scholarly journals Preparation and water vapor adsorption of “green” walnut-shell activated carbon by CO2 physical activation

2020 ◽  
Vol 38 (1-2) ◽  
pp. 60-76 ◽  
Author(s):  
Hong Zhao ◽  
Qiongfen Yu ◽  
Ming Li ◽  
Shengnan Sun
Keyword(s):  
Activated Carbon ◽  
Water Vapor ◽  
Specific Surface ◽  
Pore Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Water Vapor Adsorption ◽  
Walnut Shell ◽  
Physical Activation ◽  
Vapor Adsorption

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.

scholarly journals Determination of soil specific surface area by water vapor adsorption: II Dependence of soil specific surface area on clay and organic carbon content

1987 ◽  
Vol 59 (2) ◽  
pp. 67-72
Author(s):  
Raina Niskanen ◽  
Väinö Mäntylahti
Keyword(s):  
Water Vapor ◽  
Organic Carbon ◽  
Specific Surface ◽  
Carbon Content ◽  
Surface Area ◽  
Specific Surface Area ◽  
Mineral Soil ◽  
Water Vapor Adsorption ◽  
Organic Carbon Content ◽  
Vapor Adsorption

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-%.

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
Keyword(s):  
Water Vapor ◽  
Specific Surface ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Specific Surface Area ◽  
Molecular Sieves ◽  
Total Pore Volume ◽  
Water Vapor Adsorption ◽  
Carbon Molecular Sieves ◽  
Vapor Adsorption

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.

scholarly journals Experimental Study on Activated Carbon-MIL-101(Cr) Composites for Ethanol Vapor Adsorption

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3811
Author(s):  
Zhongbao Liu ◽  
Jiayang Gao ◽  
Xin Qi ◽  
Zhi Zhao ◽  
Han Sun
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Ethanol Vapor ◽  
Future Application ◽  
Working Fluid ◽  
Relative Pressure ◽  
Adsorption Refrigeration ◽  
Vapor Adsorption

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.

scholarly journals Pore Structure Regulation and Electrochemical Performance Characterization of Activated Carbon for Supercapacitors

2021 ◽  
Vol 9 ◽  
Author(s):  
Shijie Li ◽  
Tao Xing ◽  
Yilin Wang ◽  
Pengwei Lu ◽  
Weixue Kong ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Pore Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Activation Time ◽  
Activation Temperature ◽  
Specific Pore Volume ◽  
Impregnation Time

In order to achieve the purpose of regulating the pore structure characteristics of activated carbon by adjusting the experimental parameters, the effects of carbonization temperature, carbonization time, pre-activation temperature, pre-activation time and impregnation time on the pore structure of sargassum-based activated carbon (SAC) are studied by orthogonal experiment. The gravimetric capacitance of SAC and the relationship between the gravimetric capacitance and specific surface area are also studied. The results show that the SACs prepared at all experimental conditions have developed pore structure and huge specific surface area, reaching 3,122 m2/g. The pore size of SAC is almost all within 6 nm, in which the micropores are mainly concentrated in 0.4–0.8 nm, the mesopores are mainly concentrated in 2–4 nm, and the number of micropores is significantly higher than that of mesopores. During the preparation of SAC, the effect of carbonization temperature on the specific surface area and specific pore volume of SAC is very significant. The effect of carbonization time on the specific surface area of SAC is significant, but the effect on specific pore volume can be ignored. The effects of pre-activation temperature, pre-activation time, and impregnation time on specific surface area and specific pore volume of SAC can be ignored. In addition, SACs show good gravimetric capacitance performance as electrode material for supercapacitors, which can significantly increase the capacitance of supercapacitors and thus broaden their applications. The gravimetric capacitance and specific surface area of SACs show a good linear relationship when the activated carbons have similar material properties and pore size distribution.

scholarly journals Sisal xylem fibre-based activated carbon fibres for fuel adsorption: effect of thermal stabilization of diammonium phosphate

2020 ◽  
Vol 7 (9) ◽  
pp. 200966
Author(s):  
Zhuo Deng ◽  
Jian Hu ◽  
Hailong Li
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Pore Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Thermal Stabilization ◽  
Carbon Fibres ◽  
Desorption Process ◽  
Activated Carbon Fibres ◽  
Fuel Evaporation

Activated carbon fibres (ACFs) are considered as the next generation of activated carbon products. However, lack of structural diversity in pore structure and high prices of raw materials for ACFs has restrained the development of ACF materials. In this paper, a sisal-based activated carbon fibre (SACF) material was prepared from sisal wastes with a unique thermal stabilization treatment to maintain fibrous shapes of SACFs while dispersing in solutions, and the SACFs were prepared as raw fibre materials for fuel evaporation emissions controlling products. Experimental results of N 2 adsorption showed that SACF has a typical I-type adsorption isotherm, with specific surface area of SACF samples of approximately 1200 m 2 g −1 , and mainly microporous pore structure. Compared with commercial samples (specific surface area, 1841.29 m 2 g −1 ), the butane working capacities of SACF for advanced fuel evaporation emissions controlling product was 0.4 g/100 ml higher. Furthermore, two dynamic models, Thomas model and Clark model, were applied to adsorption breakthrough data, which showed excellent fit. And it indicated from the adsorption breakthrough curves and parameters of both models that the SACF has better performance in fuel adsorption and desorption process than the commercial samples.

scholarly journals Analysis of the physical and chemical properties of activated carbons based on hulless barley straw and plain wheat straw obtained by H3PO4 activation

BioResources ◽  
2018 ◽  
Vol 13 (3) ◽  
pp. 5204-5212
Author(s):  
Bing Wang ◽  
Yongang Li ◽  
Hongyu Si ◽  
Huiyuan Chen ◽  
Ming Zhang ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Pore Structure ◽  
Wheat Straw ◽  
Surface Area ◽  
Specific Surface Area ◽  
Barley Straw ◽  
Process Conditions ◽  
Cellulose Content ◽  
Hulless Barley

High specific surface area activated carbon was prepared by improving the process conditions of phosphoric acid activation and hulless barley straw and plain wheat straw as raw materials. The effects of the activation time on the pore structure and specific surface area of two types of activated carbon were investigated. The results revealed that soaking straws in the high concentrations of H3PO4 for 0.5 h to ensure complete soaking and then removing the straws from H3PO4 solution to activate was beneficial to the infiltration of H3PO4 in the raw material, and there was an increase in the surface area of activated carbon. The largest specific surface area of activated carbon prepared from plain wheat straw and hulless barley straw was 1524 m2/g and 1885 m2/g, respectively. Thermogravimetric analysis and scanning electron microscopy showed that the higher cellulose content, higher hemicellulose content, and smaller fiber morphology in hulless barley straw compared with wheat straw were the main reasons for the more abundant pore structure and higher specific surface area of the activated carbon.

scholarly journals Pore Structure Characteristics of Foam Composite with Active Carbon

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4038 ◽  
Author(s):  
Jungsoo Lee ◽  
Young Cheol Choi
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Pore Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Active Carbon ◽  
Micropore Volume ◽  
High Porosity ◽  
Structure Characteristics ◽  
Foam Composite

Characterization of porous materials is essential for predicting and modeling their adsorption performance, strength, and durability. However, studies on the optimization of the pore structure to efficiently remove pollutants in the atmosphere by physical adsorption of construction materials have been insufficient. This study investigated the pore structure characteristics of foam composites. Porous foam composites were fabricated using foam composite with high porosity, open pores, and palm shell active carbon with micropores. The content was substituted 5%, 10%, 15%, and 20% by volume of cement. From the measured nitrogen adsorption isotherm, the pore structure of the foam composite was analyzed using the Brunauer–Emmett–Teller (BET) theory, Barrett–Joyner–Halenda (BJH) analysis, and Harkins-jura adsorption isotherms. From the analysis results, it was found that activated carbon increases the specific surface area and micropore volume of the foam composite. The specific surface area and micropore volume of the foam composite containing 15% activated carbon were 106.48 m2/g and 29.80 cm3/g, respectively, which were the highest values obtained in this study. A foam composite with a high micropore volume was found to be effective for the adsorption of air pollutants.

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