聚合铝混凝剂凝聚特性及其机理研究

发布时间：2018-05-16 01:41

本文选题：混凝 + 絮体　；参考：《西安建筑科技大学》2013年硕士论文

【摘要】：混凝技术作为水处理中应用广泛的技术之一，在水质净化过程中起到关键作用。铝盐作为最普遍的混凝剂之一，具有处理效果好、成本低的特点。以往的研究主要是围绕以混凝剂投加量为主的定量分析的常规混凝研究，对于混凝剂在投入溶液初期絮体的性质缺乏较科学的认识，对不同条件下影响混凝剂凝聚特性的分析不够全面。因此，这方面的研究显得尤为重要。本文主要探讨了两部分内容：一、影响铝盐化学沉淀物初期絮凝体生成的因素。分析了在添加高氯酸钠的背景下，絮体粒径和Zeta电位的变化；并着重分析从投加混凝剂开始絮凝早期的沉淀物颗粒粒径变化趋势。经研究发现加入高氯酸钠之后胶体颗粒随时间的粒径分布在高氯酸钠浓度较小时，增大趋势不明显，而增大浓度时粒径增长明显。二、在恒定温度条件下不同熟化时间和不同碱化度的聚合氯化铝在不同pH值条件下的化学沉淀物的变化。在加入高氯酸钠的背景下，通过对这些不同条件的絮凝剂在不同pH值下测得的絮体的粒径和Zeta电位的变化的测定，分析了影响聚合氯化铝水化产物絮凝效果的因素；并研究了这些絮凝剂在一定pH值下溶液体系随时间变化的粒径分布。分析发现，颗粒粒径在同一pH值下随着碱化度的增大而增大；在同一碱化度下随着pH值的上升粒径逐渐变大；一小时内粒径的变化也是在碱化度大的情况下幅度较大。而Zeta电位的趋势与粒径相反，在相同pH值下随着碱化度增大而降低，，在相同碱化度下随pH值的上升而降低。另外，通过对上述试验的分析讨论为铝盐混凝剂的混凝机理提供了进一步的试验依据和理论依据。
[Abstract]:As one of the widely used technologies in water treatment, coagulation plays a key role in the process of water purification. As one of the most common coagulants, aluminum salt has the characteristics of good treatment effect and low cost. The previous studies focused on the quantitative analysis of coagulant dosage, and lack of scientific understanding of the properties of coagulant flocs in the initial phase of the solution. The analysis of the effect of coagulant coagulation under different conditions is not comprehensive enough. Therefore, this aspect of research is particularly important. This paper mainly discusses two parts: first, the factors affecting the formation of flocculants in the initial stage of aluminum salt chemical precipitation. The changes of flocs particle size and Zeta potential under the background of adding sodium perchlorate were analyzed, and the variation trend of sediment particle size in the early stage of flocculation was analyzed. It was found that the size distribution of colloidal particles with time was smaller than that of sodium perchlorate, and the increasing trend was not obvious, but the particle size increased obviously when the concentration of sodium perchlorate was increased. Secondly, the change of chemical precipitate of polyaluminium chloride with different aging time and different alkalinity at constant temperature at different pH value. Under the background of adding sodium perchlorate, the factors influencing the flocculation effect of polyaluminium chloride hydration product were analyzed by measuring the particle size and Zeta potential of flocculant under different pH values. The particle size distribution of these flocculants with time at a certain pH value was studied. It is found that the particle size increases with the increase of the alkalinity at the same pH value, the particle size increases with the increase of pH value at the same alkalinity, and the change of the particle size within an hour is larger when the alkalinity is large. However, the trend of Zeta potential is opposite to that of particle size, which decreases with the increase of alkalinity at the same pH value and decreases with the increase of pH value at the same alkalinity. In addition, the analysis and discussion of the above experiments provide further experimental and theoretical basis for the coagulation mechanism of aluminum salt coagulants.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU991.22

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