scholarly journals Water Vapor Adsorption Capacity of Thermally Fluorinated Carbon Molecular Sieves for CO2Capture

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Jin-Young Jung ◽  
Hye-Ryeon Yu ◽  
Se Jin In ◽  
Young Chul Choi ◽  
Young-Seak Lee

The surfaces of carbon molecular sieves (CMSs) were thermally fluorinated to adsorb water vapor. The fluorination of the CMSs was performed at various temperatures (100, 200, 300, and 400°C) to investigate the effects of the fluorine gas (F2) content on the surface properties. Fluorine-related functional groups formed were effectively generated on the surface of the CMSs via thermal fluorination process, and the total pore volume and specific surface area of the pores in the CMSs increased during the thermal fluorination process, especially those with diameters ≤ 8 Å. The water vapor adsorption capacity of the thermally fluorinated CMSs increased compared with the as-received CMSs, which is attributable to the increased specific surface area and to the semicovalent bonds of the C–F groups.

1987 ◽  
Vol 59 (2) ◽  
pp. 67-72
Author(s):  
Raina Niskanen ◽  
Väinö Mäntylahti

The specific surface area of 60 mineral soil samples estimated by water vapor adsorption at 20 % relative humidity ranged from 12.1 ± 3.6 to 225.1 ±18.4 m2/g. Clay (range 1—72 %) and organic carbon content (0.7—14.6 %) together explained 84 % of the variation in the surface area. The regression equation predicting the specific surface area of soil was surface area (m2/g) =2.69+ 1.23clay-% +8.69org.C-%.


2020 ◽  
Vol 38 (1-2) ◽  
pp. 60-76 ◽  
Author(s):  
Hong Zhao ◽  
Qiongfen Yu ◽  
Ming Li ◽  
Shengnan Sun

In this study, activated carbons without any chemical residue were prepared from walnut shells. The preparation method in a tube furnace included a pyrolysis carbonization process and a CO2 activation process. The influences of activation temperature and holding time on the specific surface area, yield, and pore structure were investigated. Adsorption performance of water vapor was also examined in details. Thermogravimetric analysis, N2 adsorption–desorption isotherm, and scanning electron microscope were used to characterize samples. The result shows that the activation energy at different heating rates varies from 30.16 to 64.86 kJ/mol. The highest water vapor adsorption capacity of the sample is 0.3824 g/g and it takes only 30 min to realize regeneration. And the maximum Brunauer–Emmett–Teller specific surface area of 1228 m2/g also occurs in this optimal preparation condition. CO2 physical activation method was found to have a positive effect on pore structure development of activated carbon for water vapor adsorption.


2017 ◽  
Vol 36 (3-4) ◽  
pp. 904-918 ◽  
Author(s):  
Deyong Guo ◽  
Xiaojie Guo

In this paper, scanning electron microscopy, low-temperature N2 adsorption and CH4 isothermal adsorption experiments were performed on 11 coal samples with Ro,max between 0.98 and 3.07%. The pore structure characteristics of coals (specific surface area, total volume distribution) were studied to assess the gas adsorption capacity. The results indicate that there is significant heterogeneity on coal surface, containing numerous channel-like pores, bottle-shaped pores and wedge-shaped pores. Both Langmuir volume (VL) and Langmuir pressure (PL) show a stage change trend with the increase of coalification degree. For different coalification stages, there exist different factors influencing the VL and PL values. For low-rank coals (Ro,max < 1.1%), the increase of VL values and decrease of PL values are mainly due to the abundant primary pore and fracture within coal. For middle-rank coals (1.1% < Ro,max < 2.1%), the moisture content, vitrinite content and total pore volume are all the factors influencing VL, and the reduction of PL is mainly attributed to the decrease of moisture content and inertinite content. Meanwhile, this result is also closely related to the pore shape. For high-rank coals (Ro,max > 2.1%), VL values gradually increase and reach the maximum. When the coal has evolved into anthracite, liquid hydrocarbon within pore begins pyrolysis and gradually disappears, and a large number of macropores are converted into micropores, leading to the increase of specific surface area and total pore volume, corresponding to the increase of VL. In addition, the increase of vitrinite content within coal also contributes to the increase of VL. PL, reaches the minimum, indicating that the adsorption rate reaches the largest at the low pressure stage. The result is mainly controlled by the specific surface area and total pore volume of coal samples. This research results will provide a clearer insight into the relationship between adsorption parameters and coal rank, moisture content, maceral composition and pore structure, and it is of great significance for better assessing the gas adsorption capacity.


2021 ◽  
Author(s):  
Xiaoxia Ren ◽  
Changming Zhang ◽  
Lifang Kou ◽  
Rongxian Wang ◽  
Yaqi Wang ◽  
...  

Abstract Activated carbon spheres with high specific surface area and hierarcal porous texture were prepared from polystyrene-based macroreticular resin spheres by air pre-oxidization and steam activation. The as-prepared carbon spheres had a specific surface area of 1274.95 m2 g− 1, total pore volume of 1.09 cm3 g− 1 and micropore volume of 0.47 cm3 g− 1. Moreover, these carbon spheres showed a hierarcal porous texture composed of ultrafine micropores (0.5-1 nm), micropores (1–2 nm), mesopores (10–50 nm) and macropores (50–100 nm). A CO2 adsorption capacity of 2.82 mmol g− 1 for carbon spheres can be obtained at 30 ℃ and 1 atm. Further, after introducing nitrogen-containing functional groups by gaseous ammonia at 600 ℃, these carbon spheres exhibited a high CO2 adsorption capacity of 3.2 mmol g− 1. In addition, excellent cyclic stability, low hygroscopicity and regenerability temperature suggested these carbon spheres were favorable for CO2 capture.


The sorption and desorption of medicinal plants was carried out on a vacuum installation with mercury gates and McBan quartz scales. The measurements were carried out at 293 K and a residual air pressure of 10-3 -10-4 Pa. We studied the sorption and desorption of water vapor at 293 K for medicinal forestry plants - peppermint (Mentha), nettle (Urtica), plantain (Plantago) and zizifora (Ziziphora). The characteristics of the processes of sorption and desorption of medicinal plants were studied: it was found that the specific surface area of the capillaries is 137.26 m2 /g, and the total pore volume for zisphora under convective drying is 0.095 cm3 /g. For plantain, the characteristics of sorption and desorption were revealed: the confirmed specific surface of the capillaries is 92.10 m2 /g, while the total pore volume is 0.250 cm3 /g.


Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 325
Author(s):  
Youjian Yang ◽  
Wenju Tao ◽  
Weicheng Liu ◽  
Xianwei Hu ◽  
Zhaowen Wang ◽  
...  

Smelter grade alumina (SGA) plays multiple roles in the Hall–Héroult process for primary aluminum production. Given its very porous nature, one major role of SGA is to adsorb toxic hydrogen fluoride (HF) in the dry scrubber. However, also because of its porous nature, SGA inevitably adsorbs ambient moisture. This paper discusses the influence of alumina properties, including pore size distribution and specific surface area, on the physical adsorption of water vapor on SGA, as well as the adsorption kinetics. The result shows that the adsorption enthalpy of moisture on SGA is in the range of 4–13 kJ/mol. The adsorption capacity increases significantly with the particle specific surface area and total pore volume. A higher adsorption temperature indicates a much faster adsorption rate but corresponds to a lower equilibrium adsorption capacity.


Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3811
Author(s):  
Zhongbao Liu ◽  
Jiayang Gao ◽  
Xin Qi ◽  
Zhi Zhao ◽  
Han Sun

In this study, the hydrothermal method was used to synthesize MIL-101(Cr), and activated carbon (AC) with different content was incorporated in to MIL-101(Cr), thereby obtaining AC-MIL-101(Cr) composite material with a huge specific surface area. The physical properties of MIL-101(Cr) and AC-MIL-101(Cr) were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), nitrogen adsorption and desorption and specific surface area testing, and ethanol vapor adsorption performance testing. The results show that with the increase of activated carbon content, the thermal stability of AC-MIL-101(Cr) is improved. Compared with the pure sample, the BET specific surface area and pore volume of AC-MIL-101(Cr) have increased; In the relative pressure range of 0–0.4, the saturated adsorption capacity of AC-MIL-101(Cr) to ethanol vapor decreases slightly. It is lower than MIL-101(Cr), but its adsorption rate is improved. Therefore, AC-MIL-101(Cr)/ethanol vapor has a good application prospect in adsorption refrigeration systems. The exploration of AC-MIL-101(Cr) composite materials in this paper provides a reference for the future application of carbon-based/MOFS composite adsorbent/ethanol vapor working fluid in adsorption refrigeration.


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