【摘要】 环境条件的变化能够影响和改变溶解态有机质（DOM）的组成结构及化学特征，进而影响其生物地球化学循环过程。采用同步荧光光谱、三维荧光光谱、傅里叶变换红外光谱（FTIR）,结合二维相关光谱分析方法，研究了pH条件变化对DOM特性及其与Cu²⁺相互作用的影响。结果表明，（1）随着pH值由5逐渐升高至10, DOM不同组分的荧光强度显著增强，其中类腐殖酸组分变化最显著，类富里酸组分变化最优先，这是由于pH的变化引起的醛酮、酚基、羧基等相关基团暴露导致的。（2）荧光光谱二维相关分析表明，pH的改变能够显著地影响DOM不同组分与Cu²⁺的结合能力，但并不能影响其结合顺序。三维荧光光谱结合平行因子分析共解析出3个荧光组分，荧光组分的淬灭曲线非线性拟合结果更是定量验证了这一结果。（3）FTIR结果表明高pH条件下DOM与Cu²⁺结合点位更多，结合强度更强。pH 5和pH 10条件下DOM官能团与Cu²⁺的结合顺序分别依次为：多糖C—O>酚基>醛酮CO>芳香族C—H和多糖C—O>酰胺Ⅱ带C—N>酚基>脂肪族C—H>醛酮CO>羧基C—OH>芳香族C—H>羧基CO。荧光光谱和FTIR的异谱二维相关分析进一步表明Cu²⁺与DOM类腐殖酸组分的相互作用滞后于酚基和芳基等基团。更多还原

【Abstract】 Changes in environmental conditions could alter the composition structure and chemical properties of dissolved organic matter（DOM）, then affect its biogeochemical cycling processes. In this study, synchronous fluorescence spectroscopy, three-dimensional fluorescence spectrum, and Fourier transform infrared spectroscopy（FTIR） combined with two-dimensional correlation spectroscopy were applied to evaluate the effect of pH on DOM characteristics and its interaction with Cu²⁺.（1） Our results suggested that the fluorescence intensity of different DOM components increased remarkably along with the pH value increasing from 5 to 10. Humic-like components showed the most significant changes, and fulvic-like components responded fastest to pH changes. It was caused by pH changes induced exposure of some functional groups, such as carbonyl, phenolic, and carboxyl.（2） Two-dimensional correlation analysis of fluorescence spectra revealed that changes in pH could significantly affect the Cu²⁺-binding capacity of different DOM components but could not affect the binding sequence to Cu²⁺ with DOM. Three fluorescent components were identified by parallel factor analysis of the three-dimensional fluorescence spectrum. The nonlinear fitting of quenching curve for fluorescent components quantitatively verified our results.（3） FTIR results showed that, under hinger pH conditions, DOM has more binding sites and stronger binding affinities with Cu²⁺. The structural change of DOM upon Cu²⁺ addition under pH 5 and 10 conditions followed the order ofpolysaccharide C—O>phenols>aldehyde and ketone CO>aromatic C—H and polysaccharide C—O>amide II C—N>phenols>aliphatic C—H>aldehyde and ketone CO>carboxyl C—OH>aromatic C—H>carboxyl CO, respectively. Furthermore, two-dimensional hyperspectral correlation analysis of fluorescence spectra and FTIR indicated that humic-like fractions of DOM participated in the Cu²⁺binding after the phenolic and aryl groups.更多还原