engleski

Laser synthesized colloidal nanoparticles: photocatalysis in a fast lane

Water pollution is one of the greatest environmental problems which is expected to become even larger in the future and occurs due to a large amount of industrial waste material released into natural waters. Photodegradation of pollutants (organic or inorganic) into simpler and non-toxic components using photocatalytic materials is a very promising and widely researched technique for wastewater treatment. TiO2 and ZnO are one of the most examined and promising photocatalytic semiconductor materials due to their low cost, high photocatalytic efficiency and non-toxicity. In this talk, we examined the photocatalytic efficiency of a laser-synthesized colloidal solution of TiO2 and ZnO nanoparticles synthesized by laser ablation in water. Pulsed laser ablation in liquid (PLAL) is a method which allows the synthesis of nanoparticles with very high purity compared to chemically synthesized nanoparticles. Due to its ecological acceptability, PLAL is often referred as the "green method". Photocatalytic degradation of UV-irradiated Methylene Blue and Rhodamine B solutions of different concentrations in the presence of different ZnO catalyst mass concentrations was studied in order to examine their influence on photodegradation rates. ZnO nanoparticles have shown high photocatalytic efficiency, which is limited due to different effects related to UV light transmissivity through the colloidal solution. Photocatalytic photo-degradation rate of Methylene Blue and diazepam under UV-Visible and visible irradiation is measured using crystallized ‘black’ TiO2 nanoparticles as photocatalyst and compared with photocatalysis using commercial Aeroxide P25 TiO2 nanoparticles of the same amount. Crystallized nanoparticles have shown by far the largest photocatalytic activity in visible than P25 for both MB and diazepam. These findings are important for water purification applications of laser-synthesized TiO2 and ZnO nanoparticles.

Laser ablation in liquids ; nanoparticles ; photocatalysis ; ZnO ; TiO2

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