Efficiency of poly(vinyl alcohol) and chitosan fibers produced by electrospinning in reactive dye removal by combining adsorption and filtration.

This study aimed to fabricate nonwoven materials from chitosan (QTS) polymeric fibers with poly(ethylene oxide) (PEO) and poly(vinyl alcohol) (PVA) fibers using the electrospinning technique. The chitosan and poly(ethylene oxide) nonwoven (QTS-PEO) was applied for the removal of the reactive red dye BF-4B. The materials were crosslinked and characterized using various techniques, such as thermal, structural and morphological characterizations. Batch adsorption experiments evaluated parameters such as pH (2-10), equilibrium time (1-24 h), and solution concentration (5mg/L to 35mg/L). Additionally, a fixed-bed filtration system in a sandwich format with chitosan nonwovens with PEO and PVA (PVA/QTS-PEO/PVA) was assembled and tested. The analyses showed thermal stability up to 100 °C and characteristic polymeric bands were observed by Fourier Transform Infrared Spectroscopy. Batch adsorption experiments indicated that equilibrium was reached in 24 h, with an optimal pH of 5.8 ± 0.2 and 100% dye removal at all tested concentrations. Equilibrium isotherms were favorable, with a maximum adsorption capacity of 145mg/g at a concentration of 35mg/L. The Freundlich empirical model best fitted the data, suggesting multilayer adsorption. The fixed-bed system demonstrated good mechanical stability due to the PVA support, allowing three consecutive permeation cycles with a maximum dye rejection of 39%. Thus, the study confirms the feasibility of using biodegradable polymers for the treatment of dye-contaminated wastewater, providing a sustainable alternative for environmental preservation.