A Kinetic Study on Adsorption of Congo Red from Aqueous Solution by ZnOZnFe2O4- polypyrrole Magnetic Nanocomposite

In this work, magnetically separable ZnO-ZnFe_2O_4-PPy nanocomposite as an efficient adsorbent was synthesized by two steps. At first, zinc oxide (ZnO) and ZnFe_2O_4 nanoparticles were synthesized using simple and facile precipitation method. Then, ZnO-ZnFe_2O_4 mixed oxide was modified by polypyrrole (PPy). The adsorbent was characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), UV-Vis and scanning electron microscopy (SEM). The synthesized nanocomposite were used as adsorbent to remove Congo red dye from aqueous solution and were compared with pure ZnO and ZnO-PPy adsorbents. The ZnO-ZnFe_2O_4-PPy nanocomposite adsorbent showed a superior Congo red removal efficiency than ZnO and ZnO-PPy adsorbents. This efficiency is attributed to the charge of surface obtained in nanocomposite adsorbent. Furthermore, the adsorption kinetics of Congo red onto the nanocomposite followed by the pseudosecond-order kinetic model.