functionalization. This work extends the current knowledge on CO2 sorption mechanisms providing new clues toward CO2 sorbent optimization.
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Affiliation(s)
| | | | - João Pereira
- CICECO − Aveiro Institute
of Materials, Department of Chemistry, University
of Aveiro, Campus Universitário
de Santiago, 3810-193 Aveiro, Portugal
| | - Rita Fonseca
- CICECO − Aveiro Institute
of Materials, Department of Chemistry, University
of Aveiro, Campus Universitário
de Santiago, 3810-193 Aveiro, Portugal
| | - Marina Ilkaeva
- CICECO − Aveiro Institute
of Materials, Department of Chemistry, University
of Aveiro, Campus Universitário
de Santiago, 3810-193 Aveiro, Portugal
| | - Mariana Sardo
- CICECO − Aveiro Institute
of Materials, Department of Chemistry, University
of Aveiro, Campus Universitário
de Santiago, 3810-193 Aveiro, Portugal
| | - Luís Mafra
- CICECO − Aveiro Institute
of Materials, Department of Chemistry, University
of Aveiro, Campus Universitário
de Santiago, 3810-193 Aveiro, Portugal
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10
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The latest development on amine functionalized solid adsorbents for post-combustion CO2 capture: Analysis review. Chin J Chem Eng 2021. [DOI: 10.1016/j.cjche.2020.11.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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11
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Abstract
Carbon capture from large sources and ambient air is one of the most promising strategies to curb the deleterious effect of greenhouse gases. Among different technologies, CO2 adsorption has drawn widespread attention mostly because of its low energy requirements. Considering that water vapor is a ubiquitous component in air and almost all CO2-rich industrial gas streams, understanding its impact on CO2 adsorption is of critical importance. Owing to the large diversity of adsorbents, water plays many different roles from a severe inhibitor of CO2 adsorption to an excellent promoter. Water may also increase the rate of CO2 capture or have the opposite effect. In the presence of amine-containing adsorbents, water is even necessary for their long-term stability. The current contribution is a comprehensive review of the effects of water whether in the gas feed or as adsorbent moisture on CO2 adsorption. For convenience, we discuss the effect of water vapor on CO2 adsorption over four broadly defined groups of materials separately, namely (i) physical adsorbents, including carbons, zeolites and MOFs, (ii) amine-functionalized adsorbents, and (iii) reactive adsorbents, including metal carbonates and oxides. For each category, the effects of humidity level on CO2 uptake, selectivity, and adsorption kinetics under different operational conditions are discussed. Whenever possible, findings from different sources are compared, paying particular attention to both similarities and inconsistencies. For completeness, the effect of water on membrane CO2 separation is also discussed, albeit briefly.
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Affiliation(s)
- Joel M Kolle
- Centre for Catalysis Research and Innovation, Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Mohammadreza Fayaz
- Centre for Catalysis Research and Innovation, Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Abdelhamid Sayari
- Centre for Catalysis Research and Innovation, Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
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Sisakht NN, Rouzbahani MM, Karbasi A, Zarinabadi S, Sabzalipour S. CO 2 chemical absorption from fluid catalytic cracking unit flue gases of Abadan Oil Refinery in Iran, using diethanolamine solvent. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:25312-25326. [PMID: 32342428 DOI: 10.1007/s11356-020-08708-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 04/01/2020] [Indexed: 06/11/2023]
Abstract
The Fluid Catalytic Cracking Unit process converts heavy vacuum gas oil into more valuable products in the presence of zeolite catalyst at 520 °C and 2.5 bar. The coke is burned off with air in the regenerator tower at 700 °C and 230 ton / h of flue gases are produced. The flue gases consist of CO2 (12.7% mole), N2 (66.2% mole), H2O (19.2% mole), O2 (1.7% mole), and SO2 (0.2% mole). In this study, the chemical absorption of CO2 in an absorption and desorption pilot plant was investigated and this process was simulated by Aspen Hysys. The pilot plant used has an absorber tower of 15 cm in diameter and a stripper tower of 10 cm. The towers were filled up to 1.5 m with 3-mm Raschig ring packing. A concentration of 30 wt% diethanolamine (DEA) solvent is used for CO2 absorption. Absorption was carried out at 1.1 bar, solvent temperature of 40 °C, flue gas temperature of 60 °C, and liquid to gas ratio (L/G = 3.7). Amine regeneration was carried out at 125 °C and 1.9 bar. The CO2 absorption efficiency in the pilot plant was obtained 96% and in Aspen Hysys simulation its 95%. The CO2 recovery efficiency in the stripper tower obtained 95% and CO2 purity is 94.6%. The overall efficiency of the chemical absorption with this process is 92%, and the regeneration energy in the stripper tower is 2.52 GJ/ton-co2. With this method, 1003 ton/day CO2 is captured from the FCCU flue gases and preventing emission to the atmosphere.
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Affiliation(s)
| | | | - Abdolreza Karbasi
- School of Environment, College of Engineering, Tehran University, Tehran, Iran
| | - Sorosh Zarinabadi
- Department of Engineering, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran
| | - Sima Sabzalipour
- Department of Environment, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran
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Afonso R, Sardo M, Mafra L, Gomes JRB. Unravelling the Structure of Chemisorbed CO 2 Species in Mesoporous Aminosilicas: A Critical Survey. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:2758-2767. [PMID: 30730709 DOI: 10.1021/acs.est.8b05978] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Chemisorbent materials, based on porous aminosilicas, are among the most promising adsorbents for direct air capture applications, one of the key technologies to mitigate carbon emissions. Herein, a critical survey of all reported chemisorbed CO2 species, which may form in aminosilica surfaces, is performed by revisiting and providing new experimental proofs of assignment of the distinct CO2 species reported thus far in the literature, highlighting controversial assignments regarding the existence of chemisorbed CO2 species still under debate. Models of carbamic acid, alkylammonium carbamate with different conformations and hydrogen bonding arrangements were ascertained using density functional theory (DFT) methods, mainly through the comparison of the experimental 13C and 15N NMR chemical shifts with those obtained computationally. CO2 models with variable number of amines and silanol groups were also evaluated to explain the effect of amine aggregation in CO2 speciation under confinement. In addition, other less commonly studied chemisorbed CO2 species (e.g., alkylammonium bicarbonate, ditethered carbamic acid and silylpropylcarbamate), largely due to the difficulty in obtaining spectroscopic identification for those, have also been investigated in great detail. The existence of either neutral or charged (alkylammonium siloxides) amine groups, prior to CO2 adsorption, is also addressed. This work extends the molecular-level understanding of chemisorbed CO2 species in amine-oxide hybrid surfaces showing the benefit of integrating spectroscopy and theoretical approaches.
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Affiliation(s)
- Rui Afonso
- CICECO - Aveiro Institute of Materials, Department of Chemistry , University of Aveiro, Campus Universitário de Santiago , 3810-193 Aveiro , Portugal
| | - Mariana Sardo
- CICECO - Aveiro Institute of Materials, Department of Chemistry , University of Aveiro, Campus Universitário de Santiago , 3810-193 Aveiro , Portugal
| | - Luís Mafra
- CICECO - Aveiro Institute of Materials, Department of Chemistry , University of Aveiro, Campus Universitário de Santiago , 3810-193 Aveiro , Portugal
| | - José R B Gomes
- CICECO - Aveiro Institute of Materials, Department of Chemistry , University of Aveiro, Campus Universitário de Santiago , 3810-193 Aveiro , Portugal
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Sobala K, Kierzkowska-Pawlak H. Heat of absorption of CO2 in aqueous N,N-diethylethanolamine + N-methyl-1,3-propanediamine solutions at 313 K. Chin J Chem Eng 2019. [DOI: 10.1016/j.cjche.2018.11.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Reaction Kinetics of Carbon Dioxide in Aqueous Blends of N-Methyldiethanolamine and L-Arginine Using the Stopped-Flow Technique. Processes (Basel) 2019. [DOI: 10.3390/pr7020081] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
: Reduction of carbon dioxide emission from natural and industrial flue gases is paramount to help mitigate its effect on global warming. Efforts are continuously deployed worldwide to develop efficient technologies for CO2 capture. The use of environment friendly amino acids as rate promoters in the present amine systems has attracted the attention of many researchers recently. In this work, the reaction kinetics of carbon dioxide with blends of N-methyldiethanolamine and L-Arginine was investigated using stopped flow technique. The experiments were performed over a temperature range of 293 to 313 K and solution concentration up to one molar of different amino acid/amine ratios. The overall reaction rate constant (kov) was found to increase with increasing temperature and amine concentration as well as with increased proportion of L-Arginine concentration in the mixture. The experimental data were fitted to the zwitterion and termolecular mechanisms using a nonlinear regression technique with an average absolute deviation (AAD) of 7.6% and 8.0%, respectively. A comparative study of the promoting effect of L-Arginine with that of the effect of Glycine and DEA in MDEA blends showed that MDEA-Arginine blend exhibits faster reaction rate with CO2 with respect to MDEA-DEA blend, while the case was converse when compared to the MDEA-Glycine blend.
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