Electrochemically generated sulphate radicals as an advanced oxidation technique for the removal of pharmaceutical pollutants from industrial wastewater (SO4ELECTRIC)

There is a growing concern on the ecological impact of different classes of recalcitrant organic pollutants such as active pharmaceutical ingredients (API) in natural waters. Globally, about 4000 APIs are being distributed in prescription medicines, over-the-counter therapeutic drugs, and veterinary drugs. Pharmaceutical micro-pollutants are regarded as a severe threat to the ecosystem due to their specific biological effect and the potential of inducing drug-resistant bacteria. Although present in small concentrations, (metabolites of) pharmaceutical residues were shown to have an adverse effect on fish populations and other aquatic organismsA major group of technologies currently in the picture for an efficient removal of emerging pollutants is Advanced Oxidation Processes (AOP), which are based on the oxidation of organics by OH-radicals (*OH). More recently, the use of sulphate radical (SO4*-) based oxidation processes (SR-AOP) has gained attention as an innovative alternative for typical AOP processes because of some distinct advantages. The aim of this research is to investigate electrochemical SR-AOP (eSR-AOP) for key pharmaceutical products, where the direct electrochemical generation of radicals via present sulphate ions will be assessed, which avoids the addition of the precursors, since sulphate ions are already present in most types of targeted wastewater. This is a main innovation in the development of the technology, both from a scientific and application point of view. Different types of anodes will be evaluated towards their efficiency (mixed metal oxide and boron doped diamond electrodes are the primary candidates), and influential process conditions will be determined. The efficiency of the electrochemical SR-AOP will be benchmarked versus classic eAOP. The occurring degradation mechanisms and the radicals responsible for the degradation will be elucidated using advanced analytical tools such as UHPLC-MS and UHPLC-QTOF-MS (degradation products) and electron spin resonance (radicals). The results will enable the further industrial development and considerate use of this process in the future.

Keywords:Advanced Oxidation Processes, Wastewater Treatment, Emerging pollutant, Sulphate radical, Electrochemistry

Disciplines:Industrial chemistry