【作者】 王晓娜；

【导师】 岳钦艳；

【作者基本信息】 山东大学 ， 环境工程， 2011， 博士

【摘要】 新型、高效水处理药剂与材料始终是水处理环保产业技术领域中重点发展的支柱产业,也是水工业与水污染治理工程技术与设备创新发展的基础产业。季铵化阳离子聚丙酰胺作为一种新型高效的有机阳离子絮凝剂成为目前国内外研究的热点。本论文在综合国内外大量相关文献的基础上,以丙烯酰胺(AM)、二甲基二烯丙基均聚物(PDMDAAC)为原料,用分散聚合法合成了AM/DMDAAC阳离子共聚物。主要研究适合于DMDAAC和AM共聚的分散体系,选择适用的稳定剂、介质、交联剂等,确定其配比。研究了阳离子型高聚物PDMDAAC-AM共聚物的最佳制备工艺,通过测定反应时间与转化率的关系研究DMDAAC和AM分散聚合反应的动力学。同时对PDMDAAC-AM的结构形貌进行分析表征,并且评价了其应用效果。为PDMDAAC-AM分散乳液聚合奠定理论基础,并为开发应用提供理论指导。主要内容及结果如下：1、采用分散聚合法制备阳离子絮凝剂PDMDAAC-AM,以硫酸铵的水溶液作为分散聚合的反应介质,铵盐的质量分数为总体的18%左右,所得产品比较稳定。考察其他因素对分散体系的影响,选择单体浓度在15%-22.5%范围内,稳定剂采用PVP+PD的复合型分散稳定剂,用量占体系质量的2.1%。采用V50为引发剂,投加量为单体质量的0.01%-0.04%,可以得到符合实验目的的共聚物产品。2、考察了介质极性、单体浓度、单体配比、引发剂浓度、引发温度等影响因素对产物转化率和特性粘度的影响,得出分散聚合法制备PDMDAAC-AM的最佳反应条件为：nAW:nDMDAAC=8:2, Cmonomer (wt%)=40%, Cinitiator (wt%)0.04%,乙醇含量=50%and引发温度为40℃。在该条件下,可制得特性黏度为98 cm3/g,易分离提纯,溶解迅速,絮凝效果较好的产品。加入EDTA可加快反应速度,提高产品的转化率和特性黏度(分子量)。3、考察了AM和DMDAAC分散乳液聚合和反相乳液聚合动力学实验,发现在分散乳液聚合中,聚合反应速率随着AM与DMDAAC摩尔比、单体浓度、稳定剂浓度、引发剂浓度和温度的增加而增加。特性粘度随着AM与DMDAAC摩尔比和单体浓度的增加、稳定剂和引发剂浓度的减少而增加。聚合反应速率与单体浓度、单体摩尔配比、分散稳定剂浓度、引发剂浓度四个因素线性相关,具体关系如下：Rp∝[M]1.44[I]0.60[S]0.39, [η]∝[M]1.26[I]-0.13[S]-0.36。在反相乳液聚合中,AM与DMDAAC摩尔比、单体浓度、乳化剂浓度、引发剂浓度对聚合反应速率的影响与分散聚合的相似,特性粘度随着AM与DMDAAC摩尔比、单体浓度和乳化剂浓度的增加,引发剂浓度的减少而增加,其动力学关系式为：Rp∝[M]2.11[I]1.21[E]0.48,[η]∝[M]0.87[I]-0.30[E]0.36。采用膨胀计法测定DMDAAC和AM反相乳液溶液聚合的表观活化能为20.33 kJ/mol,水溶液聚合的表观活化能为29.05 kJ/mol,分散聚合的表观活化能为37.38 kJ/mol。4、分散聚合颗粒生成和增长机理主要倾向于齐聚物沉淀机理和接枝共聚物聚结机理。在分散乳液聚合体系中单体AM和DMDAAC的竞聚率分别是6.664和0.120。AM的竞聚率比DMDAAC的竞聚率要高,表明在分散体系中AM比DMDAAC更容易发生均聚合。5、用红外光谱、核磁共振、透射电镜、扫描电镜、热分析、粒度测定仪等多种现代分析仪器和方法对分散乳液聚合法合成的有机阳离子共聚物PDMDAAC-AM的形貌结构进行了分析表征。结果表明,单体DMDAAC和AM发生了共聚,由单体转变成了聚合物。分散乳液聚合法合成的阳离子共聚物PDMDAAC-AM在溶液中呈现分散状分布的小球,反应生成的大分子在这些小球内继续与残余单体反应,同时有利于生成热的散失,使反应不易发生暴聚,对比水溶液聚合和反相乳液聚合,显示出分散乳液聚合法的特点和优点。6.PDMDAAC—AM带有的正电荷中和污泥所带的负电荷而使污泥颗粒脱稳,易于脱水,处理效果明显优于聚合氯化铁无机絮凝剂。在污泥絮凝脱水实验中还发现,阳离子含量高的产品(2:8与1:9比较)无论是在比阻抗还是脱水率的表现中都有更好的效果。但是,阳离子度的提高会使产品粘度下降,价格上升。因此,针对不同的处理对象,可以采用不同配比的产品,以达到最佳性价比。PDMDAAC—AM的除浊效果表明,PDMDAAC—AM兼有电中和与吸附架桥两种性能。一般来说,阳离子度越高,特性黏度越大,除浊效果越好。更多还原

【Abstract】 Coagulation/flocculation is a widely used process for particle removal in water and wastewater treatment. Quaternary ammonium cationic polyacrylamide become the focuses of research at home and abroad at present as a new high-efficiency organic cationic flocculant. Synthetizing references, cationic copolymer acrylamide-dimethyldiallyl ammonium chloride (PDMDAAC-AM) was synthesized from acrylamide (AM) and dimethyldiallyl ammonium chloride (DMDAAC) by dispersion polymerization. The dispersion system was selected to facilitate the polymerization of AM and DMDAAC. The experiments have been done to choose the applicative stabilizer, medium, cross-linking agent etc and determine their ratio.The optimum operating conditions for preparing PAM-DMDAAC were determined. Kinetics of dispersion polymerization of AM and DMDAAC were researched by measuring the relationship of reaction time and conversion. The structures of the product PDMDAAC-AM were investigated by varies physical chemistry methods. And its application in wastewater was assessed.The main contents and results are following:1. The cationic polyacrylamide was synthesized by dispersion polymerization using the solution of ammonium sulfate as the reaction medium. When the concentration of ammonium sulfate was about 18%, the obtained product was stable. The effect of the other factor on dispersion system were investigated, the monomer concentration of 15%～22.5%, using PVP+PD as composite stabilizer whoes concentration of 2.1% of the system mass, using V50 as initiator whose concentration of 0.01%～0.04% of monomer mass. 2. The effects of various polymerization parameters (e.g., concentration of monomer and initiator, medium polarity, the ratio of AM to DMDAAC, initial temperature and ethylene diamine tetraacetic acid disodium (EDTA)) on the intrinsic viscosity and conversion of copolymer have been investigated. The optimum operating conditions for preparing PAM-DMDAAC were determined as ethanol content 50%, [M] (wt%) 40%, nAM:nDMDAAC 8:2, [I] (wt%) 0.04% and initiate temperature 40°C. On these conditions, the synthesized copolymer with the intrinsic viscosity of 98 cm3/g could be separated, purified and dissolved easily. Adding EDTA can accelerate reaction rate and increase conversion and intrinsic viscosity (molecular weight).3. Kinetics of dispersion polymerization and inverse emulsion polymerization of AM and DMDAAC were investigated. In dispersion polymerization, The rate of polymerization (Rp) increased with the increasing of the molar ratio of AM to DMDAAC, concentrations of monomers, stabilizer and initiator and temperature. The intrinsic viscosity increased with the increasing of the molar ratio of AM to DMDAAC and concentration of monomers and the decreasing of concentrations of stabilizer and initiator. The rate of polymerization and intrinsic viscosity can be represented by Rp∝[M]1.44[I]0.60[S]0.39, [η]∝[M]1.26[I]-0.13[S]-036. In inverse emulsion polymerization, the influences of the molar ratio of AM to DMDAAC, concentrations of monomers, emulsion and initiator on polymerization is similar with dispersion polymerization. The intrinsic viscosity increased with the increasing of the molar ratio of AM to DMDAAC and concentrations of monomers and emulsion and the decreasing of concentration of initiator. Its kinetics can be expressed as Rp∝[M]2.11[I]1.21[E]0.48, [η]∝[M]0.87[I]-0.30[E]0.36. The overall activation energy for the rate of polymerization was determined with a dilatometer as 20.33 kJ/mol in inverse emulsion polymerization,29.05 kJ/mol in solution polymerization,37.38 kJ/mol in dispersion polymerization.4. The mechanism of particle generation and propagation in dispersion polymerization is inclined to oligomer precipitation mechanism and grafted copolymer coalescence mechanism. The monomer reactivity ratios of AM (r1) and DMDAAC(r2) were determined by the application of Fineman-Ross methods as 6.664 and 0.120, respectively, The analysis of reactivity ratios revealed that DMDAAC is less reactive than AM, and copolymers formed are statistically in nature.5. The characteristics of polymers synthesized in dispersion polymerization were studied by means of various instrumental analysis techniques, including including infrared spectroscopy, Transmission Electron Microscope, Scanning electron microscopy, thermal analysis et al. The results show that the monomers DMDAAC and AM turn into the copolymer PAM-DMDAAC. The dispersion polymerization is helpful to heat exchange of reaction because of its merits of emulsion.6. The positive charge of PDMDAAC-AM can neutralize the negative charge of sludge particles and leave the sludge off the stable and dehydration. The treatment effect is better than inorganic coagulant ferric chloride polymer. In sludge dewatering experiment it was found that products with high cation degree (2:8 compared with 1:9) have better results both in the dehydration rate and the resistance. However, the increasing of cationic degree can decrease the viscosity of product and raise the prices. Therefore, the products with different ratio can be used to achieve the best cost performance when treating different objects. The turbidity removel of PDMDAAC-AM showed that PDMDAAC-AM had two properties of electricity neutralization and adsorption bridging. In general, the higher the cationic degree and intrinsic viscosity is, the better the turbidity removel is.更多还原