Mode of Oleic-Acid Adsorption on Rice Hull Ash Cristobalite

by Proctor, A.; Adhikari, C.; Blyholder, G. D.

Fourier transform infrared spectroscopy was used to investigate the adsorption of oleic acid (OA) onto dry rice hull ash (RHA) silica. Adsorption partially occurred by surface hydrogen bonding of the carboxylic acid. There was also formation of carboxylate ions by reaction of OA with residual potassium oxide. These ions were strongly bound by the ash. Isopropanol inhibited OA adsorption by H-bonding and encouraged desorption of H-bonded OA, but without itself being significantly bound. RHA with 40% moisture also adsorbed a small amount of OA by H-bonding and reacted with OA to form and adsorb carboxylate ions.

Journal
Journal of the American Oil Chemists Society
Volume
72
Issue
3
Year
1995
Start Page
331-335
URL
https://dx.doi.org/10.1007/bf02541092
ISBN/ISSN
1558-9331; 0003-021X
DOI
10.1007/bf02541092