Effect of interfering ions on phosphate removal from aqueous media using magnesium oxide@ferric molybdate nanocomposite

The removal efficiency of phosphate ion from aqueous media using magnesium oxide/iron molybdate (MgO/Fe₂(MoO₄)₃) nanocomposite was investigated. MgO nanoparticles were chemically modified by ferric molybdate. Then, the structure and morphology of the nanocomposite was completely investigated using different analyses such as SEM, EDX/Map, FTIR, XRD, TGA, BET, and TEM. The TEM analysis demonstrated that the particles in the mentioned nano-composite were on a nanoscale. BET analysis proved that the nanocomposite was mesoporous with mean pore size of 9.4 nm. The sorption outcomes demonstrated that the highest phosphate sorption yield was achieved at 98.38%, exhibiting remarkable sorption efficiency. Carbonate ions showed to have the highest interfering impact compared to sulfate and nitrate ions, since phosphate ion removal efficiency decreased significantly when carbonate and phosphate ions were simultaneously available in the solution. The thermodynamic studies demonstrated that the current sorption process was spontaneous, possible, and exothermic. The sorption equilibrium investigation showed that the Freundlich isotherm model can describe the adsorption of phosphate ion better than can the Langmuir model, and the maximum sorption capacity was obtained as 30.21 mg/g. Additionally, the adsorbent was successfully regenerated four times and was able to perform the sorption and desorption process well.