Polyaniline–Zn0.2Mn0.8 Fe2O4 ferrite core–shell composite: Preparation, characterization and properties

• Polyaniline/Zn0.2Mn0.2Fe2O4 nanocomposite was synthesized and characterized by XRD, FTIR, SEM, TEM, UV–vis and TGA.
• Composite showed thermal stability, electrical, optical and magnetic properties controlled by the ferrite content.
• Nanocomposite purified dye wasted water with high efficiency.
• Composite is tested as gases sensors.

Zn0.2Mn0.8Fe2O4 ferrite nanoparticles coated with polyaniline, forming a composite structure, were synthesized by in situ chemical oxidation polymerization at different ferrite weight ratio (PANI/ZnMn ferrite = 30% and 50%). The ZnMn ferrite nanoparticles were prepared by the sol–gel combustion method using metal nitrates as precursors. The structure, morphology, electrical, gas sensing and magnetic property of the ferrite and composite samples were characterized by XRD, FT-IR, TEM, TGA, VSM, LCR instrument and sensing measurements. The results of XRD, FTIR and UV–vis spectra confirmed the formation of ZnMn ferrite/PANI composites. TEM study showed that the composites exhibited the core–shell structure. The results of TGA showed that ZnMn ferrite particles improved the thermal stability of composites indicated the existence of some interactions at the interface of polyaniline macromolecule and ZnMn particle, which influences the physical and chemical properties of the composite. The nanocomposites under applied magnetic field exhibited the hysteresis loops of superparamagnetic nature at room temperature. The ac conductivity and dielectric properties were studied in the frequency range from 102 to 107 Hz. The electronic and magnetic properties of the nanocomposites were tailored by controlling the ferrite content. The adsorption efficiency of the materials to remove toxic dye from waste water was also tested at different pH and it was found that the composite containing 50 wt% ZnMnFe2O4 exhibit excellent adsorption at pH 8. The nanocomposites have been also investigated as sensors for each of NH3, chloroform and acetone vapors in ppm level concentration.