Supercritical CO2 assisted construction of carbon black /polypropylene composite foams with bioinspired open-cell micro-nano hierarchical structure and outstanding performance for oil/water separation

Abstract A novel composite foam material with bioinspired open-cell micro-nano hierarchical structure was facilely fabricated by incorporating nano carbon black (CB) into polypropylene (PP) under supercritical CO2 condition. The results demonstrated that when the amount of CB was 10 wt.%, the enhancement of thermal conductivity greatly enhanced the heterogeneous nucleation process and promoted the appearance of a large number of open-cell structures. The fabricated PP/CB foams were confirmed to have highly open-cell structure with huge numbers of nano-cavities spread over the cell wall, forming a unique micro-nano hierarchical structure. Three kinds of commonly used oils have been tested, demonstrating with a maximum adsorption efficiency of 22.6 g/g for diesel oil. Furthermore, over broad pH conditions, the PP/CB10 foam rapidly adsorbed oil microdroplets with 95% removal efficiency. Thus, this obtained composite foam would advance the development of multifunctional open-cell foam materials for highly efficient oil/water separation application over broad pH condition.