Exploring the pressurized heterogeneous electro-Fenton process and modelling the system

In this research, a bench-scale installation was tested for the heterogeneous electro-Fenton treatment of clofibric acid. The setup consists of a pressurized flow-through electrochemical cell equipped with a catalyst fluidized-bed and aerated with a jet mixer. The novelty of the research is two-fold: the use of the pressurized-jet aerator on an electro-Fenton treatment is tested and it is one of the first studies combining pressure with heterogeneous catalysis in electro-Fenton. Moderate relative pressures, up to 2 bar, were analyzed. Initially, the electro-generation of hydrogen peroxide was tested, showing that it is remarkably boosted by the application of pressure. Then, the elimination of clofibric acid by means of an electro-Fenton treatment was carried out at 0.12 and 0.25 A, using iron-containing alginate beads as the catalyst. Regardless of the current intensity, the increase from atmospheric pressure to 1 gauge bar boosted the elimination of the pollutant and reduced the specific energy consumption of the electrochemical cell. Specifically, at 0.25 A an abatement higher than 98% was achieved in 8 h at atmospheric pressure while only 1 h was required at 1 bar of gauge pressure. However, a further increase of the pressure to 2 bar did not report a major improvement. Moreover, the effect of pressure on the catalyst was analyzed, concluding that the integrity of the alginate beads was not compromised by pressure. In fact, the iron leaching was very similar at 0, 1 and 2 bar: around 30% after 8 h of treatment. Finally, a mathematical model was developed, using the experimental data to obtain the necessary fitting parameters, which allowed to un-derstand better the behavior of the bench-scale reaction system.

Automated summary

In this research, a bench-scale installation was tested for the heterogeneous electro-Fenton treatment of clofibric acid. The use of a pressurized-jet aerator and iron-containing alginate beads as catalysts showed promising results in enhancing the efficiency of pollutant removal and reducing energy consumption. However, further increase in pressure did not lead to significant improvement. The integrity of the catalyst was not compromised by pressure. A mathematical model was also developed to better understand the behavior of the reaction system.