Engineering multifunctional and robust superhydrophilic nanofiber contamination resistance membranes for ultrafast oil–water separation

Abstract

The high demand for super-stable, environmentally friendly and multifunctional filtration membranes remains an unsolved challenge in practical complex oily wastewater treatment systems. Here, we proposed on-demand superhydrophilic and contamination resistant PLA@PAN/NiCo-LDH by facile secondary electrostatic spinning technology. The results showed that the membranes can reach ultra-high flux for various oil-in-water emulsions, the n-hexane-in-water emulsions flux can up to 12,316 L·m⁻²·h⁻¹·bar⁻¹. Meanwhile, the membranes can effectively degradate of dye wastewater in a short period of time. Most importantly, PLA@PAN/NiCo-LDH maintain outstanding stability under a variety of harsh conditions, even after 30 days of immersion in strong acids, bases and high salt concentrations, as well as under UV radiation, the separation performance of PLA@PAN/NiCo-LDH still remain unchanged. The as-prepared membranes exhibited good contamination resistance, nearly complete oil rejection (>99 %) and flux recovery up to 89.2% after a continuous 30-cycle operation. Due to the biodegradable properties of the membrane material itself, waste membranes can be efficiently recycled. Surprisingly, the recovered PAN/NiCo-LDH functional layer can be recovered again by electrostatic spinning technology. Overall, the combination of PLA, PAN and NiCo-LDH created a multifunctional surface which induces superhydrophilic character and can be used future practical oily wastewater treatment.