Organic solutes adsorption, from aqueous adsorptive characteristics

Further changes adsorption characteristics of high-silica zeolite of pentasil type and ultrastable form Y zeolite modified by boron and phosphorus, both from aqueous solutions of appropriate acids and by treating of organic derivative vapors were consideration. 

Saleem, M., et al.. Adsorption characteristics of organic dyes on alumina powder from aqueous solutions, Adsorpt, Sci, Technol., 11(2), 95-104 (1994). 

A general conclusion is that organic compounds are not adsorbed from aqueous solution by oxides when Eh,o differs from a characteristic resonance frequency, E es, of the oxide by more than about 0.1 eV. When adsorption occurs it is probably accompanied by the formation of a chemical bond as a result of the coincidence of donor levels of the adsorbate and acceptor levels of the adsorbent. This behaviour in adsorption from solution contrasts with adsorption from the gas phase where no correlation has been found between the enthalpy of adsorption, or the shift of vibration frequency of the OH groups accompanying adsorption, with the electronic properties of oxides. No explanation of this difference is offered. 

Costanzo, P. M., Giese, R. F. and van Oss, C. J., Determination of the acid-base characteristics of clay mineral surfaces by contact angle measurements - implications for the adsorption of organic solutes from aqueous media, J. Adhes. Sci. Technol, 4, 267-275 (1990). 

It was discussed in Section III.C that salts, which are inert at low concentrations and close to PZC can induce effects characteristic for specific adsorption at sufficiently high concentrations. In organic solvents (water free or containing small amounts of water) the specific interactions of electrolytes that are inert in water are commonplace, even at concentrations below 10 mol dm" (but the activities of alkali metal cations in such solutions can be higher that in 1 molar aqueous solution). Reversal of sign potential of inorganic materials from negative... 

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