Electrocatalytic removal of fluroquinolones from simulated pharmaceutical effluent: Chemometric analysis, chemical blueprint of electrodes and generated sludge

Abstract

Electrocatalytic removal of fluroquinolones from simulated pharmaceutical effluent is studied in this work. The effects of parameters like NaCl concentration, pH and initial concentration of Ofloxacin were studied. The synergistic effect of H2O2 on the degradation of Ofloxacin paves the way to move towards radical based chemistry. The process was modelled and statistically evaluated through Central Composite Design approach towards the maximum concentration of Ofloxacin degraded (for 0.8 mM) as 0.46 mM at pH-3.0 and the concentration of H2O2 at 0.2 mM. The model was analyzed mathematically and observed as saddle response based on canonical and ridge analysis. The process follows pseudo first order kinetics with k = 0.047 min−1 and reaction rate of 13.6 mg.L−1.min−1. The mineralization efficiency of the process was studied using Total Organic Carbon analysis and 76.5% removal efficiency was obtained on the simulated pharmaceutical effluent containing Ofloxacin, Ciprofloxacin and Norfloxacin. The crystal structure of the green and red colour sludge was determined by XRD to be lepidocrocite (a = 3.87 Å, b = 12.4 Å, c = 3.06 Å) and gupeiite (a = 5.6620 Å), respectively. The elemental composition of sludge and electrodes were found using SEM-EDX. Morphological change in electrode surface was determined using roughness plot.