磷在高岭土、腐殖酸及海洋沉积物上的吸附行为研究

发布时间：2018-05-04 22:36

  本文选题：磷 + 吸附　； 参考：《中国海洋大学》2014年硕士论文

【摘要】：营养盐是海洋环境质量监测的重要内容之一。海水中的磷是引起水体富营养化、赤潮等的主要营养元素之一，水体中的磷量过多会导致藻类过量繁殖进而引起水质恶化，严重破坏水体的生态平衡，威胁到水生生物的生存以及人类的健康。海洋中的沉积物能够吸附水体中的磷减缓水体的富营养化进程，尤其是沉积物中的自然胶体部分（粘土矿物、有机质及活性金属水合氧化物），其能够通过一系列物理化学反应，如吸附、络合、共沉淀等作用，从水体中富集包括磷在内的多种污染物及其他有毒物质，，对水体中磷的迁移转化发挥着极其重要的作用；另外，沉积物吸附的磷在一定条件下又可释放到水体中，严重时导致水体富营养化，造成二次污染。由于海洋中的沉积物，尤其是沉积物中的粘土矿物和有机质，其对磷的吸附作用对水体富营养化的控制发挥着非常重要的作用，因此研究沉积物、粘土矿物及有机质对磷的吸附作用具有重要的意义。 本论文研究了盐度和温度变化对磷酸盐在高岭土、腐殖酸上吸附的影响。并从长江口邻近海域采集沉积物，研究了沉积物自身性质（粒度、HCl处理去除碳酸盐、H2O2处理去除有机质等）及环境因素（介质中有机质浓度、pH等）对海洋沉积物吸附磷的影响。 主要结论如下： （1）高岭土的零净质子电荷点pHPZNPC约为3.8，离子强度对高岭土的pHPZNPC基本没有影响。高岭土对磷的动力学吸附过程用伪二级动力学方程描述较好，温度越高，高岭土对磷的吸附速率越大。等温吸附曲线用Langmuir等温式拟合较好，磷的吸附量随温度的升高、盐度的降低而增加。磷在高岭土上的吸附是自发、吸热、熵增加的过程。 （2）腐殖酸（HA）的零净质子电荷点pHPZNPC在3.5~5.8之间，离子强度对腐殖酸的pHPZNPC影响较大。腐殖酸对磷的动力学吸附过程用伪二级动力学方程描述较好，温度越高，腐殖酸对磷的吸附速率越大。等温吸附曲线用Langmuir等温式拟合较好，磷的吸附量随盐度的增加而增加；在15~25℃范围内，温度对磷在腐殖酸上的吸附量几乎没有影响；与腐殖酸原样相比，不溶NSW腐殖酸对磷的吸附能力增大。 （3）沉积物对磷的吸附可用伪二级动力学方程描述，沉积物粒度越小、初始磷浓度越大，对磷的吸附速率越大。由于沉积物一般含内源磷，等温吸附曲线可用Langmuir-交叉型等温式拟合，且拟合结果最好，磷的吸附量随粒度减小而增加。沉积物经HCl处理除去碳酸盐之后，对磷的吸附能力增强；经H2O2处理除去有机质之后，对磷的吸附能力减弱。在高浓度的HA介质中，沉积物对磷的吸附量与介质中HA的浓度正相关。pH对沉积物吸附磷的影响较为复杂：pH5时，随着pH的升高，沉积物对磷的吸附量逐渐增加；pH在5~9范围内，随着pH的升高，沉积物对磷的吸附量降低；pH9时，随着pH的升高，沉积物对磷的吸附量增加，且pH约为7~9范围内存在“稳定pH范围”。
[Abstract]:Nutrient is one of the important contents of marine environmental quality monitoring. Phosphorus in sea water is one of the main nutrient elements, such as eutrophication and red tide. Excessive phosphorus content in water will lead to algal overproduction and water quality deterioration, which will seriously damage the ecological balance of water body. It threatens the survival of aquatic organisms and human health. Sediments in the ocean can absorb phosphorus from water bodies to slow down the process of eutrophication, especially the natural colloidal parts of sediments (clay minerals, organic matter and active metal hydrated oxides), which can undergo a series of physical and chemical reactions. Such as adsorption, complexation, coprecipitation and so on, the enrichment of various pollutants, including phosphorus, and other toxic substances from the water body plays an extremely important role in the transport and transformation of phosphorus in the water body. Phosphorus adsorbed by sediment can be released into water under certain conditions, which can lead to eutrophication and secondary pollution. Because sediments in the ocean, especially clay minerals and organic matter in sediments, play a very important role in controlling eutrophication of water bodies, the adsorption of phosphorus by them plays a very important role in controlling eutrophication of water bodies. The adsorption of phosphorus by clay minerals and organic matter is of great significance. The effects of salinity and temperature on phosphate adsorption on kaolin and humic acid were studied. The effects of sediment properties (removal of carbonate and H _ 2O _ 2 by HCl treatment) and environmental factors (concentration of organic matter in medium, pH, etc.) on phosphorus adsorption in marine sediments were studied. The main conclusions are as follows: 1) the zero net proton charge point (pHPZNPC) of kaolin is about 3.8, and the ionic strength has no effect on the pHPZNPC of kaolin. The kinetic adsorption process of phosphorus on kaolin is described by pseudo-second-order kinetic equation. The higher the temperature, the higher the adsorption rate of phosphorus. The isothermal adsorption curve was fitted well by Langmuir isothermal equation. The adsorption capacity of phosphorus increased with the increase of temperature and the decrease of salinity. Phosphorus adsorption on kaolin is a spontaneous, endothermic and entropy increasing process. (2) the zero net proton charge point (pHPZNPC) of humic acid (HA) is in the range of 3.5n5.8.Ionic strength has a great effect on the pHPZNPC of humic acid. The kinetic adsorption process of humic acid on phosphorus was described by pseudo-second-order kinetic equation. The higher the temperature, the higher the adsorption rate of phosphorus. The isothermal adsorption curve was fitted well by Langmuir isothermal equation, and the adsorption capacity of phosphorus increased with the increase of salinity, and the temperature had little effect on the adsorption capacity of phosphorus on humic acid at 1525 鈩

本文编号：1845001