The role of operating parameters and irradiation on the electrochemical degradation of tetracycline on boron doped diamond anode in environmentally relevant matrices

Abstract

BACKGROUND: Nowadays, due to the inappropriate use of antibiotics, significant quantities have been detected in environmental samples. Therefore there is a need for a technology to eliminate the accumulation of pharmaceuticals in receiving water bodies. In recent years electrochemical oxidation showed superior efficiency for the purification of water from pharmaceuticals. RESULTS: boron doped diamond (BDD) showed better efficiency than platinum electrode and stainless steel for the degradation of 500 µg L?1 tetracycline (TC) with 0.1 mol L?1·Na2SO4. The presence of 200 mg L?1 bicarbonates decreased the apparent kinetic constant from 0.328 to 0212 min?1. Instead, the addition of 200 mg L?1 NaCl increased the kinetic constant by almost four times, while the presence of 10 mg L?1 of humic acid decreased the kinetic constant by 18%. The process was favored in real environmental matrices like bottled water and wastewater in comparison with ultrapure water. The use of BDD as both anode and cathode enhanced the efficiency by almost 20%. The presence of UVA or solar radiation increased the decomposition of tetracycline by 14%. Changes in toxicity to Vibrio fisheri bacteria during treatment of TC in the secondary effluent are mainly attributed to the formation of intermediates of the water matrix itself and does not follow the TC removal. CONCLUSIONS: Electrochemical oxidation was favored for removal of TC in real water matrices due to the presence of chlorides. The use of BDD as both anode and cathode with simultaneous solar irradiation is a promising technology for water remediation from TC. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry