Abstract
Novel chitosan nanosheets (NS) were developed to capacitively remove sodium chloride (NaCl) and cadmium carbonate (CdCO3) at optimized pH, concentration, and number of cycles. The nanosheets were fabricated using iron oxide (Fe3O4) nanoparticles (NPs) for their high absorption strength, poly (3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) for its high conductivity, and chitosan for its non-toxicity and cost-effectiveness. On the other hand, a nanocomposite (NC) was also fabricated using Fe3O4 NPs and PEDOT:PSS for the same purpose. The synthesis procedure was investigated by Fourier transform infrared spectroscopy (FTIR), X-Ray Diffractometer (XRD), Transmission Electron Microscope (TEM), Scanning Electron Microscope – Energy Dispersive X-ray Spectroscopy (SEM-EDX), and Brunauer–Emmett–Teller (BET); which revealed the combination of the respective functional groups, the crystallinity of the nanoparticles and amorphous nature of the polymers, dispersion of the nanomaterials, the surface morphology and elemental composition, and the surface area, pore size and pore volume of the nanomaterials, respectively. The surface area, pore size, and pore volume of the nanocomposite were 41.89 m2/g, 16.30 nm, and 0.17 cm3/g, respectively whereas the values obtained for the nanosheets were 132.22 m2/g, 0.003 nm, and 0.09 cm3/g, respectively. Both materials showed good electrochemical behaviour with quasi-rectangular cyclic voltammograms, which are characteristic of electric double layer capacitors (EDLC). The highest percentage salt electrosorption capacity (SEC) of sodium chloride was observed at 62.38 % at an optimum concentration of 100 ppm using nanosheets as positive electrode material, this had a change in capacitance of 55.06 F/g. At the same time, highest percentage SEC of cadmium carbonate was observed at 79.64 % at an optimal pH (pH 9), using the nanosheets as positive electrode material, which had a change in capacitance of 242.45 F/g. These findings show that PEDOT:PSS and chitosan combined with magnetite nanoparticles have the potential to capacitively absorb ions from aqueous solution.