The influence of operational factors on the photocatalytic degradation of methylene blue dye in aqueous Sr-Au-ZnO suspensions under UV-A light

•The photocatalytic degradation of MB by Sr-Au-ZnO has been investigated.•Sr-Au-ZnO was more effective for MB degradation than commercial catalysts.•GC-MS analysis predicted the intermediates formed during photodegradation. Any of several processes that break down dyes, ideally into harmless chemicals, is referred to as industrial dye degradation. Water waste discharges various colors, particularly those used in the textile industry like methyl red and methylene blue, into ecosystems, leading to significant pollution of the water supply. Under UV-A irradiation, the photocatalytic degradation of a commercial heterocyclic aromatic chemical molecule called methylene blue (MB) has been investigated using an aqueous solution of Sr-Au-ZnO as a photocatalyst. Research has been done on how different process characteristics affect the degradation process. For the mineralization of MB dye under UV-A light, it was found that the optimized Sr-Au-ZnO was more effective than commercial catalysts (ZnO and benchmark photocatalyst Degussa P25), single metal dopants (Sr-ZnO, Au-ZnO), and prepared ZnO. The effects of operational parameters, such as the quantity of photocatalyst, dye concentration, and starting pH, on the photo-mineralization of MB are analyzed before optimal values are given. Chemical oxygen demand (COD) measurements have confirmed that MB is mineralized. Using GC–MS analysis, the intermediates produced during photodegradation were predicted, and an appropriate degradation pathway was suggested. This procedure can be used for treating wastewater from sewage since optimized Sr-Au-ZnO is reusable. [Display omitted]