Magnetic biochar catalyst from reed straw and electric furnace dust for biodiesel production and life cycle assessment

A novel magnetic carbon-based catalyst was prepared from solid waste (reed straw and electric furnace dust) by coprecipitation and high temperature pyrolysis with excellent application potential. Single factor and response surface experiments were used to optimize the catalyst preparation process (mass ratio of reed straw/electric furnace dust of 5:1 at 500 °C in 4 h) and biodiesel production, respectively, with results of 99.89 wt% biodiesel yield in the first cycle (93.61 wt% after 11 cycles) obtained at 74.15 °C in 4.16 h with a 14.06:1 M ratio of methanol/oil and 7.75 wt% catalyst. The life cycle assessment of magnetic carbon-based catalysts for biodiesel production suggested that the soybean oil extraction stage had the greatest impact on the environment, mainly from the use of soybeans and electricity. Solid waste as raw material to prepare catalysts for biomass energy conversion was proven to be a good strategy for energy conservation and emission reduction. This study provides guidance sustainable biomass energy conversion with low cost, low energy consumption, and minimal negative environmental impact.