Magnetic wood sponge: efficient oil/water separation, dye degradation, and heavy metal removal

Herein, we successfully modified wood sponge (WS) with Fe₃O₄ (MWS) to enhance its ability to adsorb five different oils, eight organic solvents, metal ions, and degrade methylene blue (MB) from wastewater. MWS, possessing over 96% porosity, exhibited remarkable sorption capacities of 26.79 g g^− 1 for CCl₄ and 21.00 g g^− 1 for pump oil. Notably, MWS maintained high sorption capacity even after repeated use. Furthermore, MWS effectively removed toxic metal ions including As³⁺, Cr⁶⁺, and Pb²⁺ from real industrial wastewater, at pH 4 and 50 °C to levels suitable for drinking water. Also, MWS demonstrated excellent photocatalytic properties for degrading methylene blue dye. The photodegradation process involved the generation of superoxide anion radicals and the participation of hydroxyl radicals. The magnetic properties of MWS allow for easy remote retrieval using a magnet, making it a cost-effective and reusable solution for environmental remediation.