Superhydrophobic-superoleophilic heptafluorodecyl triethoxysilane/graphitic carbon spheres Co-modified porous monolith for water/oil separation

Water/oil separation has been a flourishing research focus due to severe oil-spill accidents. The current work reports on preparation, characterization and water/oil separation performance of heptafluorodecyl triethoxysilane (FAS) and graphitic carbon spheres (GCS) co-modified mullite porous ceramic (FAS/GCS-MC) with superhydrophobic and superoleophilic characters. The water contact angle of FAS/GCS-MC was determined as about 161 degrees. The continuous water/oil separation rates for paraffin, vegetable and vacuum pump oils were 3.4 x 10(4) g m(-2) min(-1), 2.2 x 10(4) g m(-2) min(-1) and 1.3 x 10(4) g m(-2) min(-1), respectively; even after 10 cycles, the separation rates remained almost unchanged in high selectivity (above 95%). The as-prepared FAS/GCS-MC was resistant to the temperature change and acid/base erosion, and showed stable superhydrophobicity and separation efficiency. In addition, the separation rate after applied a voltage to FAS/GCS-MC could be obviously enhanced by a self-heating process.