Thermodynamics of Adsorption of Organic Compounds at the Silica Gel/Nonpolar Solvent Interfaces

Zhao, Zhiwei; Zhang, Lan-Hui; Lin, Yao

doi:10.1006/jcis.1994.1266

Cited by 29 publications

(22 citation statements)

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“…Zhao et al [98] have constructed the adsorption isotherms for the adsorption of benzyl alcohol (7), benzaldehyde (8), benzoic acid (9), anisole (10) and toluene (11) from cyclohexane on silica. The first four are found to be Langmuir type and the fifth, a linear one.…”

Section: Adsorption Of Small Organic Molecules On Silica Surfacementioning

confidence: 99%

“…Although there are complexities of solid/liquid interface system and experimental difficulties, a few investigation on the thermodynamics of adsorption from the solution have been reported [294][295][296][297][298]. The adsorption thermodynamics of benzene-n-heptane system [299], organic compounds like n-fatty alcohols, cyclohexanone, toluene and the oxy-aromatic compounds at the silica gel/ carbon tetrachloride and silica gel/cyclohexane interfaces were used to calculate the standard free energy of the adsorption process (ΔG°) by the Langmuir parameters [98]. The results suggested that (i) For n-fatty alcohol homologs, the value of ΔG°follows an empirical formula,…”

Section: Thermodynamics Of Adsorptionmentioning

confidence: 99%

See 1 more Smart Citation

Adsorption of organic molecules on silica surface

Parida¹,

Dash²,

Patel³

et al. 2006

Advances in Colloid and Interface Science

620

360

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Section: Adsorption Of Small Organic Molecules On Silica Surfacementioning

confidence: 99%

Section: Thermodynamics Of Adsorptionmentioning

confidence: 99%

Adsorption of organic molecules on silica surface

Parida¹,

Dash²,

Patel³

et al. 2006

Advances in Colloid and Interface Science

620

360

View full text Add to dashboard Cite

“…Literature data support the importance of the aliphatic alcohol groups in the course of silica adsorption. Zhao et al (1994) compared the standard free adsorption energy of linear fatty alcohols at silica gel/carbon tetrachloride and silica gel/cyclohexane interfaces with that of aromatic substances. For the former, the adsorption energy range was -20.8 to -15.5 kJ mol -1 from ethanol to octanol, while for benzoic alcohol, anisole, and toluene, the range was -17.2 kJ mol -1 to -6.48 kJ mol -1…”

Section: Reactions With Lignin Model Compoundsmentioning

confidence: 99%

Solid-state ²⁹Si NMR and FTIR analyses of lignin-silica coprecipitates

Cabrera

Larsen

et al. 2016

Holzforschung

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When agricultural residues are processed to ethanol, lignin and silica are some of the main byproducts. Separation of these two products is difficult and the chemical interactions between lignin and silica are not well described. In the present study, the effect of lignin-silica complexing has been investigated by characterizing lignin and silica coprecipitates by FTIR and solid state NMR. Silica particles were coprecipitated with three different lignins, three lignin model compounds, and two silanes representing silica-inlignin model compounds. Comparison of 29 Si SP/MAS NMR spectra revealed differences in the distribution of silanol hydroxyl groups among different coprecipitates. These differences are dependent on the lignin type. The results are interpreted that the underlying mechanism of the interactions is the formation of hydrogen bonds between lignin aliphatic hydroxyl or carboxyl groups and the silanols, but not a condensation of the silica-inlignin among the silica particles and not the formation of C-O-Si bonds.

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“…The silica surface can be dehydrated and dehydroxylated upon heating; however, despite the fact that several authors [10][11][12][13][14] have studied the subject, there is still no firm agreement on the exact temperature at which dehydration (removal of adsorbed water molecules) stops and dehydroxylation (condensation of silanol groups) commences. According to Zhuravlev in his review of the work carried out in this field [13] it could be stated that the limiting temperature for dehydration is 190 ± 10 • C. The silanol groups condense forming siloxane linkages accompanied by evolution of water between 190 and 400 • C, the resulting siloxane bonds are strained and thus will readsorb water.…”

Section: Introductionmentioning

confidence: 99%