Adsorption of tetracycline from water using glutaraldehyde-crosslinked electrospun nanofibers of chitosan/poly(vinyl alcohol).

In this work, the preparation and characterization of glutaraldehyde-crosslinked electrospun nanofibers of chitosan/poly(vinyl alcohol) (GCCPN) as a new adsorbent for tetracycline (TC) is reported. Electrospun nanofibers of chitosan/poly(vinyl alcohol) (PVA) were prepared by employing a 75:25 volumetric ratio of chitosan:PVA, voltage of 30 kV, collection distance of 10 cm, and injection flow rate of 2 mL/h. Then, the nanofibers were crosslinked via applying the glutaraldehyde on them for 3 h at 40 °C. The nanofibers were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction. Uniform beadless nanofibers with minimum diameters of 3-11 and 6-18 nm were obtained before and after crosslinking, respectively. Then the applicability of the synthesized GCCPN for removal of TC from aqueous solutions was investigated. The response surface method was applied to evaluate the influence of pH (6-12), TC concentration (50-250 mg/L) and the adsorbent dose (0.05-0.25 g in 20 mL solution) on the adsorption characteristics of GCCPN. The maximum adsorption capacity was 102 mg/g. The adsorption kinetics was explained most effectively by the pseudo-second-order model. The adsorption data of TC on the GCCPN surface was explained well by the Langmuir isotherm model.