Recyclable biomass carbon@SiO2@MnO2 aerogel with hierarchical structures for fast and selective oil-water separation

Biomass carbon aerogels are emerging as attractive versatile materials have broad potential applications in various fields including energy storage, oil absorption and catalysts due to their abundance in nature, low cost and environmental friendliness. Here, we have successfully prepared a compressible, superhydrophobic and multifunctional hierarchical biomass carbon@SiO2@MnO2 aerogel (HBCSM aerogel) by using cost-effective and environmentally friendly sisal cellulose as main raw material. During this process, the cellulose@SiO2 aerogel (CS aerogel) was fabricated using sol-gel process, followed by carbonization to form biomass carbon@SiO2 aerogel (BCS aerogel). Then, the HBCSM aerogel was fabricated by in situ assembly of MnO2 nanosheets on the surface of the BCS aerogel under hydrothermal conditions. The incorporation of hierarchical SiO2@MnO2 structure into the HBCSM aerogel could not only improve the surface roughness and hydrophobic properties but also enhance the absorption capacity and mechanical durability. In addition, the HBCSM aerogel exhibits excellent superhydrophobicity with the water contact angle (WCA) of 155 degrees. The as-prepared modified HBCSM aerogel exhibits a very large absorption capacity (60-120 g g (-1)) for different oils and organic solvents and the absorption capacity of the as-prepared aerogel shows a slight decrease after the repeated absorption and release of several oil and solvents for 9 cycles. This work provides a new procedure for fabrication of hybrid carbon aerogel with well-defined 3D hierarchical porous structures that may provide a new slight on the relationship between the structure and property of biomass carbon aerogel, making it a promising candidate for industrial oilpolluted water treatments and oil spill cleanup.