Coaxial electrospun nanofibrous aerogels for effective removal of oils and separation of water-in-oil emulsions

Superabsorbents, used in the removal of oils and organic solvents, play a extremely important role in environmental protection. There is an urgent demand for environment-friendly and high-performance absorbent materials with high selectivity for oils and organic solvents, and is also challenging. Herein, a facile and fluorine-free method to fabricate Polyacrylonitrile @ Polydimethylsiloxane (PAN@PDMS) coaxial nanofibrous aerogels (NFAs) was developed. The steps for synthesis included: coaxial electrospinning - freeze drying - in situ polymerization. The obtained PAN@PDMS NFAs displayed excellent absorption capacities for various oils and organic solvents (55.43-127.37 times of its weight), and efficient water-in-oil emulsions separation with high separation flux (1718 +/- 45 L.m(-2).h(-1)) and excellent separation efficiency (above 99.47 wt%). Particularly, the NFAs showed outstanding mechanical resilience (above 83% recovery after repeating 200 cycles at 80% strain) and could be reused by simply squeezing the oil/organic solvent out of it. More importantly, the PAN@PDMS NFAs showed good resistance against various chemicals such as acids and alkalis. Therefore, this study offers a facile methodology for the fabrication of NFAs that are expected to be promising candidate materials for practical oily wastewater treatment in environmental protection.

Automated summary

A facile and fluorine-free method was developed to fabricate PAN@PDMS NFAs, which exhibited excellent absorption capacities, efficient water-in-oil emulsions separation, outstanding mechanical resilience, and good resistance against various chemicals, making them promising candidate materials for practical oily wastewater treatment in environmental protection.