Adsorption of Oil by 3-(Triethoxysilyl) Propyl Isocyanate-Modified Cellulose Nanocrystals

Abstract

Oil leaks into water bodies and increased organic pollutants harm the environment and ecosystem in several ways, and cleaning up oil spills from water bodies is a global challenge. This research aimed to construct modified cellulose nanocrystal (CNC) based aerogels with 3-triethoxysilyl propyl isocyanate (TEPIC) to evaluate their potential application in oil adsorption. Here, a freeze-drying method was employed to make CNC aerogels. The aerogels were characterized using scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) analysis, porosity and density measurements, Fourier transform infrared spectroscopy (FTIR), water contact angle (WCA) measurement, compressive strength, and oil adsorption capacity. SEM results confirmed that the aerogels have a largely porous structure, including a community of uniformly interconnected cellulose fibers. Moreover, the studied aerogels had a low density due to the high porosity. Also, the small pore diameter and high specific surface area were confirmed by the BET evaluation. FTIR confirmed the existence of functional groups and strong hydrogen bonding between CNC/TEPCI/Urea molecules. All TEPIC-modified CNC aerogels had water contact angle values greater than 130° indicating their hydrophobicity. The highest oil and glycerol adsorption was obtained with the use of modified CNC aerogels. Thus, the sample modified with 3 wt% TEPIC showed the highest adsorption capacities of 130 ± 7.22, 120 ± 4.75, and 95.28 ± 4.82 gg−1 for motor oil, vegetable oil and glycerol, respectively. The results of this study showed that ultra-light, hydrophobic and oil adsorbent materials based on chemically modified CNC aerogels can successfully be fabricated.