This research investigates the photocatalytic removal of reactive blue 19 (RB19) dye utilising Zn-Cu (zinc-copper) bimetallic oxide nanocatalysts under UV irradiation. The nanocatalysts were prepared via the co-precipitation technique and thoroughly characterised using different procedures including XRD, FTIR, BET-BJH, FESEM, TEM, and EDX. BET-BJH analysis revealed a specific surface area of 59.774 m2/g for the Zn-Cu bimetallic oxide nanocatalyst. Response surface methodology (RSM) was employed to optimise operational factors such as catalyst amount, pH, H2O2 amount, and UV power, with a quadratic model showing high reliability (R2 = 0.89). Under optimal conditions (4 mg catalyst amount, pH 6.68, 0.42 mL H2O2 dose, 23 W UV power, and 45 min reaction time), the maximum RB19 removal reached 77.14%, increasing to 98.33% after 120 min. The kinetic study revealed a reaction rate constant of 0.884 min−1, indicating efficient removal. Zn-Cu bimetallic oxides demonstrated superior RB19 removal capacity, with only a 5.92% reduction in removal yield after 5 consecutive reuse cycles. This study underscores the potential of Zn-Cu bimetallic oxide nanocatalysts for efficient removal of RB19 dye in suspension media.
