Effect of acid activation on sesame oil bleaching by rice hull ash

Citation
Yy. Chang et al., Effect of acid activation on sesame oil bleaching by rice hull ash, J CHEM EN J, 34(1), 2001, pp. 1-6
Citations number
9
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Chemical Engineering
Journal title
JOURNAL OF CHEMICAL ENGINEERING OF JAPAN
ISSN journal
0021-9592 → ACNP
Volume
34
Issue
1
Year of publication
2001
Pages
1 - 6
Database
ISI
SICI code
0021-9592(200101)34:1<1:EOAAOS>2.0.ZU;2-1
Abstract
Sesame oil bleaching by acid-activated rice hull ash is examined. Lovibond color indices of sesame oils before and after bleaching by activated rice h ull ash were determined to calculate the bleaching efficiency of the ash, S urface area meter and inductively coupled plasma-mass spectroscopy were emp loyed to determine specific surface areas and average pore diameters as wel l as metallic contents of the rice hull ashes before and after acid activat ion, respectively. Effects of the following factors on bleaching efficiency have been studied; acid type, acid concentration, activation time, ashing temperature and ashing time. Experimental results indicate that rice hull a sh activated by H2SO4 has relatively higher bleaching efficiency than that activated by H3PO4 or HCL. The increase in acid concentration or activation time did promote bleaching efficiency, though mildly. Acid activation migh t increase bleaching efficiency of rice hull ash from 0% to 43%. The effect of activation is found to be most significant when the ashing temperature is in the range of 673-773 K or the ashing time is over 1,800 s. The increa se in bleaching efficiency by acid activation might be due to the increase of number of active site available for adsorption on the pore surface of th e rice hull ash, Replacement of activated clay as an adsorbent to bleach se same oil by acid activated rice hull ash is found to be promising.