Application of response surface methodology to optimise the Metronidazole antibiotic removal by a developing Bio-Electro-Fenton process

Résumé fourni par la source

Many antibiotics are released into the environment with wastewater from pharmaceutical industry, the accumulation of these molecules in water resources has several harmful effects on the environment and human health. The incomplete removal of them by traditional wastewater treatment methods necessitated the use and the development of suitable alternative methods. In this research, the degradation of Metronidazole (MTZ) antibiotic was investigated using Bio-Electro-Fenton (BEF) process, an innovative hybrid technology that combines biological treatment with advanced oxidation processes. The optimisation was conducted through Response Surface Methodology (RSM), employing a three-factor Central Composite Design (CCD) to optimise key operating parameters: oxygen flow, current intensity, and Fe2+ concentration. The quadratic models demonstrated high reliability with an R2 value of 0.936 for BEF. Under optimum conditions (0.264 L/min O2, 0.312 A, 0,589 mmol/L Fe2+), BEF achieved 85.678% MTZ removal efficiency in 1 h with an energy consumption of 0.1872 kWh/m3.To demonstrate the enhanced performance of the BEF process, a comparative study using the Electro-Fenton (EF) process was conducted. Under optimum condition removal (0.282 L/min O2, 0.213 A, 0.408 mmol/L Fe2+), EF achieved 87.429% MTZ removal in 1 h but required significantly higher energy consumption of 9.585 kWh/m3. This comparison highlighted BEF’s superior energy-efficient, consuming 98.05% less energy while maintaining comparable degradation efficiency. The degradation pathway analysis revealed a complete mineralisation of MTZ to CO2 and H2O. These results establish BEF as an energy-efficient and environmentally friendly technology for pharmaceutical wastewater treatment.