Zinc titanate nanocomposites for bactericidal activity and pharmaceutical pollutant degradation

Nanocomposites zinc titanate (ZnTiO3) have been synthesized, and their structural, morphological, and optical properties were thoroughly investigated. X-ray diffraction analysis revealed the formation of ZnTiO3 with a dominant spinel cubic phase, with crystallite sizes ranging from 18 nm (pristine TiO2) to 42 nm (ZnTiO3 with 5% doping). Structural and optical characterizations confirmed the successful incorporation of Zn into the TiO2 lattice, resulting in the formation of a perovskite ZnTiO3 phase with a narrowed band gap of 2.95 eV, compared to 3.13 eV for TiO2 and 3.10 eV for ZnO. The photocatalytic efficiency for methylene blue degradation was significantly enhanced, achieving 98.9% degradation within 120 min, surpassing undoped TiO2 (68%) and ZnO (72%). In addition, an improved degradation rate constant of 0.0336 min−1 was obtained. The antimicrobial efficacy was evaluated against gram-positive bacteria (Staphylococcus aureus and methicillin-resistant S. aureus), gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa), and the fungal strain Candida albicans. Results demonstrated that ZnTiO3 exhibited the highest bactericidal activity at low concentrations, outperforming the standard antibiotic control (Nalidixic acid, 30 µg/ml) in many cases. Dose-dependent inhibition studies showed enhanced antimicrobial effects at 10 µg/ml, with 2.5 µg/ml identified as the optimal concentration, balancing efficacy, and minimal toxicity.