Effect of Magnetic Magnetite (Fe₃O₄) Nanoparticle Size on Arsenic (V) Removal from Water

Magnetic magnetite (Fe₃O₄) nanoparticles with average sizes of 5.11, 10.53, and 14.76 nm were synthesized by the chemical co-precipitation method. The surface area of Fe₃O₄ nanoparticles (average size of 5.11 nm) had the largest value of 167 m²/g. The adsorption capacity for removing arsenic (As(V)) from water at 3 ppm concentration was investigated by atomic absorption spectroscopy. Results showed that the As(V) adsorption capacity of Fe₃O₄ was dependent on particle size. The maximum absorption efficiency (H_max) reached 99.02%, the equilibrium time was 30 min; the maximum Langmuir isotherm adsorption capacity was 14.46 mg/g with Fe₃O₄ nanoparticle an average size of 5 nm. The results indicate that reducing the size of Fe₃O₄ nanoparticles is a promised way for As(V) ion removal from water and wastewater treatment.