Polydopamine- and polyDOPA-coated electrospun poly(vinyl alcohol) nanofibrous membranes for cationic dye removal

Mussel adhesive proteins including special functional groups, such as dopamine and 3,4-dihydroxy-l-phenylalanine (DOPA), exhibit strong adhesion and have thus been used in numerous applications. As a novel dye adsorbent for wastewater treatment, this study examineed poly(vinyl alcohol) (PVA) nanofibrous membranes (NFMs) fabricated via electrospinning and then coated with polydopamine (pDA) or polyDOPA through a simple dip coating process in dopamine or DOPA solution to examine. The surface morphology, chemical composition and hydrophilicty of PVA NFMs coated with pDA or polyDOPA were compared using scanning electron microscopy (SEM), UV photoelectron spectrometry (XPS) and contact angle analyzer, respectively. The thermal degradation temperatures of the PVA NFMs were increased significantly by about 100 °C due to the radical scavenging ability of pDA and pDOPA. Also, the differences in the adsorption performance toward a cationic dye, methylene blue (MB), for polydopamine- or polyDOPA-coated PVA NFMs were evaluated using a UV–Visible spectrophotometer. Finally, a recyclability test was conducted to confirm the applicability as a dye adsorbent.