Hydrophobic dual-polymer–reinforced graphene composite aerogel for efficient water–oil separation†

Abstract

Addressing the environmental challenges posed by oil spills and industrial wastewater is critical for sustainable development. Graphene aerogels demonstrate significant potential as highly efficient adsorbents due to their high specific surface area, excellent structural tunability and outstanding chemical stability. Among available fabrication methods, the hydrothermal self-assembly technique stands out for its low cost, high tunability and good scalability. However, brittleness caused by stacking and agglomeration of graphene layers during self-assembly remains a significant challenge. In this study, we present a green and efficient self-assembly strategy combining a one-step hydrothermal process with a solution immersion method to fabricate a PDMS-coated epoxidized natural rubber–graphene composite aerogel (P@EGA). The resulting aerogel exhibits a high specific surface area (482.362 m² g⁻¹), hierarchical pore distribution from microporous to macroporous, ultra-low density (0.0104 g cm⁻³) and excellent hydrophobicity (contact angle = 147.6°). Remarkably, it retains 97.54% of its compressive stress after 50 compression-release cycles at 80% strain and quickly recovers its shape under a 500 g load. The P@EGA aerogel demonstrates outstanding adsorption capacities (65.37–132.75 g g⁻¹) for various oils and organic solvents, complete oil absorption in 0.4 seconds, and effortless regeneration through simple squeezing. Furthermore, its dual functionality in gravity-driven and powered water–oil separation systems underscores its broad application potential in environmental remediation.