溶解有机碳
化学
激发态
环境化学
光化学
有色溶解有机物
有机化学
物理
浮游植物
营养物
核物理学
作者
Barbara A. Cottrell,Stephen Andrew Timko,Lianne Devera,Alice K. Robinson,Michael Gonsior,Ashley E. Vizenor,André J. Simpson,William J. Cooper
出处
期刊:Water Research
[Elsevier]
日期:2013-09-01
卷期号:47 (14): 5189-5199
被引量:49
标识
DOI:10.1016/j.watres.2013.05.059
摘要
Laser flash photolysis (LFP) was used to characterize a triplet excited state species isolated from Black River and San Joaquin wetlands particulate organic matter (POM). The solubilized organic matter, isolated from POM by pH-independent diffusion in distilled water, was named PdOM. UV–visible absorption spectroscopy, excitation–emission matrix spectroscopy (EEMs), and 1H NMR were used to characterize the PdOM. While LFP of dissolved organic matter (DOM) is known to generate the solvated electron, LFP of the PdOM transient in argon-, air-, and nitrous oxide-saturated solutions indicated that this was a triplet excited state species (3PdOM*). The lifetime and the reactivity of 3PdOM* with sorbic acid, a triplet state quencher, were compared with that of the triplet excited state of benzophenone, a DOM proxy. A second excited state species (designated DOM*), with a longer lifetime, was reported in a number of previous studies but not characterized. The lifetime of DOM*, measured for seventeen organic matter isolates, lignin, tannic acid, and three wetlands plant extracts, was shown to differentiate allochthonous from autochthonous DOM. 3POM* and DOM* were also observed in lake water and a constructed wetlands' water. Aqueous extracts of fresh and aged plant material from the same wetland were shown to be one source of these excited state species. This study provides evidence of a role for POM in the photochemistry of natural and constructed wetland waters.
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