title: Effectiveness and intermediates of microcystin-LR degradation by UV/H2O2via 265 nm ultraviolet light-emitting diodes.
abstract: Although the degradation of cyanotoxins by 254 nm UV/H2O2has been well elucidated, the efficiency and mechanism involved are not necessarily true for other UV wavelengths. The degradation of microcystin-LR (MC-LR), a representative cyanotoxin, was explored by UV/H2O2using 265 nm ultraviolet light-emitting diode (UV-LED). The results indicated that 265 nm UV/H2O2treatment had a high removal efficiency of MC-LR ([MC-LR] = 0.1 μM, apparent rate constants reached 0.2077 min-1, half-time at 3.3 min). The qualitative analyses demonstrated that three novel intermediates, C48H74N10O15(molecular weight = 1030.5335), C36H58N10O14(854.4134), and C33H54N10O14(814.3821), were generated in 265 nm UV/H2O2. Five published intermediates were also confirmed. The generative pathway of these products mainly involved free hydroxyl radical oxidation, resulting in consecutive hydroxyl substitutions and hydroxyl additions of unsaturated bonds in MC-LR. The toxicity of MC-LR was weaken with a relative low mineralization. The electrical energy per order values were calculated to be in the range of 0.00447 to 0.00612 kWh m-3order-1for 100-5000 μg L-1MC-LR. Overall, 265 nm UV-LED/H2O2can be used as an alternative effective technology to improve the removal efficiency of MC-LR in water.
authors.affiliation: School of Environment, Guangzhou Key Laboratory of Environmental Exposure and Health, and Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou, 510632, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Liu
authors.affiliation: School of Environment, Guangzhou Key Laboratory of Environmental Exposure and Health, and Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou, 510632, China.|Lawrence Berkeley National Laboratory, Joint Genome Institute, Walnut Creek, CA, 94598, USA.
authors.forename: Jin-Shao
authors.initials: JS
authors.lastname: Ye
authors.affiliation: School of Environment, Guangzhou Key Laboratory of Environmental Exposure and Health, and Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou, 510632, China. touhuase@jnu.edu.cn.
authors.forename: Hua-Se
authors.initials: HS
authors.lastname: Ou
authors.affiliation: School of Environment, Guangzhou Key Laboratory of Environmental Exposure and Health, and Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou, 510632, China.
authors.forename: Jialing
authors.initials: J
authors.lastname: Lin
mesh_terms: D006861:Hydrogen Peroxide / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry; D052998:Microcystins / Q000737:chemistry*; D010084:Oxidation-Reduction; D014466:Ultraviolet Rays
chemical_list: D052998:Microcystins; D017665:Hydroxyl Radical; D006861:Hydrogen Peroxide
keywords: Cyanotoxin; Drinking water treatment; Hydroxyl radical; Organic matter; Photocatalysis; Toxicology