Sustainable synthesis of Mangenese cobalt oxide nanocomposite on natural clay and optimization using response surface methodology for ciprofloxacin degradation via peroxymonosulfate activation

This study presents an innovative method for preparing of a novel composite by immobilization of cobalt manganese oxide (MnCoO) on natural clay extracted from ElHamma deposit in south of Tunisia (HC) through a co-precipitation technique. The resulting composite, known as MnCoO@HC, was tested for activating peroxymonosulfate (PMS) to break down ciprofloxacin (CIP), an antibiotic commonly found in water bodies. Characterization of MnCoO@HC using techniques like Fourier transform infrared (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy SEM and energy dispersive X-ray spectroscopy (EDS) highlighted its robust structural integrity and catalytic properties. The key operational parameters such as pH (3–10), catalyst dosage (200–800 mg/L), PMS concentration (100–400 mg/L), CIP concentration (20–40 mg/L), and temperature (25–55 °C) were optimized using a central composite design. Under optimum conditions of 400 mg/L catalyst, 300 mg/L PMS, and pH 4.4 a remarkable 100 % degradation of CIP was attained within 30 min, with a mineralization efficiency of 58 %. In addition, the catalyst exhibited high efficiency and fast degradation of various pharmaceutical pollutants, including paracetamol and ibuprofen. HCO 3 – common coexisting anion in wastewater was found to inhibit the catalytic activity of MnCoO@HC. Radical scavenging study showed that sulfate radicals (SO 4 •− ) were the primary reactive species involved. The catalyst also showed impressive reusability over three cycles, with only a slight decrease in activity and low metal leaching. This finding demonstrates a straightforward, environmentally friendly, and economic approach to remediating pharmaceutic-contaminated wastewater using PMS-based advanced oxidation processes.