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Decolorization of Rice Bran Oil Using Modified Kaolin
Author(s) -
Worasith Niramon,
Goodman Bernard A.,
Jeyashoke Narumon,
Thiravetyan Paitip
Publication year - 2011
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-011-1872-2
Subject(s) - sulfuric acid , adsorption , oxalic acid , bran , sorption , desorption , materials science , mesoporous material , chemical engineering , specific surface area , grinding , chemical modification , nuclear chemistry , chemistry , composite material , inorganic chemistry , organic chemistry , metallurgy , polymer chemistry , catalysis , raw material , engineering
Abstract Measurements show that kaolin from Ranong, obtained from a major deposit in southern Thailand, can be modified to produce a material that is suitable for decolorizing rice bran oil. Its sorption properties were determined after various physical and chemical modifications of this kaolin. Physical modification was achieved by grinding via a planetary ball mill (300 rpm for 1 h), and this was followed by chemical treatment using sulfuric or oxalic acids. The optimum decolorization capacity (~80%) was achieved by using 2 M sulfuric acid. With oxalic acid, the best results were obtained with 0.7 M, but these were slightly lower than those obtained with 2 M sulfuric acid. Compared to the original kaolin sample, the specific surface area of the modified clay increased from ~13 to ~244 cm 2 g −1 , and the total pore volume from 0.06 to 0.43 cm 3 g −1 . The pore size distribution curves show that most pores are in the mesoporous region with their diameters between 3.0–4.5 nm, and are suitable for adsorption of pigment molecules that are present in rice bran oil. Desorption and spectroscopic studies suggest that both electrostatic and chemical processes are involved in the interaction between pigments and active sites on the clay surface.