Sunflower oil bleaching by adsorption onto acid-activated bentonite

Abstract

-Two bentonite clays with different mineralogical compositions from Mendoza, Argentine, were activated with H 2 SO 4 solutions of 4 and 8 N at 90°C for 3.5 hours. This treatment affected clay structural properties, as was shown by thermogravimetry, infrared spectrometry and chemical analysis. Bleaching efficiency for sunflower oil was strongly dependent on the acid concentration used for clay activation. The samples have bleaching capacity comparable to that observed with a commercial adsorbent standard. The mineralogical composition of natural clays influenced the properties of the activated clays.

Adsorption in Biodiesel Refining - A Review

“…After pressing of oil seeds, and after degumming and caustic refining of the virgin oil, a step of bleaching is commonplace in order to improve the colour by adsorbing chlorophylls, carotenoids and other pigments, and the removal of other undesired components such as metals and free fatty acids, that contribute to the unstability of the oil under oxidizing conditions. Bleaching of oils can be done with natural clays such as bentonite, smectite, montmorillonite, etc., or activated clays produced by acid treatment (Foletto et al, 2011). Clays are mainly used for removing high molecular weight organic compounds but their affinity for polar compounds and metals is low.…”

Effect of thermal treatment on the catalytic activity of a Fe-rich bentonite for the photo-Fenton reaction

“…Bentonite is an aluminosilicate mineral clay containing a significant fraction of smectite-group phase [18][19][20]. It is ubiquitous in most soils, exhibits a low cost, low permeability and has excellent characteristics for the diffusion of pollutant molecules.…”

Soybean Oil Bleaching by Adsorption onto Bentonite/Iron Oxide Nanocomposites

“…The bleaching of edible vegetable oils involves removal of a variety of impurities, which include phosphatides, fatty acids, gums and trace metals, etc., followed by decolourisation. 1,2 In refinery processing of vegetable oils, adsorbents are used to remove carotene, chlorophyll and other components formed during the refining process. Common adsorbents are hydrated aluminium silicates, commonly known as bleaching clays.…”

“…3,4 Among them, activated bentonites is by far the most common adsorbent for purification and colour improvement of fats and oils. 1,3,5 Metal oxides have recently been applied to remove heavy metals and dyes from water and wastewater. 6,7 Clays/metal oxide composites are one of the most widely studied composites among the new group of developed microporous materials with high surface area.…”