Journal articles: 'CO2 adsorption and separation'

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Yan, Junzhi, Yuming Sun, Junxi Cai, Ming Cai, Bo Hu, Yan Yan, Yue Zhang, and Xu Tang. "Construction of ZnCdS Quantum-Dot-Modified CeO2 (0D–2D) Heterojunction for Enhancing Photocatalytic CO2 Reduction and Mechanism Insight." Catalysts 14, no. 9 (September 6, 2024): 599. http://dx.doi.org/10.3390/catal14090599.

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It is important to improve the separation ability of photogenerated electrons and the adsorption capacity of carbon dioxide (CO2) for efficient photoreduction of CO2. Here, we synthesized ZnCdS quantum dots (ZCS-QDs) and cerium dioxide nanosheets (CeO2) using the solvothermal method and calcination method. We combined CeO2 and ZCS-QDs to effectively enhance the charge separation efficiency, and the lifetime of photogenerated electrons was increased 4.5 times. The CO evolution rate of the optimized composite (ZCS-QDs/CeO2) was up to 495.8 μmol g−1 h−1, and it had 100% product selectivity. In addition, the stability remained high after five cycles. The CO2 adsorption capacity of the catalyst surface was observed by in situ FTIR. The test results showed that improving CO2 capture ability and promoting photogenic electron separation had positive effects on enhancing photoreduction of CO2. This study provides a reference for constructing a zero-dimensional–two-dimensional (0D–2D) heterojunction and explores potential CO2 reduction reaction mechanisms.

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Hasegawa, Yasuhisa, Mayumi Natsui, Chie Abe, Ayumi Ikeda, and Sean-Thomas B. Lundin. "Estimation of CO2 Separation Performances through CHA-Type Zeolite Membranes Using Molecular Simulation." Membranes 13, no. 1 (January 3, 2023): 60. http://dx.doi.org/10.3390/membranes13010060.

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Chabazite (CHA)-type zeolite membranes are a potential material for CO2 separations because of their small pore aperture, large pore volume, and low aluminum content. In this study, the permeation and separation properties were evaluated using a molecular simulation technique with a focus on improving the CO2 separation performance. The adsorption isotherms of CO2 and CH4 on CHA-type zeolite with Si/Al = 18.2 were predicted by grand canonical Monte Carlo, and the diffusivities in zeolite micropores were simulated by molecular dynamics. The CO2 separation performance of the CHA-type zeolite membrane was estimated by a Maxwell–Stefan equation, accounting for mass transfer through the support tube. The results indicated that the permeances of CO2 and CH4 were influenced mainly by the porosity of the support, with the CO2 permeance reduced due to preferential adsorption with increasing pressure drop. In contrast, it was important for estimation of the CH4 permeance to predict the amounts of adsorbed CH4. Using molecular simulation and the Maxwell–Stefan equation is shown to be a useful technique for estimating the permeation properties of zeolite membranes, although some problems such as predicting accurate adsorption terms remain.

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Lyu, Weifeng, Linghui Sun, Lu Wang, Zemin Ji, Sainan Zhou, Yong Chen, and Xiaoqing Lu. "Nitrogen Atom-Doped Layered Graphene for High-Performance CO2/N2 Adsorption and Separation." Energies 15, no. 10 (May 18, 2022): 3713. http://dx.doi.org/10.3390/en15103713.

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The development of high-performance CO2 capture and separation adsorbents is critical to alleviate the deteriorating environmental issues. Herein, N atom-doped layered graphene (N-MGN) was introduced to form triazine and pyridine as potential CO2 capture and separation adsorbents via regulation of interlayer spacings. Structural analyses showed that accessible surface area of the N-MGN is 2521.72 m2 g−1, the porosity increased from 9.43% to 84.86%. At ultra-low pressure, N-MGN_6.8 have exhibited a high CO2 adsorption capacity of 10.59 mmol/g at 298 K and 0.4 bar. At high pressure, the absolute adsorption capacities of CO2 in N-MGN_17.0 (40.16 mmol g−1) at 7.0 MPa and 298 K are much larger than that of N-doping slit pore. At 298 K and 1.0 bar, the highest selectivity of CO2 over N2 reached up to ~133 in N-MGN_6.8. The research shows that N doping can effectively improve the adsorption and separation capacity of CO2 and N2 in layered graphene, and the interlayer spacing has an important influence on the adsorption capacity of CO2/N2. The adsorption heat and relative concentration curves further confirmed that the layered graphene with an interlayer spacing of 6.8 Å has the best adsorption and separation ability of CO2 and N2 under low pressure. Under high pressure, the layered graphene with the interlayer spacing of 17.0 Å has the best adsorption and separation ability of CO2 and N2.

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Jingyi Shan, Jingyi Shan, Xiangling Wang Xiangling Wang, Junkai Wang Junkai Wang, Shixuan Zhang Shixuan Zhang, and Qianku Hu and Aiguo Zhou Qianku Hu and Aiguo Zhou. "Electric Field Controlled Separation and Capture of CO2 over S-Doped Graphene: A First-Principles Calculation." Journal of the chemical society of pakistan 43, no. 6 (2021): 623. http://dx.doi.org/10.52568/000964/jcsp/43.06.2021.

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The selective adsorption and capture of CO2 from post-combustion gases carries huge significance for the reduction of greenhouse effect. In this research, the computations of density functional are performed to investigate the CO2 selective adsorption of S-doped graphene in thrall to applied electric field (E-F). Introducing the applied E-F, the adsorption between S-doped graphene and CO2 is strong chemisorption, and CO2 can be effectively captured. Removing the applied E-F, the adsorption restores to physisorption and CO2 is easily desorbed. Therefore, the CO2 seize and clearing can be realized merely by controlling the E-F. Besides, the adsorption energy of N2 (H2O) on S-decorated graphene is positive when introduce the applied E-F. The results demonstrated that S-doped graphene can selectively adsorb CO2 from the post-combustion gases by controlling the E-F.

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Hernández, Miguel Ángel, Karla Quiroz-Estrada, Gabriela I. Hernandez-Salgado, Roberto Ignacio Portillo, Juana Deisy Santamaría-Juárez, Ma de los Ángeles Velasco, Efraín Rubio, and Vitalii Petranovskii. "Nanoporosity and Isosteric Enthalpy of Adsorption of CH4, H2, and CO2 on Natural Chabazite and Exchanged." Separations 9, no. 6 (June 10, 2022): 150. http://dx.doi.org/10.3390/separations9060150.

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This paper describes the isosteric enthalpy through narrow pores at low levels of coverage through adsorption of CO2, CH4, and H2 on pores in natural chabazite exchanged with aqueous solutions of Na+, Mg2+, and Ca2+ salts at different concentrations, and with variable time and temperature of treatment. Experimental data of CO2, CH4, and H2 adsorption were treated by the Freundlich and Langmuir equations. Complementarily, the degree of interaction of these gases with these zeolites was evaluated by the evolution of isosteric enthalpy of adsorption. The exchange with Mg2+ and Na+ favors an increase in the adsorption capacity for CO2. while that of Ca2+ and Mg2+ favor adsorption through to H2 and CH4. These cations occupy sites in strategic positions S4 and S4’, which are located in the channels and nanocavities of these zeolites. The presence of Ca2+ and Mg2+ at S4 and S4′ sites causes increased adsorption into the nanocavities and on the external area of the ion-exchanged zeolites. Depending on the conditions of the exchange treatment, Ca2+ and Mg2+, and Na+ were found to be most favorable, well distributed, and accessible for CO2, CH4, and H2 adsorption.

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Wan, Yinji, Yefan Miao, Ruiqin Zhong, and Ruqiang Zou. "High-Selective CO2 Capture in Amine-Decorated Al-MOFs." Nanomaterials 12, no. 22 (November 17, 2022): 4056. http://dx.doi.org/10.3390/nano12224056.

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Amine-functionalized metal-organic framework (MOF) material is a promising CO2 captor in the post-combustion capture process owing to its large CO2 working capacity as well as high CO2 selectivity and easy regeneration. In this study, an ethylenediamine (ED)-decorated Al-based MOFs (named ED@MOF-520) with a high specific area and permanent porosity are prepared and evaluated to study the adsorption and separation of CO2 from N2. The results show that ED@MOF-520 adsorbent displays a superior CO2 capture performance with a CO2/N2 separation factor of 50 at 273 K, 185% times increase in the CO2/N2 separation efficiency in comparison with blank MOF-520. Furthermore, ED@MOF-520 exhibits a moderate-strength interaction with 29 kJ mol−1 adsorption heat for CO2 uptake, which not only meets the requirement of CO2 adsorption but also has good cycle stability. This work provides a promising adsorbent with a high CO2/N2 separation factor to deal with carbon peak and carbon neutrality.

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Yusubov, F. V., I. A. Aliyev, and S. N. Guliyeva. "Study of adsorption separation of gas mixtures under non-stationary conditions." Theoretical and Applied Ecology, no. 2 (June 25, 2024): 101–7. http://dx.doi.org/10.25750/1995-4301-2024-2-101-107.

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The influence of the initial concentration, rate and temperature of adsorption on the adsorption separation of gas mixtures (CO2, CH4, N2, H2S) is investigated. Components: N2 – 5%, H2S – 5%, CO2 – 5% and CH4 – 85%. And as an adsorbent granule of clinoptilolite of irregular shape were used. Isothermal adsorption of CO2 was obtained at different temperatures (293, 313, and 323 K). The obtained isotherms of CO2 adsorption showed that with an increase in temperature, the adsorption of CO2 decreased. The type of isotherms corresponds to Langmuir. The output curves of gas mixture adsorption depending on the gas flow rate and various main components of CO2 were also experimentally studied. The output curves of the adsorption of the CO2 component were studied at various gas flow rates of 20, 50, and 80 mL/min. Equilibrium time increases with a decrease in the gas flow rate. Output curves were also obtained depending on the initial CO2 concentrations of 5%, 10% and 20%. It was determined that with a decrease in the initial concentration of CO2, the equilibrium time also increases. Gas mixture components sorbed downwards: H2S→CO2→CH4→N2. The resulting system of model equations describing the adsorption separation of gas mixtures in a fixed adsorbent layer represents a complete mathematical model of the process under unsteady conditions. The obtained regularities of the process of adsorption of gas mixtures testify to the fact that the process takes place under non-stationary conditions. The proposed models for the optimal design of industrial absorbers can be used for adsorption separation of gas mixtures in the conditions of their unsteady flow.

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Yang, Lingzhi, Wenpeng Xie, Qiuju Fu, Liting Yan, Shuo Zhang, Huimin Jiang, Liangjun Li, et al. "Highly Selective Separation of C2H2/CO2 and C2H2/C2H4 in an N-Rich Cage-Based Microporous Metal-Organic Framework." Adsorption Science & Technology 2023 (March 1, 2023): 1–9. http://dx.doi.org/10.1155/2023/4740672.

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The separation of acetylene (C2H2) from carbon dioxide (CO2) and the purification of ethylene (C2H4) from C2H2 are quite essential processes for the chemical industry. However, these processes are challenging due to their similar physical properties, including molecule sizes and boiling points. Herein, we report an N-rich cage-based microporous metal-organic framework (MOF), [Cd5(Tz)9](NO3) (termed as Cd-TZ, TZ stands for tetrazole), and its highly efficient separation of C2H2/CO2 and C2H2/C2H4. Single-component gas adsorption isotherms reveal that Cd-TZ exhibits high C2H2 adsorption capacity (3.10 mmol g-1 at 298 K and 1 bar). The N-rich cages in Cd-TZ can trap C2H2 with a higher isosteric heat of adsorption (40.8 kJ mol-1) than CO2 and C2H4 owing to the robust host-guest interactions between the noncoordinated N atoms and C2H2, which has been verified by molecular modeling studies. Cd-TZ shows a high IAST selectivity for C2H2/CO2 (8.3) and C2H2/C2H4 (13.3). The breakthrough simulations confirm the potential for separating C2H2/CO2 and the purification of C2H4 from C2H2.

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Li, Yao, Shiying Wang, Binbin Wang, Yan Wang, and Jianping Wei. "Sustainable Biomass Glucose-Derived Porous Carbon Spheres with High Nitrogen Doping: As a Promising Adsorbent for CO2/CH4/N2 Adsorptive Separation." Nanomaterials 10, no. 1 (January 19, 2020): 174. http://dx.doi.org/10.3390/nano10010174.

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Separation of CO2/CH4/N2 is significantly important from the view of environmental protection and energy utilization. In this work, we reported nitrogen (N)-doped porous carbon spheres prepared from sustainable biomass glucose via hydrothermal carbonization, CO2 activation, and urea treatment. The optimal carbon sample exhibited a high CO2 and CH4 capacity, as well as a low N2 uptake, under ambient conditions. The excellent selectivities toward CO2/N2, CO2/CH4, and CH4/N2 binary mixtures were predicted by ideal adsorbed solution theory (IAST) via correlating pure component adsorption isotherms with the Langmuir−Freundlich model. At 25 °C and 1 bar, the adsorption capacities for CO2 and CH4 were 3.03 and 1.3 mmol g−1, respectively, and the IAST predicated selectivities for CO2/N2 (15/85), CO2/CH4 (10/90), and CH4/N2 (30/70) reached 16.48, 7.49, and 3.76, respectively. These results should be attributed to the synergistic effect between suitable microporous structure and desirable N content. This report introduces a simple pathway to obtain N-doped porous carbon spheres to meet the flue gas and energy gas adsorptive separation requirements.

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Ismail, Marhaina, Mohamad Azmi Bustam, Nor Ernie Fatriyah Kari, and Yin Fong Yeong. "Ideal Adsorbed Solution Theory (IAST) of Carbon Dioxide and Methane Adsorption Using Magnesium Gallate Metal-Organic Framework (Mg-gallate)." Molecules 28, no. 7 (March 28, 2023): 3016. http://dx.doi.org/10.3390/molecules28073016.

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Ideal Adsorbed Solution Theory (IAST) is a predictive model that does not require any mixture data. In gas purification and separation processes, IAST is used to predict multicomponent adsorption equilibrium and selectivity based solely on experimental single-component adsorption isotherms. In this work, the mixed gas adsorption isotherms were predicted using IAST calculations with the Python package (pyIAST). The experimental CO2 and CH4 single-component adsorption isotherms of Mg-gallate were first fitted to isotherm models in which the experimental data best fit the Langmuir model. The presence of CH4 in the gas mixture contributed to a lower predicted amount of adsorbed CO2 due to the competitive adsorption among the different components. Nevertheless, CO2 adsorption was more favorable and resulted in a higher predicted adsorbed amount than CH4. Mg-gallate showed a stronger affinity for CO2 molecules and hence contributed to a higher CO2 adsorption capacity even with the coexistence of a CO2/CH4 mixture. Very high IAST selectivity values for CO2/CH4 were obtained which increased as the gas phase mole fraction of CO2 approached unity. Therefore, IAST calculations suggest that Mg-gallate can act as a potential adsorbent for the separation of CO2/CH4 mixed gas.

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Rodriguez Acevedo, Elizabeth, Farid B. Cortés, Camilo A. Franco, Francisco Carrasco-Marín, Agustín F. Pérez-Cadenas, Vanessa Fierro, Alain Celzard, Sébastien Schaefer, and Agustin Cardona Molina. "An Enhanced Carbon Capture and Storage Process (e-CCS) Applied to Shallow Reservoirs Using Nanofluids Based on Nitrogen-Rich Carbon Nanospheres." Materials 12, no. 13 (June 28, 2019): 2088. http://dx.doi.org/10.3390/ma12132088.

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The implementation of carbon capture and storage process (CCS) has been unsuccessful to date, mainly due to the technical issues and high costs associated with two main stages: (1) CO2 separation from flue gas and (2) CO2 injection in deep geological deposits, more than 300 m, where CO2 is in supercritical conditions. This study proposes, for the first time, an enhanced CCS process (e-CCS), in which the stage of CO2 separation is removed and the flue gas is injected directly in shallow reservoirs located at less than 300 m, where the adsorptive phenomena control CO2 storage. Nitrogen-rich carbon nanospheres were used as modifying agents of the reservoir porous texture to improve both the CO2 adsorption capacity and selectivity. For this purpose, sandstone was impregnated with a nanofluid and CO2 adsorption was evaluated at different pressures (atmospheric pressure and from 3 × 10−3 MPa to 3.0 MPa) and temperatures (0, 25, and 50 °C). As a main result, a mass fraction of only 20% of nanomaterials increased both the surface area and the molecular interactions, so that the increase of adsorption capacity at shallow reservoir conditions (50 °C and 3.0 MPa) was more than 677 times (from 0.00125 to 0.9 mmol g−1).

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Wang, Shiqing, Xu Jiang, Yutong Wang, Jiaxin Liu, Xiaolong Qiu, Lianbo Liu, Shiwang Gao, Xiong Yang, Jing Ma, and Chuanzhao Zhang. "Molecular Simulation of Adsorption of CO2 from a Combustion Exhaust Mixture of Zeolites with Different Topological Structures." Processes 12, no. 12 (December 2, 2024): 2730. https://doi.org/10.3390/pr12122730.

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In this work, a molecular simulation method was used to study the adsorption of seven combustion products (CO2, H2O, SO2, N2, O2, NO and NO2) on three zeolites with different topological structures (4A, MIF and MOR). Adsorption isotherms of pure components and mixtures at a wide range of temperatures (253–333 K) were calculated using the Monte Carlo method, obtaining equilibrium parameters including the adsorption capacity, adsorption heat and energy distribution. The calculation results indicated that 4A zeolite with more micropores has a stronger adsorption performance for CO2. The presence of water significantly reduced the CO2 capture efficiency of the three zeolites, and the CO2 adsorption amount decreased by more than 80%. Adsorption kinetics was studied using the molecular dynamic (MD) method, MFI and MOR, with channel-type pore structures exhibiting stronger gas diffusion performance, though their separation efficiency was not high. A 4A zeolite has the potential for kinetic separation of CO2.

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Huang, Hengcong, Luyao Wang, Xiaoyu Zhang, Hongshuo Zhao, and Yifan Gu. "CO2-Selective Capture from Light Hydrocarbon Mixtures by Metal-Organic Frameworks: A Review." Clean Technologies 5, no. 1 (December 20, 2022): 1–24. http://dx.doi.org/10.3390/cleantechnol5010001.

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CO2 represents a typical impurity in light hydrocarbon feedstocks, which affects the quality of subsequent chemical products. Owing to their highly similar nature, industrial separation requires large amounts of energy. Adsorptive gas separation based on porous materials is considered an efficient alternative, as it can offer faster kinetics, higher selectivity, long-term stability and more energy-efficient regeneration. For the adsorption separation method, preferential CO2 capture from gas mixtures in one step is more energy-efficient for direct purification than light hydrocarbons, saving about 40% energy by eliminating energy-intensive post-regeneration processes such as countercurrent vacuum blowdown. Therefore, CO2-selective adsorbents are more sought-after than light hydrocarbon-selective adsorbents. Metal-organic frameworks (MOFs) have been demonstrated as outstanding physisorbents for CO2 capture due to their configurable channels for CO2 recognition, structural flexibility and large specific surface area. Many highly selective CO2 adsorption behaviors of MOFs have been reportedly achieved by precise modulation of pore size, pore chemistry or structural flexibility. In this review, we discuss the emerging development of MOFs for CO2-selective capture from different light hydrocarbon mixtures. The challenges of CO2 recognition and the strategies employed to achieve CO2 selectivity over light hydrocarbon mixtures by MOFs are summarized. In addition, the current challenges and prospects in the field of MOFs for CO2 capture are discussed and elaborated.

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Jian, Weiwei, Qiuyan Hai, Adili Youlidaxi, Tianqiang Liu, Danzhu Ma, and Fengrui Jia. "Modification of Copper Benzene-1,3,5-tricarboxy Late (Cu-BTC) Composites with Multiwalled Carbon Nanotubes and Amino Groups for Enhanced CO2/CH4 Selective Adsorption Performance and Water Stability." Processes 12, no. 4 (April 7, 2024): 745. http://dx.doi.org/10.3390/pr12040745.

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CNT-NH2-Cu-BTC was prepared via hydrothermal synthesis for the adsorption and separation of CO2/CH4 mixtures with 2, 6, and 10% multiwalled carbon nanotube (MWCNT) additions. NH2-BTC composites were synthesized by changing the organic ligand and adding NH2-BDC (15, 25, 35, and 45%) to improve the adsorption capacity. MWCNTS were loaded to enhance the water stability of the material. The structure, surface morphology, and pore size distribution of the composites were characterized using X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and specific surface area and pore structure measurements. The CO2/CH4 selective adsorption performance was studied via breakthrough experiments using a self-made adsorption device. The CO2 adsorption capacity of Cu-BTC increased due to the addition of NH2-BDC, with 35%NH2-Cu-BTC exhibiting the best CO2 adsorption property, i.e., a CO2 adsorption capacity of 1.82 mmol/g and a CO2/CH4 separation coefficient of 1.44 at 35 °C and 20 mL/min. After adding MWCNTs, 6%CNT-NH2-Cu-BTC exhibited the best CO2 adsorption property and water stability, with the CO2 adsorption capacity increasing to 2.06 mmol/g. 6%CNT-NH2-Cu-BTC with wet impregnation retained 79% of the CO2 adsorption capacity of the sample without wet impregnation, demonstrating its excellent water stability under humid conditions. Cyclic experiments with and without wet impregnation were performed.

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Jin, Xin, Hui Jiang, Yi Chen, Xin Han, Ken Sun, Linlin Shi, Xin-Qi Hao, and Mao-Ping Song. "A Cavity-Tailored Metal-Organic Tetrahedral Nanocage and Gas Adsorption Property." Nanomaterials 12, no. 24 (December 9, 2022): 4402. http://dx.doi.org/10.3390/nano12244402.

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Porous organometallic nanomaterials are a new class of materials based on a three-dimensional structure. They have excellent applications in different fields, but their applications in gas storage and separation have not been fully developed. CO2 adsorption storage and hydrocarbon separation has been a challenging industrial problem. Several typical molecular adsorbents have been used to study the separation, but the problems of long-term stability, high selectivity and synthetic complexity of these adsorbents remain to be solved. Here, we have designed and synthesized tetrahedral metal supramolecular nanocage with custom cavities based on the unique rigid structure of triptycene derivatives. Using the unique discrete porous structure of tetrahedral metal nanocages, the gas adsorption and separation performance of the metal supramolecular nanocage was investigated. By analyzing the adsorption and desorption isotherms and the multi-component competitive adsorption curves, we noticed that the tetrahedral supramolecular nanocages had good CO2 storage capacity and good separation capacity for C2H2/CO2 and C2H2/N2. All these indicate that porous organic metal nanomaterials are expected to be a new energy saving separation material.

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Selmert, Victor, Ansgar Kretzschmar, Hans Kungl, Hermann Tempel, and Rüdiger-A. Eichel. "Breakthrough analysis of the CO2/CH4 separation on electrospun carbon nanofibers." Adsorption 30, no. 1 (January 2024): 107–19. http://dx.doi.org/10.1007/s10450-023-00435-6.

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AbstractThe removal of the main impurity CO2 is a crucial step in biogas upgrading. In this work, the separation of CO2 from CH4 on electrospun polyacrylonitrile-based carbon nanofibers (CNFs) is investigated using breakthrough experiments. The CNFs are prepared at various carbonization temperatures ranging from 600 to 900 °C and feature a tailorable pore size that decreases at higher carbonization temperatures. The adsorption properties of the different CNFs are studied measuring pure component isotherms as well as column breakthrough experiments. Adsorption kinetics are discussed using a linear driving force approach to model the breakthrough experiment and obtain the adsorption rate constant. Moreover, different approaches to determine the selectivity of the competitive CO2/CH4 adsorption are applied and discussed in detail. The results clearly prove that a size exclusion effect governs the adsorption selectivity on the CNFs. While CH4 cannot adsorb in the pores of CNFs prepared at 800 °C or above, the smaller CO2 is only excluded from the pores of CNFs prepared at 900 °C. For CNFs carbonized in the range from 600 to 750 °C, values of the CO2/CH4 selectivity of 11–14 are obtained. On the CNFs prepared at 800 °C the CH4 adsorption is severely hindered, leading to a reduced adsorbed amount of CH4 and consequently to an improved CO2/CH4 selectivity of 40. Furthermore, owing to the shrinking pores, the adsorption rates of CH4 and CO2 decrease with higher carbonization temperature.

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Bayati, Behrouz, Asma Ghorbani, Kamran Ghasemzadeh, Adolfo Iulianelli, and Angelo Basile. "Study on the Separation of H2 from CO2 Using a ZIF-8 Membrane by Molecular Simulation and Maxwell-Stefan Model." Molecules 24, no. 23 (November 28, 2019): 4350. http://dx.doi.org/10.3390/molecules24234350.

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The purification of H2-rich streams using membranes represents an important separation process, particularly important in the viewpoint of pre-combustion CO2 capture. In this study, the separation of H2 from a mixture containing H2 and CO2 using a zeolitic imidazolate framework (ZIF)-8 membrane is proposed from a theoretical point of view. For this purpose, the adsorption and diffusion coefficients of H2 and CO2 were considered by molecular simulation. The adsorption of these gases followed the Langmuir model, and the diffusion coefficient of H2 was much higher than that of CO2. Then, using the Maxwell–Stefan model, the H2 and CO2 permeances and H2/CO2 permselectivities in the H2–CO2 mixtures were evaluated. Despite the fact that adsorption of CO2 was higher than H2, owing to the simultaneous interference of adsorption and diffusion processes in the membrane, H2 permeation was more pronounced than CO2. The modeling results showed that, for a ZIF-8 membrane, the H2/CO2 permselectivity for the H2–CO2 binary mixture 80/20 ranges between 28 and 32 at ambient temperature.

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Chakraborty, Anindita, Syamantak Roy, Muthusamy Eswaramoorthy, and Tapas Kumar Maji. "Flexible MOF–aminoclay nanocomposites showing tunable stepwise/gated sorption for C2H2, CO2 and separation for CO2/N2 and CO2/CH4." Journal of Materials Chemistry A 5, no. 18 (2017): 8423–30. http://dx.doi.org/10.1039/c6ta09886j.

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Miricioiu, Marius Gheorghe, Anca Zaharioiu, Simona Oancea, Felicia Bucura, Maria Simona Raboaca, Constantin Filote, Roxana Elena Ionete, Violeta Carolina Niculescu, and Marius Constantinescu. "Sewage Sludge Derived Materials for CO2 Adsorption." Applied Sciences 11, no. 15 (August 2, 2021): 7139. http://dx.doi.org/10.3390/app11157139.

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The study tried to contribute to solving two serious environmental issues: CO2 reducing and sewage sludge disposal. Thus, sewage-sludge-derived materials were obtained in order to be evaluated for CO2 adsorption capacity. Therefore, the char resulted after the sewage sludge pyrolysis was subjected to oxidation and chemical activation processes by using different quantities of alkaline hydroxide. One of the obtained materials, activated with a lower quantity of alkaline hydroxide, was also treated with acid chloride. Further, the materials were structural and texturally characterized, and material treated with acid chloride was used for CO2 adsorption tests, due to high surface area and pore volume. The handmade system coupled to a gas chromatograph allowed the adsorption efficiency evaluation using different feed gases (rich and poor in CO2) by completed purge of pipe line and on-line check. Additionally, the adsorption capacity, separation efficiency, and CO2 recovery were calculated. Taking into account the values for adsorption capacity (separation efficiency and CO2 recovery), it can be concluded that the sewage sludge derived material could be a promising solution for CO2 reduction and waste disposal.

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Su, Yiru, Siyao Liu, and Xuechao Gao. "Impact of Impure Gas on CO2 Capture from Flue Gas Using Carbon Nanotubes: A Molecular Simulation Study." Molecules 27, no. 5 (March 1, 2022): 1627. http://dx.doi.org/10.3390/molecules27051627.

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We used a grand canonical Monte Carlo simulation to study the influence of impurities including water vapor, SO2, and O2 in the flue gas on the adsorption of CO2/N2 mixture in carbon nanotubes (CNTs) and carboxyl doped CNT arrays. In the presence of single impure gas, SO2 yielded the most inhibitions on CO2 adsorption, while the influence of water only occurred at low pressure limit (0.1 bar), where a one-dimensional chain of hydrogen-bonded molecules was formed. Further, O2 was found to hardly affect the adsorption and separation of CO2. With three impurities in flue gas, SO2 still played a major role to suppress the adsorption of CO2 by reducing the adsorption amount significantly. This was mainly because SO2 had a stronger interaction with carbon walls in comparison with CO2. The presence of three impurities in flue gas enhanced the adsorption complexity due to the interactions between different species. Modified by hydrophilic carboxyl groups, a large amount of H2O occupied the adsorption space outside the tube in the carbon nanotube arrays, and SO2 produced competitive adsorption for CO2 in the tube. Both of the two effects inhibited the adsorption of CO2, but improved the selectivity of CO2/N2, and the competition between the two determined the adsorption distribution of CO2 inside and outside the tube. In addition, it was found that (7, 7) CNT always maintained the best CO2/N2 adsorption and separation performance in the presence of impurity gas, for both the cases of single CNT and CNT array.

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Li, Pengli, Yongli Shen, Dandan Wang, Yanli Chen, and Yunfeng Zhao. "Selective Adsorption-Based Separation of Flue Gas and Natural Gas in Zirconium Metal-Organic Frameworks Nanocrystals." Molecules 24, no. 9 (May 11, 2019): 1822. http://dx.doi.org/10.3390/molecules24091822.

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Carbon capture from flue gas and natural gas offers a green path to construct a net-zero emissions economic system. Selective adsorption-based gas separation by employing metal-organic frameworks (MOFs) is regarded as a promising technology due to the advantages of simple processing, easy regeneration and high efficiency. We synthesized two Zirconium MOFs (UiO-66 and UiO-66-NH2) nanocrystals for selective capture and further removal of CO2 from flue gas and natural gas. In particular, UiO-66-NH2 nanocrystals have a smaller grain size, a large amount of defects, and pending –NH2 groups inside their pores which display effective CO2 selective adsorption abilities over CH4 and N2 with the theoretical separation factors of 20 and 7. This breakthrough experiment further verified the selective adsorption-based separation process of natural gas and flue gas. In one further step, we used the Monte Carlo simulation to investigate the optimized adsorption sites and energy of CO2, N2 and CH4 molecules in the gas mixture. The significantly large adsorption energy of CO2 (0.32 eV) over N2 (0.19 eV) and N2 (0.2 eV) may help us to reveal the selective adsorption mechanism.

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Vieira, Luciana Onofre, Alexandre Canarin Madeira, Aline Merlini, Carolina Resmini Melo, Erlon Mendes, Maria Glória Santos, Márcio Roberto da Rocha, and Elídio Angioletto. "Synthesis of 4A-Zeolite for Adsorption of CO₂." Materials Science Forum 805 (September 2014): 632–37. http://dx.doi.org/10.4028/www.scientific.net/msf.805.632.

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The gas separation is a very expensive step in the chemical industry and unquestionable relevance. In this work, was verified the efficiency of the use of type A-zeolites in the separation of CO2 in a gas mixture containing 25% CO2, 4% O2 and 71% N2. These concentrations are similar to the effluent gases from combustion processes. To this end, was synthesized type A-zeolites using commercial kaolin and mounted to an adsorption column to test the effectiveness of zeolites in the adsorption of CO2. The synthesized zeolites had surface area equal to 66.22 m2/g. The CO2 concentration was determined by gas chromatography with TCD detector. After adjusting the data to the Langmuir model, it was obtained the kinetic parameters of adsorption. Based on these parameters was found the ability of the zeolite to adsorb CO2, using a column of 0.461285 mg/g. The adsorption results have proved promising and showed maximum adsorption of 78.4% after a time of 10 seconds.

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Zang, Xiaoya, Na Zhang, Xuebing Zhou, Lihua Wan, and Deqing Liang. "Experimental Investigation of the Hydrate-Based Gas Separation of Synthetic Flue Gas with 5A Zeolite." Energies 13, no. 17 (September 2, 2020): 4556. http://dx.doi.org/10.3390/en13174556.

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Coal combustion flue gas contains CO2, a greenhouse gas and driver of climate change. Therefore, CO2 separation and removal is necessary. Fortunately, 5A zeolites are highly porous and can be used as a CO2 adsorbent. In addition, they act as nuclei for hydrate formation. In this work, a composite technology, based on the physical adsorption of CO2 by 5A zeolite and hydrate-based gas separation, was used to separate CO2/N2 gas mixtures. The influence of water content, temperature, pressure, and particle size on gas adsorption and CO2 separation was studied, revealing that the CO2 separation ability of zeolite particles sized 150–180 μm was better than that of those sized 380–830 μm at 271.2 K and 273.2 K. When the zeolite particles were 150–180 μm (type-B zeolite) with a water content of 35.3%, the gas consumption per mole of water (ngas/nH2O ) reached the maximum, 0.048, and the CO2 separation ratio reached 14.30%. The CO2 molar concentration in the remaining gas phase (xCO2gas) was lowest at 271.2 K in the type-B zeolite system with a water content of 47.62%. Raman analysis revealed that CO2 preferentially occupied the small hydrate cages and there was a competitive relationship between N2 and CO2.

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Wang, Yutong, Xu Jiang, Xiong Yang, Shiqing Wang, Xiaolong Qiu, Lianbo Liu, Shiwang Gao, Ziyi Li, and Chuanzhao Zhang. "Molecular Simulation of Adsorption Separation of CO2 from Combustion Exhaust Mixture of Commercial Zeolites." Processes 11, no. 10 (October 16, 2023): 2987. http://dx.doi.org/10.3390/pr11102987.

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The adsorption thermodynamics and kinetics of CO2 and six combustion products (H2O, SO2, N2, O2, NO and NO2) of two most commonly used commercial zeolites (13X and 5A) were studied based on validated molecular simulations. Adsorption isotherms at wide range of temperatures (253–333 K) were fitted by a Langmuir model, obtaining equilibrium parameters including the adsorption capacity, strength, heterogeneity and CO2 selectivity from the mixture. The diffusion coefficients, isosteric adsorption heats and distributions of potential energy were simulated for further explanation. The comprehensive evaluation results suggest that, in actual combustion product mixtures, the presence of H2O in combustion products has a significant impact on CO2 capture efficiency. Under the influence of water, the adsorption capacity of CO2 was reduced by over 80%.

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Vannak, Heak, Yugo Osaka, Takuya Tsujiguchi, and Akio Kodama. "Air-Purge Regenerative Direct Air Capture Using an Externally Heated and Cooled Temperature-Swing Adsorber Packed with Solid Amine." Separations 10, no. 7 (July 21, 2023): 415. http://dx.doi.org/10.3390/separations10070415.

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CO2 capture from air is crucial in achieving negative emissions. Based on conventional or newly developed high-enriching processes, we investigated the rough enrichment of CO2 from air via an externally heated or cooled adsorber (temperature-swing adsorption, TSA), along with air purge using double-pipe heat exchangers packed with low-volatility polyamine-loaded silica. A simple adsorption–desorption cycle was attempted in a TSA experiment, by varying the temperature from 20 °C to 60 °C using moist air, yielding an average CO2 concentration of product gas that was ~17 times higher than the feed air, but the CO2 recovery rate was poor. A double-step adsorption process was applied to increase CO2 adsorption and recovery simultaneously. In this process, substantial-CO2-concentration gas was used as the product gas, and the remaining gas was used as the reflux feed gas for adsorber. This method can provide a product gas with ~100 times higher CO2 concentration than raw gas, with a recovery ratio ~60% under the shortest adsorption/desorption time and the longest refluxing time of cycle operation. Therefore, the refluxing step significantly helped to enhance CO2 capture via adsorption from elevated-CO2-concentration recirculating gas. With this CO2 concentration, the product gas can serve as the CO2 supplement for the growing plant processes.

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Mitropoulos, Athanasios Ch, Ramonna I. Kosheleva, Margaritis Kostoglou, and Thodoris D. Karapantsios. "The Effect of Rotation on Gas Storage in Nanoporous Materials." Separations 11, no. 3 (February 24, 2024): 72. http://dx.doi.org/10.3390/separations11030072.

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Nanoporous materials offer a promising solution for gas storage applications in various scientific and engineering domains. However, several crucial challenges need to be addressed, including adsorptive capacity, rapid loading, and controlled gas delivery. A potential approach to tackle these issues is through rotation-based methods. In this study, we investigate the impact of rotation on CO2 adsorption using activated carbon, both at the early and late stages of the adsorption process. Towards this direction, three sets of experiments were conducted: (i) adsorption isotherm with rotation at each gas loading, (ii) adsorption kinetics with multiple rotations performed in sequence 15 min after CO2 introduction, and (iii) adsorption kinetics with a single rotation after 40 h of adsorption and repetition after another 20 h. For the first two cases, the comparison was performed by respective measurements without rotation, while for the last case, results were compared to a theoretical pseudo-first-order kinetic curve. Our findings demonstrate that rotation enhances the adsorptive capacity by an impressive 54%, accelerates kinetics by a factor of 3.25, and enables controllable gas delivery by adjusting the angular velocity. These results highlight rotation as a promising technique to optimize gas storage in nanoporous materials, facilitating advancements in numerous scientific and engineering applications.

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Zhang, Fucan, Ping Liu, Kan Zhang, and Qing-Wen Song. "Chemical Adsorption Strategy for DMC-MeOH Mixture Separation." Molecules 26, no. 6 (March 19, 2021): 1735. http://dx.doi.org/10.3390/molecules26061735.

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The effective separation of dimethyl carbonate (DMC) from its methanol mixture through simple, inexpensive and low energy-input method is a promising and challenging field in the process of organic synthesis. Herein, a reversible adsorption strategy through the assistance of superbase and CO2 for DMC/methanol separation at ambient condition was described. The process was demonstrated effectively via the excellent CO2 adsorption efficiency. Notably, the protocol was also suitable to other alcohol (i.e., monohydric alcohol, dihydric alcohol, trihydric alcohol) mixtures. The study provided guidance for potential separation of DMC/alcohol mixture in the scale-up production.

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Ismail, Marhaina, Mohamad Azmi Bustam, and Yin Fong Yeong. "Gallate-Based Metal–Organic Frameworks, a New Family of Hybrid Materials and Their Applications: A Review." Crystals 10, no. 11 (November 5, 2020): 1006. http://dx.doi.org/10.3390/cryst10111006.

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Within three decades of fundamental findings in research on metal–organic frameworks (MOFs), a new family of hybrid materials known as gallate-based MOFs, consisting of metal salt and gallic acid, have been of great interest. Due to the fact that gallic acid is acknowledged to display a range of bioactivities, gallate-based MOFs have been initially expended in biomedical applications. Recently, gallate-based MOFs have been gradually acting as new alternative materials in chemical industrial applications, in which they were first reported for the adsorptive separation of light hydrocarbon separations. However, to date, none of them have been related to CO2/CH4 separation. These porous materials have a bright future and can be kept in development for variety of applications in order to be applied in real industrial practices. Therefore, this circumstance creates a new opportunity to concentrate more on studies in CO2/CH4 applications by using porous material gallate-based MOFs. This review includes the description of recent gallate-based MOFs that presented remarkable properties in biomedical areas and gas adsorption and separation, as well as their future potential application.

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Yuan, Qin, Hong Hong Yi, Xiao Long Tang, Kai Li, Fen Rong Li, and Yun Dong Li. "Adsorption and Separation Research of CO₂/CH₄ on Modified Activated Carbon Fiber." Advanced Materials Research 986-987 (July 2014): 13–16. http://dx.doi.org/10.4028/www.scientific.net/amr.986-987.13.

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In this paper, activated carbon fibers were modified by different chemical reagents. The modified adsorbents were used to investigate adsorption and separation performance of CO2/CH4 gases mixture, and then it could get the best modified adsorbent. The experimental results show that amine can't great grafting on activated carbon fiber. Compared with blank activated carbon fibers, the adsorption property of CO2 did not have much influence on the activated carbon fiber modified by amine. However, it can increase the nitrogen functional groups and the specific surface area on the surface of activated carbon fiber that were modified with nitric acid and ammonia. The above two points were conductive to the adsorption and separation of CO2/CH4 mixture gases.

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Alias, Nur Hashimah, K. S. N. Kamarudi, Nurul Aimi Ghazali, T. A. T. Mohd, Arina Sauki, and Mohd Redwan Jaafar. "Carbon Dioxide Separation Using Amine Modified Zeolite in Pressure Swing Adsorption System." Key Engineering Materials 594-595 (December 2013): 160–67. http://dx.doi.org/10.4028/www.scientific.net/kem.594-595.160.

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Carbon dioxide (CO2) removal from natural gas attracts more attention than other impurities due to its corrosiveness property and it also possess no heating value in the sales natural gas. Amine based chemical absorption has been used commercially for CO2 separation in gas processing plant. However, the liquid amine based processes pose operating difficulties due to high regeneration energy, large equipments size and solvent leakage. This research studies modification of porous materials, zeolite NaY by grafting amine functional group using monoethanolamine directly to the surface of the solid sorbents. The structures and physical properties of amine modified adsorbent were characterized using powder X-Ray Diffraction (XRD), nitrogen adsorption at 77K and thermogravimetric analysis. Since application of Pressure Swing Adsorption (PSA) has been widely used in various plants in the world, this research was extended to study carbon dioxide separation using amine modified adsorbents in PSA experimental system. Effects of adsorption and regeneration behaviour on CO2 separation were investigated. Amine modified NaY showed better result compared to unmodified NaY in term of improvement in physical and chemical properties, high CO2 adsorption capacity and modified adsorbents were ease of regeneration.

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Li, Yao, Ran Xu, Binbin Wang, Jianping Wei, Lanyun Wang, Mengqi Shen, and Juan Yang. "Enhanced N-doped Porous Carbon Derived from KOH-Activated Waste Wool: A Promising Material for Selective Adsorption of CO2/CH4 and CH4/N2." Nanomaterials 9, no. 2 (February 15, 2019): 266. http://dx.doi.org/10.3390/nano9020266.

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Separation of impurities (CO2 and N2) from CH4 is an important issue for natural gas alternatives (such as coalbed gas, biogas, and landfill gas) upgrading. It is notably challenging to synthesize high N-doped porous carbon with an appropriate porous structure. In this work, high N content (14.48 wt %) porous carbon with micropore size of 0.52 and 1.2 nm and specific surface area of 862 m2 g−1 has been synthesized from potassium hydroxide (KOH) activated waste wool upon the urea modification. Pure component adsorption isotherms of CO2, CH4, and N2 are systematically measured on this enhanced N-doped porous carbon at 0 and 25 °C, up to 1 bar, to evaluate the gases adsorption capability, and correlated with the Langmuir model. These data are used to estimate the separation selectivities for binary mixtures of CO2/CH4 and CH4/N2 at different mixing ratios according to the ideal adsorbed solution theory (IAST) model. At an ambient condition of 25 °C and 1 bar, the predicted selectivities for equimolar CO2/CH4 and CH4/N2 are 3.19 and 7.62, respectively, and the adsorption capacities for CO2, CH4, and N2 are 2.91, 1.01, and 0.13 mmol g−1, respectively. This report introduces a simple pathway to obtain enhanced N-doped porous carbon with large adsorption capacities for gas separation of CO2/CH4 and CH4/N2.

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Wei, Jian Wen, and Song Sheng Zhao. "Capture of Carbon Dioxide by Adsorption- A Review." Advanced Materials Research 538-541 (June 2012): 2240–45. http://dx.doi.org/10.4028/www.scientific.net/amr.538-541.2240.

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Carbon dioxide is the largest contributor in regard of its emission amount contributing to 60 percent of global warming effects. Various methods are proposed and researched in CO2 separation and adsorption process is the most promising method. An overview of the adsorbents in the capture of CO2 by adsorption is presented in this paper and the focus is on the advances of mesoporous silicas functionalized by amino modification, coating and impregnation in CO2 capture. Future promising research directions in the CO2 adsorption by the mesoporous silicas are suggested.

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Wotzka, Alexander, Majid Namayandeh Jorabchi, and Sebastian Wohlrab. "Separation of H2O/CO2 Mixtures by MFI Membranes: Experiment and Monte Carlo Study." Membranes 11, no. 6 (June 10, 2021): 439. http://dx.doi.org/10.3390/membranes11060439.

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The separation of CO2 from gas streams is a central process to close the carbon cycle. Established amine scrubbing methods often require hot water vapour to desorb the previously stored CO2. In this work, the applicability of MFI membranes for H2O/CO2 separation is principally demonstrated by means of realistic adsorption isotherms computed by configurational-biased Monte Carlo (CBMC) simulations, then parameters such as temperatures, pressures and compositions were identified at which inorganic membranes with high selectivity can separate hot water vapour and thus make it available for recycling. Capillary condensation/adsorption by water in the microporous membranes used drastically reduces the transport and thus the CO2 permeance. Thus, separation factors of αH2O/CO2 = 6970 could be achieved at 70 °C and 1.8 bar feed pressure. Furthermore, the membranes were tested for stability against typical amines used in gas scrubbing processes. The preferred MFI membrane showed particularly high stability under application conditions.

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Dhedia, Muhammad Fannka, Mahidin Mahidin, Husni Husin, Hisbullah Hisbullah, Nasrullah Razali, Alvan Ade Reza, and Abdul Hadi. "Carbon Dioxide (CO2) Separation Study Using Chemically Activated Serpentine as an Adsorbent." Jurnal Rekayasa Kimia & Lingkungan 19, no. 2 (December 19, 2024): 237–50. https://doi.org/10.23955/rkl.v19i2.41399.

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The increase in carbon emissions resulting from industrial activities has become a major concern for environmental and climate conditions. Carbon Capture and Storage (CCS) represents a significant effort to mitigate the CO2 problem. Aceh Province possesses a potential distribution of serpentine, which may serve as an effective material for CCS applications. This study evaluates the effects of gas flow rate, particle size, sorbent weight, and pressure on CO2 adsorption using chemically activated serpentine. The activation process involved hydrochloric acid (HCl) at three concentrations: 8%, 9%, and 10%, with particle sizes of 50 mesh, 100 mesh, and 150 mesh. Activation was conducted at room temperature with an acid-to-serpentine ratio of 10:1 for 30 minutes. Adsorption tests were performed at ambient temperature under pressures of 2, 3, and 4 bar, with adsorption times of 30, 60, and 120 minutes. Results indicate that activated serpentine treated with 9% HCl and a particle size of 150 mesh achieved the highest performance, demonstrating an adsorption efficiency of 33.01% and an adsorption capacity of 82.22% (0.0488 g CO2/g adsorbent) at a pressure of 2 bar. Both the Langmuir and Freundlich isotherm models closely fit the data (R² = 1). This study concludes that HCl activation significantly enhances the capacity and efficiency of serpentine as a CO2 adsorbent.

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Li, Yanxi, Yuhua Bai, Zhuozheng Wang, Qihan Gong, Mengchen Li, Yawen Bo, Hua Xu, Guiyuan Jiang, and Kebin Chi. "Exquisitely Constructing a Robust MOF with Dual Pore Sizes for Efficient CO2 Capture." Molecules 28, no. 17 (August 28, 2023): 6276. http://dx.doi.org/10.3390/molecules28176276.

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Developing metal–organic framework (MOF) adsorbents with excellent performance and robust stability is of critical importance to reduce CO2 emissions yet challenging. Herein, a robust ultra-microporous MOF, Cu(bpfb)(bdc), with mixed ligands of N, N′-(1,4-phenylene)diisonicotinamide (bpfb), and 1,4-dicarboxybenzene (bdc) was delicately constructed. Structurally, this material possesses double-interpenetrated frameworks formed by two staggered, independent frameworks, resulting in two types of narrow ultra-micropores of 3.4 × 5.0 and 4.2 × 12.8 Å2, respectively. The above structural properties make its highly selective separation at 273~298 K with a CO2 capacity of 71.0~86.2 mg/g. Its adsorption heat over CO2 and IAST selectivity were calculated to be 27 kJ/mol and 52.2, respectively. Remarkably, cyclic breakthrough experiments corroborate its impressive performance in CO2/N2 separation in not only dry but also 75% RH humid conditions. Molecular simulation reveals that C-H···OCO2 in the pores plays a pivotal role in the high selectivity of CO2 adsorption. These results point out the huge potential application of this material for CO2/N2 separation.

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Rozaini, Muhamad Tahriri, Denys I. Grekov, Mohamad Azmi Bustam, and Pascaline Pré. "Shaping of HKUST-1 via Extrusion for the Separation of CO2/CH4 in Biogas." Separations 10, no. 9 (September 6, 2023): 487. http://dx.doi.org/10.3390/separations10090487.

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HKUST-1 is a metal-organic framework (MOF) that is widely studied as an adsorbent for CO2 capture because of its high adsorption capacity and good CO2/CH4 selectivity. However, the numerous synthesis routes for HKUST-1 often result in the obtention of MOF in powder form, which limits its application in industry. Here, we report the shaping of HKUST-1 powder via the extrusion method with the usage of bio-sourced polylactic acid (PLA) as a binder. The characterization of the composite was determined by XRD, FTIR, TGA and SEM analyses. The specific surface area was determined from the N2 adsorption isotherm, whereas the gas adsorption capacities were investigated via measurements of CO2 and CH4 isotherms of up to 10 bar at ambient temperature. The material characterization reveals that the composite preserves HKUST-1’s crystalline structure, morphology and textural properties. Furthermore, CO2 and CH4 adsorption isotherms show that there is no degradation of gravimetric gas adsorption capacity after shaping and the composite yields a similar isosteric adsorption heat as pristine HKUST-1 powder. However, some trade-offs could be observed, as the composite exhibits a lower bulk density than pristine HKUST-1 powder and PLA has no impact on pristine HKUST-1’s moisture stability. Overall, this study demonstrates the possibility of shaping commercial HKUST-1 powder, using PLA as a binder, into a larger solid-state-form adsorbent that is suitable for the separation of CO2 from CH4 with a well-preserved pristine MOF gas-adsorption performance.

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Awadallah-F, Ahmed, and Shaheen A. Al-Muhtaseb. "Influence of Carbon Uniformity on Its Characteristics and Adsorption Capacities of CO2 and CH4 Gases." Applied Sciences 11, no. 1 (December 29, 2020): 265. http://dx.doi.org/10.3390/app11010265.

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Activated carbons of resorcinol-formaldehyde aerogels (AC-RFA) were prepared and mixed with multiwall carbon nanotubes (MWCNTs) with various ratios. Samples were characterized by different techniques. The novelty of the study is in evaluating the effect of uniformity of carbon nanocomposites on their performance for the adsorption of CH4 and CO2 gases as well predicting the separation of their mixtures. The results indicated that, by increasing the percentage of MWCNTs into the sample, its structural uniformity and order ascend. The capacities of CH4 and CO2 by adsorption were measured at various temperatures, and were correlated with the extended dual site Langmuir (DSL) model. Overall, results showed that the adsorption capacity of MWCNTs towards gases is relatively very low compared to that of activated carbons. The DSL model was utilized to forecast the separation of the binary CO2/CH4 mixed gas based on knowledge of single component adsorption isotherm parameters. Adsorption equilibrium data of the CO2/CH4 binary gas mixture was forecasted at different temperatures by DSL model in accordance with the perfect-negative (PN) or perfect-positive (PP) behaviors on the heterogeneous surface of the adsorbent.

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Aleksandrzak, Tomasz, Kamila Zabielska, and Elżbieta Gabruś. "Modeling and experimental studies of carbon dioxide separation on zeolite fixed bed by cyclic pressure swing adsorption." Polish Journal of Chemical Technology 26, no. 1 (March 1, 2024): 8–15. http://dx.doi.org/10.2478/pjct-2024-0002.

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Abstract The paper presents the results of experimental and model studies of the pressure swing adsorption (PSA) process in a column with a zeolite 13X bed with a height of 0.5 m. The gas mixture consisted of CO2 (10–20%), N2, and H2O (RH 50%) in different ratios. As a result of the column tests, concentration, and temperature evolutions were obtained for each of the adsorption and desorption stages, which were used to determine the breakthrough and bed saturation times and other parameters important for the analysis of the column operation. A mathematical model of the PSA process for the separation of CO2 from the gas mixture was developed. The system of second-order partial differential equations was solved using Matlab software. The research focuses on adsorptive CO2 capture and shows the influence of water vapor and operational parameters on the quality of model validation.

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Liu, Quan, Zhonglian Yang, Gongping Liu, Longlong Sun, Rong Xu, and Jing Zhong. "Functionalized GO Membranes for Efficient Separation of Acid Gases from Natural Gas: A Computational Mechanistic Understanding." Membranes 12, no. 11 (November 16, 2022): 1155. http://dx.doi.org/10.3390/membranes12111155.

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Membrane separation technology is applied in natural gas processing, while a high-performance membrane is highly in demand. This paper considers the bright future of functionalized graphene oxide (GO) membranes in acid gas removal from natural gas. By molecular simulations, the adsorption and diffusion behaviors of several unary gases (N2, CH4, CO2, H2S, and SO2) are explored in the 1,4-phenylenediamine-2-sulfonate (PDASA)-doped GO channels. Molecular insights show that the multilayer adsorption of acid gases evaluates well by the Redlich-Peterson model. A tiny amount of PDASA promotes the solubility coefficient of CO2 and H2S, respectively, up to 4.5 and 5.3 mmol·g−1·kPa−1, nearly 2.5 times higher than those of a pure GO membrane, which is due to the improved binding affinity, great isosteric heat, and hydrogen bonds, while N2 and CH4 only show single-layer adsorption with solubility coefficients lower than 0.002 mmol·g−1·kPa−1, and their weak adsorption is insusceptible to PDASA. Although acid gas diffusivity in GO channels is inhibited below 20 × 10−6 cm2·s−1 by PDASA, the solubility coefficient of acid gases is certainly high enough to ensure their separation efficiency. As a result, the permeabilities (P) of acid gases and their selectivities (α) over CH4 are simultaneously improved (PCO2 = 7265.5 Barrer, αCO2/CH4 = 95.7; P(H2S+CO2) = 42075.1 Barrer, αH2S/CH4= 243.8), which outperforms most of the ever-reported membranes. This theoretical study gives a mechanistic understanding of acid gas separation and provides a unique design strategy to develop high-performance GO membranes toward efficient natural gas processing.

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Damasceno Borges, Daiane, and Douglas S. Galvao. "Schwarzites for Natural Gas Storage: A Grand-Canonical Monte Carlo Study." MRS Advances 3, no. 1-2 (2018): 115–20. http://dx.doi.org/10.1557/adv.2018.190.

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ABSTRACTThe 3D porous carbon-based structures called Schwarzites have been recently a subject of renewed interest due to the possibility of being synthesized in the near future. These structures exhibit negatively curvature topologies with tuneable porous sizes and shapes, which make them natural candidates for applications such as CO2 capture, gas storage and separation. Nevertheless, the adsorption properties of these materials have not been fully investigated. Following this motivation, we have carried out Grand-Canonical Monte Carlo simulations to study the adsorption of small molecules such as CO2, CO, CH4, N2 and H2, in a series of Schwarzites structures. Here, we present our preliminary results on natural gas adsorptive capacity in association with analyses of the guest-host interaction strengths. Our results show that Schwarzites P7par, P8bal and IWPg are the most promising structures with very high CO2 and CH4 adsorption capacity and low saturation pressure (<1bar) at ambient temperature. The P688 is interesting for H2 storage due to its exceptional high H2 adsorption enthalpy value of -19kJ/mol.

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Chen, Lei, Takumi Watanabe, Hirofumi Kanoh, Kenji Hata, and Tomonori Ohba. "Cooperative CO2 adsorption promotes high CO2 adsorption density over wide optimal nanopore range." Adsorption Science & Technology 36, no. 1-2 (June 9, 2017): 625–39. http://dx.doi.org/10.1177/0263617417713573.

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Separation of CO2 based on adsorption, absorption, and membrane techniques is a crucial technology necessary to address current global warming issues. Porous media are essential for all these approaches and understanding the nature of the porous structure is important for achieving highly efficient CO2 adsorption. Porous carbon is considered to be a suitable porous media for investigating the fundamental mechanisms of CO2 adsorption, because of its simple morphology and its availability in a wide range of well-defined pore sizes. In this study, we investigated the dependence of CO2 adsorption on pore structures such as pore size, volume, and specific surface area. We also studied slit-shaped and cylindrical pore morphologies based on activated carbon fibers of 0.6–1.7 nm and carbon nanotubes of 1–5 nm, respectively, with relatively uniform structures. Porous media with larger specific surface areas gave higher CO2 adsorption densities than those of media having larger pore volumes. Narrower pores gave higher adsorption densities because of deep adsorption potential wells. However, at a higher pressure CO2 adsorption densities increased again in nanopores including micropores and small mesopores. The optimal pore size ranges of CO2 adsorption in the slit-shaped and cylindrical carbon pores were 0.4–1.2 and 1.0–2.0 nm, respectively, although a high adsorption density was only expected for the narrow carbon nanopores from adsorption potentials. The wider nanopore ranges than expected nanopore ranges are reasonable when considering intermolecular interactions in addition to CO2–carbon pore interactions. Therefore, cooperative adsorption among CO2 in relatively narrow nanopores can allow for high density and high capacity adsorption.

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Susanti, Indri. "Technologies and Materials for Carbon Dioxide Capture." Science Education and Application Journal 1, no. 2 (October 5, 2019): 84. http://dx.doi.org/10.30736/seaj.v1i2.147.

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This paper was aims to review the technologies and materials for CO2 capture. Carbon dioxide is one of the triggers for the greenhouse effect and global warming. Some methods to reduce CO2 are separation technologies include air capture, CO2 Capture Utilization and Storage (CCUS) and CO2 Capture and Storage (CCS) technology. CCS technology have several systems namely post-combution, pre-combustion and oxy-fuel combustion. Post-combution systems can be done in various systems including absorption, adsorption, membrane, and cryogenic. Adsorption proses for CO2 capture applied with porous material such us mesopore silica, zeolite, carbon, MOF dan COF. This review was described the advantages and disadvantages of each technology for CO2 capture. Materials for CO2 adsorption also descibed in this review.

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Yang, Li Yan, Yi Hui Guo, and Li Li Yu. "Preparation and Thermodynamics Adsorption Performance of Cobalt Ions on the Crosslinked Starch Microspheres." Advanced Materials Research 726-731 (August 2013): 435–39. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.435.

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A type of cross-linking starch microspheres (CSMs) has been synthesized by reversed phase suspension method using soluble starch as raw material. Crosslinked starch microsphere has good adsorption performance to metal ions in water. The static adsorption behaviors of Co2+on the cross-linked starch microspheresand were investigated. The CSMs and its adsorption product were comparatively characterized by Fourier Transform Infrared Spectroscopy (FTIR). The adsorption behaviour of CSMs in different temperatures is in agreement with the Freundlich isothermal equation and isothermal equation of Langmiur. The thermodynamic parameters of adsorption process indicate that entropy is the main adsorption driving force, and physical adsorption is main about the adsorption behaviors of CSMs on Co2+.These data are helpful for the adsorption separation of metal ions and the treatment of the wastewater containing Co2+. Keywords: cross-linked starch microspheres;cobalt ions;adsorption mechanism;thermodynamics adsorption

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Salazar Duarte, Gabriel, Benedikt Schürer, Christian Voss, and Dieter Bathen. "Adsorptive Separation of CO2 from Flue Gas by Temperature Swing Adsorption Processes." ChemBioEng Reviews 4, no. 5 (June 26, 2017): 277–88. http://dx.doi.org/10.1002/cben.201600029.

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Mulgundmath, V. P., F. H. Tezel, T. Saatcioglu, and T. C. Golden. "Adsorption and separation of CO2/N2 and CO2/CH4 by 13X zeolite." Canadian Journal of Chemical Engineering 90, no. 3 (July 22, 2011): 730–38. http://dx.doi.org/10.1002/cjce.20592.

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Gomez, Luis Fernando, Renju Zacharia, Pierre Bénard, and Richard Chahine. "Simulation of Binary CO2/CH4Mixture Breakthrough Profiles in MIL-53 (Al)." Journal of Nanomaterials 2015 (2015): 1–15. http://dx.doi.org/10.1155/2015/439382.

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MIL-53 (Al) aluminum terephthalate, a commercial metal-organic framework, has been studied as a potential candidate for pressure swing adsorption separation of CO2/CH4binary mixtures. Pure gas isotherms of CH4and CO2measured over 0–6 MPa and at room temperature are fitted with the Dubinin-Astakhov (D-A) model. The D-A model parameters are used in the Doong-Yang Multicomponent adsorption model to predict the binary mixture isotherms. A one-dimensional multicomponent adsorption breakthrough model is then used to perform a parametric study of the effect of adsorbent particle diameter, inlet pressures, feed flow rates, and feed compositions on the breakthrough performance. Commercial MIL-53 with a particle diameter of 20 μm renders high tortuous flow; therefore it is less effective for separation. More effective separation can be achieved if MIL-53 monoliths of diameters above 200 μm are used. Faster separation is possible by increasing the feed pressure or if the starting compositions are richer in CO2. More CH4is produced per cycle at higher feed pressures, but the shortened time at higher pressures can result in the reduction of the CH4purity.

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Zhang, Qiang, Guan-Nan Han, Xin Lian, Shan-Qing Yang, and Tong-Liang Hu. "Customizing Pore System in a Microporous Metal–Organic Framework for Efficient C2H2 Separation from CO2 and C2H4." Molecules 27, no. 18 (September 12, 2022): 5929. http://dx.doi.org/10.3390/molecules27185929.

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Selective-adsorption separation is an energy-efficient technology for the capture of acetylene (C2H2) from carbon dioxide (CO2) and ethylene (C2H4). However, it remains a critical challenge to effectively recognize C2H2 among CO2 and C2H4, owing to their analogous molecule sizes and physical properties. Herein, we report a new microporous metal–organic framework (NUM-14) possessing a carefully tailored pore system containing moderate pore size and nitro-functionalized channel surface for efficient separation of C2H2 from CO2 and C2H4. The activated NUM-14 (namely NUM-14a) exhibits sufficient pore space to acquire excellent C2H2 loading capacity (4.44 mmol g−1) under ambient conditions. In addition, it possesses dense nitro groups, acting as hydrogen bond acceptors, to selectively identify C2H2 molecules rather than CO2 and C2H4. The breakthrough experiments demonstrate the good actual separation ability of NUM-14a for C2H2/CO2 and C2H2/C2H4 mixtures. Furthermore, Grand Canonical Monte Carlo simulations indicate that the pore surface of the NUM-14a has a stronger affinity to preferentially bind C2H2 over CO2 and C2H4 via stronger C-H···O hydrogen bond interactions. This article provides some insights into customizing pore systems with desirable pore sizes and modifying groups in terms of MOF materials toward the capture of C2H2 from CO2 and C2H4 to promote the development of more MOF materials with excellent properties for gas adsorption and separation.

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Huang, Binxin. "Research progress of CO₂ separation technology by solvent absorption." E3S Web of Conferences 385 (2023): 04032. http://dx.doi.org/10.1051/e3sconf/202338504032.

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The combustion of fossil fuels emits a large amount of CO2, which causes the greenhouse effect and leads to global warming and poses a serious threat to life on earth. CO2 capture technology can effectively reduce the concentration of CO2 in the atmosphere, alleviate the greenhouse effect, and improve the environment. CO2 capture technologies include absorption, membrane separation and adsorption separation, among which chemical absorption and separation have the advantages of high efficiency, low cost and easy availability of materials. In this paper, the advantages and disadvantages of three main chemical absorption and separation methods (inorganic reagents, organic amines and ionic liquids) adsorb CO2 are summarized. Among inorganic adsorbents, NH3·H2O can achieve rapid and efficient absorption of CO2, and it is relatively stable and not easy to degrade. Common types of organic amine adsorbents are monoethanolamine, methanolamine, and sterically hindered amine. However, it is difficult for a single organic amine adsorbent to meet the requirements of high absorption rate, high absorption capacity and low reaction heat at the same time. Therefore, mixing organic amine absorbents with different characteristics can improve their performance in absorbing CO2. Ionic liquids have the advantages of good thermal stability, very low saturation vapor pressure, and designable structure, and are a new type of CO2 adsorbent, but ionic liquids have high viscosity themselves. Combining ionic liquids with organic or inorganic porous materials to form loaded ionic liquid materials, which can be used as CO2 adsorbent not only to improve the separation effect, but also to avoid the problem of high viscosity caused by direct absorption of ionic liquids, thus improving CO2 adsorption efficiency.

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Kong, Xueying, Shangsiying Li, Maria Strømme, and Chao Xu. "Synthesis of Porous Organic Polymers with Tunable Amine Loadings for CO2 Capture: Balanced Physisorption and Chemisorption." Nanomaterials 9, no. 7 (July 17, 2019): 1020. http://dx.doi.org/10.3390/nano9071020.

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The cross-coupling reaction of 1,3,5-triethynylbenzene with terephthaloyl chloride gives a novel ynone-linked porous organic polymer. Tethering alkyl amine species on the polymer induces chemisorption of CO2 as revealed by the studies of ex situ infrared spectroscopy. By tuning the amine loading content on the polymer, relatively high CO2 adsorption capacities, high CO2-over-N2 selectivity, and moderate isosteric heat (Qst) of adsorption of CO2 can be achieved. Such amine-modified polymers with balanced physisorption and chemisorption of CO2 are ideal sorbents for post-combustion capture of CO2 offering both high separation and high energy efficiencies.

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Ballesteros-Plata, Daniel, Juan Antonio Cecilia, Isabel Barroso-Martín, José Jiménez-Jiménez, Antonia Infantes-Molina, and Enrique Rodríguez-Castellón. "Materials Design for N2O Capture: Separation in Gas Mixtures." Catalysts 12, no. 12 (November 29, 2022): 1539. http://dx.doi.org/10.3390/catal12121539.

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The adsorption of greenhouse gases (GHG) as a method to reduce their emissions into the atmosphere is an alternative that is easier to implement industrially and cheaper than other existing technologies, such as chemical capture, cryogenic separation, or membrane separation. The vast majority of works found in the literature have focused their efforts on capturing CO2 as it is the largest GHG. However, although N2O emissions are not as large as CO2, the impact that N2O has on the stratosphere and climate is much larger in proportion, despite which there is not much research on N2O capture. Since both gases are usually emitted into the atmosphere together (along with other gases), it is necessary to design selective adsorbents capable of capturing and separating these gases from each other and from other gases, to mitigate the effects of climate change. This review aims to compile the existing information to date on porous adsorbents, the characteristics of the N2O adsorption processes and, above all, aims to focus the reader’s gaze on the importance of designing selective adsorbents for greenhouse gas mixtures.

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Journal articles on the topic 'CO2 adsorption and separation'

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