The effect of concentration and origin of dissolved organic matter (DOM) on acenaphthene (Ace) photodegradation in liquid water and ice was investigated, and the components in DOM which were involved in Ace photodegradation were identified. The DOM samples included Suwannee River fulvic acid (SRFA), Elliott soil humic acid (ESHA), and an effluent organic matter (EfOM) sample. Due to the production of hydroxyl radical (OH) and triplet excited-state DOM (DOM*) which react with Ace, DOM had promotion effects on Ace photodegradation. However, the promotion effects of DOM were prevailed over by their suppressing effect of DOM including screening light effect, intermediates reducing effect and RS quenching effect, and thus, the photodegradation rates of Ace decreased in the presence of the three DOM with concentrations of 0.5–7.5 mg C/L in liquid water and ice. ESHA had higher light absorption and thus had higher screening light effect on Ace photodegradation in liquid water than SRFA and EfOM. At each DOM concentration, ESHA exhibited higher promotion effect on Ace photodegradation than SRFA and EfOM, in liquid water and ice. The binding of Ace with DOM was indicated by decreases in fluorescence intensity of Ace when coexisted with DOM. However, the binding of Ace to DOM played an unimportant role in suppressing Ace photodegradation. The photodegradation behavior of fluorophores in Ace with DOM present in ice was not similar to that in liquid water. C–O, C═O, carboxyl groups O–H and aliphatic C–H functional groups in DOM were involved in the interaction of DOM with Ace. The presence of Ace seemed to have no influence on the photodegradation behavior of functional groups in DOM.

中文翻译：

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溶解有机物在液态水和冰中苊光降解中作用的光谱研究

研究了液态水和冰中溶解有机物(DOM)的浓度和来源对苊(Ace)光降解的影响，并鉴定了DOM中参与Ace光降解的成分。 DOM 样品包括苏万尼河黄腐酸 (SRFA)、埃利奥特土壤腐植酸 (ESHA) 和流出物有机物 (EfOM) 样品。由于与Ace反应生成羟基自由基(OH)和三重激发态DOM(DOM*)，DOM对Ace的光降解有促进作用。然而，DOM的促进作用被DOM的抑制作用所压倒，包括屏蔽光效应、中间体还原效应和RS猝灭效应，因此，在浓度为0.5-3的DOM存在下，Ace的光降解率降低。液态水和冰中为 7.5 mg C/L。 ESHA具有较高的光吸收率，因此对液态水中的Ace光降解具有比SRFA和EfOM更高的遮光作用。在液态水和冰中，在每个 DOM 浓度下，ESHA 对 Ace 光降解的促进作用均高于 SRFA 和 EfOM。当与 DOM 共存时，Ace 的荧光强度降低表明 Ace 与 DOM 的结合。然而，Ace 与 DOM 的结合在抑制 Ace 光降解方面发挥的作用并不重要。冰中存在 DOM 的 Ace 中荧光团的光降解行为与液态水中的光降解行为不同。 DOM中的C-O、C=O、羧基O-H和脂肪族C-H官能团参与了DOM与Ace的相互作用。 Ace 的存在似乎对 DOM 中官能团的光降解行为没有影响。