scholarly journals Carbon Dioxide Adsorption on Carbon Nanofibers with Different Porous Structures

2021 ◽  
Vol 11 (16) ◽  
pp. 7724 ◽  
Author(s):  
Yu-Chun Chiang ◽  
Chih-Cheng Huang ◽  
Wei-Ting Chin
Keyword(s):  
Carbon Nanofibers ◽  
Co2 Capture ◽  
Co2 Adsorption ◽  
Breakthrough Curves ◽  
Porous Structures ◽  
Carbon Dioxide Adsorption ◽  
Cyclic Tests ◽  
Surface Areas ◽  
Co2 Adsorption Capacity ◽  
Hierarchical Pore

Electrospinning techniques have become an efficient way to produce continuous and porous carbon nanofibers. In view of CO2 capture as one of the important works for alleviating global warming, this study intended to synthesize polyacrylonitrile (PAN)-based activated carbon nanofibers (ACNFs) using electrospinning processes for CO2 capture. Different structures of PAN-based ACNFs were prepared, including solid, hollow, and porous nanofibers, where poly(methyl methacrylate) (PMMA) was selected as the sacrificing core or pore generator. The results showed that the PMMA could be removed successfully at a carbonization temperature of 900 °C, forming the hollow or porous ACNFs. The diameters of the ACNFs ranged from 500 to 900 nm, and the shell thickness of the hollow ACNFs was approximately 70–110 nm. The solid ACNFs and hollow ACNFs were microporous materials, while the porous ACNFs were characterized by hierarchical pore structures. The hollow ACNFs and porous ACNFs possessed higher specific surface areas than that of the solid ACNFs, while the solid ACNFs exhibited the highest microporosity (94%). The CO2 adsorption capacity on the ACNFs was highly dependent on the ratio of V<0.7 nm to Vt, the ratio of Vmi to Vt, and the N-containing functional groups. The CO2 adsorption breakthrough curves could be curve-fitted well with the Yoon and Nelson model. Furthermore, the 10 cyclic tests demonstrated that the ACNFs are promising adsorbents.

Using of Modified SBA-15 Mesoporous Silica Materials for CO2 Capture

2018 ◽  
pp. 122-137 ◽  
Author(s):  
Filiz Akti
Keyword(s):  
Mesoporous Silica ◽  
Co2 Capture ◽  
Carbon Dioxide Emissions ◽  
Co2 Adsorption ◽  
High Surface ◽  
Surface Areas ◽  
Silica Materials ◽  
Mesoporous Silica Materials ◽  
Co2 Adsorption Capacity ◽  
Silica Wall

Carbon dioxide emissions cause global warming, and greenhouse gases and climate change are very serious problems. Mesoporous silica material SBA-15 has been preferred mostly as an ideal adsorbent for CO2 due to its excellent properties such as high surface areas and pore volumes, larger pore diameter, and thicker silica wall. In the literature studies, SBA-15 has been modified by different functional groups and the effects of modification methods on the CO2 adsorption have been investigated. Modified SBA-15 adsorbents showed high CO2 adsorption capacity. The aim of this chapter is to review the use of modified-SBA-15 mesoporous silica materials as adsorbent for CO2 capture.

scholarly journals CO2 Adsorption Capacity of Organic Alkali Sorbent CPEI from Polyethyleneimine

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Feng Wang ◽  
Lu Yu ◽  
Youhua Li ◽  
Dengfa Huang
Keyword(s):  
Co2 Capture ◽  
Gas Flow ◽  
Bubble Column ◽  
Breakthrough Curves ◽  
Bubble Column Reactor ◽  
Diffusion Resistance ◽  
Order Kinetic ◽  
Order Kinetic Model ◽  
Co2 Adsorption Capacity ◽  
Temperature Swing Adsorption

Support-free cross-linked polyethyleneimine sorbent (CPEI) for CO2 capture was evaluated as the regenerable sorbent. The total amines available for the CO2 capture on CPEI were determined by the polyethyleneimine/glutaraldehyde ratio for the synthesis of CPEI. The CO2 capacity of CPEI in the slurry bubble column reactor reached 4.92 mmol/g, which is 1.97 times higher than that obtained under anhydrous conditions. The adsorption kinetics of CPEI in the reactor were investigated in terms of the CPEI amount, the CO2 fraction, the gas flow rate, temperature, and the total amines available. The experimental breakthrough curves for the sorbent were well-fitted with a fractional-order kinetic model. The modeling analysis found the influence of diffusion resistance on the adsorption is more significant than that of the driving force. The CO2 capacity of CPEI remained almost constant during the temperature swing adsorption/desorption cycles.

scholarly journals CVD Synthesis, Functionalization and CO2 Adsorption Attributes of Multiwalled Carbon Nanotubes

Processes ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 634 ◽  
Author(s):  
Shazia Shukrullah ◽  
Muhammad Yasin Naz ◽  
Norani M. Mohamed ◽  
Khalid A. Ibrahim ◽  
Nasser M. AbdEl-Salam ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Nanotubes ◽  
Adsorption Capacity ◽  
Multiwalled Carbon Nanotubes ◽  
Functional Groups ◽  
Co2 Adsorption ◽  
Breakthrough Curves ◽  
Multiwalled Carbon ◽  
Amine Functionalized ◽  
Co2 Adsorption Capacity

Carbon dioxide is one of the major greenhouse gases and a leading source of global warming. Several adsorbent materials are being tested for removal of carbon dioxide (CO2) from the atmosphere. The use of multiwalled carbon nanotubes (MWCNTs) as a CO2 adsorbent material is a relatively new research avenue. In this study, Fe2O3/Al2O3 composite catalyst was used to synthesize MWCNTs by cracking ethylene gas molecules in a fluidized bed chemical vapor deposition (CVD) chamber. These nanotubes were treated with H2SO4/HNO3 solution and functionalized with 3-aminopropyl-triethoxysilane (APTS). Chemical modification of nanotubes removed the endcaps and introduced some functional groups along the sidewalls at defected sites. The functionalization of nanotubes with amine introduced carboxylic groups on the tube surface. These functional groups significantly enhance the surface wettability, hydrophilicity and CO2 adsorption capacity of MWCNTs. The CO2 adsorption capacity of as-grown and amine-functionalized CNTs was computed by generating their breakthrough curves. BELSORP-mini equipment was used to generate CO2 breakthrough curves. The oxidation and functionalization of MWCNTs revealed significant improvement in their adsorption capacity. The highest CO2 adsorption of 129 cm3/g was achieved with amine-functionalized MWCNTs among all the tested samples.

scholarly journals Adsorption Performance of Physically Activated Biochars for Postcombustion CO2 Capture from Dry and Humid Flue Gas

2020 ◽  
Vol 10 (1) ◽  
pp. 376 ◽  
Author(s):  
Joan J. Manyà ◽  
David García-Morcate ◽  
Belén González
Keyword(s):  
Wheat Straw ◽  
Co2 Capture ◽  
Co2 Adsorption ◽  
Packed Bed ◽  
Dry Conditions ◽  
Stable Performance ◽  
High Concentrations ◽  
Hierarchical Pore ◽  
Cyclic Adsorption ◽  
Adsorption Desorption

In the present study, the performance of four biomass-derived physically activated biochars for dynamic CO2 capture was assessed. Biochars were first produced from vine shoots and wheat straw pellets through slow pyrolysis (at pressures of 0.1 and 0.5 MPa) and then activated with CO2 (at 0.1 MPa and 800 °C) up to different degrees of burn-off. Cyclic adsorption-desorption measurements were conducted under both dry and humid conditions using a packed-bed of adsorbent at relatively short residence times of the gas phase (12–13 s). The adsorbent prepared from the vine shoots-derived biochar obtained by atmospheric pyrolysis, which showed the most hierarchical pore size distribution, exhibited a good and stable performance under dry conditions and at an adsorption temperature of 50 °C, due to the enhanced CO2 adsorption and desorption rates. However, the presence of relatively high concentrations of water vapor in the feeding gas clearly interfered with the CO2 adsorption mechanism, leading to significantly shorter breakthrough times. In this case, the highest percentages of a used bed were achieved by one of the other activated biochars tested, which was prepared from the wheat straw-derived biochar obtained by pressurized pyrolysis.

scholarly journals Evaluation of Kaolinite and activated carbon performance for CO2 capture

2021 ◽  
Author(s):  
◽  
Stephen Okiemute Akpasi
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Co2 Capture ◽  
Gas Flow ◽  
Co2 Adsorption ◽  
Carbon Composite ◽  
Composite Adsorbent ◽  
Bed Height ◽  
Co2 Adsorption Capacity

Global climate change is one of the major threats facing the world today and can be due to increased atmospheric concentrations of greenhouse gases (GHGs), such as carbon dioxide (CO2). There is also an immediate need to reduce CO2 emissions, and one of the potential solutions for reducing CO2 emissions is carbon capture and storage (CCS). This work investigated the performance assessment of kaolinite and activated carbon (AC) adsorbent for CO2 capture. In particular, the effect of operating parameters such as temperature, bed height, inlet gas flow rate etc. on CO2 adsorption behaviour of the adsorbents was also investigated. Extensive research on the development of adsorbents that can adsorb large amounts of CO2 with low energy consumption has recently been carried out. In CO2 adsorption technology, the challenge is to develop an adsorbent that is not only non-toxic, eco-friendly, and cost-effective, but also has the potential to extract CO2 gas from a mixed gas stream selectively and effectively. Due to the possibility of a potential adsorbent due to its low cost, rich natural abundance and high mechanical and chemical stability, this study proposes kaolinite. As the presence of clay minerals in soils serves as a pollutant collector to enhance the atmosphere, kaolinite has the potential to be an efficient adsorbent for CO2 capture. Kaolinite was investigated as an adsorbent in this research to confirm if it is suitable for CO2 capture. Kaolinite/activated carbon composite adsorbents were synthesized. Sugarcane bagasse was used in preparing the activated carbon (AC). ZnCl2 was impregnated onto sugarcane bagasse during the preparation of activated carbon (AC) to improve the physical properties (surface area, pore size and pore volume) and the CO2 adsorption capacity of the activated carbon (AC) adsorbent developed. The materials were characterized and tested for CO2 adsorption (activated carbon and kaolinite). BET, FTIR and SEM studies were used to classify the adsorbents for their surface area and pore properties, functional groups, and surface morphology, respectively. BET analysis was conducted and the pore volume, pore size and surface area of the adsorbent materials were reported. Functional groups were actively present in the adsorption process. This was verified using FTIR spectroscopy. The kaolinite adsorbent was not feasible for CO2 capture. BET, SEM, and custom-built CO2 adsorption equipment have confirmed this. In contrast to literature, the CO2 adsorption capacity of kaolinite was low. This is due to the fact that kaolinite used in this study is not suitable as adsorbent for CO2 capture as they exhibited a low CO2 adsorption capacity. The results obtained in this study show that temperature, bed height and inlet gas flow rate influenced the adsorption behaviour of activated carbon (AC), kaolinite and kaolinite/activated carbon composite adsorbent during CO2 capture. At 30 0C, activated carbon (AC) exhibited an adsorption capacity of 28.97 mg CO2/g, the highest capacity among all the adsorbents tested. Kaolinite-activated carbon composite adsorbent offered CO2 adsorption capacities of 18.54 mg CO2/g. Kaolinite provides the lowest capacity of 12.98 mg CO2/g. In conclusion, this research verified that CO2 adsorption with kaolinite and activated carbon is favoured at low temperatures, low operating CO2 flowrates and high column bed height.

scholarly journals Continuous Fixed Bed CO2 Adsorption: Breakthrough, Column Efficiency, Mass Transfer Zone

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1233
Author(s):  
Mohammed K. Al Mesfer ◽  
Mohd Danish ◽  
Mohammed Ilyas Khan ◽  
Ismat Hassan Ali ◽  
Mudassir Hasan ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Adsorption Capacity ◽  
Co2 Capture ◽  
Molecular Sieve ◽  
Co2 Adsorption ◽  
Superficial Velocity ◽  
Column Efficiency ◽  
Co2 Adsorption Capacity ◽  
Mass Transfer Zone ◽  
Transfer Zone

The increased levels of carbon dioxide in the environment have incited the search for breakthrough technologies to lessen its impact on climate. The CO2 capture from a mixture of CO2/N2 was studied using a molecular sieve (MS) and silica gel type-III. The breakthrough behavior was predicted as a function of temperature, superficial velocity, and CO2 partial pressure. The breakpoint time reduced significantly with increased temperature and increased superficial velocity. The CO2 adsorption capacity increased appreciably with decreased temperature and increased CO2 pressure. The saturation CO2 adsorption capacity from the CO2/N2 mixture reduced appreciably with increased temperature. The molecular sieve contributed to higher adsorption capacity, and the highest CO2 uptake of 0.665 mmol/g was realized for MS. The smaller width of the mass transfer zone and higher column efficiency of 87.5% for MS signify the efficient use of the adsorbent; this lowers the regeneration cost. The findings suggest that a molecular sieve is suitable for CO2 capture due to high adsorption performance owing to better adsorption characteristic parameters.

scholarly journals K2CO3-Impregnated Al/Si Aerogel Prepared by Ambient Pressure Drying for CO2 Capture: Synthesis, Characterization and Adsorption Characteristics

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3741
Author(s):  
Yanlin Wang ◽  
Baihe Guo ◽  
Jingnan Guo ◽  
Man Zhang ◽  
Hairui Yang ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Co2 Capture ◽  
Adsorption Process ◽  
Co2 Adsorption ◽  
Ambient Pressure ◽  
Ambient Pressure Drying ◽  
Fixed Bed Reactor ◽  
X Ray ◽  
Adsorption Performance ◽  
Co2 Adsorption Capacity

A new potassium-based adsorbent for CO2 capture with Al aerogel used as support is proposed in this work. The adsorbents with different surface modifiers (tetraethyl orthosilicate (TEOS) and trimethyl chlorosilane (TMCS)) and different K2CO3 loadings (10%, 20%, 30% and 40%) were prepared by sol-gel and iso-volume impregnation processes with ambient pressure drying. The CO2 adsorption performance of the adsorbents were tested by a fixed-bed reactor, and their adsorption mechanisms were studied by scanning electron microscopy (SEM), Brunauer Emmett Teller (BET), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and X-ray fluorescence spectrometry (XRF). Furthermore, the adsorption kinetics and the cycling performance were investigated. The results show that using TEOS to modify the wet gel can introduce SiO2 to increase the strength of the skeleton. On the basis of TEOS modification, TMCS can further modify –OH, thus effectively avoiding the destruction of aerogel structure during ambient drying and K2CO3 impregnation. In this work, the specific surface area and specific pore volume of Al aerogel modified by TEOS + TMCS are up to 635.32 cm2/g and 2.43 cm3/g, respectively. The aerogels without modification (Al-B), TEOS modification (Al/Si) and TEOS + TMCS modification (Al/Si-TMCS) showed the best CO2 adsorption performance at 20%, 30% and 30% K2CO3 loading, respectively. In particular, the CO2 adsorption capacity and K2CO3 utilization rate of Al/Si-TMCS-30K are as high as 2.36 mmol/g and 93.2% at 70 degrees Celsius (°C). Avrami’s fractional order kinetic model can well fit the CO2 adsorption process of potassium-based adsorbents. Al-B-20K has a higher apparent activation energy and a lower adsorption rate during the adsorption process. After 15 adsorption-regeneration cycles, Al/Si-TMCS-30K maintain a stable CO2 adsorption capacity and framework structure, while the microstructure of Al/Si-30K is destroyed, resulting in a decrease in its adsorption capacity by nearly 30%. This work provides key data for the application of Al aerogel in the field of potassium-based adsorbent for CO2 capture.

scholarly journals Effect of Thermal Stabilization on PAN-Derived Electrospun Carbon Nanofibers for CO2 Capture

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4197
Author(s):  
Elisa Maruccia ◽  
Stefania Ferrari ◽  
Mattia Bartoli ◽  
Lorenzo Lucherini ◽  
Giuseppina Meligrana ◽  
...  
Keyword(s):  
Carbon Nanofibers ◽  
Co2 Capture ◽  
Carbon Capture ◽  
Thermal Stabilization ◽  
Co2 Uptake ◽  
Stabilization Temperature ◽  
Co2 Adsorption Capacity ◽  
Nitrogen Doped Carbon ◽  
Poly Acrylonitrile ◽  
Pan Fibers

Carbon capture is amongst the key emerging technologies for the mitigation of greenhouse gases (GHG) pollution. Several materials as adsorbents for CO2 and other gases are being developed, which often involve using complex and expensive fabrication techniques. In this work, we suggest a sound, easy and cheap route for the production of nitrogen-doped carbon materials for CO2 capture by pyrolysis of electrospun poly(acrylonitrile) (PAN) fibers. PAN fibers are generally processed following specific heat treatments involving up to three steps (to get complete graphitization), one of these being stabilization, during which PAN fibers are oxidized and stretched in the 200–300 °C temperature range. The effect of stabilization temperature on the chemical structure of the carbon nanofibers is investigated herein to ascertain the possible implication of incomplete conversion/condensation of nitrile groups to form pyridine moieties on the CO2 adsorption capacity. The materials were tested in the pure CO2 atmosphere at 20 °C achieving 18.3% of maximum weight increase (equivalent to an uptake of 4.16 mmol g−1), proving the effectiveness of a high stabilization temperature as route for the improvement of CO2 uptake.

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