Nature-Inspired Directional Fluid Transport Enables Silanized Topo-Vascular Cellulose Aerogel for Efficient Oil/Water Separation

Abstract

Oil pollution from petroleum-related activities and oily industrial wastewater pose a persistent challenge to aquatic environments, motivating the development of efficient sorbent and separation materials. However, conventional aerogels usually require multistep fabrication and show limited mechanical robustness. Herein, a silanized topo-vascular cellulose aerogel (STVCA) is developed through a top-down strategy using the oriented transport architecture of Spatholobus suberectus Dunn stems as a structural template. Vapor-phase silanization tailors the cellulose interface while the processed scaffold retains key topological features of the native hierarchical vascular architecture, combining low-surface-energy chemistry with the inherited channel organization and mechanical integrity. The resulting STVCA serves as a robust, fast mass-transfer medium for oil/water separation, showing rapid oil wetting, stable hydrophobicity, and anisotropic capillary transport. Dry STVCA reaches a compressive stress of 28.41 MPa at 80% radial strain (σ80), whereas oil-loaded STVCA reaches σ80 = 27.14 MPa and retains 91% of its initial σ80 after 80 compression cycles. The cross-sectional surface and longitudinal faces have mean static water contact angles of 151.05 ± 4.01° and 143.80 ± 5.92°, while a representative internal cut-surface measurement reaches 155.7°. Owing to the preserved vascular-bundle topology, STVCA achieves anisotropic mass transfer, a chloroform uptake capacity of 11.73 ± 0.61 g·g–1, a continuous separation flux of 13126 L·m-2·h–1, and a separation efficiency of up to 99%. This biomass-derived aerogel provides a durable platform for oil-spill remediation.