Preparation and oil sorption properties of in-situ growth of ZnO particles on cellulose fibers to fabrication hydrophobic esterified lignin-cellulose fiber/ZnO composite aerogel: synthesis and characterization.

Oily wastewater is a significant global environmental challenge, which has been intensified by rapid population growth and industrialization. Traditional treatment methods often require high energy inputs and are prone to secondary pollution. Advanced separating materials, particularly superwetting three-dimensional (3D) lignocellulosic aerogels modified with inorganic nanoparticles, are gaining attention due to their unique combination of sustainability, high sorption capacity, and biodegradability. This study focuses on the synthesis of a hydrophobic esterified lignin-cellulose fiber/ZnO composite aerogel, achieved through in situ growth of ZnO on cellulose fibers via hydrothermal treatment and freeze-drying techniques. The composite aerogels were characterized using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, and Brunauer-Emmett-Teller (BET) surface area analysis. These characterizations confirmed the successful growth of ZnO in a flower-like pattern on the cellulose fiber surface. The BET specific surface area of the composite aerogel was 5.443 m/g, with an average pore size of 38.83 nm. The resultant aerogels exhibited excellent oil sorption capacities (18 to 38 g/g) and high selectivity for oils and organic solvents, demonstrating significant potential for oily wastewater treatment. This work highlights the promising application of lignocellulose-based ZnO composite aerogels for sustainable and efficient oil-water separation.