Modeling and Experimental Evaluation of Ni(II) and Pb(II) Sorption from Aqueous Solutions Using a Polyaniline/CoFeC₆N₆ Nanocomposite

Herein, a modified polyaniline nanocomposite containing CoFeC₆N₆ was prepared and tested for its sorption of Pb²⁺ and Ni²⁺ ions from aqueous solutions. The adsorbent was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Brunauer–Emmett–Teller and Fourier transform infrared analyses. The adsorption percentage increased with increasing CoFeC₆N₆ in the nanocomposite material. A pseudo-second-order model and Langmuir adsorption described the behavior of the material. Additionally, the adsorption capacity was increased by increasing the temperature. The prediction of concentrations was performed using a model based on pore diffusion and the implicit finite difference method. From a mass transfer standpoint, the best data set of D_e for Pb²⁺ (1.12 × 10^–9 m² s^–1) and Ni²⁺ (0.98 × 10^–13 m² s^–1) was determined.