A charcoal-shaped catalyst NiFe2O4/Fe2O3 in electro-Fenton: high activity, wide pH range and catalytic mechanism

Application of perovskite oxides and their composites for degrading organic pollutants from wastewater using advanced oxidation processes: Review of the recent progress

In the recent years, perovskite oxides are gaining an increasing amount of attention owing to their unique traits such as tunable electronic structures, flexible composition, and eco-friendly properties. In contrast, their catalytic performance is not satisfactory, which hinders real wastewater remediation. To overcome this shortcoming, various strategies are developed to design new perovskite oxide-based materials to enhance their catalytic activities in advanced oxidation process (AOPs). This review article is to provide overview of basic principle and different methods of AOPs, while the strategies to design novel perovskite oxide-based composites for enhancing the catalytic activities in AOPs have been highlighted. Moreover, the recent progress of their synthesis and applications in wastewater remediation (pertaining to the period 2016-2022) was described, and the related mechanisms were thoroughly discussed. This review article helps scientists to have a clear outlook on the selection and design of new effective perovskite oxide-based materials for the application of AOPs. At the end of the review, perspective on the challenges and future research directions are discussed.

Efficient electro-Fenton catalysis by self-supported CFP@CoFe2O4 electrode

In this work, the bimetallic iron oxide self-supported electrode was prepared by a simple solvothermal as well as thermal method. CoFe₂O₄ magnetic nanoparticles were grown in situ on the CFP surface and characterized to reveal the morphology, composition, and electrochemical properties of the electrode. Compared to CFP and CFP@Co-Fe, CFP@CoFe₂O₄ equipped more efficient mineralization current efficiency and lower energy consumption due to the improved electrocatalytic capacity of CoFe₂O₄ properly grown on the conductive substrate surface. Further studies showed that the manufactured electrode maintained a high level of stability after continuous operation. According to the free radical trapping experiment, EPR, and liquid mass spectrometry analysis, the rational reaction mechanism of p-nitrophenol was finally proposed, in which ·OH and SO₄·^- were considered as the main active oxidants. This work demonstrated the great potential of establishing an electro-Fenton system based on CoFe₂O₄ immobilized self-supporting cathode for environmental remediation.

Catalytic ozonation of dibutyl phthalate in the presence of Ag-doped NiFe2O4 and its mechanism

In this study, NiFe₂O₄ and Ag_0.1Ni_0.95Fe₂O₄ were successfully prepared by the sol-gel method and applied to catalyze ozone for dibutyl phthalate (DBP) degrading. The synthesized catalysts were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, and vibrating sample magnetometer. The removal efficiency was compared with different catalyst dosage, pH condition, and initial DBP concentration for the two catalysts. The results showed that the introduction of Ag_0.1Ni_0.95Fe₂O₄ enhanced the ozone decomposition and the utilization efficiency of ozone from 32.2% (ozone alone) to 56.5% and improved the degradation efficiency of DBP significantly. The two catalysts both presented good recycling performance. Furthermore, the scavenger test displayed DBP degradation by catalytic ozonation dominated by OH in this study. These insights into the catalytic ozonation mechanism on Ag_0.1Ni_0.95Fe₂O₄ will advance their practical application to the catalytic degradation of organic pollutants.