title: Monitoring of TiO2-catalytic UV-LED photo-oxidation of cyanide contained in mine wastewater and leachate.
abstract: 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 CO3(2-), 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.
authors.affiliation: Department of Earth and Environmental Sciences and Research Institute of Natural Science (RINS), Gyeongsang National University, Jinju 660-701, Republic of Korea.
authors.forename: Seong Hee
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Earth and Environmental Sciences and Research Institute of Natural Science (RINS), Gyeongsang National University, Jinju 660-701, Republic of Korea.
authors.forename: Sang Woo
authors.initials: SW
authors.lastname: Lee
authors.affiliation: Department of Information and Statistics and Research Institute of Natural Science (RINS), Gyeongsang National University, Jinju 660-701, Republic of Korea.
authors.forename: Gye Min
authors.initials: GM
authors.lastname: Lee
authors.affiliation: School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, Republic of Korea.
authors.forename: Byung-Tae
authors.initials: BT
authors.lastname: Lee
authors.affiliation: Department of Earth and Environmental Sciences and KU-KIST Green School (Graduate School of Energy and Environment), Korea University, Seoul 136-701, Republic of Korea.
authors.forename: Seong-Taek
authors.initials: ST
authors.lastname: Yun
authors.affiliation: Department of Earth and Environmental Sciences and Research Institute of Natural Science (RINS), Gyeongsang National University, Jinju 660-701, Republic of Korea. Electronic address: sokim@gnu.ac.kr.
authors.forename: Soon-Oh
authors.initials: SO
authors.lastname: Kim
mesh_terms: D002384:Catalysis; D003486:Cyanides / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D017665:Hydroxyl Radical; D008027:Light; D008906:Mining; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D010777:Photochemistry / Q000379:methods; D014025:Titanium / Q000032:analysis*; D062065:Wastewater; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D003486:Cyanides; D017665:Hydroxyl Radical; D010100:Oxygen; D014025:Titanium; D062065:Wastewater; D014874:Water Pollutants, Chemical; C009495:titanium dioxide
keywords: Cyanide; Hydroxyl radical; Photo-catalyst; Photo-oxidation; Titanium dioxide; UV-LED