Mechanism of cation exchange on silica gels

Strazhesko, D.N.; Strelko, Vladimir B.; Belyakov, V. N.; Rubanik, Svetlana C.

doi:10.1016/s0021-9673(01)85446-7

Cited by 62 publications

(22 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The results obtained with hydrous silica are similar to those reported by other workers using cation exchange (Houng et al, 1966;Strazhenko et al, 1974) and :potentiometric titration (Bolt, 1957) methods. The pH-dependent negative charge present arises from ionization of the weakly acidic surface silanol groups (Si--OH ~ Si--O-+ H+).…”

Section: Hydrous Oxidessupporting

confidence: 90%

Surface Charge Characteristics of Amorphous Aluminosilicates

Perrott

1977

Clays and clay miner.

View full text Add to dashboard Cite

Abstract--The surface charge characteristics of a range of synthetic amorphous aluminosilicates, hydrous alumina, hydrous silica and two allophanic soil clays were determined by the retention of Na ~ and C1 as counter-ions from 0.1 M NaC1 solution. In the pH range investigated (3-9), only negative charges could be detected in the hydrous silica and the most siliceous aluminosilicate [A1/(A1 + Si) = 0.29], and only positive charges were detected in the hydrous alumina; whereas both positive and negative charges were detected in the more aluminous aluminosilicates and the soil allophanes. In all cases, the surface charges were pH-dependent and in the aluminosilicate series negative charge decreased and positive charge increased with A1/(A1 + Si). Consequently, the point of zero charge increased with AI/(A1 + Si).The charge characteristics of the amorphous aluminosilicates could be explained by current models of their structure. Negative charge can be attributed to isomorphous substitution of A1 for Si in the silicate structure and to the dissociation of silanol groups in structural and adsorbed silicate. Positive charge is attributed to protonation of hydroxy-aluminum species occupying cation exchange sites.

show abstract

Section: Hydrous Oxidessupporting

confidence: 90%

Surface Charge Characteristics of Amorphous Aluminosilicates

Perrott

1977

Clays and clay miner.

View full text Add to dashboard Cite

show abstract

“…Similarly, pH PZC shifts to lower values have been observed for silica surfaces (Foissy and Persello, 1998). The shifts for silica were explained by an increase of surface-site acidity with polymerization and structuration (Strazhesko et al, 1974;Milonjić, 1987;Foissy and Persello, 1998). Possibly, the acidity of sulfide surface groups increases with crystallinity as well.…”

Section: Surface Chemistry Of Fesmentioning

confidence: 99%

Surface chemistry of disordered mackinawite (FeS)

Wolthers

Charlet

Linde

et al. 2005

Geochimica et Cosmochimica Acta

161

140

View full text Add to dashboard Cite

Abstract-Disordered mackinawite, FeS, is the first formed iron sulfide in ambient sulfidic environments and has a highly reactive surface. In this study, the solubility and surface chemistry of FeS is described. Its solubility in the neutral pH range can be described by K s app ϭ {Fe 2ϩ } · {H 2 S(aq)} · {H ϩ } Ϫ2 ϭ 10 ϩ4.87Ϯ0.27 . Acid-base titrations show that the point of zero charge (PZC) of disordered mackinawite lies at pH ϳ7.5. The hydrated disordered mackinawite surface can be best described by strongly acidic monocoordinated and weakly acidic tricoordinated sulfurs. The mono-coordinated sulfur site determines the acid-base properties at pH Ͻ PZC and has a concentration of 1.2 ϫ 10 Ϫ3 mol/g FeS. At higher pH, the tricoordinated sulfur, which has a concentration of 1.2 ϫ 10 Ϫ3 mol/g FeS, determines surface charge changes. Total site density is 4 sites nm Ϫ2 . The acid-base titration data are used to develop a surface complexation model for the surface chemistry of FeS.

show abstract

“…The somewhat higher ph', values observed in our work may be due to the higher surface coverage obtained for the materials used for titration relative to surface coverage of pireviously titrated materials. I t has been shown that the pH', values of polyelectrolytes (which includes these materials) are influenced by the degree of neutralization (24). Higher surface coverage affects the surface and therefore may affect the pK, values obtained.…”

Section: E X P E R I M E N T a L Sectionmentioning

confidence: 99%

Synthesis of silica-immobilized 8-quinolinol with (aminophenyl)trimethoxysilane

Marshall¹,

Mottola²

1983

Anal. Chem.

119

View full text Add to dashboard Cite

A more efflcleint and tlme-savlng synthetic route to sllicalmmoblllzed 8-quinolinol has been developed that results In a product exhibltlng a relatively large exchange capacity. A comparison of dlfferent sllica supports has been performed and the resulting slllca-bound 8-qulnolinol materlals have been characterized with regard to exchange capaclty, carbon content, acid-base properties, and stablllty. The dependence of capaclty on surface area and pore size Is dlscussed and a comparison i o conventionally prepared silica-lmmoblllzed 8-qulnolinols is made. A posslble explanatlon of apparent discrepancies in the heterogeneous acid dissoclatlon constants of slllca-immoblllzed 8-qulnollnol Is also proposed.

show abstract

Mechanism of cation exchange on silica gels

Cited by 62 publications

References 6 publications

Surface Charge Characteristics of Amorphous Aluminosilicates

Surface Charge Characteristics of Amorphous Aluminosilicates

Surface chemistry of disordered mackinawite (FeS)

Synthesis of silica-immobilized 8-quinolinol with (aminophenyl)trimethoxysilane

Contact Info

Product

Resources

About