Synthesis and characterization of carbon cryogel microspheres from lignin-furfural mixtures for biodiesel production

The synthesis of carbon cryogel from lignin-furfural mixture, prepared via sol-gel polycondensation at 90. °C for 0.5. h, has been investigated for biodiesel production. The effect of lignin to furfural (L/F) ratios, lignin to water (L/W) ratios and acid concentration on carbon cryogel synthesis was studied. The carbon cryogels were characterized and tested for oleic acid conversion. The thermally stable amorphous spherical carbon cryogel has a large total surface area with high acidity. Experimental results revealed the optimum FAME yield and oleic acid conversion of 91.3. wt.% and 98.1. wt.%, respectively were attained at 65. °C for 5. h with 5. wt.% catalyst loading and 20:1 methanol to oleic acid molar ratio. Therefore, carbon cryogel is highly potential for heterogeneous esterification of free fatty acid to biodiesel.