Designing 3D fractal morphology of eco-friendly nanocellulose-based composite aerogels for water remediation

The renewable and economic aspects of cellulose nanofibril (CNF)-based aerogels are reviving interest in green adsorbents for water remediation. However, the combination of CNF chemical pre-treatment, fibrillation pro-cesses, and a solvent-free hydrophobization route to obtain structurally wet-resilient and eco-friendly porous adsorbent is lacking in the literature. Herein, the oxidation/fibrillation approaches to isolating CNF from sugarcane bagasse and producing CNF-based aerogels were investigated. These porous materials were designed through ice-templating, followed by a freeze-drying method. Oxidated CNF aerogels containing 3-times-micro-fluidization (TMI3) exhibited the most homogeneous interconnected regular structure, with micro-and nano-porous structures achieving robust compressive mechanical properties (Young's modulus similar to 400 kPa). Natural rubber latex (NR) was combined with TMI3, yielding a water-resilient and hydrophobic composite aerogel (TMI/ NR). The removal capacity of TMI/NR ranged from 108 to 420 mg.g(-1) for Cu (II) and 159-334 mg.g(-1) for methylene blue (MB) dye, with reuse performance ranging from 66 to 98 % over the reuse cycles. Furthermore, TMI/NR aerogel showed its effectiveness for Cu (II) removal from water in an environmentally relevant con-centration (20 and 60 mu g.L-1 Cu (II)) without posing additional toxicity to Daphnia similis aquatic model or-ganisms. These findings indicate TMI/NR composite aerogels as promising and efficient green adsorbents of pollutants from contaminated water.

Automated summary

This study investigates the isolation of cellulose nanofibrils (CNF) from sugarcane bagasse and the production of CNF-based aerogels using oxidation/fibrillation processes. The resulting TMI/NR composite aerogels exhibit excellent adsorption performance and are able to effectively remove pollutants from water.