Removal of polycyclic aromatic hydrocarbons (PAHs) from water through degradable polycaprolactone electrospun membrane

Polycyclic aromatic hydrocarbons (PAHs) are common and persistent environmental pollutants produced during the incomplete combustion of fuels. They are known for their carcinogenic and mutagenic properties. Thus, their removal from water bodies is highly crucial and has become a critical issue globally. As a solution, here an electrospun polycaprolactone (PCL) membrane with a mean fiber diameter of 2.74 ± 1.3 μm was produced by electrospinning. Water contact angle (WCA) analysis confirmed the hydrophobic nature of the PCL membrane with a WCA of 124°, which remained stable over time. Differential scanning calorimetry analysis (DSC) revealed the semicrystalline nature of the membrane with the respective melting temperature (T_m) of 61.5 °C and crystallization temperature (T_c) of 29.6 °C. X-ray diffraction (XRD) analysis demonstrated that the crystalline structure of the PCL membrane could be preserved after electrospinning. Scanning electron microscopy analysis revealed that the membrane could be stretched without any rupture. The PCL membrane was used to scavenge PAHs (i.e. phenanthrene and anthracene) from water; the membrane could reach equilibrium capacity in a few hours, demonstrating the rapid removal of PAHs from water. The adsorption capacities for anthracene and phenanthrene were found to be 173 ± 17 and 560 ± 51 μg/g, respectively. The adsorption data fitted well with the pseudo-first-order kinetics model for both PAH molecules. The sorption could be attributed to hydrophobic adsorption, which allowed using the PCL membrane repeatedly with ethanol exposure to get rid of the adsorbed PAHs from the membrane’s surface. The partial degradation of the fibrous membrane in water was observed due to their hydrolysis-induced bulk erosion. However, the degradation was slow for the membrane kept in the air for 3 months. Overall, the PCL membrane with inherent biocompatibility, biodegradability, and good PAH sorption performance is a promising material for water depollution from toxic PAH compounds.