Author(s):
1. Zoran Petrović, Univerzitet u Istočnom Sarajevu.Tehnološki fakultet Zvornik, Republic of Srpska, Bosnia and Herzegovina
2. Ana Đokić, Serbia
3. Pero Dugić, Republic of Srpska, Bosnia and Herzegovina
4. Dragana Kešelj, Republic of Srpska, Bosnia and Herzegovina
5. Nebojša Vasiljević, Univerzitet u Istočnom Sarajevu Tehnološki fakultet Zvornik, Republic of Srpska, Bosnia and Herzegovina
6. Marija Jevtić, Zeochem doo Zvornik, Republic of Srpska, Bosnia and Herzegovina

Abstract:
Bentonite clays are widely used due to their phase and chemical composition, as well as the possibility of modification by various procedures. Activation improves the adsorption energy, and they can be used in various adsorption processes, including in the process of bleaching edible oils. Chemical activation of bentonite clays is mainly performed with sulfuric or hydrochloric acid, as well as sodium hydroxide at different parameters. In this paper, the chemical activation of pre-irradiated bentonite powder from Šipovo (Republika Srpska, Bosnia and Herzegovina) with 8% m/m hydrochloric acid (HCl) solution and the bleaching of rapeseed oil ("Bimal" Brčko) were carried out. Activation parameters of bentonite powder was: temperature 95°C, contact time 30 minutes, ratio of bentonite powder: HCl = 1:5. The results obtained by the XRPD, FTIR, SEM/EDS and BET methods determined the following: the activated bentonite powder consists of montmorillonite and nontronite, the ratio of SiO2 oxides increased, the ratio of Al2O3 and Fe2O3 oxides decreased while CaO was completely removed, obtained activated bentonite powder has a significantly higher specific surface area (316.28 m2/g) and adsorption capacity (180 cm3/g), smaller particle sizes, and smaller volume and surface area of micropores comparing to raw bentonite clay. Bleaching of rapeseed oil was carried out with activated bentonite powder and commercial bleaching earth at the following parameters: bleaching temperature 95°C, time 30 minutes, ratio of bleaching agent: 0.2% m/m, 1% m/m, 2% m/m and 3% m/m. The soap content, peroxide value, color and fatty acid composition (GC), free fatty acid content and loss of rapeseed oil were determined before and after bleaching. The results of the analysis showed that there is no soap in bleached rapeseed oil, there was a decrease in the peroxide number, the color change is better with the application of a larger amount of activated bentonite powder, there is a slight change in the fatty acid composition and the effects of bleaching with activated bentonite powder are similar or greater than the effects of commercial bleaching earths.

Key words:
bleaching, color, fatty acid composition (GC), hydrochloric acid activated bentonite, oil losses, peroxide number, rapeseed oil, soap content

Thematic field:
SYMPOSIUM A - Science of matter, condensed matter and physics of solid states

Date of abstract submission:
01.08.2022.

Conference:
Contemporary Materials 2022 - Savremeni materijali