The efficient removal of methylene blue from water samples using three-dimensional poly (vinyl alcohol)/starch...

In the present study, a simple, fast, and economical method was introduced to eliminate methylene blue from dye wastewater water using a non-toxic, inexpensive, stable, and efficient adsorbent. The poly (vinyl alcohol) (PVA)/starch hydrogel nanofiber membrane with high surface area and the three-dimensional structure was fabricated in water via electrospinning strategy, and the cross-linking reaction was done by thermal treatment. The characterization of the nanofibers was carried out using Fourier-transform infrared spectrometer (FT-IR) and field-emission scanning electron microscopy (FE-SEM), and the cross-linked PVA/starch nanofiber was applied as a membrane for the removal of methylene blue (MB). The recovery of MB was performed by methanol solution containing 5% (v/v) HCl. Langmuir isotherm model successfully described the adsorption of MB on nanosorbent, and the maximum adsorption capacity (q_m) was 400 mg g^-1. Also, the kinetic of adsorption was well fitted by the pseudo-second-order model. In this study, because of the high stability of fabricated membrane (based on the tensile testing), it can be used as a filter for the fast separation of MB (cationic dye) and methyl orange (MO, anionic dye). Graphical abstract.