泥沙沉降对水体中溶解性有机物的影响

发布时间：2018-05-22 16:33

本文选题：溶解性有机物 + 泥沙沉降　；参考：《辽宁大学》2017年硕士论文

【摘要】：为了研究泥沙沉降过程对水体中溶解性有机物的影响,本实验以辽宁省沈阳市新开河为研究对象,考察了泥沙沉降过程中,沉降时间、泥沙含量、pH、盐度等因素对水体中溶解性有机碳(DOC)浓度和水体中溶解性有机物的光谱学特性的影响。实验结果表明,在泥沙沉降过程中,不同的影响因素均会对水体中DOC产生影响。在泥沙沉降的初始阶段,可溶性的腐殖酸与疏水性有机物结合,使水体中可溶性有机物的含量增加。随着泥沙沉降时间的增长,泥沙对水体中有机物的吸附量增加,DOC含量呈现先上升后下降的变化。随着泥沙含量的增加,取样口处水样的DOC含量呈现先下降后上升的趋势。随着pH值的增大,溶解性有机碳的酸性官能团羧基和酚羟基的解离会使其所带的负电荷增多,同时水体中OH-含量不断增加,使得DOC在水体中排斥力增强,不利于带负电荷的颗粒泥沙对DOC进行吸附。盐度的增加,会使水样中DOC含量逐渐减小,且下层水体DOC含量受盐度影响要高于上层水体。随着沉降时间的增加,水样的UV-254呈现出先增大后减小的趋势,SUVA呈先增大后逐渐平衡的状态,水体中芳香性物质含量逐渐达到平衡状态。随着泥沙含量的增加,水样UV-254均表现为先减小后增大,这与相同条件下DOC的变化趋势一致。SUVA先增大后减小,说明水中芳香性有机物的含量先增多后减少。pH值增大,UV-254和SUVA也逐渐增大,并且下层水体的UV-254受酸碱度的影响要大于上层水体。一定盐度范围内,随着盐度的增大,A、B两取样口处水样的UV-254和SUVA逐渐减小,说明水体中芳香性物质在逐渐减少,同时水体中DOM分子量不断减小。三维荧光光谱图表明,不同的影响因素下,泥沙沉降后的水体中所含有的荧光峰主要为类腐殖酸荧光峰和类富里酸荧光峰,还有两个以“峰肩”形式存在的荧光峰,为类溶解性微生物代谢产物荧光峰和类芳香族蛋白质荧光峰。同步荧光光谱图表明,不同的影响因素下,泥沙沉降后的水体中可以看到两个明显的特征峰,分别是激发波长为280~300nm和330~350nm的荧光物质,两荧光峰位于类溶解性微生物代谢产物荧光区和类腐殖酸荧光区。
[Abstract]:In order to study the effect of sediment sedimentation process on dissolved organic matter in water body, this experiment took Xinkai River, Shenyang City, Liaoning Province as the research object, and investigated the settling time in the process of sediment sedimentation. The effects of pH and salinity on the concentration of dissolved organic carbon (DOC) and the spectral characteristics of dissolved organic matter in water were studied. The experimental results show that DOC in water is affected by different factors in the process of sediment sedimentation. In the initial stage of sediment deposition, soluble humic acid combined with hydrophobic organic compounds increased the content of soluble organic matter in water. With the increase of sedimentation time, the amount of organic matter adsorbed by sediment increased and the content of DOC increased first and then decreased. With the increase of sediment content, the DOC content of the water sample at the sampling port decreased first and then increased. With the increase of pH value, the dissociation of carboxyl groups and phenolic hydroxyl groups of dissolved organic carbon will increase the negative charge, and the content of OH- in water will increase continuously, which makes the repulsion of DOC in water enhanced. It is unfavorable for the negatively charged particles to adsorb DOC. With the increase of salinity, the content of DOC in the water will gradually decrease, and the content of DOC in the lower water will be more affected by salinity than that in the upper water. With the increase of sedimentation time, the UV-254 of water samples increased first and then decreased, and the content of aromatic substances in water gradually reached equilibrium. With the increase of sediment content, the UV-254 of water samples decreased first and then increased, which was consistent with the change trend of DOC under the same conditions. The results showed that the content of aromatic organic matter in water increased at first and then decreased. The increase of pH value and the increase of UV-254 and SUVA also increased gradually, and the UV-254 of the lower water was more affected by pH than that of the upper water. In a certain range of salinity, the UV-254 and SUVA of water samples decreased with the increase of salinity, indicating that the aromatic substances in water gradually decreased and the molecular weight of DOM in water decreased. Three-dimensional fluorescence spectra showed that the fluorescence peaks in the sediment subsidence water were mainly humic acid-like fluorescence peaks and similar fulvic acid-like fluorescence peaks, and there were two fluorescence peaks in the form of "peak shoulder". It is the fluorescence peak of metabolites of dissolvable microorganisms and aromatic proteins. The synchronous fluorescence spectra show that two distinct characteristic peaks can be seen in the water after sediment deposition under different influence factors, namely, the excitation wavelength of 280~300nm and the fluorescence of 330~350nm. The two fluorescence peaks were located in the fluorescence region of metabolites of dissolved microorganisms and the fluorescence region of humic acid.
【学位授予单位】：辽宁大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X52;TV142.1

【参考文献】