Treatment of whey wastewater by electro-Fenton and photocatalytic hybrid process

This study investigates the sequential treatment of diluted whey wastewater using electro-Fenton and UV/photocatalytic methods with a hybrid process approach. Anatase TiO₂, Fe-doped, and N-doped TiO₂ catalysts were used in the experiments. To gain a comprehensive understanding of the prepared catalysts, multiple analytical techniques were employed, including scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area analysis, X-ray diffraction (XRD), and Raman spectroscopy. Particle size and surface area of Fe-doped and N-doped TiO₂ catalysts were measured as 44.70 nm and 31.96 m²/g for Fe-doped, and 34.21 nm and 41.76 m²/g for N-doped TiO₂, respectively. The crystal size and crystallinity percentage of both doped catalysts were found to be around 12–14 nm and 80%, respectively. In the photocatalytic treatment experiments, the effects of parameters such as pH, catalyst amount, and H₂O₂ concentration were investigated. According to the results, the total organic carbon (TOC) removal efficiency obtained with Anatase TiO₂ (46.57%) was found to be slightly higher compared to the TOC removal efficiencies of Fe and N-doped catalysts (36.32% and 37.58%, respectively). When examining the sequential treatment TOC removal efficiency, it was observed that using 2 g/L Anatase TiO₂ at pH 2, a mineralization efficiency of 69.48% could be achieved within 3 h.