Low-temperature synthesis of novel polyvinylalcohol (PVA) nanofibrous membranes for catalytic dye degradation

Abstract

Electrospun nanofibre membranes are employed to treat wastewater from dye pollution because of their outstanding properties. In this study, novel polyvinyl alcohol (PVA)-based hydrophilic electrospun nanofibre membranes were prepared using low-temperature synthesis (LTS) at 50 °C with a persulfate (PS) reagent and applied successfully to catalytic methylene blue (MB) dye degradation. The prepared nanofibre membranes were characterised with scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR) spectroscopy, and thermogravimetric analysis (TGA). The LTS–based PVA nanofibre membranes had small diameters, and exhibited better mechanical stability and enhanced hydrophilicity. The catalytic degradation percentage of MB increased in the presence of the LTS PVA membrane due to the generation of sulphate radicals and the crosslinking between PVA and PS. The degradation of MB by the LTS PVA membrane was also found to be satisfactory when MB was mixed with methyl orange (MO) in a binary system. The influences of operational parameters including solution pH, initial MB concentration, and catalyst dosage on the degradation performance of MB were evaluated. The role of inorganic ions such as NaCl and NaHCO3 on MB degradation was also investigated under optimised conditions. The LTS PVA nanofibre membrane exhibited excellent stability after repeated recycling experiments (90% after five cycles), and provided an economical, sustainable process with low carbon emissions 18,75% lower than the HTS process, for good environmental impact.