A photo-oxidation process using UV-LEDs and TiO2 was studied for removal of cyanide contained in mine wastewater and leachates. This study focused on monitoring of a TiO2-catalyzed LED photo-oxidation process, particularly emphasizing the effects of TiO2 form and light source on the efficiency of cyanide removal. The generation of hydroxyl radicals was also examined during the process to evaluate the mechanism of the photo-catalytic process. The apparent removal efficiency of UV-LEDs was lower than that achieved using a UV-lamp, but cyanide removal in response to irradiation as well as consumption of electrical energy was observed to be higher for UV-LEDs than for UV-lamps. The Degussa P25 TiO2 showed the highest performance of the TiO2 photo-catalysts tested. The experimental results indicate that hydroxyl radicals oxidize cyanide to OCN-, NO2-, NO3-, HCO3-, and CO32-, which have lower toxicity than cyanide. In addition, the overall efficacy of the process appeared to be significantly affected by diverse operational parameters, such as the mixing ratio of anatase and rutile, the type of gas injected, and the number of UV-LEDs used.
Bibliographical noteFunding Information:
This research was supported by the Basic Science Research Program through the National Research Foundation (NRF) of Korea funded by the Korean Ministry of Education (grant number: 2012R1A1A4A01001692 ).
© 2015 Elsevier Ltd.
- Hydroxyl radical
- Titanium dioxide
ASJC Scopus subject areas
- Public Health, Environmental and Occupational Health
- General Chemistry
- Health, Toxicology and Mutagenesis
- Environmental Engineering
- Environmental Chemistry