Graphitizing carbon black

The above methods for obtaining D, as well as other ones, are reviewed in Refs. 3-12, and Refs. 7-9 give tables of D values for various adsorbents. For example, D is close to 3 for the highly porous silica gels and close to 2 for nonporous fumed silica and for graphitized carbon black coconut charcoal and alumina were found to have D values of 2.67 and 2.79, respectively [7]. 

Fig. XVII-21. Continued) (c) Isosteric heats of adsorption of n-hexane on ice powder Vm = 0.073 cm STP. (From Ref. 125). (d) Isosteric heats of adsorption of Ar on graphitized carbon black having the indicated number of preadsorbed layers of ethylene. (From Ref. 126.)...

It is noted in Sections XVII-10 and 11 that phase transformations may occur, especially in the case of simple gases on uniform surfaces. Such transformations show up in q plots, as illustrated in Fig. XVU-22 for Kr adsorbed on a graphitized carbon black. The two plots are obtained from data just below and just above the limit of stability of a solid phase that is in registry with the graphite lattice [131]. 

Fig. XVII-22. Isosteric heats of adsorption for Kr on graphitized carbon black. Solid line calculated from isotherms at 110.14, 114.14, and 117.14 K dashed line calculated from isotherms at 122.02, 125.05, and 129.00 K. Point A reflects the transition from a fluid to an in-registry solid phase points B and C relate to the transition from the in-registry to and out-of-registry solid phase. The normal monolayer point is about 124 mol/g. [Reprinted with permission from T. P. Vo and T. Fort, Jr., J. Phys. Chem., 91, 6638 (1987) (Ref. 131). Copyright 1987, American Chemical Society.]...

Such isothemis are shown in figure B 1,26.4 for the physical adsorption of krypton and argon on graphitized carbon black at 77 K [13] and are examples of type VI isothemis (figure B 1.26.3 ). Equation (B1.26.7)) further... 

Figure Bl.26.4. The adsorption of argon and krypton on graphitized carbon black at 77 K (Eggers D F Jr, Gregory N W, Halsey G D Jr and Rabinovitch B S 1964 Physical Chemistry (New York Wiley) eh 18).

Similar results with graphitized carbon blacks have been obtained for the heat of adsorption of argon,krypton,and a number of hydrocarbons (Fig. 2.12). In all these cases the heat of adsorption falls to a level only slightly above the molar heat of condensation, in the vicinity of the point where n = n . 

Molecular area, a (Ar) of argon at 77 K on graphitized carbon blacks (Argon BET plots constructed with p (liquid) surface areas determined by BET-nitrogen, with a (Na)... 

An example of a stepped isotherm, for krypton at 90 K, is shown in Fig. 2.21(a), where the adsorbent is graphitized carbon black, which is known to possess a very uniform surface. Figure 2.21(h) shows the steps obtained, also with krypton, on cadmium bromide. 

Fig. 2.22 Adsorption isotherms of argon on graphitized carbon black at a number of temperatures," plotted as fractional coverage 0 against relative pressure p/p°. (Courtesy Prenzlow and Halsey.)...

Fig. 2.23 Adsorption isotherms on graphitized carbon black at 77 K. (A) argon (B) krypton. (Courtesy Dash.)...

Fig. 5.10 The adsorption isotherms of n-hexane (A) and of water (B) on graphitized carbon black.Solid symbols denote desorption. (After...

GCB = graphitized carbon black SPME = solid-phase microextraction PDMS = polydimethylsiloxane PS = polystyrene DVB = divinylbenzene SDB = styrene-divinylbenzene. 

Activated carbon disks have also been used for the extraction of polar pesticides from environmental water samples. Slobodnik et alP used an Empore activated carbon disk (EACD) and Envi-Carb graphitized carbon black (GCB) and CPP-50 graphitized carbon for the trace enrichment of polar pesticides from water. 

Starting aaterial for their preparation and subsequent activation. Graphitized carbon blacks have low surface areas, usually less than 100 K /g and typically 5-30 u /g. They have a low capacity for low molecular weight analytes but have been used successfully for the isolation of heavier nonpolar analytes that might be difficult to recover from more active forms of carbon [169,170]. The most common form of carbon used for trace enrichment is granular activated carbon, generally prepared by tbe low temperature... 

Various forms of carbon are used to sample those analytes whose breakthrough volume is too low on Tenax for sufficient preconcentration [8,395-399]. Charcoal, graphitized carbon blacks, and ceurbosieves with wface areas from 5 to 900 w /g are commercially availablJ Bhe high surface area sorbents are used... 

Extraction of estrogens and progestagens is mostly performed by off-line SPE (on-line SPE has been reported by Lopez de Alda et al. [60]), using either disks or, more frequently, cartridges. Octadecyl (C18)-bonded silica in both cartridge [7,57] and disk [36] format, graphitized carbon black [35,58,59],Isolut... 

Specific separation effects can be understood from the multicomponent solubility parameter theory. Specific effects for nonpolar compounds are predictable with perfluorinated and graphitized carbon black stationary phases. Specific selectivity for polar compounds in reversed-phase HPLC can be realized with polar additives to the mobile phase. 

Figure 9.16 The practical examples of comparative plots (a) N2 adsorption on a graphitized carbon black, modified by physical adsorption of methanol (the numbers correspond to the amount of CH3 OH in the fractions of monolayer capacity) [83] (b) the usual types of comparative plots by [3] and (c) N2 isotherms on microporous titanium oxide after various amount of preadsorbed nonane by [53].

BRUNER, F., CICCIOLI, P., and DINARDO, F., Use of Graphitized Carbon Black in Environmental Analysis. Laboratorio sull Inquinamento Atmosferico del C.N.R. Via Montorio Romano, 3600131 Rome (Italy). 

Water Sample passed through graphitized carbon black, eluted with methylene chloride Ion-suppression reversed phase LC 50-100 ng/L 91-97% Di Corcia et al. 1996... 

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