DOI: 10.1016/j.watres.2018.06.018
Scopus记录号: 2-s2.0-85049301938
论文题名: Wavelength-dependent chlorine photolysis and subsequent radical production using UV-LEDs as light sources
作者: Yin R. ; Ling L. ; Shang C.
刊名: Water Research
ISSN: 431354
出版年: 2018
卷: 142 起始页码: 452
结束页码: 458
语种: 英语
英文关键词: Chlorine photodecay
; Model
; Radical formation
; UV-LED
; Wavelength-dependency
Scopus关键词: Chlorine
; Chlorine compounds
; Light emitting diodes
; Models
; Photolysis
; Quantum yield
; Rate constants
; Water treatment
; Fluence-based rate constant
; Hydroxyl radicals
; Hypochlorous acids
; Molar absorption coefficient
; Radical formation
; Radical generation
; Radical production
; Wavelength dependency
; Alkalinity
; chlorine
; hydroxyl radical
; hypochlorite
; hypochlorous acid
; radical
; absorption coefficient
; chlorine
; electrode
; hydroxyl radical
; model
; organic acid
; photolysis
; ultraviolet radiation
; water treatment
; wavelength
; absorption
; alkalinity
; Article
; pH
; photolysis
; priority journal
; quantum yield
; rate constant
; ultraviolet C radiation
; ultraviolet radiation
; water treatment
英文摘要: UV-LEDs are considered as the most promising UV light sources, because it has the potential to replace conventional UV lamps in some water treatment applications in the foreseeable future. In this study, UV-LEDs at four wavelengths in the UV-C or near UV-C range (i.e., 257.7, 268, 282.3, and 301.2 nm) were used to investigate the wavelength-dependency on chlorine photolysis and its subsequent radical formation. The fluence-based photodecay rates of hypochlorous acid (HOCl) and hypochlorite (OCl−) were monotonically correlated to their molar absorption coefficients and quantum yields, and the chlorine photodecay rates were much more significantly affected by molar absorption coefficients (β = 0.949) than quantum yields (β = 0.055). An empirical model that incorporated the chlorine photodecay rate constants, quantum yields, and molar absorption coefficients of HOCl and OCl− was established, validated and then used to predict the chlorine photodecay rate at any wavelength (257.7–301.2 nm) and pH (5−10). The modelling results suggested that the maximum fluence-based rate constant (1.46 × 10−4 m2 J−1) was obtained at 289.7 nm and pH 9.95. The wavelength dependency was larger at alkaline pH than at acidic pH, and the pH dependency was the largest at the longest wavelength. The formation of hydroxyl radicals (HO·) and reactive chlorine species (RCS) decreased with increasing wavelength at pH 6, and increased with increasing wavelength at pH 7. More HO· was formed at pH 6 than pH 7, but RCS showed the opposite pH-dependency. The findings in this study provide the fundamental information in selecting UV-LEDs with specific wavelength for enhancing/optimizing chlorine photodecay and/or its radical generation at different pHs in real-world applications. © 2018 Elsevier Ltd Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/112621
Appears in Collections: 气候减缓与适应
There are no files associated with this item.
作者单位: Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong; Hong Kong Branch of Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
Recommended Citation:
Yin R.,Ling L.,Shang C.. Wavelength-dependent chlorine photolysis and subsequent radical production using UV-LEDs as light sources[J]. Water Research,2018-01-01,142