Purification of biodiesel by dry washing and the use of starch and cellulose as natural adsorbents: Part II - study of purification times

This work describes the use of adsorbents as starch from different sources (corn, potato, cassava and rice), cellulose and Select 450(R) and compared to conventional wet washing with hot water in biodiesel purification, varying the time: 1, 2.5, 5, 7.5, 10, and 15 min in relation to weight/volume fixed at 5%. The adsorbents were characterised by SEM and BET analysis. For the acidity index, all purification processes resulted values in agreement with the specifications of the ANP in Brazil. The levels of free glycerin with the use of Select 450(R) (at all times, except 10 min), cassava starch (at all times, except 5 min), and cellulose (at all times, except 1 and 10 min) were also in agreement with ANP specifications. In relation to a combined alkalinity test, the best results were obtained with the use of Select 450(R) and potato and cassava starches. The turbidity was satisfactorily reduced with the use of potato (10 and 15 min), cassava (15 min), and rice (2.5 min) starches as well as Select 450(R) (at all times). In terms of water content, there was a decrease compared with crude biodiesel and biodiesel purified by conventional wet washing.

Automated summary

This study investigated the use of different sources of starch, cellulose, and Select 450(R) as adsorbents in biodiesel purification, showing that these adsorbents can effectively improve the purification efficiency and meet the specifications of ANP in Brazil. Select 450(R) along with potato and cassava starch showed the best results in a combined alkalinity test, while potato, cassava, and rice starches as well as Select 450(R) were effective in reducing turbidity.