Characterization of cellulose nanocrystals prepared by different delignification methods and application of ultra-light, hydrophobic aerogels as oil absorbent in food systems

Abstract

In this study, cellulose nanocrystals (CNCs) were isolated and characterized from sugarcane pith (SP), a renewable, low-cost agro-industrial residue. The effects of bleaching methods on CNCs morphology and physicochemical properties were investigated. Then, an ultralight and hydrophobic nanocellulose-based aerogel was fabricated as an oil absorbent for food systems. The results showed that hydrogen peroxide bleached CNC retained its good characteristics (a whisker-like shape, L/D 38, CrI 72.1%, zeta potential −29.97 ± 0.05 mV) and the typical shear-thinning rheological behavior, an eco-friendly delignification. In addition, the obtained MTMS-modified aerogels exhibited ultralight density (0.031–0.053 g/cm3), high porosity (96.45–97.44%), lipophilicity (water contact angle as high as 130.2 ± 5.8°), and reusability. Furthermore, their absorption capacity was up to 49.8 g/g, with a wide range of catering oils and organic solvents. This study provides insight into the high value-added utilization of agro-industrial residues and the application of nanocellulose-based aerogels for oil-water separation in food systems.