Removal of diazinon pesticide from aqueous solution by adsorption onto neodymium orthoferrite nanoparticles

One of the most widely used organic phosphorus toxins is diazinon, which is widely used in agriculture. This toxin is resistant to biodegradation, which will cause many problems for the environment if it leaks into water bodies. In this study, neodymium orthoferrite nanoparticles (NdFeO₃) were synthesized by co-synthesis method and spherical NdFeO₃ nanoparticles with an average particle size of 28–38 nm were obtained. Morphology, lattice parameters and particle size were studied and identified by infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. These nanoparticles were used to remove diazinon from laboratory samples. The parameters of pH, contact time, adsorbent dose, and residual concentration of diazinon were investigated. Residual diazinon concentration was measured using gas chromatography. Daphnia magna biotoxicity test was used to determine the toxicity effect of nanoparticles. The results of this study showed that under optimal conditions of 50 mg/L diazinon at pH = 3, after 30 min of contact time, using 0.06 g/L NdFeO₃ nanoparticles, the removal efficiency was 92%. The LC₅₀ (96 h) and toxicity unit (96 h) of nanoparticles were measured as 1237 and 0.08 mg/L, respectively.