rGO/BC nanocomposite aerogels exhibit recyclable adsorption of organic solvents and oils with enhanced flame resistance

In this study, a simple and eco-friendly method was developed to prepare nanocomposite aerogels composed of bacterial cellulose (BC) and graphene oxide (GO) via freeze-drying. Nanocomposite aerogels with different ratios of BC to GO 50:50, 80: 20, and 90: 10 were synthesized. Various preparation methods and conditions were employed including room temperature, reflux, hydrothermal treatment, reduction in a hydrogen furnace, and chemical reduction with different reducing agents (hydrazine, ethylenediamine, and ascorbic acid) and using glutaraldehyde as a linker. The structure and morphology of the nanocomposites were characterized using FT-IR, Raman spectroscopy, UV-Vis, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and Brunauer-Emmett-Teller (BET) surface area and porosity analysis. Thermal stability was assessed using thermogravimetric analysis (TGA). The performance of aerogels in adsorbing various organic solvents-such as cyclohexane, dichloromethane, dimethyl sulfoxide, and dimethylformamide as well as oils like pump oil and olive oil, was investigated. The rGO /BC-90G nanocomposite exhibited the highest adsorption capacity, up to 116 g of organic liquids (dichloromethane) per gram of aerogel, and significantly greater surface area (188 m². g^-1) than other prepared aerogels. In this study, the hydrophobicity of aerogels and their functions as thermal insulation were also investigated. Among the as-prepared composites, rGO/BC-90H₂ demonstrated pronounced hydrophobicity and rGO/BC-90G exhibited superior thermal stability, while rGO/BC-50H1 showed distinct decomposition behavior related to partial reduction. Notably, the aerogels could be reused for up to five adsorption cycles while retaining a high fraction of their initial adsorption capacity, highlighting their potential for sustainable adsorption applications.