Publication Date:
2013-04-26
Description:
This study evaluates the photoactivity of novel zeolite-based TiO 2 composites modified with metal particles for the photoreduction of Cu 2+ , depending on the zeolite and metal particles (Ag or Fe) content and to establish the photoreduction mechanism. The composites have been prepared by incorporating zeolite particles in the sols during the sol-gel preparation of the TiO 2 , followed by impregnation of the gels in solutions containing metal ions. The zeolite-based TiO 2 composites have been characterized using X-ray diffraction, Raman and FTIR spectroscopy techniques and TEM microscopy. The role of zeolite particles in the photoreduction process was demonstrated by using different kinetic models. The apparent constant rate for photoreduction increases in direct proportion with the content of zeolite and is higher for the composites modified with Fe than for those modified with Ag nanoparticles. The results demonstrate that composites have a higher photocatalytic efficiency than TiO 2 . The experiments in this study reveal that the migration of Cu 2+ in solution occurs rapidly and that the diffusion through the film on the composite's surface and, subsequently, the photoreduction process are the rate limiting steps. The role of the zeolite in photoreduction is to diminish the recombination rate of the charge carriers.
Print ISSN:
1546-542X
Electronic ISSN:
1744-7402
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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