标题: Binding of Calcium and Magnesium Ions to Terrestrial Chromophoric Dissolved Organic Matter (CDOM): A Combination of Steady-State and Time-Resolved Fluorescence Study

作者: Liu, J (Liu, Juan); Zhou, RY (Zhou, Ruiya); Zhang, X (Zhang, Xu)

来源出版物: WATER卷: 13期: 16文献号: 2182 DOI: 10.3390/w13162182出版年: AUG 2021

摘要: Revealing the binding properties of calcium ion (Ca2+) and magnesium ion (Mg2+) to terrestrial chromophoric dissolved organic matter (CDOM) facilities understanding the effect of natural water components on the photophysics of dissolved organic matter. Steady-state and time-resolved fluorescence spectrometry, and dynamic light scattering were applied to investigate the fluorescence quenching process of CDOM by Ca2+ and Mg2+. Due to a remarkable decrease of the steady-state fluorescence intensity and a slight decrease of fluorescence lifetime, the fluorescence quenching of CDOM by cations mainly occurred through a static process. The fluorescence quenching was profound under longer excitation and emission wavelengths. The binding constant (K, L/mol) for Ca2+ to CDOM ranged from 4.29 to 5.09 (lgK), which was approximately one order of magnitude higher than that of Mg2+ to CDOM (3.86 to 4.56). Nevertheless, the efficiency of CDOM fluorescence quenching by Ca2+, Mg2+ was much lower than that by Cu2+. Fluorescence decay became faster in the presence of a high concentration of Ca2+ (>20 mg/L) and Mg2+ (>50 mg/L). In the presence of these two metal ions, particularly for Ca2+, the lifetime of CDOM excited states shifted to the relatively small value side, indicating fluorescence quenching of CDOM mainly occurred through the interaction of Ca2+/Mg2+ with relatively long-lived fluorophores.

入藏号: WOS:000689974300001

语言: English

文献类型: Article

作者关键词: CDOM; calcium; magnesium; fluorescence quenching; lifetime distribution

地址: [Liu, Juan; Zhou, Ruiya; Zhang, Xu] Wuhan Univ, Sch Resources & Environm Sci, Dept Environm Sci, Wuhan 430079, Peoples R China.

通讯作者地址: Zhang, X (通讯作者)，Wuhan Univ, Sch Resources & Environm Sci, Dept Environm Sci, Wuhan 430079, Peoples R China.

电子邮件地址: juanliu@whu.edu.cn; ruiyazhou@whu.edu.cn;xuzhangwhu@gmail.com

影响因子：3.103