Synthesis and characterization of magnetic nanocomposites based on Hydrogel-Fe 3 O 4 and application to remove of organic dye from waste water

Abstract

In this work a new magnetic nanocomposites based on Fe₃O₄-Hydrogel and Fe₃O₄@SiO₂-Hydrogel were synthesized. The poly(styrene-alt-maleic anhydride) was used as hydrogel compound. The hydrogel has the strong ability to remove some organic and inorganic compounds like methylene blue from water samples. Fe₃O₄ nanoparticles have the magnetic character that could help to the separation of hydrogel from the water after removal process by a magnet. The morphology of the hydrogel, Fe₃O₄, Fe₃O₄-Hydrogel and Fe₃O₄@SiO₂-Hydrogel was examined by scanning electron microscope (SEM). The structure of hydrogel and presence of the Fe₃O₄ and SiO₂ particles in the hydrogel nanocomposite was verified by FT-IR spectroscopy. The synthesized nanocomposites were used to remove the methylene blue from wastewater samples. Central Composite Design (CCD) and response surface method were used to optimize some parameters that affect the magnetic character, removal ability and removal efficiency, so the time of removal (minute), pH and the amount of hydrogel (mg) as important parameters were optimized by designing experiments. Determination of removal efficiency was done by spectrophotometric method. Results showed that the Fe₃O₄@SiO₂-Hydrogel had the more efficiency than Fe₃O₄-Hydrogel and the removal efficiency of methylene blue from water by synthesized Fe₃O₄@SiO₂-Hydrogel was between 50–95% that in the optimized condition it was almost 95%. Relative standard deviation (RSD) for 5 replicates the removal of methylene blue with synthesized sorbent was 4%.