Carbon nanofiber from ecofriendly Poly (vinyl alcohol) electrospun mat as an effective electrode for water desalinization

MARÍA ALICIA VERGARA RUBIO; CARRONE, GUILLERMO ALEJANDRO; LAURA RIBBA; SILVIA GOYANES; ROBERTO CANDAL

CABA

Congreso; 11th World Congress of Chemical Engineering and its associated events; 2023

Water desalination (WD) is an option for obtaining fresh water from brackish sources. The currentmethods for WD are costly both in terms of energy consumption and the type of materials used.Capacitive deionization (CDI) is a promising alternative with low environmental impact, lowerenergy consumption and efficiency in the removal of ions from an aqueous solution. Theperformance of this technique is strongly determined by the electrode materials [1]. Carbonmaterials are widely used in adsorption and electroadsorption processes, due to their goodconductivity and high surface area. These characteristics can be maximized if they are formed bynanofibers. In this work, different materials were developed for using as electrodes, formed bycarbon nanofibers, obtained by pyrolysis of polyvinyl alcohol (PVA) mat obtained byelectrospinning. By modifying the chemical structure of PVA with iodine and thanks to a controlledheat treatment [2], it was possible to obtain carbon nanofibers with integrity, higher carbon yield(>20 wt%) and surface area (>900 m2/g). The materials were characterized by Fourier transforminfrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction, scanning electronmicroscopy and nitrogen adsorption. In addition, the electrochemical properties were evaluated bycyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). These materialsshow a quasi-rectangular CV curve implying the ideal behavior of an electric double-layercapacitance. The specific capacitance of the different materials was determined from the CVcurves showing values in the range of 12.5- 104.4 F/g for a sweep rate of 10mV/s. An increase inthe capacitance value indicates greater accessibility of the electrolyte ions into the pore intersticesand hence better performance in the capacitive desalination process for this material. It isimportant to note that the performance of the developed materials is strongly influenced by thepretreatments prior to pyrolysis. Moreover, these results are superior compared to other carbonmaterials obtained from PVA fibers according to the literature.