چكيده به لاتين
In this study, nanochitosan/clinoptilolite composite, activated by hydrochloric acid and nanocomposite functionalization with pentaethylenehexamine has been used to removal of nitrate ions (NO_3^-) from aqueous media. The structural order and textural properties of the nanocomposite were studied by X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and N2 adsorption–desorption analysis. The prepared nanocomposite functionalization with pentaethylenehexamine composite possess enhanced NO_3^- adsorption capacity of 277.77 mg/g than nanocomposite activated by hydrochloric acid and nanochitosan/clinoptilolite composite were found to be 227.27 and 185.18 mg/g, respectively. The effects of different parameters on the removal of NO_3^- such as chemical modification, contact time, initial concentration, adsorbent dose solution pH and co-anions were studied in detail. The equilibrium data are fitted into Langmuir, Freundlich and Dubinin–Radushkevich (D–R) equations to determine the correlation between the isotherm models and experimental data. The experimental data were also analyzed using three most common kinetic models, namely first- and second-order and intra particle diffusion. Thermodynamic parameters studies revealed that the nature of adsorption NO_3^- by nanocomposites synthesized is spontaneous and exothermic. Desorption process was carried out with NaOH and proven it was an effective agent in the discharge of NO_3^-. The experimental results indicated that NO_3^- was adsorbed from aqueous solutions efficiently and quickly by the nanocomposites synthesized, suggesting that CS/Clino@PEHA, Nano-CS/Clino@H and Nano-CS/Clino can be ideal candidates for removing NO_3^- from wastewater.
