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

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 Fe 2+ 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 Fe 2+ 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 Fe 2+ 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 pretreated 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 BOD 5 /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.