Effect of Natural Clays on Color and Physico-Chemical Properties of Model Oil

The objective of this study was to compare the color removal capacities of 9 natural clays and 2 commercial bleaching earths (C.B.E.) for beta carotene and chlorophyll pigments added model oil. Halloysite, zeolite, bentonite, sepiolite, diatom earth, Magnesol XL, kaolin, montmorillonite and perlite were added at 0.5% weight ratio into model oil and mixed for 30 min at 80°C, before filtering and analyzing for instrumental color, oil loss, free fatty acidity, acid number and peroxide values. The total color difference (?E) for beta carotene were highest with 2.3, 2.1, and 1.8 for C.B.E.-1, C.B.E.-2 and halloysite treated samples. In this group, weight loss was minimum at 22.1% for bentonite, and maximum at 45.3% for perlit treatments. Also, free fatty acidity (FFA) was reduced at most (7.7%) with Magnesol XL treatment. Similarly, C.B.E.-1 and sepiolite treated samples yielded 0, and kaolin treated sample yielded 79.1 meqO2/kg oil peroxide values (PV). In this group, sepiolite and Magnesol XL were the most successful clays. In chlorophyll added samples, the color was most successfully removed by sepiolite (?E=6.2). The maximum weight loss (52.9%) was with perlit, and the minimum was (23.5%) with bentonite treated samples. FFA was reduced at most (5.9%) with Magnesol XL, and PV was lowered at most (0 meqO2/kg oil) with C.B.E.-2 and zeolite clays. In this group, bentonite and Magnesol XL were most successful. Halloysite, which was not studied for this purpose, had generally good results. For all clays, acid activation, grinding, preparing as nano clays, and sonication were suggested as modification techniques. © 2022 Sidas Medya A.S. All rights reserved.