Tin-tuned ZnO nanoparticles for dual-mode environmental remediation: UV and solar driven RR 120 dye breakdown and microbial control

• Sn incorporation tuned the structural, optical, and surface properties of ZnO. • Sn-ZnO (3 wt %) achieved ≈100 % RR 120 dye removal under UV and solar light. • Superoxide and hydroxyl radicals played key roles in photocatalytic degradation. • GC–MS confirmed intermediate products and the degradation pathway of RR 120. • The material demonstrated dual functionality in wastewater remediation and microbial control. Contaminants introduced by human activity, particularly synthetic dyes, pose significant ecological and adverse health implications linked to their enduring presence in aquatic systems and their recalcitrance to environmental degradation processes. In the current work, we synthesized and systematically investigated tin (Sn)-loaded zinc oxide (ZnO) nanomaterials to enhance photocatalytic and antibacterial performance. The crystallographic, photonic, and surface morphological characteristics of pristine and Sn-loaded ZnO (with varying Sn loadings from 1 wt% to 4 wt%) were thoroughly characterized using XRD, FT-IR, Raman, PL, UV-DRS, FE-SEM, EDX, HR-TEM, XPS, and UV–visible spectroscopy. Among the synthesized samples, 3 wt% Sn-ZnO exhibited superior photocatalytic efficiency, achieving ≈100% degradation of the azo dye Reactive Red 120 (RR 120) dye removal investigated under UV and solar light exposure at neutral (pH 7). Furthermore, GC–MS analysis revealed the intermediate degradation products, supporting the proposed dye degradation pathway. The 3 wt% Sn-ZnO catalyst demonstrated excellent reusability over multiple cycles without significant loss of activity. Beyond photocatalysis, the material exhibited potent investigation of bactericidal action toward model Gram-positive and Gram-negative strains: Staphylococcus aureus, Bacillus subtilis, Escherichia coli , and Pseudomonas aeruginosa . These findings highlight Sn-ZnO as a promising dual-functional nanomaterial for efficient wastewater remediation and antimicrobial applications.