Characterization and Reactivity of MnO_x Supported on Mesoporous Zirconia for Herbicide 2,4-D Mineralization with Ozone

Abstract

Manganese oxide was supported on mesoporous zirconia (MnO x / MZIW) by wet impregnation, drying, water washing, and calcinations with manganese acetate tetrahydrate as the metal precursor for the first time and was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fouriertransform infrared spectra (FTIR), temperature-programmed reduction (TPR), temperature-programmed oxygen desorption (O 2 -TPD), and UV-vis diffuse reflectance spectra (UV-vis DRS) measurements. The catalyst was found to be highly effective for the mineralization of 2,4-dichlorophenoxyacetic acid (2,4-D) aqueous solution with ozone. The characterization studies showed that nonstoichiometrically MnO x was highly dispersed on mesoporous zirconia by the strong interaction of the [Mn(H 2 O) 6 ] 2+ complex with surface hydroxyls of the support. Moreover, the multivalence oxidation states of MnO x enhanced the electron transfer, causing the higher catalytic reactivity. On the basis of all information obtained under different experimental conditions, MnO x /MZIW enhanced the mineralization of 2,4-D by the formation of • OH radicals resulting from the catalytic decomposition of ozone.

Enhanced inhibition of bromate formation in catalytic ozonation of organic pollutants over Fe–Al LDH/Al2O3

“…Recently, there are increasing interests on catalytic ozonation with various catalysts to improve the oxidation efficiency of ozonation [11][12][13]. Our and other studies have verified that more reactive oxygen species were generated from the interaction of ozone and surface Lewis acid sites of catalysts [14][15][16].…”

Superparamagnetic Fe3O4 nanoparticles as catalysts for the catalytic oxidation of phenolic and aniline compounds

“…To confirm the existence of hydroxyl free radical, tert-butanol, a strong radical scavenger [44], was added into the solution just before reaction. Fig.…”

The Application and Reaction Mechanism of Catalytic Ozonation in Water Treatment

“…The structure and dispersion of the catalysts are affected by the preparation method, so good catalyst preparation process can significantly improve the catalytic activity. Currently, the supports for heterogeneous system are including Al 2 O 3 , TiO 2 , active carbon, and clay; the active components are Fe, Co, Mn, Cu, Ni and so on [35,37,44,[77][78][79][80][81][82][83][84][85][86]. The results show that the supported catalysts give excellent activity during the ozone decomposition.…”