Hyperporous Magnetic Materials With Biomimetic Cellular Structures and Excellent Oil Retention for Oil–Water Separation

ABSTRACT Oily wastewater leakage from petroleum, industry, and domestic sources severely impacts ecosystems, necessitating efficient cleanup materials with high oil retention to prevent secondary pollution. A hyperporous magnetic material (HMM) is designed with good absorption and high retention capabilities for oils over a wide range of viscosities, owing to its unique biomimetic cellular structures. The HMM was synthesized using the emulsion template method, incorporating styrene (St), divinylbenzene (DVB), Span 80, and methacrylate silane‐modified Fe 3 O 4 nanoparticles. This material displays robust superhydrophobicity, as evidenced by a water contact angle of 164.1°. It also exhibits a rapid oil absorption capacity for high‐viscosity oils of > 600 mPa·s, allowing for convenient and magnetically controlled oil recovery, along with good cycle stability. The biomimetic microporous structure of the HMM is particularly noteworthy, as the larger outermost pores enable rapid oil absorption, while the smaller inner pores effectively prevent oil from flowing out. As a result, the HMM demonstrates outstanding oil‐retention capacity, retaining more than 66 wt% of oil at 2000 rpm. Furthermore, the bulk HMM, with a length of 40 cm, exhibits an impressive oil retention rate of 96.27%. These excellent properties position the HMM as a highly promising material for oil–water separation.