In recent decades, the release of drugs into aquatic ecosystems has heightened human apprehension. The literature includes multiple studies that have recorded Ciprofloxacin (CIP) levels in diverse sources, such as wastewater treatment facilities, untreated drinking water, hospital effluent, lakes, and discharge from pharmaceutical manufacturers. This literature review indicates that semiconductor-based AOPs can be used to effectively remove pharmaceuticals from wastewater. In order to facilitate the water splitting reaction, it is necessary to use catalysts that are highly active, stable, low-cost, and abundant.

The synthesis of molybdenum diselenide and the doping of zinc metal (X= weight percentages, 2.5%,5%, 7.5%,10%) into it have been conducted in this study. Using techniques such as FESEM, EDX, XRD, Raman, FTIR, and XPS, extensive investigations have been conducted which indicate the catalyst's efficient production. FESEM confirms the nanoflower structure with a size range of 30-50 nm. UV-VIS DRS analysis has been carried out to assess the synthesized sample's optical characteristics; it also helps to identify the band gap that promotes effective visible light absorption. The semiconductor type, charge transfer kinetics, and charge separation and transfer inside the on and off zones have been investigated using the Mott--Schottky plot, an Electrochemical Impedance Spectroscopy (EIS) study, and photocurrent investigation, respectively. An appropriate photochemical reactor was used to break down ciprofloxacin (CIP), and the reaction rate constant was measured. Under optimal conditions, the residual concentration of the antibiotic decreased to a point where it was no longer detectable after 45 minutes.

Further, the 5% doping of Zinc metal over molybdenum diselenide allowed for maximum photocatalytic efficiency due to the Se vacancy creation in the MoSe₂ structure under visible light illumination. Also, Zinc doping reduces the residence time to achieve faster reaction rates.