Constructing tubular/porous structures toward highly efficient oil/water separation in electrospun stereocomplex polylactide fibers via coaxial electrospinning technology

The wide application of biodegradable polymers in wastewater treatment is of great significance because it can greatly reduce the risk of secondary pollution during the employ of polymers. In this work, a coaxial electrospinning technology was applied to prepare the polylactide (PLA)-based fibers. The solution of poly(L-lactide) (PLLA), poly(D-lactide) (PDLA) and gamma-Fe2O3 nanoparticles was used to construct the tube wall, while the mineral oil was used as the core. As a result, the PLA fibers exhibited the tubular hollow structure with extensive pores on the tube wall after mineral oil was removed by solvents. The prepared PLA membrane exhibited superhydrophobicity and high porosity due to the special porous structure of the fibers. The maximum adsorption capacity toward castor oil was 219.5 g g-1, exhibiting excellent oil adsorption ability. In addition, the membrane showed high oil flux of 57324.8 L m-2h- 1 and good oil/water separation ability. The gravity-driven separation flux of emulsion achieved 3401.4 L m-2h- 1, and it still remained high level during separating acidic, alkaline and hypersaline emulsions. Besides, the high mechanical property of the membrane endowed it with excellent cycling stability. This work paves the way for the practical applications of environmentally friendly adsorption/separation membranes in oil/water cycling separation.

Automated summary

In this study, a coaxial electrospinning technology was used to prepare PLA fibers with superhydrophobicity and high porosity, showing excellent performance in oil/water separation. The prepared membrane exhibited high oil adsorption capacity, oil flux, and oil/water separation ability, as well as good stability during cycling and separating various emulsions. This work paves the way for the practical applications of environmentally friendly adsorption/separation membranes in oil/water cycling separation.