Photocatalytic Degradation of Toxic Dyes and Antimicrobial Activities by Cadmium Doped Magnesium Ferrites Synthesized by Combustion Method

The structural properties of nanocrystalline spinel ferrites with chemical formula Mg 0.8−x Cd x Fe 2 O 4 (x = 0.2, 0.4 and 0.6) prepared by combustion method and characterized by XRD, FTIR, SEM, EDX, TEM and UV studies. The X-ray diffraction (XRD) measurements confirmed the formation of a cubic spinel structure with space group Fd3m. Fourier transform infrared (FTIR) spectroscopy confirmed the existence of metal oxygen (M–O) bonding in the prepared samples. Absorption bands observed in FTIR spectra around 590 cm −1 and 434 cm −1 corresponds to vibrations of tetrahedral and octahedral complexes respectively. Scanning electron microscopic (SEM) analysis of surface morphology revealed irregular agglomeration of ferrite particles. The elemental compositions of the prepared NPs were analysed by EDX. TEM studies reveal the formation of spherical nanoparticles with agglomeration. The UV–visible study showed the optical band gaps decreased from 4.4 to 3.6 eV with increasing Cd 2+ doping. The photocatalytic reduction of Methylene Blue (MB) and Congo Red (CR) was also investigated using the prepared nanocatalysts. CR was more effectively degraded as compared to MB. Antibacterial results showed the activity against Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans and Aspergillus Flaves. All ferrite nanoparticles showed antimicrobial activity toward all pathogens selected. Of these, the most powerful was Cd 0.2 Mg 0.6 Fe 2 O 4 , showing zone of inhibition of 32 mm against P. aeruginosa .