Relationship between the Activated Carbon Surface Area and Adsorption Model Coefficients for Removal of Phenol from Water

1995 ◽  
Vol 30 (2) ◽  
pp. 325-338 ◽  
Author(s):  
Peter Samaras ◽  
Evan Diamadopoulos ◽  
George P. Sakellaropoulos
Keyword(s):  
Mass Transfer ◽  
Activated Carbon ◽  
Surface Area ◽  
Activated Carbons ◽  
Carbon Surface ◽  
Adsorptive Capacity ◽  
Mineral Matter ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Commercial Carbon

Abstract The present study investigated the relationship between the activated carbon surface area, as measured by the BET nitrogen adsorption method, and its adsorptive capacity. Aqueous solutions of phenol at pH 7 were used. The activated carbons were produced in the laboratory from raw and demineralized lignite. Adsorption experiments took place under equilibrium or kinetic conditions and the results were simulated by mathematical modelling. Freundlich and Langmuir models were used to describe equilibrium, while the Peel-Benedek non-equilibrium model was applied for the kinetic study. The results showed that for activated carbons produced from different starting materials, the adsorptive capacities could not be solely explained by their BET surface area. While laboratory-made activated carbons with a surface area of 300 m2/g demonstrated similar capacities under equilibrium, their kinetic behaviour was different. Activated carbon produced from raw lignite showed faster kinetics, due to wider porosity, which was facilitated by the mineral matter during activation. These results were in agreement with the mass transfer coefficients in macropores and micropores estimated by the Peel-Benedek model. Comparison of a laboratory-made activated carbon, with a surface area of 500m2/g, with a commercial activated carbon having twice the surface area showed that the maximum adsorptive capacity under equilibrium of the commercial carbon was only 35% higher than that of the lab-made carbon. Yet, the mass transfer coefficients of the commercial carbon were one to two orders of magnitude higher than those of the laboratory-produced carbon. Finally, the use of the qualitative D-R plots has been suggested to elucidate the porous structure of the activated carbons.

The Effect of Activated Carbon Properties on the Adsorption of Toxic Substances

1992 ◽  
Vol 25 (1) ◽  
pp. 153-160 ◽  
Author(s):  
E. Diamadopoulos ◽  
P. Samaras ◽  
G. P. Sakellaropoulos
Keyword(s):  
Activated Carbon ◽  
Fulvic Acid ◽  
Surface Area ◽  
Activated Carbons ◽  
High Surface ◽  
High Surface Area ◽  
Ash Content ◽  
Adsorptive Capacity ◽  
Toxic Substances ◽  
Carbon Loading

The objectives of this work were to relate the activated carbon properties to its adsorptive capacity. The activated carbon needed was produced in the lab from Greek lignite coal. Subsequently, adsorption studies were performed in order to evaluate the efficiency of the various activated carbons to remove toxic substances from water. Two organic substances were used. These were phenol and fulvic acid. Additionally, the adsorption of arsenic (V) was, also, investigated. It was found that the adsorptive capacity of the activated carbons depended primarily on the ash content and the compound. The capacity of the carbon to remove phenol, expressed as mg of phenol removed per g of activated carbon (carbon loading), decreased linearly as the amount of ash in the activated carbon increased. Ash-free activated carbons could adsorb 4 times as much phenol as the activated carbons with a high ash content. On the other hand, fulvic acid and arsenic adsorbed poorly on the ash-free activated carbons. Even for the high surface area activated carbons (over 1000 m2/g), the quantity of fulvic acid or arsenic adsorbed was significantly less than that exhibited by the high ash activated carbons (maximum surface area measured hardly exceeded 300 m2/g). As the amount of ash in the carbon increased, the carbon loading increased as well, up to a certain level, beyond which the amount of ash played no significant role. The beneficial role of ash was explained by the ability of the fulvic acid and arsenic to interact with metal oxides and metal ions, which constitute a significant fraction of the ash.

Mass Transfer Coefficients in Cryosorption of Hydrogen Isotopes on Molecular Sieves or Activated Carbon at 77 K

1995 ◽  
Vol 28 (3P1) ◽  
pp. 717-722 ◽  
Author(s):  
Masabumi Nishikawa ◽  
Mitsuru Uetake ◽  
Ken-ichi Tanaka ◽  
Tomofumi Shiraishi
Keyword(s):  
Mass Transfer ◽  
Activated Carbon ◽  
Molecular Sieves ◽  
Hydrogen Isotopes ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients

Effect of Base Material on the Pore Size Distribution and Surface Area of Activated Carbon

2009 ◽  
Vol 62-64 ◽  
pp. 352-356 ◽  
Author(s):  
O.O. Ojo
Keyword(s):  
Activated Carbon ◽  
Pore Size ◽  
Surface Area ◽  
Surface Properties ◽  
Activated Carbons ◽  
Palm Kernel ◽  
Adsorptive Capacity ◽  
Corn Cobs ◽  
Base Materials ◽  
Materials Used

Powdered activated carbons were produced from palm kernel shells, corn cobs and cow bones by carbonization, pulverization and activation. The resulting granule has a surface area of 430.04 m2/g, 4022.15 m2/g and 733.60 m2/g respectively with controlled pore size. The characterized surface area enables the carbon to absorb vapors from gases, and substances from liquids. The surface properties are function of the base materials used in the preparation. Determinations of their adsorptive capacities show that activated carbon prepared from corn cobs has the highest adsorptive capacity. The surface properties are function of the base materials used in the preparation. Determinations of their adsorptive capacities show that activated carbon prepared from corn cobs has the highest adsorptive capacity.

Simple Procedure to Estimate Mass Transfer Coefficients from Uptake Curves on Activated Carbons

2018 ◽  
Vol 41 (8) ◽  
pp. 1622-1630 ◽  
Author(s):  
Rafael Magalhães Siqueira ◽  
Enrique Vilarrasa-García ◽  
Antônio Eurico Belo Torres ◽  
Diana Cristina Silva de Azevedo ◽  
Moisés Bastos-Neto
Keyword(s):  
Mass Transfer ◽  
Activated Carbons ◽  
Simple Procedure ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients
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