Einfluß der Struktur und der Morphologie von Bleicherden auf die Bleichwirkung bei Ölen und Fetten

Influence of the Structure and Morphology of Bleaching Earths on Their Bleaching Action on Oils and Fats In the manufacture of highly active bleaching earths from bentonite, the acid activation causes alterations in the chemical composition and structural as well as morphological properties of bentonite, depending on the concentration of acid, temperature, time etc. This has been demonstrated by changes in specific surface, volume of the micropores, particle size distribution and proportion of soluble silicic acid, and the impact of these alterations on the bleaching of vegetable oils is discussed. The results are supported by electron optical and X-ray investigations. Studies on repeated removal of silicic acid formed by acid treatment of bentonite as well as repeated acid activation indicate that the bleaching action of these earths depends not only on specific surface, but also, to a considerable extent, on the volume of micropores.