Abstract
In this study, a porous, hierarchical flower-like zinc oxide (ZnO) structure was successfully synthesized via a hydrothermal method using urea and CTAB as shape-directing agents to optimize photocatalytic efficiency for environmental remediation. Structural characterization via scanning electron microscopy (SEM) and X-ray diffraction (XRD) confirmed the formation of a highly crystalline, pure hexagonal wurtzite phase assembled from ultrathin nanosheet building blocks. The photocatalytic performance of the synthesized ZnO was evaluated through the degradation of methylene blue (MB) dye under UV light illumination (365 nm). The catalyst achieved a (98.7 ± 0.5)% degradation efficiency within 40 minutes, following a pseudo-first-order kinetic model with a reaction rate constant of 0.109 min-1. Optimization studies identified a catalyst dosage of 0.2 g/L as near-optimal, while coexistence tests demonstrated that the system maintains high stability and excellent removal efficiency in the presence of various competing environmental anions (Cl- , NO3 - , HCO3 - , CO3 2-). Radical scavenger investigations revealed a clear inhibition hierarchy, establishing that the degradation mechanism is predominantly driven by hydroxyl radical-mediated oxidation alongside secondary contributions from photogenerated holes. These findings highlight the prepared porous ZnO architecture as an efficient, stable, and sustainable candidate for the degradation of persistent organic pollutants in municipal wastewater.