Facile synthesis of magnetic biochar from an invasive aquatic plant and basic oxygen furnace slag for removal of phosphate from aqueous solution

This study addresses the challenges of water pollution and solid waste treatment by presenting a two-step wet ball mill pyrolysis method for synthesizing magnetic biochar (MBC) from Water Hyacinth (Eichhornia crassipes) and basic oxygen furnace slag (BOFs) for adsorbing phosphate in water. The MBC showed excellent magnetic properties, with a coercivity of 259.3 Oe and a remanence of 0.552 emu center dot g(-1), and a high specific surface area (similar to 57.9 m(2)center dot g(-1)) and micropore volume (0.070 m(3)center dot g(-1)). The MBC had a rough surface and compact regular pore structure with a distribution of (FeO4)-O-3 and FeO. It exhibited a high phosphate adsorption capacity, reaching a maximum adsorption capacity of 39 mg center dot g(-1), and the adsorption process followed the pseudo-second-order kinetic model. The main adsorption mechanism was found to be chemical adsorption. The experiment investigated the loading efficiency of iron from BOFs and the mechanism of phosphate adsorption. This approach is cost-effective, environmentally friendly, and efficient, achieving the concept of "waste treating waste."