Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
47202 | Applied Catalysis B: Environmental | 2010 | 6 Pages |
The microwave specific effect(s) that can impact a microwave-assisted and photo-assisted reaction occurring on the surface of ZnO or TiO2 (P-25) particles was (were) examined by comparing the process occurring under rich magnetic field conditions and under magnetic/electric field conditions. The features of the photo-assisted process in the presence of microwaves rich in a magnetic field (H) and an electric field (E) are described on the basis of (i) the degradation dynamics of 4-chlorophenol (4-CP) at ambient temperatures, (ii) the number of OH radicals produced, and (iii) the dielectric properties of the metal oxides (in pellet form). For ZnO, the photoactivity is enhanced by a microwave specific non-thermal (i.e. non-caloric) effect originating from the microwaves’ magnetic field, but decreased by the thermal (i.e. caloric) factor originating from the microwaves’ electric field. Contrary to ZnO, the photoactivity of TiO2 (P-25) was enhanced by the synergistic effect between the magnetic and electric fields of the microwave radiation. Photocorrosion of ZnO in the aqueous dispersions was negligibly small (<0.05%) under UV, MW-EH, and UV/MW-EH irradiation conditions.
Graphical abstractMicrowave specific effects originating from either the magnetic and/or electric field of the microwaves that may impact the photoactivity of TiO2 and ZnO have been examined in the photodegradation of the 4-chlorophenol toxin.Figure optionsDownload full-size imageDownload as PowerPoint slide