Synthesis of monolithic porous carbon aerogels from sorghum straw and their application in rapid oil removal

By employing the inexpensive sorghum straw as precursor, we obtained an ultralight monolithic porous carbon aerogel (MPCA) with extremely low density (6−10 mg cm), superb mechanical performance, macroporous structure and strong hydrophobicity as well. The adsorption capacity of the optimized MPCA material carbonized at 400 C for various oily organic matters was 49−124 times of its own weight, which is higher than those of most biomass adsorbents. The excellent ability for rapid oil adsorption from water was demonstrated by the oil droplet floating on the water surface or sinking under the water. Moreover, the adsorbed oil with low boiling point (BP) could be entirely released by distillation, and, for high BP oil, it could be recycled by mechanical squeezing. In addition, the recycled MPCA possessed the superior reusability in the successive cycles.