Virgin carbon

Hong, C.K. and Isayev, A.I., Blends of ultrasonicaby devulcanized and virgin carbon black fibed NR, J. Mater. Sci., 37, 385, 2002. 

The effluent from the ion exchange station is adjusted, if necessary, to the desired pH level (4.5 to 4.8) before it is further decolorized with activated carbon. This step is usually carried out in two stages and the adsorbent is utilized countercurrently. Thus, the virgin carbon is applied to the liquor concentrated to about 50 to 55% solids and this once used adsorbent is re-used on the more dilute effluent from the ion exchange station. The liquor must be filtered thoroughly to remove all traces of carbon prior to concentration, in vacuo, to about 74% solids. 

A simple mechanism of adsorption/oxidation of hydrogen sulfide was first proposed by Hedden and coworkers [31]. According to them, dissociation of hydrogen sulfide occurs in the film of adsorbed water at the virgin carbon surface and then hydrogen sulfide ions, HS , are oxidized by oxygen radicals to elemental sulfur. Since then many studies have been done to account for such factors as a role of water [26, 32, 34, 36, 37, 40, 48, 49], role of oxygen [18—27], autocatalysis by sulfur [27, 28], influence of pore sizes [19, 29, 33, 35, 38], role of carbon surface chemistry [41—44], the effects of ash [49, 58—60], and last but not least, speciation of surface oxidation products [41—46]. 

A combination with distillation is illustrated by the purification of glycerine. Ordinarily, it is difficult to decolorize crude glycerine to water-whiteness, but the task is easier after one distillation, and even more so after redistillation. In industrial practice, virgin carbon is applied to the twice-distilled glycerine, and the spent carbon from this stage is added to the crude glycerine to remove foam-formers that hinder distillation. 

Then unit R is taken off the line, the exhausted carbon in it is replaced with virgin carbon, and the unit is restored to service, but it now becomes the final unit in the series. The raw liquor now enters unit S from which it goes to T and finally to R. 

In time the carbon in unit S becomes exhausted and is replaced with virgin carbon to become the final unit in the series. This arrangement, whereby an exhausted unit is recharged is continued for the duration of the operation. 

Critical Bed Depth In a carbon column the critical bed depth is the depth of granular carbon that is partially spent. It lies between the fresh virgin carbon and the spent carbon, and is the zone where adsorption takes place. In a single-column system this is the amount of carbon that is not completely utilized. 

Replacing with virgin carbon and disposal of the spent carbon. 

Testing and properties of virgin carbon fiber and composites... 

Figure 12.30 Weight loss of virgin carbon fibers in air at SISK S in relation to Na content determined by ESCA.

Testing of PAN Precursor, Virgin Carbon Fibers, Carbon Fiber Composites and Related Products... 

TESTING OF OXIDIZED PAN FIBER (OPF) AND VIRGIN CARBON FIBER 17.3.1 Mass per unit length... 

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