Experimental design methodology applied to electrochemical oxidation of carbamazepine using Ti/PbO2 and Ti/BDD electrodes

Abstract

Carbamazepine (CBZ), a widely consumed psychotropic pharmaceutical, is one of the most frequently detected pharmaceutical active compounds (PhACs) in water bodies. Its removal has become an issue from the human health and environmental risks point of view, due to its latent recalcitrance and toxicity properties. The oxidative removal of carbamazepine in aqueous medium has been investigated by electrooxidation processes using Ti/PbO2 and Ti/BDD circular anode electrodes in the presence of NaSO4 as electrolyte in a batch electrochemical reactor. The effect of different parameters such as current intensity (from 1 to 2A), electrolysis time (from 60 to 120min), recirculation flow rate (from 167 to 333mlmin−1), and anode material (PbO2 and BDD) were investigated by an experimental design methodology. A Factorial Design 24 was firstly used to determine the effect of parameters mentioned above on CBZ removal. The electrolysis time and current intensity were the main parameters affecting CBZ removal rate. Then, the optimal experimental parameters for carbamazepine removal were investigated using a Central Composite Design. The optimal conditions determined turned out to be Ti/PbO2 anode, current intensity 1.37A, electrolysis time 101min, and recirculation flow rate 232mlmin−1. Under these conditions the removal of 88±1.2% of CBZ and 3.159mgL−1min−1 of p-nitrosodimethylaniline were achieved. The decay kinetics was fitted a first-order reaction.