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

Abstract

This work describes the use of adsorbents as starch from different sources (corn, potato, cassava and rice), cellulose and Select 450^® 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^® (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^® 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^® (at all times). In terms of water content, there was a decrease compared with crude biodiesel and biodiesel purified by conventional wet washing.

Keywords:

• Sunflower oil
• biodiesel
• purification
• natural adsorbents

Acknowledgements

The authors thank CAPES, CNPq, and FAPEMIG by financial support and the Sanitation Laboratory of Civil Engineering from Federal University of Uberlândia for conducting the turbidity tests.

Disclosure statement

No potential conflict of interest was reported by the authors.