Comparative Studies on Photo-Degradation of Landfill Leachate Using TiO2 Doped Fe2O3 and Cu

Abstract

Leachate generation is a serious problem for groundwater quality in and around municipal solid waste dumpsites. The degradation of leachate water contaminants using TiO₂-doped nanocomposites as photocatalysts is studied. The Fe₂O₃-doped TiO₂ and Cu-doped TiO₂ nanocomposites are synthesized by the sol–gel method to degrade landfill leachate water contaminants. The impregnation of Fe₂O₃ and Cu into TiO₂ aims to enhance the separation and migration of electron–hole pairs, increase the generation of reactive oxygen species, and ultimately improve the efficiency of photocatalytic degradation of contaminants in landfill leachate.SEM, XRD, EDX, FITR, and UV-DRS are used to analyze the surface morphology, particle size, elemental composition, and band gap energy of the prepared photocatalysts. The XRD results show Fe₂O₃/TiO₂ and Cu/TiO₂ have crystalline sizes of 40.03 nm and 18.15 nm, respectively. The surface morphologies of Fe₂O₃/TiO₂ have a non-uniform size and a spherical shape, but Cu/TiO₂ are tiny, spherical, and slightly clustered. The bandgap energies of Fe₂O₃/TiO₂ and Cu/TiO₂ are 3.75 eV and 3.87 eV, respectively. The optimal parameters, such as pH, catalyst dosage, and light intensity, are studied to determine the degradation of chemical oxygen demand (COD) and color removal. Results revealed that in the trapezoidal reactor, the maximum decolorization of 67%, 90%, and 78% and COD removal of 63%, 81%, and 72% are achieved for TiO₂, Fe₂O₃/TiO₂, and Cu/TiO₂ photocatalysts, respectively, at 3.5 h. Similarly, for the cylindrical reactor, color removal of 60%, 80%, and 70% and COD removal of 55%, 72%, and 65% are achieved for TiO₂, Fe₂O₃/TiO₂, and Cu/TiO₂ photocatalysts, respectively, at 3 h. The results of photocatalytic degradation of the leachate ensures the efficiency of the reactor and it is reused for several times to attain the maximum stability for real-time application in the treatment of landfill leachate.

Graphic Abstract