Lightweight and robust cellulose-based porous polyurethane foam decorated with Co Ni-LDH/PFDTES for highly efficient oil-water separation.

Oil and organic solvent spills pose significant environmental and ecological hazards, driving the need for high-performance oil-water separation materials. The development of high-performance bio-based materials for oil-water separation is critically important for environmental remediation. In this study, a series of porous Co Ni-LDH/polyurethane foams (PUF-x) were prepared via a solvothermal method using cellulose-based polyols (CPP) derived from the liquefaction of powdered cellulose. After surface modification with 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES), hydrophobic foams (SPUF-x) were obtained. Among these, SPUF6 sample (containing 6 wt% CPP) exhibited an optimal balance of properties. Co Ni-LDH particles formed a petal-like nanostructure that significantly increased surface roughness, and together with PFDTES modification, imparted high hydrophobicity (water contact angle of 139.3°) and strong oleophilicity to the foam. SPUF6 demonstrated excellent adsorption capacities ranging from 16.71 to 27.96 g/g for various organic pollutants, including engine oil, dichloromethane, toluene, and edible oil. It also showed outstanding reusability, maintaining stable adsorption performance over 20 cycles of engine oil and trichloromethane removal via mechanical squeezing. The foam exhibited good thermal stability (up to 190 °C), high elastic recovery (>94% after 30 compression cycles), and remarkable chemical durability under acidic, alkaline, and saline conditions, as well as under UV irradiation. Furthermore, SPUF6 enabled effective gravity-driven and pump-assisted continuous oil-water separation, achieving separation efficiencies above 97.7% for light oils. This work demonstrates a sustainable route to fabricate robust, high-performance hydrophobic foams from cellulose-based polyols, offering promising potential for oily wastewater treatment and the valorization of biomass resources.