Adsorption of Polar Vapors

FIGURE 1.20 Effect of surface oxidation in air at 700°C on different carbon fiber and 

FIG U RE 1.21 Water vapor sorption isotherms on polyvinyledene chloride (PVDC and urea formaldehyde resin (UF) carbons before and after outgassing and oxidation. (From Bansal, R.C., Dhami, T.L., and Prakash, S., Carbon, 16, 389, 1978. With permission.) 

FIGURE 1.22 Adsorption isotherms of benzene on (a) PVDC carbon, (b) Spheron-6, and (c) Mognl before and after ontgassing at different temperatures. (From Bansal, R.C. and Dhami T.L., Carbon, 15, 153, 1977. With permission.) 

The heats of immersion in both water and methanoP decreased continuously on evacuation of the carbon samples at temperatures above 300°C. The continuous decrease in the case of water resulted from the removal of surface oxides that provide hydrophilic centers for hydrogen bonding. The final heat of immersion value, when all the surface oxygen has been removed, agreed fairly well with the value obtained by Wade on graphon, which was completely free of any combined oxygen and 

FIGURE 1.23 Heat of immersion of charcoals in relation to chemisorbed oxygen. (After Puri, B.R., Singh, D.D., and Sharma, L.R., J. Phys. Chem., 62, 756, 1958. With permission.) 

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