Effective visible light photodegradation of Alizarin Red S dye and antibacterial activity studies with magnetically separable NiFe2O4/TiO2/ZrO2 ternary nanocomposites

Novel NiFe₂O₄/TiO₂/ZrO₂ ternary nanocomposites were designed for efficient photodegradation of organic contaminants. Zirconium dioxide, a stable and eco-friendly photocatalyst, primarily operates in the UV spectrum, necessitating materials active under visible light. This study synthesized NiFe₂O₄/TiO₂/ZrO₂ composites for visible-light-driven degradation of Alizarin red S dye. Characterization using FTIR, SEM, TEM, XRD and UV-DRS revealed an average crystallite size of 28.34 nm, with Ni, Fe, O, Ti, and Zr present at 15.62 %, 29.71 %, 29.79 %, 12.73 %, and 12.14 %, respectively. The composite, with a 3.03 eV band gap (UV-DRS), achieved 100 % dye degradation in 40 min under visible light and exhibited strong antibacterial activity against gram-positive and gram-negative bacteria. The NiFe₂O₄/TiO₂/ZrO₂ ternary composite stands out due to its enhanced charge separation, visible-light activation, magnetic recoverability, and high structural stability. These properties make it an efficient and reusable photocatalyst, surpassing conventional TiO₂based catalysts in many aspects. The antibacterial mechanism of NiFe₂O₄/TiO₂/ZrO₂ involves ROS generation, direct membrane disruption, metal ion toxicity, and physical damage. These synergistic effects make it a promising antimicrobial agent, especially in water disinfection, medical coatings, and antibacterial surfaces.