Impedance spectroscopy as a tool to monitor the adsorption and removal of nitrate ions from aqueous solution using zinc aluminum chloride anionic clay

In this study, Zn(3)AlCl ionic clay was used to investigate the adsorption mechanism of the nitrate ions in solutions containing nitrate ions at different contact time. The clay was synthesized by coprecipitation method at room temperature, and this sample was characterized by XRD, Fourier transform-infrared (FT-IR) and inductively coupled plasma (ICP). This sample was crystallized in a rhombohedral symmetry (Space group: R-3 m). Impedance spectroscopy was used as a tool to evaluate and monitor the adsorption process at different contact time 5; 10; 20; 30; 60 min and the clay alone. The impedance measurement was well analyzed and fitted with an equivalent circuit containing both (R//CPE) connected in series. Furthermore, the σ(ac) conductivity was also investigated as a function of frequency. It was analyzed and fitted using double power law: [Formula: see text] This study reveals the existence of two relaxation processes with different relaxation times, which could be attributed to the grain and grain boundaries, and exhibit high values of dielectric constant at low frequencies.