Phosphate removal from aqueous solutions using polyaniline/Ni0.5Zn0.5Fe2O4 magnetic nanocomposite

Background: Phosphorus is an indispensable element for the growth of animals and plants. There are several environmental problems related to phosphate; therefore, the technical and economic methodsof removing phosphate are of great importance. This study evaluated the efficiency of polyaniline/ Ni0.5Zn0.5Fe2O4 magnetic nanocomposite in removing phosphate from aqueous environments. Methods: The adsorbent was characterized by several methods, including X-ray diffraction (XRD),scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and Fourier transform infrared (FT-IR) spectroscopy. Then, the potential of the adsorbentto adsorb phosphate was investigated.The effects of the parameters of contact time (5-60 minutes), pH (3-9), adsorbent dosage (0.05-0.6 g), and initial phosphate concentration (2-100 mg/L) on the phosphate removal yield were studied. Allphosphate ion concentrations were measured using the ammonium molybdate spectrophotometric method.Results: The results showed that a time of 30 minutes, pH of 5, and adsorbent dose of 0.4 g were theoptimum conditions for phosphate removal through adsorption. Increasing the initial concentration of phosphate from 2 to 100 mg/L decreased the removal efficiency from 90.3% to 32%. The experimental data was fitted well with the Freundlich isotherm model (R2 = 0.997). Conclusion: Polyaniline/Ni0.5Zn0.5Fe2O4 magnetic nanocomposite removes phosphate from aqueoussolutions with a simple and environmentally benign procedure. The maximum adsorption capacity based on Langmuir isotherm (R2 = 0.931) is 85.4 mg/g. This magnetic nanocomposite is applicable in managing water resource pollution caused by phosphate ions.

Keywords:

Adsorption , Phosphates , Nanocomposites , Polyaniline