扰动条件下不同尺度磷形态数量分布的研究

发布时间：2019-01-20 13:33

【摘要】：扰动引起的沉积物再悬浮对于水体中磷的迁移转化有着重要影响。粒径作为沉积物及悬浮物重要的物理特性之一,对磷的吸附沉降起着非常重要的作用。但目前对于不同粒径分布条件下的水体中磷的迁移转化规律研究甚少,,并且,粒径变化对水体中磷特别是不同尺度磷有何影响也不得而知。因而研究不同粒径分布条件下磷在上覆水中的分布规律、不同尺度形态磷数量分布以及不同粒级沉积物中磷形态数量分布对于了解各种不同赋存形态的磷在不同物理条件下的水体及沉积物中的分布规律有重要意义。本研究不仅在一定程度上丰富了磷在自然水体中的迁移转化规律,也能为实际中的水体的改善修复提供一定的数据支持和理论依据。研究发现,静止状态下,上覆水中悬浮物粒径分布变化不明显,但间歇扰动下,上覆水中粒径分布及上覆水中各不同磷形态含量发生明显变化,其中大颗粒粒径有明显增加的趋势。说明间歇扰动促使大粒径颗粒在上覆水中的平均占比增加。并且,通过粒径变化与上覆水中磷形态数量变化的相关性分析可知,静置水体中粒径变化与磷形态数量变化无明显相关关系,而有间歇扰动水体中两者有较好的相关性,说明上覆水中粒径分布对磷形态数量分布有很大影响。另外,通过对外源磷实验组中粒径分布与磷数量的数据分析,外源磷加入的情况下,小粒径对外源磷的吸收率增加了95%,而大粒径对外源磷的吸收率仅增加20%,说明扰动下小粒径颗粒对磷的吸附占主要地位。在通过上述实验验证了磷形态数量分布和悬浮物粒径有良好的相关性的基础上,将研究细化到上覆水中不同尺度的磷形态数量分布及不同粒级沉积物中磷形态数量分布。研究发现,将四种滤膜的孔径差划分为3种尺度,其中A2尺度在多数情况下具有最大的持磷数量优势,这可能和扰动条件及A2尺度中微粒自身特性有关。而从DIP占TP贡献率角度来说,静置样中DIP/TP值在A2尺度中为最高,而扰动样中DIP/TP值在A3尺度中为最高,这可能与不同粒径微粒对于磷的固定能力不同有关。通过对于不同粒级沉积物中不同赋存形态磷的含量分析可知,从Tot-P角度来讲,扰动致使底泥对磷的吸收能力强于静止条件;粒级越小的沉积物中总磷含量越高,吸收能力越强。从不同粒级沉积物中NH4Cl-P角度来说,扰动条件下的E2和E4中粒级越小吸收的NH4Cl-P的含量越高,而仅存在外源磷加入的静置组E3中NH4Cl-P各粒径吸收量无明显规律。从不同粒级沉积物中Fe/Al-P角度来说,仅为扰动样的E2中Fe/Al-P吸收能力随着粒级减小而变弱。E3中吸收能力随着粒级减小而变强。E4中条件复杂,粒级对于Fe/Al-P吸收规律不明显。从不同粒级沉积物中Ca-P角度来说,静置水样中不同粒级对于Ca-P吸收无明显差异,而扰动水样中显示为粒级2对于Ca-P的吸收量最高。
[Abstract]:The sediment resuspension caused by disturbance has an important effect on the transport and transformation of phosphorus in water. As one of the important physical properties of sediments and suspended solids, particle size plays a very important role in the adsorption and sedimentation of phosphorus. However, there are few studies on the transport and transformation of phosphorus in water under different particle size distribution conditions, and it is not clear how the change of particle size affects phosphorus in water, especially in different scales. Therefore, the distribution of phosphorus in overlying water under different particle size distribution conditions was studied. The quantitative distribution of phosphorus forms in different scales and in sediments of different grain sizes is of great significance in understanding the distribution of phosphorus in water and sediment under different physical conditions. This study not only enriches the law of phosphorus migration and transformation in natural water to a certain extent, but also provides certain data support and theoretical basis for the improvement and restoration of water body in practice. It was found that the particle size distribution of suspended matter in overlying water did not change obviously under static condition, but the particle size distribution and phosphorus content in overlying water changed obviously under intermittent disturbance. Among them, the size of large particles increased obviously. The results show that intermittent disturbance increases the average percentage of large particle size in overlying water. Through the correlation analysis of particle size change and phosphorus form quantity change in overlying water, it can be seen that there is no obvious correlation between particle size change and phosphorus form quantity change in static water body, but there is good correlation between them in intermittent disturbance water body. The results show that the particle size distribution of overlying water has a great influence on the distribution of phosphorus species. In addition, through the analysis of the data of the particle size distribution and the amount of phosphorus in the experimental group of exogenous phosphorus, the absorption rate of exogenous phosphorus increased by 95% for small particle size, and only 20% for large particle size. The results show that the adsorption of phosphorus by small particle size is dominant under disturbance. On the basis of the above experiments, it was verified that there was a good correlation between the distribution of phosphorus species and the particle size of suspended solids, and the study was carried out on the basis of refinement of the quantitative distribution of phosphorus forms to different scales in overlying water and the quantitative distribution of phosphorus forms in sediments of different grain sizes. It is found that the pore size difference of the four kinds of membranes is divided into three scales, and the A2 scale has the largest phosphorus holding advantage in most cases, which may be related to the disturbance conditions and the characteristics of the particles in the A2 scale. From the point of view of the contribution of DIP to TP, the DIP/TP value of stationary sample is the highest in A2 scale, while the DIP/TP value of disturbed sample is the highest in A3 scale, which may be related to the different fixation ability of different particle size to phosphorus. According to the analysis of phosphorus content in different sediment forms, from the point of view of Tot-P, the phosphorus absorption ability of sediment is stronger than that of static condition. The smaller the grain size is, the higher the total phosphorus content is and the stronger the absorption capacity is. From the point of view of NH4Cl-P in different granular sediments, the content of NH4Cl-P in E _ 2 and E _ 4 was higher than that in E _ (2) and E _ (4), but there was no obvious regularity of the absorption of NH4Cl-P in the static group E3 with exogenous phosphorus. From the point of view of Fe/Al-P in different granular sediments, the absorption capacity of Fe/Al-P in E2, which is only disturbed, becomes weaker with the decrease of grain size, and the absorption capacity in E3 becomes stronger with the decrease of grain size. The conditions in E4 are complex. The grain-level absorption of Fe/Al-P was not obvious. From the point of view of Ca-P in different grain-grade sediments, there was no significant difference in Ca-P uptake between static water samples and disturbed water samples, but the highest Ca-P uptake was observed in disturbed water samples.
【学位授予单位】：苏州科技学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X52

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