Supercritical carbon dioxide–activated copper/bacterial cellulose aerogels for the capture of hydrophobic organic liquids

In this study, bacterial cellulose was derived from coconut water via fermentative production of nata de coco, a common food in Southeast Asia. Bacterial cellulose offers distinct advantages over plant cellulose resources, including three-dimensional structure, high porosity, high cellulose purity, and the absence of required polluting treatments, making it an ideal candidate for the facile preparation of various functional aerogel materials. Surface modification of nata de coco-derived cellulose fibers was obtained by incorporating Cu species (approximately 15 wt%) through an aqueous reaction of Cu(CH 3 COO) 2 with N 2 H 4 at room temperature. The Cu-coated bacterial cellulose aerogels were fabricated via supercritical carbon dioxide drying to maintain the natural three-dimensional matrix and subsequently characterized by various techniques confirming high porosity and crystallinity and successful Cu coating onto the cellulose fiber surface. The Cu-containing aerogel showed a significantly improved adsorption uptake for n-hexane (12.6 g g −1 ) in comparison with pure bacterial cellulose–based aerogel (3.2 g g −1 ). Furthermore, notable adsorption performances of 13.6–19.9 g g −1 were found for cyclohexane, ethyl acetate, and soybean oil, indicating the high efficiency of the supercritical carbon dioxide–activated bacterial cellulose aerogel containing Cu species in the adsorption of water-insoluble liquids. Notably, applying supercritical carbon dioxide drying afforded the stable aerogel structure for reusing over several cycles with almost unchanged trapping capacity.