Carbon black adsorption

OS3(CO)l2 Amorphous carbon black Adsorption from solution and thermal treatment under H2 Os particles active in methanation [71]... 

Figure 10.10 Schematic representation of the physical network structure in a carbon-black-filled elastomer [62]. The symbol - indicates elastomer - carbon black adsorption junctions. The length scales in this figure and the EPDM/carbon black volume ratio are fictional. For simplicity, none of the contacting carbon black aggregates, which form agglomerates, have been included...

The results obtained for unvulcanised EPDM and NR filled with carbon black provide convincing evidence that the physical network has a bimodal structure [62, 79]. Two types of EPDM chains and/or chain fragments with widely differing densities of EPDM-carbon black adsorption junctions are present in the rubbery matrix outside the EPDM-carbon black interface (tightly bound rubber) (Figure 10.11) [62],... 

Applications . NMR has found the following applications in filled systems carbon black adsorption of SBR, the effect of carbon black loading on cure rate of natural rubber, gel-like behavior of polybutadiene/carbon black mixtures, structure and dynamics of carbon black filled rubber vulcanizalcs, " interaction of... 

Solvent partition Solvent partitisolvent removal Horn dilute solutistudying biological effects of solvents and solutes, and to design system for solvent extraction. 

FIGURE 8.15 Adsorption and Desorption isotherms of CCI4 at 35°C on different carbon blacks. Adsorption = open desorption = closed. (After Puri, B.R., Arora, V.M., and Verma, S.K., J. Indian Ghent. Soc., 56, 802, 1979. With permission.)... 

Bobyleva, M.S., et al.. Relation between structure of molecules of nitrogen-containing heterocyclic compounds and their adsorption on graphitized carbon black, Adsorpt. Sci. Technol., 2(3), 165-176 (1985). 

These effects can be illustrated more quantitatively. The drop in the magnitude of the potential of mica with increasing salt is illustrated in Fig. V-7 here yp is reduced in the immobile layer by ion adsorption and specific ion effects are evident. In Fig. V-8, the pH is potential determining and alters the electrophoretic mobility. Carbon blacks are industrially important materials having various acid-base surface impurities depending on their source and heat treatment. 

There are complexities. The wetting of carbon blacks is very dependent on the degree of surface oxidation Healey et al. [19] found that q mm in water varied with the fraction of hydrophilic sites as determined by water adsorption isotherms. In the case of oxides such as Ti02 and Si02, can vary considerably with pretreatment and with the specific surface area [17, 20, 21]. Morimoto and co-workers report a considerable variation in q mm of ZnO with the degree of heat treatment (see Ref. 22). 

Many solids have foreign atoms or molecular groupings on their surfaces that are so tightly held that they do not really enter into adsorption-desorption equilibrium and so can be regarded as part of the surface structure. The partial surface oxidation of carbon blacks has been mentioned as having an important influence on their adsorptive behavior (Section X-3A) depending on conditions, the oxidized surface may be acidic or basic (see Ref. 61), and the surface pattern of the carbon rings may be affected [62]. As one other example, the chemical nature of the acidic sites of silica-alumina catalysts has been a subject of much discussion. The main question has been whether the sites represented Brpnsted (proton donor) or Lewis (electron-acceptor) acids. Hall... 

Fig. XVn-21. (a) Differential heat of adsorption of N2 on Graphon, except for Oand , which were determined calorimetrically. (From Ref. 89.) (b) Differential heat of adsorption of N2 on carbon black (Spheron 6) at 78.5 K (From Ref. 124).

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.)...

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).

Fig. 2.11 Curves of the differential enthalpy of adsorption of nitrogen against surface coverage 0 (= for samples of Sterling carbon black heated at the following temperatures (a) 1500°C (fc) 1700°C (c) 2200 C (d) 2700°C. The curve for 2000°C was similar to (c). but with a lower peak. The calorimetric temperature was 77-5, 77-7, 77-4, 77-4 K in (a), (fc), (c) and (d) respectively.

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 . 

Fig. 2.13 Adsorption of nitrogen on a carbon black before graphitiz-ation. - The difTerential heat of adsorption Ji, plotted against n/n , was determined calorimetrically at 78 K (O, , A) and was also calculated from the isotherms at 78 6 and 90-1 K (+ ). (Courtesy Joyner and Emmett.)...

Fig. 2.15 Isosteric heat of adsorption of nitrogen on molecular (low-evergy) solids and on carbons (high-energy solids), plotted as a function of i/n . (A) Diamond (B) gruphitized carbon black. P.33 (D) Benzene (E) Teflon. The curve for amorphous carbon was very close to Curve (A). (Redrawn from a Figure of Adamson . )...

Specific surface area of carbon blacks before and after graphitization, determined by electron microscopy (A,) end by nitrogen adsorption (A ]t... 

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. 2.24 Adsorption isotherms of argon at 78 K on Spheron-6 carbon black, heated to various temperatures indicated in °C on each isotherm. (After Polley, Schaeffer and Smith. )...

Fig. 2.25 The differential heat of adsorption of argon on carbon blacks at 78 K, before and after graphitizalion.. Spheron O, Graphon. , and El denote molar heat of sublimation and of evaporation respectively.

Fig. 2.29 Comparison of nitrogen adsorption at 78 K on a carbon black (Sterling FT) before and after graphitization (a) The amount adsorbed on the ungraphitized sample plotted against the amount x, adsorbed on the graphitized sample, at the same pressure, b) The corresponding isotherms O, adsorption, , desorption on the ungraphitized sample (4 runs) A. adsorption A desorption, on the graphitized sample (4 runs).

Fig. 4.6 Plat of the net differential heat of adsorption q — qj against the relative adsorption n/no.j, where H(,.2 is the adsorption at p/p° = 0-2. (A) active carbon (B) carbon black. (After Dubinin.)...

Fig. 4.13 The pre-adsorption method (a) adsorption isotherms of nitrogen at 77 K on a sample of Mogul I carbon black charged with different amounts x of pre-adsorbed nonane. Values ofx (mg g (A) 63 (B)48 (C) 29 (D) 16 (E) 0. (See Table 4.5.) (Some points at low pressures omitted for the sake of clarity.)...

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