【作者】 刘颖；

【导师】 张代钧；

【作者基本信息】 重庆大学 ， 环境工程， 2002， 硕士

【摘要】 混凝过程（混合、凝聚、絮凝）是水处理工艺中应用最普遍的关键环节之一，在使用该法处理废水时，药剂费占处理成本的50%。因此，对于高效、廉价的混凝剂的研制开发工作一直受到人们的关注。铝盐作为生活用水、工业用水和工业废水处理剂已得到广泛应用，为了提高其电荷中和能力或增强其配位能力，可以在聚合铝中引入其它离子而形成复合型聚铝盐。本文以硫酸铝、水玻璃等为原料采用共聚法（将一定的NaOH加入到不同Al/Si摩尔比和硅酸聚合度的混合液）和复合法（按一定的Al/Si摩尔比将不同聚合度的硅酸加入到不同碱化度的聚合硫酸铝溶液）两种制备方法研制出具有不同硅酸聚合度、碱化度（B）、Al/Si摩尔比的新型絮凝剂聚合硅酸硫酸铝（PASiS）。本文采用Al-Ferron逐时络合比色法和显微电泳技术对PASiS进行研究,探讨了制备方法和参数变化对PASiS形态分布和水解产物荷电特征的影响，并将PASiS用于水处理实验。实验结果表明，聚硅酸和铝水解聚合物发生相互作用生成了聚合度更大的铝硅络合物，已经发生水解聚合作用的铝水解产物以及高聚合度的硅酸的络合作用能力较小。PASiS仍是以羟基聚合物为主要形态分布，当B=1、Al/Si摩尔比为2.5、硅酸聚合时间为150min时，PASiS的ζ电位高于PAS。B值对PASiS的铝水解形态分布和絮凝效果有较大影响，在0.5～1.5范围内B值的增加有助于生成聚合度更大的多羟基聚合体和提高絮凝性能；Al/Si摩尔比和硅酸聚合状态对PASiS的铝水解形态分布和絮凝效果有一定影响，在适当的Al/Si摩尔比和硅酸聚合状态条件下，PASiS的絮凝效果良好。PASiS的絮凝效果优于PAC、PAS、PASC、PAM等絮凝剂，又以共聚法制备的PASiS的絮凝效果好于复合法制备的PASiS。 通过铝水解形态、ζ电位和絮凝性能分析，本文得出PASiS具有良好的电中和和吸附架桥能力，但以吸附架桥和网捕沉淀为PASiS主要絮凝机理。在此基础上，推测PASiS中聚硅酸与铝水解聚合产物主要以下面两种方式相互作用：一种方式为聚硅酸直接与铝水解产物中的羟基成氢键连接(Si-O…HO-Al)，生成[Alx(OH)y]H3SiO4(3x-y-1)+等，这种结构较为牢固。另一方面聚硅酸可能与铝水解产物中的铝以氧桥连接(Si-O-A)形成大的络合物分子，在微量滴定的过程中，"SiO4"结构取代“AlO4”结构形成类似于Al12AlO4(OH)247+的SiO4Al12（OH）248+结构，这种键合方式更为牢固。最后实验得出，聚合硅酸硫酸铝（PASiS）混凝剂不是一种化合物，而是一种聚硅酸与聚铝的水解络合产物再聚合后的混合物，PASiS在起絮凝作用时，是由铝水解络合物与含硅氧基的络合物及聚硅酸共同作用的，絮凝效果与这三部分的含量和形态有关。在水处理中不同碱化度、硅酸聚合度及Al /Si摩尔比的PASiS表<WP=5>现出不同的絮凝性能，具体情况应视处理水样的不同而有所不同。更多还原

【Abstract】 Coagulation is an important technology used generally in water treatment. The cost of coagulants approximately accounts for 50 percent of the total cost of the water treatment. Therefore, the researches of high efficient、cheap coagulants have been concern. Polyaluminum salt have been widely used as water treatment agent for living, industrial water service and industrial effluent. To improve its abilities of neutralizing electric charge or complexing, it is effective to introduce some other ions into polyaluminum salt to form polyblend of aluminum salt. A series of polyaluminum silicate sulfate (PASiS) with different basicities（B）、Al/Si molar ratios and polymerization degree of silicic acid were prepared by means of two kinds of preparation methods: one is to add NaOH into Al2(SO4)3 and polysilicic acid mixed solution at different Al/Si molar ratios and polymerization degree; the other is to add polysilicic acid with different polymerization degree into polyaluminum sulfate(PAS) solution with different basicities（B） at Al/Si molar ratios.The effects of aluminum species distribution and charged characteristic of hydrolysis products of PASiS prouced by various preparation methods and factors were investigated by the Al-Ferron timed complex colorimetric methodand the micro -electrophoresis method. Then PASiS were applied in the wastewater treatment. The experimental results show that the interaction between polysilicic acid and hydrolysis aluminum species in PASiS forms aluminum-silicate polymer composite with larger size polymer. But it is difficult to the hydrolyzed aluminum species and the large polymerization degree of silicic acid to interact with each other. The multinuclear hydroxy aluminum is still the major species in PASiS. Especially the ζ-potential of this PASiS with B=1, Al/Si=2.5,t=150min is higher than that of PAS. B has agreat effect on the distribution of aluminum species andζ-potential and flocculation property. With the B value increasing in the range of B=0.5～1.5, the larger polymer aluminum-silicate composite would form, the better flocculation efficiency would be. But the more B would make silicic acid coagulate. Al/Si molar ratio and polymerization degree of silicic acid also effect on the distribution of aluminum species of PASiS. <WP=7>Through studies of the species and ζ-potential and flocculation property, it was suggested that PASiS has the favorable abilities of charge neutralization and absorption -bridging, and absorption-bridging is the dominate mechanism. The interaction patterns between silicic acid and hydrolysis aluminum has two ways: one is that silicic acid interact directly with hydroxyl of hydrolysis aluminum by hydrogen bond(Si-O...HO-Al) to form the structure such as [Alx(OH)y]H3SiO4(3x-y-1)+; the other is that silicic acid bind the hydrolysis aluminum by oxygen bridge (Si-O-Al). During the microtitration, the structure "SiO4"would partly take the palace of the structure"AlO4" to form the larger polymer molecule such as [SiO4Al12(OH)248+], which is similar to Al12AlO4(OH)247+.PASiS flocculant is not a compound but a mixture, which included polymeric aluminum-silicate composite and polysilicic acid and polymeric hydrolyzed aluminum species. In the wastewater treatment, it is polymeric aluminum-silicate composite and polysilicic acid and polymeric hydrolyzed aluminum species that took effect together. The flocculation properties of PASiS are related to the contents and species of the three parts above. PASiS with different B and Al/Si molar ratio and polymerization degree of silicic acid would show different flocculation properties in the treatment of different water and wastewater.The PASiS could be good flocculating efficiency only at a proper Al/Si molar ratio and polymerization degree of silicic acid. The PASiS has better flocculation property than PAS, and the PASiS prepared by the copolymerization technique has better flocculation property than the PASiS prepared by the composite technique.更多还原