title: Variable Temperature Infrared Spectroscopy Investigations of Benzoic Acid Desorption from Sodium and Calcium Montmorillonite Clays.
abstract: Processes involved in thermal desorption of benzoic acid from sodium and calcium montmorillonite clays are investigated by using variable temperature diffuse reflection Fourier transform infrared spectroscopy (DRIFTS). By monitoring the temperature dependence of infrared absorbance bands while heating samples, subtle changes in molecular vibrations are detected and employed to characterize specific benzoic acid adsorption sites. Abrupt changes in benzoic acid adsorption site properties occur for both clay samples at about 125 °C. Difference spectra absorbance band frequency variations indicate that adsorbed benzoic acid interacts with interlayer cations through water bridges and that these interactions can be disrupted by the presence of organic anions, in particular, benzoate.
authors.affiliation: Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, 101 Stephenson Parkway, University of Oklahoma, Norman, OK 73019-5251 USA.
authors.forename: Tara M
authors.initials: TM
authors.lastname: Nickels
authors.forename: Audrey L
authors.initials: AL
authors.lastname: Ingram
authors.forename: Dalia K
authors.initials: DK
authors.lastname: Maraoulaite
authors.forename: Robert L
authors.initials: RL
authors.lastname: White
mesh_terms: D001546:Bentonite / Q000032:analysis / Q000737:chemistry*; D019817:Benzoic Acid / Q000032:analysis / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry; D012964:Sodium / Q000737:chemistry; D013055:Spectrophotometry, Infrared / Q000379:methods*
chemical_list: D001546:Bentonite; D019817:Benzoic Acid; D012964:Sodium; D002118:Calcium