Efficient Photocatalytic Degradation of Methylene Blue and Methyl Orange Using Calcium-Polyoxometalate Under Ultraviolet Irradiation

Abstract

With the increasing demand for eco-friendly water treatment solutions, the development of novel photocatalysts such as calcium polyanion (Ca-POM) plays a vital role in mitigating industrial wastewater pollution. In this research, calcium polyanion, H60N6Na2Ca2W12O60 (Ca–POM), was successfully synthesized via a self-assembly reaction from metal-oxide subunits. The synthesized Ca–POM was verified to have a polycrystalline structure with a broad size distribution, with an average particle diameter of approximately 623.62 nm. Powder X-ray diffraction (XRD) analysis confirmed the polycrystalline structure of the Ca–POM, with a calculated band gap energy of 3.29 eV. The photocatalytic behavior of the Ca-POM sample was tested with two model dyes, methylene blue (MB) and methyl orange (MO). The reaction mixture was then exposed to ultraviolet (UV) irradiation for durations ranging from 20 to 140 min. The synthesized cluster demonstrated photocatalytic efficiency (PCE%) values of 81.21% for MB and 25.80% for MO. This work offers a valuable basis for applying Ca–POM as a heterogeneous photocatalyst for treating industrial wastewater organic pollutants and highlights the potential of Ca–POM in sustainable water treatment applications.