张翼鹏,文杨,薛爽,惠秀娟,张丽娜,王杰.水体冻结过程中荧光物质的迁移转化研究[J].环境科学学报,2015,35(6):1710-1720
水体冻结过程中荧光物质的迁移转化研究
- Migration and transformation of fluorescent materials during water freezing
- 基金项目:国家自然科学基金(No.21107039);辽宁省教育厅科学技术研究项目(No.L2011002);辽宁省科学技术计划项目(No.2011230009)
- 张翼鹏
- 1. 辽宁大学环境学院, 沈阳 110036;2. 沈阳铝镁设计研究院有限公司, 沈阳 110036
- 摘要:本研究利用荧光区域积分法考察了在水体冻结过程中,溶解性有机物(DOM)组分中荧光物质的迁移转化.同时,利用XAD树脂,将DOM分为3个部分:疏水性有机酸(HPO-A)、过渡亲水性有机酸(TPI-A)和亲水性有机物(HPI).结果表明,在水体冻结过程中,HPO-A、TPI-A和HPI的DOC浓度在水相中逐渐增加,而在冰相中先减少后增加,并且这3种DOM组分在冰、水两相间的分配系数排序为:HPI >TPI-A> HPO-A.在水体冻结过程中,水相中HPO-A和HPI的总累计荧光强度(ΦT,n)值,以及冰相中3种DOM组分的总ΦT,n值随冻结时间的变化趋势均为先降低后升高.在水体冻结过程中,水相中3种DOM组分的类腐殖酸荧光峰发生蓝移.冻融作用导致HPO-A和HPI的荧光性降低.与HPO-A和HPI相比,TPI-A的荧光性受冻融作用的影响相对较小.此外,在4类荧光物质中,冻融作用对DOM组分中的类富里酸荧光物质和类腐殖酸荧光物质的影响较显著.
- Abstract:The objective of this study was to investigate the migration and transformation of fluorescent materials in dissolved organic matter (DOM) fractions by means of fluorescence regional integration (FRI) during water freezing. Using XAD resins, DOM was fractionated into 3 fractions: hydrophobic acid (HPO-A), transphilic acid (TPI-A) and hydrophilic fraction (HPI). The results showed that DOC concentrations of HPO-A, TPI-A and HPI in liquid phase increased gradually while those in ice phase initially decreased and then increased during water freezing. Moreover, the partition coefficient of the three DOM fractions between the ice and the liquid phases could be ranked as follows: HPI >TPI-A> HPO-A. The total cumulative excitation-emission matrix (EEM) volume (ΦT,n) in HPO-A and TPI-A in liquid phase, as well as that in three DOM fractions in ice phase initially decreased and then increased with freezing time during water freezing. Humic acid-like fluorescent materials in three DOM fractions in liquid phase exhibited a blue shift of peak position during water freezing. The fluorescence of HPO-A and HPI decreased as a result of freeze/thaw. The freeze/thaw had less effect on the fluorescence of TPI-A than that of HPO-A and HPI. In addition, the effect of freeze/thaw on fulvic acid-and humic acid-like fluorescent materials in DOM fractions was relatively significant among the four types of fluorescent materials.
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