Ambient-dried, scalable and biodegradable cellulose nanofibers aerogel for oil-spill cleanup

Abstract

Aerogels made of surface-modified cellulose nanofibers (CNF) have the potential to be a long-term solution for oil spill cleanup and industrial waste-water treatment, but their use is currently constrained by high preparation costs, lengthy processing times, and use of hazardous chemicals. In this study, a cost-effective and easily scalable cellulose nanofibers aerogel is developed using sugarcane bagasse as the cellulose source. The aqueous suspension of CNF and urea is freeze-thawed and then dried at ambient temperatures to produce CNF aerogels, avoiding the costly and time-consuming freeze-drying or supercritical drying methods. The role of urea in the aerogel structure is investigated using molecular dynamics. The aerogel exhibited an elastic modulus of 1345 KPa and a porosity of 96.9 %. To enhance the hydrophobicity of the surface of these aerogels, they are coated with the biodegradable polymer polycaprolactone (PCL). Further, two molecular weights (MW) PCL 10,000 and 80,000 are used to examine the impact of PCL MW on the performance and biodegradability of aerogel. Moreover, the efficacy of these green modifications is being compared to the conventional silane modifications. The 10,000 MW PCL-modified aerogel demonstrated a water-contact angle measuring 125.5°, an oil sorption capacity of 24 g/g, and exceptional recyclability even after undergoing 20 cycles. Further, after 15 days, the aerogel showed excellent biodegradability.