Tailored investigation and characterization of heterogeneous {Mn,Cu}/TiO2 catalysts embedded within a ceria-based framework for the wet peroxide oxidation of hazardous pollutants

In this work, novel catalyst frameworks including Mn/TiO2–CeO2, Cu/TiO2–CeO2, Mn–Ce–O, Mn–Cu–O, and TiO2–CeO2 were investigated for the catalytic wet peroxide oxidation of phenol-like pollutants. Aiming to gain further insights into the heterogeneous catalysis of manganese and copper metals supported on titanium and cerium oxides, the abatement efficiency was evaluated under different operating conditions and in terms of individual phenolic compounds depletion. Here, Mn/TiO2–CeO2 was found as the most active promoter for the highest detoxification rate. Second, pH profiles and reaction intermediates unveiled a free-radical mechanism and underlined the synergism behavior in catalytic wet peroxide oxidation. The titanium based oxides exhibited the strongest catalytic stability by the quantification of metal leaching and carbon adsorption. Afterwards, the integrated metal framework encompassed by Mn/TiO2–CeO2 and Cu/TiO2–CeO2 catalysts was realized in X-ray diffraction analysis and the TEM pattern gave rise to superior homogenous structures for Mn/TiO2–CeO2, which has been ascribed to the integration of the lanthanide into the lattice framework of titanium oxide. Finally, several sequential feed-batch trials were carried out emphasizing that 67% of pollutant conversion can be retained after long term catalytic runs.

Normalized total organic carbon concentration as function of time for a sequential batch experiment with phenolic mixture injection each 60 min.Figure optionsDownload as PowerPoint slideHighlights
► We investigate the CWPO of phenol-like pollutants under milder operating conditions.
► {Mn/Cu}TiO2–CeO2 were characterized by means of XRD, BET, SEM, and TEM.
► Embedded lanthanide frameworks were the most active toward the complete mineralization.
► Mn/TiO2–CeO2 exhibited worthy properties concerning long term catalytic stability.