Easy fabrication of ultralight CNx foams with application as absorbents and continuous flow oil–water separation

Developing highly efficient sorbent materials for organic solvents or oils is crucial for the recollection of devil liquor and addressing chemical leakage accidents. Light foams with high porosity and low density are promising sorbent materials. Here, hierarchical CNx monoliths with three-dimensionally connected macropores were prepared via a simple and time-saving route by using melamine foam as raw materials. The obtained CNx monoliths show low density (lower than 10 mg/cm3), strong hydrophobicity, big macropore volume, and tailorable shape. They show excellent performance as an adsorbent for various organic solvents and oils with high adsorption capacity and fast collecting rate. The CNx monoliths can be recycled and did not show adsorption capacity decrease after five test cycles through distillation. Moreover, the continuous flow oil–water separation was demonstrated with these CNx foams. The easy preparation and potential application of the CNx monliths as adsorption material shed new light on the development of light weight adsorbents for a variety of applications.