Investigation of structural, magnetic and antibacterial activities of Cr_xFe_{3− x}O₄ ferrofluids

This study aimed to investigate the structural, magnetic, and antibacterial activities of Cr_xFe_{3− x}O₄ ferrofluids. Cr_xFe_{3− x}O₄ nanoparticles were synthesized from iron sand by a co-precipitation method using Cr³⁺ ion variants (x content) of 0, 0.05, 0.1, 0.15, and 0.2. The prepared nanoparticles were then characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and Fourier transform infrared (FTIR). The results of XRD analysis showed that the addition of Cr⁺ ions caused a shift in the diffraction peak, indicating the successful penetration of Cr⁺ ions into the Fe₃O₄ octahedral atomic site. The average particle size of Fe₃O₄ nanoparticles determined by TEM morphology analysis was 13.7 nm. In addition, the magnetic properties of Cr_xFe_{3− x}O₄ ferrofluids analyzed via VSM showed that the saturation magnetization ranged between 6.95 and 42.71 emu/g, while the magnetic moments were in the range of 7.47 × 10⁻¹⁹–19.76 × 10⁻¹⁹ J/T, which varied with the addition of Cr³⁺ ions. Furthermore, an analysis of the antibacterial activities of Cr_xFe_{3− x}O₄ ferrofluids revealed that bacterial viability decreased with increase in the number of Cr³⁺ ions. Thus, the Cr_xFe_{3− x}O₄ ferrofluids prepared from iron sand are potentially excellent antibacterial agents.