Nitrate Removal from Aqueous Solution by Magnetic Nanoparticle

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.
The removal of nitrate from aqueous solutions by magnetic nanoparticle 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.
According to SEM and TEM images, the adsorbent particles were nanosized and spheroidal; the sizes were about 20–30 nm. The experiment's 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.
The results showed that, magnetic nanoparticles can be used as a low cost and efficient adsorbent for removal of nitrate from aqueous solutions.