A magnetite catalysed heterogeneous solar photo electro-Fenton system enhanced with lanthanum doped bismuth ferrite photoanode for the degradation of aspirin in water

Abstract

The effect of photoanode on a solar photo electro-Fenton system (SPEF) consisting of a magnetite nanoparticle catalyst impregnated carbon felt cathode is studied by coupling the SPEF system to a lanthanum-doped bismuth ferrite (La-BFO) photoanode. The resulting system, referred to as La-BFO /SPEF, was used in the degradation of acetyl salicylic acid in wastewater. The synthesised La-doped/undoped BFO photoanodes and magnetite nanoparticles were characterised with SEM, XRD and FTIR. The heterogeneous electro-Fenton system was prepared by attaching the magnetite nanoparticle to a carbon felt electrode through magnetisation. The effects of La dopant concentration in the photoanode material (doped and undoped BFO on a fluorine doped tin oxide substrate), pH values, current density and anodic oxidation contribution to the SPEF system were explored through parameters such as total organic carbon (TOC) measurements and mineralization current efficiency. A TOC removal of 68 % and 54 % was recorded for the La-doped photoanode (La-BFO/SPEF) and undoped system (BFO/SPEF) respectively, thus reflecting the contribution from the band gap tuning of the photoanode material. The predominant species in the degradation of acetyl salicylic acid were deduced by radical scavenging experiments. The coupling approach and the irradiation with visible light, enhanced the overall performance of the degradation system.