Bio-based hydrophobic fiberglass filters functionalized with RPTES for efficient oil-water separation

• Sustainable Functionalization: Unlike conventional approaches that rely on nanoparticles, which pose potential environmental risks, our study employs a solvent-free aminolysis reaction to synthesize RPTES from castor oil. This eco-friendly process adheres to the principles of green chemistry, offering a safer and more sustainable alternative. • Superior Performance: The FG-Castor filters achieved outstanding separation efficiencies, reaching up to 98.71% for gasoline-water mixtures, with a maximum permeated flux of 5760 L/m²h for n-hexane. The filters maintained high performance after 20 reuse cycles, demonstrating remarkable durability. • Enhanced Surface Properties: Surface characterization confirmed a significant increase in fiber roughness and diameter after RPTES functionalization. The root mean square roughness (Rq) increased from 150 nm (pristine fiberglass) to 420 nm (FG-Castor), while the fiber diameter increased from 14 µm to 21 µm, contributing to the superhydrophobic properties with a water contact angle of 146.31°. • Environmental and Industrial Relevance: The absence of hazardous byproducts, combined with high efficiency, mechanical stability, and reusability, makes FG-Castor filters a promising candidate for industrial wastewater treatment and environmental remediation. This study introduces a sustainable and highly efficient method for oil-water separation using fiberglass fabric (FG-Castor) functionalized with ricinoleamidopropyl-triethoxysilane (RPTES), a novel hydrophobic compound synthesized from castor oil via a solvent-free aminolysis reaction. The resulting superhydrophobic filter exhibits a high water contact angle of 146.31° and effectively separates petroleum-based solvents—including gasoline, kerosene, and n-hexane—from water under gravity-driven conditions. Characterization by SEM-EDX, X-ray mapping, and ¹³C NMR confirmed successful surface modification and amide bond formation. The FG-Castor filters demonstrated exceptional separation efficiency (up to 98.71%) and high permeated flux (up to 5760 L/m²·h), while maintaining stable performance over 20 reuse cycles. The filters also retained high efficiency under varying pH and temperature conditions, highlighting their robustness and versatility. These findings demonstrate the potential of bio-derived, solvent-free surface treatments in advancing green, cost-effective technologies for industrial wastewater management and oil spill remediation.