Properties of activated carbon

The effectiveness of activated carbon for the removal of organic pollutants from water by carbon adsorption is enhanced by its large surface area, an important factor in the adsorption process. The surface area of activated carbon typically can range from 500 to 1400 nP/g. Table 2 presents the surface areas of several commercially available activated carbons (6). Some have large surface areas as high as 2500 aP/g. 

Rate of adsorption increases as particle size decreases. Head loss through packed column increases as particle size decreases. 

A measure of the area available for adsorption. The larger the surface area, the greater the adsorptive capacity. Measured by determining the amount of nitrogen adsorbed by the carbon and reported as m /g. 

Measure of total macropore and micropore volume within the carbon particles. Measured in cm /g. 

Refers to milligrams of iodine adsorbed during standard test. Measures the volume present in pores from 10 to 28 A in diameter. Carbons with a high percentage of pore sizes in this range would be suitable for adsorbing low-molecular-weight substances. 

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The stmcture of activated carbon is best described as a twisted network of defective carbon layer planes, cross-linked by aHphatic bridging groups (6). X-ray diffraction patterns of activated carbon reveal that it is nongraphitic, remaining amorphous because the randomly cross-linked network inhibits reordering of the stmcture even when heated to 3000°C (7). This property of activated carbon contributes to its most unique feature, namely, the highly developed and accessible internal pore stmcture. The surface area, dimensions, and distribution of the pores depend on the precursor and on the conditions of carbonization and activation. Pore sizes are classified (8) by the International Union of Pure and AppHed Chemistry (lUPAC) as micropores (pore width <2 nm), mesopores (pore width 2—50 nm), and macropores (pore width >50 nm) (see Adsorption). 

Source references for frequentiy used test procedures for determining properties of activated carbon are shown in Table 4. A primary source is the Jinnual Book ofyimerican Societyfor Testing and Materials (ASTM) Standards (61). Other usehil sources of standards and test procedures include manufacturers of activated carbon products, the American Water Works Association (AWWA) (33,34), and the Department of Defense (54). 

Lin, R. Y. and Economy, J., Preparation and properties of activated carbon fibers derived from phenolic resin precursor, Appl. Polym. Symp., 1973, 21, 143 152. 

Properties of activated carbons produced by Westvaco for automotive applications are presented in Table 5. 

The general aim of this work is to show the properties of activated carbon-ionic liquid interface (AC-IL) as well as performance of capacitors based on activated carbons as electrode materials and ionic liquids as electrolytes. 

A. Nakayama, K. Suzuki, T. Enoki, K. Koga, M. Endo, N. Shindo, Electronic and magnetic properties of activated carbon fibers. Bull. Chem. Soc. Jpn., 69(2) (1996) 333-339. 

Dubinin MM. Porous structure and adsorption properties of active carbons. In Walker PL, ed. Chemistry and Physics of Carbon, vol. 2, New York Marcel Dekker. 1966 p. 51. 

The unique surface property of activated carbon, in contrast to the other major sorbents, is that its surface is nonpolar or only slightly polar as a result of the surface oxide groups and inorganic impurities. This unique property gives activated carbon the following advantages ... 

In addition to the developed pore structure, small pore sizes, and large surface area, surface hydrophobicity is an extremely helpful property of active carbon [170-175], This property is particularly useful for the adsorption of organic species [176],... 

Abstract. The influence of an inert impregnant (NaCl) on the adsorption properties of activated carbon Norit R 0.8 Extra was studied on breakthrough dynamics of tert-butylbenzene (TBB) and dimethylmethylphosphonate (DMMP). Pre-adsorbed NaCl (5-20 wt.%) strongly affects both structural (e.g. volume of nanopores and mesopores) and adsorption (adsorption potential, breakthrough time, kinetic saturation capacity, etc.) characteristics. 

In recent years, extensive studies have been undertaken by Kaneko and his coworkers of the properties of activated carbon fibres (ACFs) produced from cellulose, polyacrylonitrile (PAN) and pitch. X-ray diffraction and electron microscopy revealed that the PAN-based and pitch-based fibres had a more homogeneous pore structure than that of the cellulose-based material, although the latter had the largest surface area and pore volume (Kakei et al., 1990). 

Seida, Y. and Nakano, Y., Removal property of activated carbon with mesopore and dispersed iron nanoparticle for humic substances, Proc. 2nd International Water Association World Conference, P2126, 1-6(2001), CD-ROM version. 

SURFACE PROPERTIES OF ACTIVATED CARBONS CONTAINING BASIC HYDROXIDE IONS AND NOx ADSORPTION-DESORPTION PROCESS... 

B. Specifie Properties of Active Carbon in Relation to Other... 

II. Properties of Active Carbons Important for Their Electrochemical... 

III. Physicochemical Properties of Active Carbons Used for Electrode... 

II. PROPERTIES OF ACTIVE CARBONS IMPORTANT FOR THEIR ELECTROCHEMICAL BEHAVIOR... 

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