Treatment of statins drug (pravastatin and rosuvastatin) in water by electro-Fenton process: Kinetics of degradation/mineralization and optimization of experimental conditions for a biological post-treatment

Abstract

<jats:p>The treatment of pravastatin and rosuvastatin contaminated water as much as toxic and persistent organic pollutant was carried out by Electro-Fenton method EF. Several experiments were conducted in a cell compartment equipped with a platinum anode and a carbon felt cathode. The effects of several parameters such as the applied current and the catalyst Fe2+ concentration have been studied. Mineralization aqueous solutions of pravastatin followed by the chemical oxygen demand COD gave a higher degree of reduction of more than 90% for 6 hours of treatment at a current of 100 mA and Fe2+ concentration of 0.2 mM. The study of the degradation kinetics was followed during electrolysis by HPLC giving a pseudo first order reaction using a current of 100 mA and Fe2+ concentration of 0.1mM. A number of intermediate products for pravastatin and rosuvastatin have been identified using HPLC and liquid chromatography-mass spectrometry analyses. Biodegradability of the pre-treated solutions of two statins by EF was evaluated in order to decide the optimal moment to introduce the biological process. It was given by the ratio BOD5/COD which increases from 0 initially to 1.3 after 2 hours for pravastatin and from 0 initially to 1.5 after 3 hours for rosuvastatin as the COD decreases. It implies that EF tends to enhance the biodegradability and could be used as a pre-treatment step for biological treatment.</jats:p>