Magnetic hydrophobic carbon black sponge: Preparation and oil removal mechanism study

The severe environmental and ecological problems caused by oily wastewater from industries such as petrochemicals have become a major global concern. In recent years, magnetic hydrophobic materials have become a research hotspot due to their combined magnetic responsiveness and high-efficiency oil-water separation performance. This study presents a convenient strategy: using a mechanical ball-milling method to prepare CB/Fe3O4 composite particles, which synergistically integrate hydrophobicity and magnetism on the surface of a melamine sponge, successfully fabricating the G-MS@CF material. The tunable hierarchical structure of the prepared sponge significantly enhances its water repellence. Owing to its high porosity, excellent water repellence, strong paramagnetism, and robust mechanical stability, the sponge exhibits remarkable oil-spill cleanup performance, characterized by fast oil absorption speed, high adsorption capacity, good recyclability, and convenient recovery. The adsorption capacity for high-viscosity oils can reach up to 49.5 g/g. In addition, the modified sponge can also be used to separate stable emulsions of oil/water mixtures based on its selective adsorption of oil. This study effectively addresses the key issues of insufficient synergy between magnetism and hydrophobicity, easy detachment of coatings, and difficulty in recovery in conventional materials. It provides an efficient magnetic adsorbent material for the treatment of oily wastewater.