Organic solutes adsorption, from aqueous adsorbent characteristics

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. 

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