Preparation of magnetite nanoparticles and their application in the removal of methylene blue dye from wastewater.

Wastewater is discharged in large amounts from different industries; thus, wastewater treatment is currently one of the main concerns, advanced oxidation is a promising technique for wastewater treatment. This research aims to synthesize magnetite nanoparticles and study their application in wastewater treatment via adsorption and advanced oxidation processes. Magnetite nanoparticles were synthesized via coprecipitation technique between ferric and ferrous sulfate at a molar ratio of 2:1. The prepared sample was characterized using FTIR, XRD, TEM, BET surface area, zeta potential, VSM, and UV‒visible spectroscopy. XRD confirmed the formation of a single face-centered cubic (FCC) spinel structure of FeO. TEM revealed an average particle size of 29.2 nm and a BET surface area of 70.1 m g. UV‒visible spectroscopy revealed that the UV-visible peak of the sample was obtained at 410 nm. VSM confirmed the attraction of the sample to a magnet with a magnetization of 60 (emu/g). The removal efficiency of methylene blue was studied using adsorption and advanced oxidation methods. For adsorption, the studied parameters were dye concentration 2-10 ppm, 3-10 pH, and 50:300 mg FeO/L. For advanced oxidation, peroxide was used with nanomagnetite as a catalyst, and the studied parameters were pH 2-11, magnetite dose 20-200 PPM, and peroxide dose 500-2000 PPM. The removal efficiency by adsorption reached 95.11% by adding 50 mg of FeO/L and 10 ppm dye conc at 6.5 pH; on the other hand, in advanced oxidation, it reached 98.5% by adding 110 PPM magnetite and 2000 ppm HO at pH 11. The magnetite nanoparticles were reused for ten cycles of advanced oxidation, for a 10% reduction in removal efficiency at the tenth cycle.