Hydrothermal Fabrication of Fe3O4@Carbonaceous Microspheres for Efficient Removal of Oil and Metal Ions from the Aqueous Phase

In this study, we synthesized a magnetic Fe3O4@carbonaceous sphere composed of microsphere-like nanostructures having a shape similar to that of visciola using a simple and low-cost strategy. As the magnetic core, the Fe3O4 nanosphere was synthesized using a hydrothermal procedure. Using starch and diallylamine as sources of carbon and amine, respectively, an amino-containing carbonaceous was coated on the surface of Fe3O4. We used aminopropyl triethoxysilane to modify the carbonaceous surface so that it can support the lipophilicity of the final material amino-Fe3O4@C-x-O. The amino-Fe3O4@C-x-O material was composed of spherical particles having diameters of 250-350 nm and an ultrasmallball (30-SO nm)@big-ball (250-300 nm) structure; its saturation magnetization was 75.54 emu/g. The adsorption results reveal that the amino-Fe3O4@C-x-O material shows excellent adsorption performance for Cu2+ ions with a maximum adsorption capacity of 42.01 mg/g that was estimated using the Langmuir model. Furthermore, the amino-Fe3O4@C-x-O material can absorb oil contaminants upto 16 times its own weight and the material has a high oil absorption capacity after 10 cycles. For purifying oily wastewater with metal ions, the removal ratios of both oil and heavy metal ions were as high as 99%. Even after five purification-regeneration cycles, the amino-Fe3O4@C-x-O materials still remain enough stability.