Granular Carbon Materials

The activated carbon materials are produced by either thermal or chemical activation as granular, powdered, or shaped products. In addition to the form of the activated carbon, the final product can differ in both particle size and pore structure. The properties of the activated carbon will determine the type of application for which the carbon will be used. 

Intimate mixtures with carbon or phosphorus may ignite or explode [1]. Other readily oxidisable materials (probably antimony, arsenic, boron, sulfur, selenium) also form explosive mixtures [2], Use of finely powdered carbon, rather than the granular carbon specified for a reagent, mixed with sodium peroxide caused an explosion [3],... 

Granular carbonaceous material such as Bugbird carbon is impregnated with a solution of a fire-proofing material such as Amm phosphate or Ca chloride and the treated material is used as a carrier for liq oxygen. G.B. Holderer, USP 2119050 (1938) CA 32,... 

Table 1 summarizes the results of the N2 and H2 physisorption measurements of the materials analysed. All samples are highly micro-and mesoporous carbon materials. In our experiments four samples of carbon Busofit-AYTM (1 - 4) and three samples of wood-based activated carbon (5 - 7) obtained by new technology were investigated. The activated carbon 207C (8) is made in the Great Britain from coconut shell. Samples 9 and 10 - granular activated carbons, specially developed for effective storage of methane. 

As seen in Table 1, the greatest values of a surface area and micropore volume among carbon fibrous materials has Busofit-M8 among wood-based activated carbons it is stand out WAC 3-00 , granular carbons - Sutcliff . 

We have found that the waste wood and used tealeaves showed high adsorption capabilities for ammonia gas in low equilibrium pressure (< 13.3 kPa). The amount of the adsorbed ammonia for these carbonized materials were much higher that of the activated carbon Granular Shirasagi GS3 x 4/6. These results suggest that the carbonized materials from organic wastes could be utilized as adsorbents for ammonia... 

Various organic wastes were carbonized with super-heated water vapor using a rotary drum super-heated water vapor generator (SJH-IOM, Johnson Boiler, Japan) and a rotary kiln (JBT-1OM, Johnson Boiler, Japan). The organic wastes were processed at 623 K for 30 - 90 min. Process data and properties of various carbonized materials are summarized in Table 1. An activated carbon (Granular Shirasagi GS3 x 4/6, Takeda Chemical Industries Ltd., Japan) and an activated carbon prepared for alkaline gas adsorption (GAH 4-8, Cataler Corp., Japan) were used as controls. 

Surface areas determined by nitrogen gas adsorption (Sn2)> nd those determined by carbon dioxide (Sco2) for the various carbonized materials are summarized in Table 2. The carbonated materials showed much smaller Sn2 than the activated carbon Granular Shirasagi. The Sco2> on the other hand, of the carbonated materials were almost the same order of magnitude to that of the activated carbon. These results show that the carbonized materials have mesopores whose diameter is less than SO nm. 

It should be noted that the adsorption capacities of the waste wood and the used tealeaves for ammonium gas in the low equilibrium pressure are much higher than that of Granular Shirasagi, and are compatible to that of GAH 8-4 which is specialized for alkaline gas adsorption. These carbonized materials probably can be used as the substituted materials for the activated carbon. 

Sorption capacities of granular activated carbons and activated carbon fibers were measured, but they were relatively low, e.g., 1 g/g for activated carbon granules with llOOm /g surface area and 19g/g for those with 1220m /g, and no relation to the Brunauer, Emmett, and Teller (BET) surface area was observed. Therefore, the experimental results on different carbon materials showed that macropores, which make bulk density lower, are mainly responsible for their large sorption capacity. Fibrous particles of carbon may be advantageous for easy deformation of macropores to be suitable for sorption of heavy oils. 

Among the mechanical properties of greatest practical impact on catalysis applications is the attrition and crushing resistance of powdered or granular activated carbons, the most commonly used catalytic carbon materials, versus that of activated carbon fibers (ACFs) or of other, less-surface-active carbons (e.g.. 

A large variety of carbon materials can and have been used as catalyst supports. The most important are granular and powdered activated carbons and carbon blacks, but there is increasing interest in related materials, such as activated carbon fibers and cloths, nanotubes, and nanofibers [8]. A comprehensive review... 

Other properties of activated carbons, however, may be even more important than their textural properties. One example is particle size. A classification of carbon axisorbents based on size divides them into Powdered Activated Carbons (PAC) or Granular Activated Carbons (GAC). For certain specific applications a choice must be made between PAC or GAC regardless of porous properties. For example, in order to clean up a gas stream in a fixed bed, a granular material must be used. Otherwise the pressure drop would be enormous. Furthermore, granular carbon must be dense, hard and with a low abrasion index. 

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