Highly stable NaFeO2-Fe3O4 composite catalyst from blast furnace dust for efficient production of biodiesel at low temperature

Highly stable catalysts were prepared by wet impregnation of blast furnace dust (BFD) in Na 2 CO 3 ·H 2 O, Na 2 CO 3 ·10H 2 O, NaHCO 3 and Na 2 CrO 4 solution and subsequent calcination at 300–600 °C. At low temperature of 65 °C for 2 h with methanol/oil molar ratio of 15/1, high biodiesel yield of 100 wt% was obtained with for both Na 2 CO 3 ·H 2 O@BFD 300 and Na 2 CO 3 ·H 2 O@BFD 400 catalyst (impregnating with Na 2 CO 3 ·H 2 O solution and calcining at 300 and 400 °C) at 7 wt% for the first use. Na 2 CO 3 ·H 2 O@BFD 300 catalyst exhibited outstanding stability and recyclability with biodiesel yield of 100 wt% at the fifth use (93 wt% at the twelfth use) owing to the formation of stable and active nanocomponents of NaFeO 2 (32.42 nm) and magnetic nanocomponent of Fe 3 O 4 (size of 3.14 nm and magnetization of 6.16 Am 2 /kg). This study finds a solution to use solid waste for the green production of biodiesel.