Nature-inspired foam for treating oil-polluted water with enhanced fire protection

Abstract

The depletion of petrochemical resources, coupled with the pressing issue of oil-contaminated water, necessitates a surge in the development of sustainable adsorbent materials. In this study, a superhydrophobic-flame retardant material (M-BASiP) derived from biomass was developed by using hydrophobic nano-silica from rice husk, polydimethylsiloxane, and non-halogenated flame retardant amonium polyphosphate combined with bamboo-based polyurethane substrate through a simple dip-coating method. The incorporation of fire retardant significantly improved the flame retardancy of the prepared foam, which is crucial for practical applications, given the high flammability of oils and solvents. The M-BASiP foam exhibited superhydrophobicity, as indicated by a water contact angle of 155°, and demonstrated a high adsorption capacity ranging from 13 to 53 g·g⁻¹ for various oils and organic solvents. Notably, its adsorption performance remained (75%-96%) over 10 consecutive adsorption-desorption cycles, highlighting its efficiency and reusability for practical applications. Continuous oil/solvent-water separation of M-BASiP was also conducted using a vacuum pump, yielding an oil recovery of approximately 83–87%. The outstanding separation efficiency of foam, along with it eco-friendly and energy-efficient production process, makes it as a potential solution for oily wastewater treatment.