Optimization on the heterogeneous photocatalytic degradation of Azorubine E122 dye using nanocomposite via CuO nanoparticles with sodium mordenite

Abstract

The study details the development and characterization of a novel photocatalyst, a combination of cupric oxide nanoparticles and sodium mordenite (CuO NPs/NaMOR), designed for the degradation of Azorubine (E122) dye in water under air conditions using sunlight irradiation. Various analytical techniques, including Powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), Scanning electron microscope (SEM), UV–Vis diffuse reflectance spectroscopy (UV–Vis DRS), and Brunauer–Emmett–Teller (BET) were employed for thorough photocatalyst characterization. The resulting photocatalyst exhibits noteworthy characteristics, such as a large specific surface area of 129.22 m2/g, pore volume is 0.46 cm3/g, an average pore radius of 1.450 nm, and an overall pore size of 0.123 cm3/g. An optical band gap energy of 1.78 eV. Achieving a maximum degradation efficiency of 91 % for E122 dye after 120 min, the photocatalyst follows first-order Langmuir kinetics with a rate constant of 0.035 min−1. Radical trapping tests support the involvement of radicals like •OH and •O2− in the photocatalytic degradation process. Additionally, the computed potential energies of the valence and conduction bands were found to be 0.42 and 2.20 eV, respectively. The photocatalyst demonstrated remarkable stability, registering degradation efficiencies of 91.0 %, 89.9 %, 88.8 %, 87.5 and 86.0 % across five reuse cycles. Photoluminescence experiments using terephthalic acid confirmed the generation of •OH free radicals during irradiation. Overall, the CuO NPs/NaMOR photocatalyst emerges as a promising candidate for solar-driven environmental remediation applications, owing to its effectiveness, stability, and reusability. The photocatalytic degradation was enhanced utilizing Box-Behnken design.