Fabrication of Magnetically and Photothermally Functionalized Materials Based on Corn Stalk Pith Framework for...

To address critical challenges in marine oil spill remediation, including limited penetration of high-viscosity crude oil and inefficient adsorbent recovery, it is imperative to develop environmentally friendly materials integrating high-efficiency adsorption, in situ viscosity reduction, and controllable recovery. In this study, a delignified corn pith (CPDL) with a three-dimensional porous structure was employed as a green matrix. Through constructing a Fe₃O₄/expansible graphite (EG)/polyvinylidene fluoride (PVDF) composite functional coating combined with silanization modification, a multifunctional biomass-based oil sorbent (Fe₃O₄/EG/PVDF-CPDL) was successfully fabricated. The material maintains the inherent porous architecture while forming a stable micro/nano-rough surface, exhibiting excellent superhydrophobicity with a water contact angle of approximately 155°, and demonstrating exceptional stability in harsh acidic/alkaline/saline environments and multiple cycles. Benefiting from the synergistic photothermal effect of Fe₃O₄ and EG, under one sun illumination (1 kW/m²), the material surface temperature rapidly reaches above 80 °C within 100 s, reducing the viscosity of high-viscosity crude oil by over 95% (from 1.39 × 10⁵ to approximately 6.0 × 10³ mPa·s), thereby enabling rapid penetration and adsorption within 50 s. Moreover, the composite coating significantly enhances mechanical performance, achieving a compressive strength of 320 kPa (approximately eight times higher than that of the pristine substrate), ensuring structural integrity during handling and compression recovery. Meanwhile, the material demonstrates precise directional manipulation and efficient recovery through external magnetic fields due to its superior magnetic responsivity. Experimental results reveal a broad-spectrum adsorption capacity (14.8-30.2 g/g) and separation efficiency exceeding 96% after 20 adsorption-desorption cycles. In summary, this work presents an innovative strategy with significant application potential for efficient and controllable remediation of marine oil spills, particularly high-viscosity crude oil, by integrating synergistic functions of porous adsorption, superhydrophobic corrosion resistance, photothermal viscosity reduction, mechanical reinforcement, and magnetic control.