Optimizing Bisphenol A Removal Using Fe ₃ O ₄ @SiO ₂ –EN Doped Zn–Al–Layered Double Hydroxides Nanocomposites: A Central Composite Design Approach in Photocatalysis

ABSTRACT In the current study, Fe 3 O 4 @SiO 2 –ethylenediamine (EN) doped Zn–Al–layered double hydroxides (FSZAL) as a photocatalyst was prepared through the hydrothermal method. Response surface methodology (RSM) was utilized to optimize operational parameters, and the results indicated that individual factors had a greater influence compared to interactions. Analysis of variance (ANOVA) in RSM emphasized that over 95% of the variables could be explained by the model. The presence of interfering substances in the reaction environment reduced the Bisphenol A (BPA) decomposition rate by 10%–25%, and the greatest impact was from the chloride ion. Mineralization experiments suggested that the FSZAL photocatalyst could convert over 92.3% of BPA molecules. Stability tests revealed that over 95% of photocatalytic decomposition could be retained after five consecutive reaction cycles. In the assessment of wastewater toxicity, the growth inhibition rate of Escherichia coli ( E. coli ) bacteria in the photocatalytic reactor containing FSZAL decreased from 100% to 5%.