Pomelo peel and sugar beet pulp as novel biosorbents in purification of biodiesel

Abstract

Pomelo peel and sugar beet in their native forms were proposed as novel biosorbents. They were investigated as 1%, 3% and 5% (w/v) loadings for dry purification of biodiesel samples synthesized from animal fat and vegetable oil using a conventional method. The effects of biosorbents were examined by determining the following biodiesel quality parameters: acid value (AV), peroxide value (PV), density, viscosity, flash point (FP), soap and free glycerol (FG) content. Dry washing was compared to the water washing technique. Biosorbents characterization was performed by FTIR and SEM analysis. The 5% loadings of both biosorbents reduced the soap content to below 36 ppm. In contrast, the soap content after water washing was 172.6 ppm in biodiesel from vegetable oil and 256 ppm in biodiesel from lard. The FG removal efficiency was in a linear correlation with the biosorbents’ loadings. The lowest FG values in biodiesel from vegetable oil (0.25 ppm) and from lard (0.23 ppm) were found upon purification with 5% pomelos peel and 5% sugar beet, respectively. Best results were achieved using 5% pomelo peel, closely followed by 3% pomelo peel. Such adsorption capacity can be explained by the porous structure and the functional groups present in pomelo peel.