Efficient production of biodiesel at low temperature using highly active bifunctional Na-Fe-Ca nanocatalyst from blast furnace waste

In this study, nanocatalysts for biodiesel production were prepared via wet impregnation of blast furnace dust (BFD) in Na 2 CO 3 (Na-BFD) and CaCO 3 (Ca-BFD) suspension solutions and calcination at 500 and 600 °C, respectively. Biodiesel yields of 100.0 wt% (Na-BFD 500 ) and 98.3 wt% (Ca-BFD 600 ) were achieved at 65 °C. Synthesized catalysts showed outstanding activity and recyclability, due to the transition of CaCO 3 , Na 2 CO 3 and Fe 2 O 3 to nanocrystals of NaFeO 2 (29.9 nm), Ca 2 Fe 2 O 5 (10.5 nm), CaO (100.1 nm) and Ca 2 Fe 2 O 5 (50.0 nm). Na-BFD 500 achieved 95.8 wt% biodiesel yield with 16 cycles, whereas Ca-BFD 600 reached 94.1 wt% biodiesel yield with 7 cycles via magnetic separation. BFD containing convertible magnetic and active components (Fe 2 O 3 and CaCO 3 ) was an ideal raw material to synthesize catalyst for biodiesel production with high catalytic efficiency and easy separation. The study provided a practical utilization of industrial solid waste for biodiesel production.