Nitrate Removal from Aqueous Solutions by Magnetic Nanoparticle

Introduction: Due to causing methemoglobinemia, different cancers, and teratogen effects in human nitrate contamination of water resources has become a critical environmental problem Therefore, the aim of this work was to determine the optimum condition of nitrate sorption onto magnetic nanoparticle. Materials and Methods: The removal of nitrate from aqueous solutions by magnetic nanoparticles has been studied through using batch adsorption method. X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM) was applied to characterize the synthesized Fe3O4. The effect of pH, nano-magnetic, adsorbent dose, initial concentration of nitrate, and contact time were investigated. Results: According to SEM and TEM images, the adsorbent particles were nanosized and spheroidal; the sizes were about 20–30 nm. The experiments' results indicated that the optimum adsorbent dose was 750 mg in 1000 ml of solution, with a contact time of 90 min, while the optimum pH was 9. The kinetic models for nitrate adsorption showed rapid sorption dynamics by both first-order kinetic (R2 = 0.97) and second-order kinetic (R2 = 0.96) models. Nitrate adsorption equilibrium data were fitted well to the Freundlich isotherm than Langmuir isotherm. Conclusion: The results showed that, magnetic nanoparticles can be used as a low cost and efficient adsorbent for removal of nitrate from aqueous solutions.