An evaluation of the reliability of the characterization of the porous structure of activated carbons based on incomplete nitrogen adsorption isotherms

The porous structures of synthetic active carbons have been examined in detail on the basis of nitrogen adsorption isotherms at 77 K using the αS method, the Dubinin–Stoeckli approach and the regularization technique. Analysis of the porosity of synthetic active carbons shows that carbons obtained under identical conditions have dissimilar adsorption properties depending on the size of the granule. The application of the Dubinin–Stoeckli equation for the characterization of strongly heterogeneous carbons overestimates the maximum amount adsorbed in the micropores. In contrast to the Dubinin–Stoeckli equation, the regularization method gives a two-peak micropore size distribution and enables adsorbents with a bimodal porous structure to be estimated.

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Preparation and Characterization of Activated Carbon from Palm Shell by Catalytic Activation with Steam

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.787.46 ◽

2013 ◽

Vol 787 ◽

pp. 46-51 ◽

Cited By ~ 2

Author(s):

Hao Guo ◽

Xian Lun Deng

Keyword(s):

Activated Carbon ◽

Potassium Carbonate ◽

Activated Carbons ◽

Potassium Phosphate ◽

Nitrogen Adsorption ◽

Physical Activation ◽

Catalytic Activation ◽

Palm Shell ◽

Nitrogen Adsorption Isotherms

The use of palm shells as a precursor for the production of activated carbon with physical activation was investigated. The carbonized material was impregnated with potassium carbonate and potassium phosphate to improve the yield and adsorption capability of activated carbon. The produced activated carbons were characterized by Iodine number text, Methylene blue adsorption text, Nitrogen adsorption isotherms, Scanning electron microscope in order to understand the palm shell activated carbon. The results showed that palm shell is an appropriate precursor for activated carbon. The optimum activation condition is: temperature 850°C, activating time 60 min, and steam flow rate 1.0g min-1. Potassium carbonate-impregnated and potassium phosphate-impregnated sample showed higher value of surface area which attained 982m2/g and 973m2/g, respectively.

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Computer Analysis of the Porous Structure of Activated Carbons Derived from Various Biomass Materials by Chemical Activation

Materials ◽

10.3390/ma14154121 ◽

2021 ◽

Vol 14 (15) ◽

pp. 4121

Author(s):

Mirosław Kwiatkowski ◽

Elżbieta Broniek

Keyword(s):

Porous Structure ◽

Adsorption Isotherms ◽

Computer Analysis ◽

Activated Carbons ◽

Chemical Activation ◽

Adsorbed Layer ◽

Dry Mass ◽

Mass Ratio ◽

Adsorption Volume ◽

Homogeneous Surface

In this study, the preparation of activated carbons from various materials of biomass origin by activation with potassium hydroxide and a comprehensive computer analysis of their porous structure and adsorption properties based on benzene (C6H6) adsorption isotherms were carried out. In particular, the influence of the mass ratio of the activator’s dry mass to the char mass on the formation of the microporous structure of the obtained activated carbons was analysed. The summary of the analyses carried out based on benzene adsorption isotherms begged the conclusion that activated carbon with a maximum adsorption volume in the first adsorbed layer and homogeneous surface can be obtained from ebony wood at a mass ratio of the activator to the char of R = 3. The obtained results confirmed the superiority of the new numerical-clustering-based adsorption analysis (LBET) method over simple methods of porous structure analysis, such as the Brunauer–Emmett–Teller (BET) and Dubinin–Raduskevich (DR) methods. The LBET method is particularly useful in the evaluation of the influence of the methods and conditions of production of activated carbons on the formation of their porous structure. This method, together with an appropriate economic analysis, can help in the precise selection of methods and conditions for the process of obtaining activated carbons at specific manufacturing costs, and thus makes it possible to obtain materials that can successfully compete with those of other technologies used in industrial practice and everyday life.

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