Photoelectrocatalytic degradation of chlortetracycline using Ti/TiO 2 nanostructured electrodes deposited by means of a Pulsed Laser Deposition process

Abstract

Ti/TiO 2 electrode was prepared by means of the Pulsed Laser Deposition method and used in a photoelectrocatalytic oxidation (PECO) process in order to degrade chlortetracycline (CTC). The deposited TiO 2 coatings were found to be of rutile structure. High treatment efficiency of CTC was achieved by the PECO process compared to the conventional electrochemical oxidation, direct photolysis and photocatalysis processes. Several factors such as current intensity, treatment time, UV lamp position and initial concentration of CTC were investigated. Using a 2 4 factorial matrix, the best performance for CTC degradation (74.3% of removal) was obtained at a current intensity of 0.5 A during 120 min of treatment time and when the UV lamp was immersed in the solution in the presence of 25 mg L −1 of CTC. The current intensity and treatment time were the main parameters influencing the degradation rate of CTC. Subsequently, a central composite design methodology has been investigated to determine the optimal experimental parameters for CTC degradation. The PECO process applied under optimal conditions (at current intensity of 0.39 A during 120 min with internal position of the UV lamp) is able to oxidize around 74.2 ± 0.57%, of CTC.