Reuse of Bleaching Earth: The Green Solution for Rapeseed Oil Producers

Abstract

The main purpose of the presented research is to characterize the relationship between the amount of bleaching earth used in the bleaching process of rapeseed oil and the efficiency of this process. Changes in the content of chlorophyll and carotenoid pigments were examined using spectrophotometric and colorimetric methods. The process was carried out on a plate filter with different thicknesses of bleaching earth (BE) layers (1–3% in relation to the amount of oil). On the basis of the conducted research, a decrease in the content of chlorophylls (from 59 to 97%) and carotenoids (from 55 to 78%) was found, which affected the overall color of the oil. Based on the research results, it was found that the bleaching earth does not lose all of its adsorption properties after reaching the maximum, but they decrease in the next cycle. For some time, the sorbent can be used successfully, but to a lesser extent (40–45% of the original properties). This information is crucial as it will reduce BE consumption by up to 30% and shorten the oil bleaching cycle, as it will reduce the setup time of the machine.