Solvent-free nanoalumina loaded nanocellulose aerogel for efficient oil and organic solvent adsorption

Hypothesis: Cellulose-based aerogel, due to its rich reserves, environmental friendliness and porous structure, is considered as a new type of adsorbents for treating oil and water pollution. However, the functionalization of cellulose aerogel is still required for the efficient increase of its adsorption performance in wide applications. The combination of nanomaterials could significantly improve the adsorption capability of nanocellulose aerogel. Experiments: In this work, nanocomposite aerogels comprising of nanocellulose and nanoalumina (NC/Al₂O₃) are produced via a solvent-free method and the effect of weight ratios between nanocellulose and nanoalumina on the adsorption properties of NC/Al₂O₃ aerogels has been studied. Findings: The results reveal that the NC/Al₂O₃ aerogel with a low density of 5.1 mg cm⁻³ could obtain the optimal pore microstructures and the highest oil and organic solvent adsorption capacities with the preparation condition under the nanocellulose/nanoalumina weight ratio of 1:0.25 and 0.4 wt% of nanocellulose in aqueous solution. The presence of nanoalumina facilitates the change of microstructure morphologies, the increase of BET specific surface area and the adsorption capacities of NC aerogel. Compared with pure NC aerogel (74.07 ± 1.67, 69.87 ± 1.01, 81.21 ± 3.20, 52.07 ± 1.70, 48.49 ± 1.01, 75.45 ± 3.58 and 87.03 ± 0.46 g g⁻¹ for thiophene, anhydrous ethanol, ethyl acetate, cyclohexane, sesame oil, acetone and dichloromethane, respectively), the NC/Al₂O₃ aerogel manifests an outstanding adsorption capacity (108.07 ± 0.37, 89.91 ± 4.83, 93.93 ± 3.81, 71.13 ± 2.48, 64.83 ± 2.25, 85.19 ± 3.87 and 117.65 ± 5.68 g g⁻¹, accordingly). By considering the desirable performance features and the convenient fabrication approach, this nanocellulose nanocomposite aerogel might be a feasible alternative for oily waste water recovery and conservation of environment.