【作者】 冯欣蕊；

【导师】 蒋绍阶；

【作者基本信息】 重庆大学 ， 市政工程， 2014， 博士

【摘要】 混凝是重要的水处理工艺之一，混凝剂的开发是混凝工艺的核心技术，混凝剂的优劣是决定混凝效果甚至整个水处理效果的关键因素。随着水和废水处理规模的迅猛发展，对混凝剂的质量和品种需求也越来越大。开发新型高效低耗、安全无害的混凝剂以提高水处理效果、降低成本一直是水处理领域的研究重点。聚合氯化铝-聚二甲基二烯丙基氯化铵（PAC-PDMDAAC）杂化絮凝剂是基于聚合氯化铝较强的电中和作用和聚二甲基二烯丙基氯化铵有机高分子絮凝剂优异的吸附架桥能力的协同作用而开发的新型高效絮凝剂。与传统的无机絮凝剂相比，它具有絮体形成快，颗粒密度大，沉降速度快等特点，且无二次污染，高效低耗，适用范围广，可取代价格昂贵的有机高分子絮凝剂。PAC-PDMDAAC杂化高分子絮凝剂有着良好的发展和应用前景，可以用于饮用水处理和纺织、印染废水等处理工艺中。论文的主要研究内容和结论如下:（1）采用原位聚合法以聚合氯化铝、二甲基二烯丙基氯化铵为原料，以过硫酸铵为引发剂制备了离子型PAC-PDMDAAC杂化絮凝剂，并进行Box-Behnken中心组合实验和响应面分析，得出最佳制备条件：DMDAAC质量分数为37%，引发剂质量分数为0.6%，反应温度为75℃，反应时间为5h。在对絮凝剂结构表征分析中，FT-IR及TGA测试结果表明杂化絮凝剂有机-无机组分间是由PDMDAAC链端（-SO42-）与带正电荷的羟基铝粒子以离子键性质键合。SEM结果显示，杂化絮凝剂PAC-PDMDAAC颗粒尺寸和比表面积均比其复合型絮凝剂更大。（2）采用溶胶-凝胶法以硅烷偶联剂KH570为无机改性剂，以聚合氯化铝、二甲基二烯丙基氯化铵为原料，以过硫酸铵为引发剂制备了共价型PAC-PDMDAAC杂化絮凝剂，并用响应面设计预测并根据实际情况得到最优制备条件为：DMDAAC质量分数为33%，引发剂质量分数为0.6%，反应温度为64℃，反应时间为3h。在对絮凝剂结构表征分析中，电导测试、FT-IR、13C-NMR及TGA结果表明PAC-PDMDAAC杂化絮凝剂的有机-无机组分间以共价键形式键合，性质稳定；其SEM照片显示其结构疏松，粒度较大。（3）分别通过高岭土模拟水的混凝烧杯实验和硅藻土模拟水的量筒沉降实验，考察了PAC和自制两种杂化絮凝剂的电中和能力和絮凝性能。高岭土模拟水的混凝烧杯实验结果表明，两种PAC-PDMDAAC杂化絮凝剂的电中和能力突出。硅藻土模拟水的量筒沉降实验结果表明，两种PAC-PDMDAAC杂化絮凝剂的絮体粒度和沉降速度明显高于PAC，絮凝性能优异。对重庆嘉陵江和长江原水的混凝效果表明，两种杂化型絮凝剂对浊度、UV254和CODMn均表现出优异的去除效果。（4）使用激光粒度分析仪对杂化絮凝剂处理高岭土模拟水样进行混凝动态过程研究，采用两种杂化絮凝剂时，随投加量的增加，pH越接近中性，形成的絮体粒径越大。相比PAC，形成稳定絮体所需时间短。两种杂化絮凝剂絮体抗剪切强度高于PAC，且在相同条件下恢复能力强。随破碎时间的延长，杂化絮凝剂形成絮体的强度因子和恢复因子均呈下降趋势。（5）应用扫描电子显微镜对杂化絮凝剂絮凝后絮体进行观察，将絮体分为絮粒、絮团和絮网三个不同的生长阶段,通过假设颗粒结合位置符合正四面体,建立了絮体结构模型,在一定程度上能够反映杂化高分子絮凝剂絮凝高岭土颗粒生成的絮体结构。更多还原

【Abstract】 Coagulation process has already become one of the most important part in watertreatment. The core technology of coagulation process is the development of flocculants,which determined not only the flocculation effect but also the entire water treatmenteffect. Currently, because of the continuous decrease of water resources and theincreasing discharge scale of wastewater, the composition of contaminants in water ismore complex and the harm to the environment is increasing. Development of newefficient quality flocculants to improve flocculation effect in water treatment, reducecosts and expand new application fields, has already become the focus of research inwater treatment field.Polyaluminum chloride-poly diallyl dimethyl ammonium chloride (PAC-PDMDAAC) hybrid flocculant is a new efficient flocculant which is developed basedon the strong electric neutralization capacity of PAC and the excellent adsorptionbridging capacity of PDMDAAC. Compared with traditional inorganic flocculant, it hascharacteristics of fast floc formation, high particle density and fast settling velocity. Inaddition, this new hybrid flocculant has no secondary pollution, high efficiency withlow cost, and can replace expensive organic polymer flocculant. PAC-PDMDAAChybrid flocculant has excellent prospects for development and application. It will playan important role in drinking water, textile wastewater and dyeing wastewater treatmentprocesses.The main contents and conclusions in this study are as follows:(1) The ionic bond PAC-PDMDAAC hybrid flocculant was prepared by usingpolyaluminum chloride and diallyl dimethyl ammonium chloride as raw materials,ammonium persulfate as the initiator in situ hybridization method. The Box-Behnkenmathematical relational model was established and response surface analysis wasintroduced. The optimum preparation conditions were: DMDAAC mass fraction37%,initiator mass fraction0.6%, reaction temperature75℃and reaction time5h. FT-IRand TGA test results showed that the organic and inorganic components were connectedby ionic bond between the chain end of PDMDAAC (-SO42-) and hydroxy aluminumparticles which had positive charges. SEM results showed the particle size and specificsurface area of PAC-PDMDAAC hybrid flocculant were larger than PAC-PDMDAACcomposite flocculant. (2) The covalent bond PAC-PDMDAAC hybrid flocculant was prepared by usingKH570as modifying agent, polyaluminum chloride and diallyl dimethyl ammoniumchloride as raw materials, ammonium persulfate as the initiator in sol-gel method. Theresponse surface analysis was introduced. The optimum preparation conditions were:DMDAAC mass fraction33%, initiator mass fraction0.6%, reaction temperature64℃and reaction time3h. In the flocculant structural characterization analyzes,conductivity, FT-IR,13C-NMR and TGA results showed there was covalent bondbetween organic and inorganic components in PAC-PDMDAAC hybrid products. ItsSEM photograph showed the hybrid flocculant had loose structure and large particlesize.(3) Through coagulation experiment of kaolin simulated water and sedimentationexperiment of diatomite simulated water, the charge neutralization and flocculatingperformance of PAC and two kinds of hybrid flocculants were investigated. The kaolincoagulation experiment showed that the charge neutralization capacity of ionic bondPAC-PDMDAAC hybrid flocculant was the strongest. While charge neutralizationcapacity of covalent bond hybrid flocculant was also more prominent. In thesedimentation experiment of diatomite simulated water, these two kinds of hybridflocculant had larger floc size and higher sedimentation rate than PAC, which playedexcellent flocculating performance. In coagulation tests of Chongqing Jialing River andthe Yangtze River, the two hybrid flocculants showed excellent removal efficiencies onturbidity, UV254and CODMn.(4) Coagulation dynamic process of kaolin simulated water was studied by usinglaser particle size analyzer. The floc size was larger with the increase of dosage and thepH close to neutral when these two hybrid flocculants were used. Compared with PAC,the stable floc formation time was shorter in hybrid flocculants. In the same shear forces,these two kinds of hybrid flocculants had stronger shear resistances and recoverycapabilities than PAC. As the extension of broken time, the strength factors andrecovery factors of the two kinds of hybrid flocculants decreased.(5) The flocs of hybrid flocculants after flocculation were observed by scanningelectron microscope. Flocs could be divided into three different stages. By assumingthat the particle-bond location met regular tetrahedron, floc structure model wasestablished， which to some extent reflected the floc structure of kaolin particles byhybrid flocculants.更多还原