Adsorption Studies of Imidacloprid from Aqueous Solution using Polyacrylamide Coated Magnetite Nanoparticles as a Potential Nanoadsorbent

In the present investigation, polyacrylamide-coated magnetite nanoparticles (PAM-MNPs) were successfully synthesized through the chemical co-precipitation method and were employed to remove most consumable imidacloprid insecticide from the aqueous system through batch experiments. FTIR, FESEM, XRD, TGA, VSM, and UV-Vis analyses were used to analyze the synthesized nanoparticles' physio-chemical characteristics. The influencing factors, including pH, insecticide concentration, adsorbent dosage, contact duration, and temperature, were investigated for effective imidacloprid removal. The results indicated that 96.71% of the imidacloprid had been eliminated after 100 minutes. The experimental results of the adsorption kinetics were an excellent match with the pseudo-second-order kinetic model. Moreover, the Temkin adsorption isotherm model fits the adsorption isotherms better than the Freundlich and Langmuir model. Based on the thermodynamic investigation (free energy change, enthalpy change, and entropy change), the IMC insecticide adsorption process onto the surface of PAM-MNPs was exothermic and spontaneous. The reusability of these nano-adsorbents was further investigated using desorption tests. The results of these investigations showed that the polyacrylamide-coated magnetite nanoparticles possessed good adsorption capability, and these nanoadsorbent might be employed to treat wastewater that includes the insecticide imidacloprid as a lethal contaminant.