Experimental assessment of a hybrid process including adsorption/photo Fenton oxidation and microbial fuel cell for the removal of dicarboxylic acids from aqueous solution

In this study, the application of adsorption/photo Fenton oxidation and Microbial Fuel Cell was investigated for the degradation of dicarboxylic acids such as succinic acid and fumaric acid. The feasibility of a hybrid system combining an adsorption / photo Fenton-like oxidation and biological oxidation in a Microbial Fuel Cell (MFC) was investigated for the removal of succinic acid from aqueous solution. Adsorption and photo Fenton-like oxidation tests were carried out by using Fe-TiO2/AC (AC: Biomass derived activated carbon) as a catalyst. A removal of about 40.8 % was achieved in adsorption tests within 2 h at room temperature and 4 g/L of Fe-TiO2/AC loading. A slight improvement of the pollutant removal from the water phase was observed by the addition of an oxidant (H2O2) and the UV light source. The succinic acid solution was sent to a subsequent treatment in MFC: after 20 days a further removal of the pollutant of about 49.4 % with a mineralization of 35.5 % were observed. The adoption of a bioelectrochemical system allowed to convert the organics into electricity with a coulombic efficiency of 25.0 %. The biochemical oxidation of succinic acid and fumaric acid, the main product of the catalytic oxidation of succinic acid, was then carried out in a microbial fuel cell. A significant TOC reduction was achieved for both compounds, thus proving that they can be successfully used as electron source in microbial fuel cell treatment.