Electrospun Carboxymethyl Cellulose/Polyvinyl Alcohol Nanofiber Membranes for Enhanced Metal Ion Removal

Carboxymethyl cellulose (CMC)/polyvinyl alcohol (PVA) composite nanofiber membranes were prepared by electrostatic spinning, using CMC and PVA as raw materials and glutaraldehyde as a cross-linking agent. The structure, morphology, thermal stability, and filtration performance of CMC/PVA nanofiber membranes were characterized by advanced instrumental analysis methods such as scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, ultraviolet analysis, and energy spectrum analysis. The results show that the average fiber diameter decreases from 381 nm to 183 nm when the spinning voltage is 23 KV and the jet speed is 2 µL/min. The obtained fiber has the smallest particle size and the most uniform distribution. Infrared spectroscopy analysis confirms that the adsorption behavior of nanofiber membranes on Cu2+ and Cr6+ is chemical adsorption. The retention rates of CMC/PVA nanofiber membranes for Cu2+ and Cr6+ reached 97.2% and 98.8%, respectively. The adsorption capacities of Cu2+ and Cr6+ were 26.34 and 28.93 mg·g−1, respectively. The adsorption of heavy metal ions by nanofiber membranes can be explained by the pseudo-second-order kinetic mechanism of the chemisorption process and the Langmuir isotherm model.