Removal of Tetracycline Using Different Treatment Processes; Electrocoagulation, Ultrasound and Ultrasound Assisted Electrocoagulation

Abstract

This study examined the elimination of tetracycline (TC) in aqueous samples by electrocoagulation (EC), ultrasonography (US), and US-assisted EC methods. The effects of TC removal with EC method were examined using different types of junctions, i.e., monopolar parallel (MP-P), monopolar serial (MP-S), bipolar serial (BP-S), and eight various combinations of aluminum and iron hybrid electrodes. The effectiveness of EC variables on TC and Chemical Oxygen Demand (COD) removal efficiencies was investigated, including the combination of hybrid electrodes, the initial value of pH, current density, initial concentration of TC, airflow volume, conductivity of the solution, and connection configuration. Optimal conditions for the 5-min EC time were found to be: Al-Fe-Fe-Fe electrode configuration, pH initial value of 6, current density of 50 A/m2, TC concentration of 100 mg/L, airflow volume of 2 L/min, solution conductivity of 1000 µS/cm, and MP-P connection type. Under these conditions, TC and COD removal efficiencies were 96.3% and 91.2%, respectively. Additionally, under optimal operating criteria in the fixed-power, fixed-frequency US-coupled EC process, TC and COD removal efficiencies were 100% and 97.5%, respectively. UV absorbance was measured before and after treatment using EC, US, and US-assisted EC techniques. Taking into account electrode, energy, and chemical consumption, the operating costs for EC and EC-US were determined to be 0.215 €/m3 and 0.76 €/m3, respectively. The results showed that the US-assisted EC and EC process was highly effective in removing TC from aqueous solutions.