共价键型有机硅铝复合絮凝剂的制备及其混凝性能研究

发布时间：2018-01-18 10:33

本文关键词：共价键型有机硅铝复合絮凝剂的制备及其混凝性能研究　出处：《西安建筑科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：混凝沉淀技术是饮用水处理以及废水处理常用的单元操作，其效果主要是取决于所使用混凝剂的种类和性能。无机-有机复合型高分子絮凝剂兼具有无机絮凝剂和有机絮凝剂二者的优点，可以提高絮凝效果，并降低处理成本，更重要的是有利于去除某些新兴特殊污染物。因此絮凝剂研发的一个新的热点是将有机组分和无机组分用共价键的形式组合为复合型的高分子。论文采用了3-三乙氧基硅基丙基三甲基氯化铵以及氯化铝合成了一种新型的共价键型高分子絮凝剂。通过向硅铝絮凝剂中引入特定的强碱性离子交换基团，使得絮凝剂在混凝过程中不但可以去除水中憎水性的大分子物质，还可以去除小分子的溶解性物质双氯芬酸和水杨酸。应用多种现代分析方法包括红外光谱、透射电镜、zeta电位测定等，系统地研究了共价键型有机硅铝复合絮凝剂的制备参数包括碱化度、Si/Al摩尔比等。对于絮凝剂的结构形态及荷电特征的影响，并对絮凝剂除浊脱色性能进行了验证，最后研究了共价键型有机硅铝复合絮凝剂对双氯芬酸和水杨酸的混凝去除效果。以3-三乙氧基硅基丙基三甲基氯化铵做为硅源的共价键型有机硅铝复合絮凝剂具有较高的稳定性。当总铝浓度（AlT）是0.2mol/L时，该共价键型复合高分子絮凝剂能够在Si/Al摩尔比为0.6、B值为2.5时仍然保持稳定。和常规的硅铝系复合絮凝剂相比，这类共价键型复合高分子絮凝剂能够保持稳定的Si/Al摩尔比上限以及B值上限有了大幅提高。另外由红外光谱可知，制备出的新型絮凝剂中的有机组分和无机组分是通过共价键结合的，并且强碱性离子交换基团是通过此共价键嫁接于絮凝剂中的。对共价键型有机硅铝复合絮凝剂物化特性的评价结果表明，制得的共价键型有机硅铝复合絮凝剂均为酸性，其本身pH值随着Si/Al摩尔比和B值的增大而升高；该絮凝剂的zeta电位随Si/Al摩尔比增大而逐渐升高，随着B值的增大而逐渐降低。由透射电镜结果可知，当B值为2的共价键型有机硅铝复合絮凝剂聚集体较较容易形成网状的密实结构，当B值为2.5的共价键型有机硅铝复合絮凝剂中存在一些游离的聚合体，其聚合体尺度通常在几十到几百纳米之间。共价键型有机硅铝复合絮凝剂对于常规污染物质的絮凝性能十分优异，可高效去除水中的浊度和色度。B值和Si/Al摩尔比对该新型絮凝剂的混凝效果都有着明显的影响。共价键型有机硅铝复合絮凝剂可以高效去除水中的药品及个人护理品（PPCPs）代表物，而常规絮凝剂对于这类物质几乎不能去除。该新型絮凝剂对与双氯芬酸的去除效果是随着Si/Al摩尔比及B值的增大而增大，去除效果基本不受体系pH影响。当双氯芬酸配水浓度接近环境浓度时，该新型絮凝剂仍有很好的去除效果，这表明该絮凝剂将在未来的水处理领域能发挥应用作用。
[Abstract]:Coagulation and sedimentation technology is a common unit operation for drinking water treatment and wastewater treatment. The effect mainly depends on the kind and performance of the coagulant used. Inorganic-organic compound polymer flocculant has the advantages of both inorganic flocculant and organic flocculant which can improve the flocculation effect. And reduce the processing cost. More importantly, it is beneficial to remove some new special pollutants. Therefore, a new hot spot of flocculant research and development is to combine the composition and inorganic components in the form of covalent bonds into composite polymers. In this paper, a novel covalent polymer flocculant was synthesized by using 3-triethoxysilylpropyl trimethyl ammonium chloride and aluminum chloride, and a specific strong basic ion exchange group was introduced into the silicon-aluminum flocculant. The flocculant can not only remove hydrophobic macromolecular substances, but also the dissolvable substances diclofenac and salicylic acid in the coagulation process. The preparation parameters including alkalinity of covalently bonded organosilicon-aluminum composite flocculant were systematically studied by transmission electron microscope (TEM) and Zeta potential measurement. The effects of Si/Al molar ratio on the structure morphology and charge-charge characteristics of flocculant were investigated and the decolorization performance of flocculant was verified. Finally, the coagulation removal effect of diclofenac and salicylic acid was studied. The covalent organosilica-aluminum composite flocculant with 3-triethoxysilylpropyl trimethyl ammonium chloride as silicon source has high stability when the total aluminum concentration is 0.2 mol / L. The covalently bonded composite polymer flocculant can remain stable when the molar ratio of Si/Al is 0.6nb = 2.5.Compared with the conventional Si-Al composite flocculant. This kind of covalent composite polymer flocculant can maintain stable upper limit of Si/Al molar ratio and upper limit of B value. The organic and inorganic components of the new flocculant are bound by covalent bond, and the strong basic ion exchange group is grafted to the flocculant by this covalent bond. The evaluation of the physical and chemical properties of covalently bonded organosilica-aluminum composite flocculants shows that the covalent organosilica-aluminum composite flocculants are all acidic. The pH value increases with the increase of Si/Al molar ratio and B value. The zeta potential of the flocculant increases with the increase of Si/Al molar ratio and decreases with the increase of B value. When the B value is 2, the covalent organosilicon-aluminum composite flocculant aggregates are easy to form the network dense structure, when B value is 2.5, there are some free polymers in the covalently bonded organosilicon-aluminum composite flocculant. The size of the polymer is usually in the range of tens to hundreds of nanometers. Covalently bonded organosilicon-aluminum composite flocculants have excellent flocculation performance for conventional pollutants. The turbidity, chroma. B value and Si/Al molar ratio of the new flocculant can be effectively removed. Covalently bonded organosilica-aluminum composite flocculant can effectively remove the drugs in water. Personal Care products (. PPCPs). The effect of the new flocculant on the removal of diclofenac and diclofenac increased with the increase of Si/Al molar ratio and B value. When the concentration of diclofenac was close to the environmental concentration, the new flocculant still had a good removal effect. This indicates that the flocculant will play an important role in the field of water treatment in the future.
【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】：2014
【分类号】：TU991.22;X703.5

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