Construction of Super-Hydrophobic Lignocellulosic Nanofibrils Aerogels as Speedy Oil Absorbents

Lignocellulosic nanofibrils (LCNF) aerogels have a three-dimensional structure, with large specific surface area, low density, which is promising to be developed into a new type of adsorbent with high absorption capacity. However, LCNF aerogels have the problem of simultaneous oil and water adsorption. This high hydrophilicity directly leads to low adsorption efficiency in oil-water systems. This paper suggests a facile and economical method for the synthesis of biocompatible CE-LCNF aerogels using LCNF and Castor oil triglycidyl ether (CE) was successfully established. The use of LCNF enabled aerogels to possess remarkably uniform pore size and structural integrity, while the introduction of hydrophobic silica produced stable superhydrophobicity for more than 50 days at room temperature. These aerogels presented desirable hydrophobicity (131.6°), excellent oil adsorption capacity (62.5 g/g) and excellent selective sorption property, making them ideal absorbents for oil spill cleaning. The effects of ratios of LCNF to CE composition, temperatures and oil viscosity on the oil adsorption performance of aerogels were estimated. The results displayed that the aerogels had the maximum adsorption capacity at 25 °C. The pseudo-secondary model had higher validity in oil adsorption kinetic theories compared to the pseudo-first-order model. The CE-LCNF aerogels were excellent super-absorbents for oil removal. Moreover, the LCNF was renewable and nontoxic, which has the potential to promote environmental applications. Graphical abstract: [Figure not available: see fulltext.].