Photo-Oxidation of Ammonia to Molecular Nitrogen in Water under UV, Vis and Sunlight Irradiation

Titanium dioxide-based photocatalysts have been used to perform the photo-oxidation of ammonium/ammonia to molecular nitrogen. Different light sources were employed, i.e., UV, LED visible light and natural sunlight, and their performance was compared in order to understand which setup was the most efficient. It was found that under selected conditions, the LED lamp, in combination with silver-promoted TiO2, was able to push the conversion of ammonium toward 48% after 4 h of reaction time. On the other hand, with a more powerful UV lamp, lower conversion was achieved, ca. 40%. Natural sunlight under the same conditions attained more than 38% conversion, but the fluctuation of the reaction conditions remain a very critical issue for the real exploitation of sunlight in water treatment.

Automated summary

The combination of LED lamp and silver-promoted TiO2 was found to be the most efficient way for the photo-oxidation of ammonium to molecular nitrogen, achieving a conversion rate of 48%. A lower conversion rate of approximately 40% was achieved with a more powerful UV lamp. While natural sunlight could reach over 38% conversion, the fluctuation of reaction conditions remains a critical issue.