Treatment of pharmaceutical wastewater containing cefazolin by electrocoagulation (EC) : Optimization of various parameters using response surface methodology (RSM), kinetics and isotherms study

Pharmaceutical wastewaters presently remain as one of the primary roots of environmental pollution. The current study mainly concentrated on removing cefazolin (CEZ) from pharmaceutical wastewater employing the electrocoagulation (EC) process using iron electrodes. The EC experimental conditions were achieved by using response surface methodology (RSM) with an efficiency of 85.65% under optimal working conditions of pH = 8.0, current density (16 mA/cm(2)), initial CEZ concentration (25 mg/L), and inter-electrode distance (d = 1.0 cm) at an equilibrium electrolysis time of 40 min. The experimental results obtained were in good agreement with the predicted CEZ removal efficiency of 86.7%. Besides, Analysis of variance (ANOVA) revealed that the experimental model was best suited to a second-order polynomial equation, with an R-2 value of 0.92. Moreover, the fisher's F-value of 13.67 and low probability value (p < 0.0001) suggest a decent correlation between the experimental and predicted CEZ elimination levels. Additionally, the kinetic adsorption and isotherm results indicated that the model follows pseudo-second-order kinetic adsorption with R-2 = 0.999. The Langmuir isotherm with R-2 = 0.9508 provides the best match when compared to the Freundlich model. Finally, the energy consumption, electrode dissolution, and operating cost per kg COD eliminated under optimal conditions were calculated to be 0.7395 kW h, 1.513 kg, and 0.89 USD, respectively. (C) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

The study focused on removing cefazolin from pharmaceutical wastewater using the electrocoagulation process with iron electrodes, achieving an efficiency of 85.65% under optimal conditions. The experimental model was best suited to a second-order polynomial equation, with good correlation between experimental and predicted CEZ elimination levels.