Determination of physisorbed and chemisorbed waters on silica gel and porous silica glass by means of desorption isotherms of water vapor

Naono, Hiromitu; Fujiwara, Reiko; Yagi, Masahide

doi:10.1016/0021-9797(80)90272-6

Cited by 57 publications

(31 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The inner surface of the line (silica glass) where the equilibrium occurred is about 0.2 m 2 . The adsorbed volume can be estimated from reliable adsorption isotherm of porous silica glass (e.g., Naono et al, 1979): 4 lmol was adsorbed at max on the inner walls, corresponding to 7.2 · 10 À2 ll. As a consequence, the total quantity of water vapor and of water adsorbed on the silica tube adsorbates was always greater by several orders of magnitudes than the amount adsorbed on the inner surface of the line.…”

Section: Experimental Protocolmentioning

confidence: 99%

Experimental study of D/H isotopic fractionation factor of water adsorbed on porous silica tubes

Richard

Mercury

Massault

et al. 2007

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

Section: Experimental Protocolmentioning

confidence: 99%

Experimental study of D/H isotopic fractionation factor of water adsorbed on porous silica tubes

Richard

Mercury

Massault

et al. 2007

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

“…As a result, the first desorption isotherms do not return to the origin. The amounts of chemisorbed water or the regenerated silanol groups were determined from the difference between the first and second desorption isotherm (12), whose result is given in Table 3. The regenerated silanol groups per nm 2 are found to be 4.02, 3.76, 4.56, and 4.08 for PS-C12-D, PS-C14-D, PS-C16-D, and PS-C18-D, respectively.…”

Section: Ples (Ps-c12-d Ps-c14-d Ps-c16-d and Ps-c18-d)mentioning

confidence: 99%

“…Brunauer and his co-workers (8)(9)(10)(11) have emphasized that the water isotherms make possible an independent check on the pore size distribution determined by the nitrogen isotherms. In addition to the analysis of porous texture, the water isotherms play an important role in characterization of the pore surface of the MCM-41 or FSM-16 mesoporous silica (12)(13)(14). The purpose of the present paper is to measure systematically the adsorption-desorption isotherms of nitrogen gas (77 K) and water vapor (298 K) for a series of the MCM-41 mesoporous silicas with different pore sizes.…”

Section: Introductionmentioning

confidence: 99%

Porous Texture and Surface Character of Dehydroxylated and Rehydroxylated MCM-41 Mesoporous Silicas—Analysis of Adsorption Isotherms of Nitrogen Gas and Water Vapor

Naono

Hakuman

Tanaka

et al. 2000

Journal of Colloid and Interface Science

Self Cite

View full text Add to dashboard Cite

“…Silicate and aluminosilicate are typical examples of systems on which there exist physisorbed and chemisorbed molecules at the same time [2]. It is known that surface hydroxyl groups act as primary centres in the physical adsorption of water [3][4][5].…”

mentioning

confidence: 99%

The kinetics of water desorption from porous glasses

Dondur

Fidler

Adnadjević

et al. 1987

Journal of Thermal Analysis

View full text Add to dashboard Cite

The kinetics of water desorption from porous glasses silica gel and porous aluminosilicates were followed through the TG and DTG methods.In all cases only one thermodesorption peak appeared. The kinetic parameters were determined by standard nonisothermal methods. The activation energy is constant and independent of the coverage degree and pore diameter in the system porous glass-water. The function E (0) were determined for the silica gel and porous aluminosilicates E = E 0 + a exp ( -bO). The parameters Eo, a and b depend on the SiO2/A1203 ratio and on the distribution of active centers on the surface.Desorption kinetics is most commonly presented by the equation:In which n is the reaction order, A the pre-exponential factor and E the activation energy. In the general case, kinetic parameters depend upon the degree of coverage [1].Such an equation can be applied to high-energy chemisorbed states and to lowenergy physisorbed states. Silicate and aluminosilicate are typical examples of systems on which there exist physisorbed and chemisorbed molecules at the same time [2]. It is known that surface hydroxyl groups act as primary centres in the physical adsorption of water [3][4][5]. Zettlemoyer [5] considers the hydroxy ! groups to be donors and water molecules to be acceptors of hydrogen-bonds. According to the results of Kiselev [6], an adsorptive complex is formed in which approximately two hydroxyl groups correspond to one molecule of water. Dehydroxylation (associative desorption) is preceded by the desorption of physically adsorbed water and, due to the considerable difference in bond energy, it can be expected that these processes take place as two independent consecutive stages. It is probable that John Wiley & Sons, Limited, Chichester AkadOmiai Kiad6, Budapest

show abstract

Determination of physisorbed and chemisorbed waters on silica gel and porous silica glass by means of desorption isotherms of water vapor

Cited by 57 publications

References 18 publications

Experimental study of D/H isotopic fractionation factor of water adsorbed on porous silica tubes

Experimental study of D/H isotopic fractionation factor of water adsorbed on porous silica tubes

Porous Texture and Surface Character of Dehydroxylated and Rehydroxylated MCM-41 Mesoporous Silicas—Analysis of Adsorption Isotherms of Nitrogen Gas and Water Vapor

The kinetics of water desorption from porous glasses

Contact Info

Product

Resources

About