Adsorption studies of water vapor on porous glass

Infrared study of methanol adsorption on Aerosil. I. Chemisorption at room temperature

“…Our aim in this study of the physical adsorption of methanol on Aerosil is to contribute to the solution of the following problems: (1) to compare volumetric with spectroscopic data and so establish if it is possible to determine adsorption isotherms by means of infrared spectroscopy alone; (2) to study any heterogeneity of adsorption sites and hence the different species adsorbed; in fact, infrared spectrophotometry…”

“…I. Chemisorption at Room Temperature by Enzo Borello, Adriano Zecchina, and Claudio Morterra Introduction Several authors1-7 have studied the problem of methanol adsorption on silica gels but it is difficult to make useful comparisons of their conclusions because of the differences in types of silica employed and experimental conditions. For example, Kawasaki, et al, 1 Sidorov,6 and McDonald7 seem to think that surface methylation takes place through esterification of surface hydroxyls according to the reaction f + CH3OH A </ CHg + H20 /|\ (1) Thus the number of methoxyls formed is equal to the number of hydroxyls consumed. On the other hand, Kiselev, et al, 4•5 think that the surface methylation reaction takes place according to the reaction They base this conclusion on the fact that the irreversible adsorption of methanol on the surface of silica is greater, the higher the temperature at which it was outgassed, namely, the lower the surface content of hydroxyls.…”

Effect of substrate oxidation on spreading of plasma-sprayed nickel on stainless steel

“…Preheating the substrates forms an oxide layer that changes the defect sites [33,35] and reduces readsorption of contaminants during cooling. Kawasaki et al [33] showed that when porous glass is heated above 350°C, then cooled, less water was readsorbed than on a surface that had never been heated. Kittaka et al [35] have shown that preheating chromium oxide reduces the ability of the surface to adsorb water, and that increasing the preheating temperature reduces the adsorption of water even further.…”

“…It is more difficult to understand why preheating a surface and then cooling it should reduce thermal contact resistance. Adsorption of water molecules and other contaminants on the metal substrates typically occurs at defect sites on the surface [33,34]. Preheating the substrates forms an oxide layer that changes the defect sites [33,35] and reduces readsorption of contaminants during cooling.…”

“…Adsorption of water molecules and other contaminants on the metal substrates typically occurs at defect sites on the surface [33,34]. Preheating the substrates forms an oxide layer that changes the defect sites [33,35] and reduces readsorption of contaminants during cooling. Kawasaki et al [33] showed that when porous glass is heated above 350°C, then cooled, less water was readsorbed than on a surface that had never been heated.…”