Shamala Ramasamy, Kamarudin Hussin, and Adsorption .
Then the kaolin is put in the used oil. After stirring with a magnetic stirrer for 1 hour then stirring for 24 hours then filtered with Buchner funnel and using the vacuum pump. This filtering process is done for many times until the kaolin is completely lost. After that, an evaporation process is done to take nbutanol in the mixture.