title: Thermodynamic characteristics of the adsorption of sulfanilamide, phenol, and n-butanol on bio-gel beads.
abstract: The thermodynamic properties of the adsorption of sulfanilamide, phenol and n-butanol on Bio-Gel beads have been studied. Bio-Gel was chosen as the adsorbent as it possesses both hydrophobic and hydrophilic sites on its surface. Adsorption of the former two adsorbates was found to be exothermic, and the relevant thermodynamic parameters at 20 degrees are in the ranges: deltaH degrees = -2.7 to -5.4 kcal/mole; deltaF degrees = -6.0 to -7.6 kcal/mole; deltaS degrees = +7.7 to +11.6 e.u. In the presence of urea, adsorption of sulfanilamide and phenol was partially disrupted. This, together with the large entropy gain of the process, indicates that both hydrogen bonding and hydrophobic bonding contribute cooperatively to the adsorption. On the contrary, adsorption of n-butanol, which was not susceptible to urea, was an endothermic process with the parameters, deltaH degrees = +5.8kcal/mole, deltaF degrees = -1.8 kcal/mole, and deltaS = +26.1 E.U. at 20 degrees. These data conform to the thermodynamic properties of hydrophobic bond formation. Finally, possible implications of these data in the structural assembly of lipoprotein molecules are discussed.
mesh_terms: D000327:Adsorption; D000440:Butanols; D005782:Gels; D006860:Hydrogen Bonding; D010636:Phenols; D013424:Sulfanilamides; D013696:Temperature; D013816:Thermodynamics; D014508:Urea
chemical_list: D000440:Butanols; D005782:Gels; D010636:Phenols; D013424:Sulfanilamides; D014508:Urea