【作者】 王熙；

【导师】 唐宏科；

【作者基本信息】 陕西科技大学 ， 分析化学， 2012， 硕士

【摘要】 接枝类淀粉改性高分子絮凝剂是近年来发展较快的一种高效絮凝产品，研究人员利用淀粉分子上的多羟基结构，通过自由基反应引入具有絮凝效应的单体和一些具有多种功能的单体，使淀粉不仅获得良好的絮凝效果，同时又有其他的作用效果。本研究以淀粉分子为主体，通过水溶液聚合引入丙烯酰胺、乙酸乙烯酯等功能性单体，并利用羟甲基化反应使产物阳离子化，合成新型的疏水缔合阳离子淀粉接枝絮凝剂。由于疏水单体的引入，不仅大大的提高了絮凝效率，而且利用疏水基团的疏水亲油的特性，可以轻易使含油废水破乳除油，对含油量较大的废水有良好的吸附絮凝效果，同时疏水基团提高了絮团的脱水能力，使滤饼强度增加，易于絮凝沉降。本研究先采用单因素实验来考察单体质量比、引发剂浓度、反应温度、反应时间等因素对絮凝产品的影响，随后在较好的范围内采用正交实验的方式确定疏水缔合淀粉絮凝剂的最佳工艺条件为：淀粉单体比为1:2.5，加入溶剂量为体系总量的92%，引发剂量为单体量的1.25%，在60℃下反应时间为3小时，其中疏水单体量占总单体量的10%，互溶剂乙醇用量为1ml；阳离子化实验中，采用单因素法确定羟甲基化反应的最佳工艺条件为：质量配比丙烯酰胺：甲醛：二甲胺=1:1:1.5，反应温度为60℃，时间为2h，制得的疏水缔合阳离子淀粉絮凝剂的接枝率可达125.91%，接枝效率也可达到92.47%，胺化度为68.7%，分子量为38.4万，并利用红外光谱仪对接枝共聚物的组成和结构进行表征，证明了接枝共聚物的存在。对絮凝剂产品进行絮凝性能测试，测试结果显示，该絮凝剂处理废水时用量较少，效率高，pH适应范围较广，在碱性环境下的絮凝性能较好，但温度和离子浓度对其絮凝性能有一定的影响，高温下会使絮凝效果大幅下降；将研究制得的絮凝剂产品分别应用于造纸废水，油田废水、电镀废水和生活废水中，并与接枝不同疏水单体的同类絮凝剂产品进行比较发现，该絮凝剂对浊度和悬浮物（SS）去除率均优于其他产品，因此对造纸和电镀废水有较好的处理效果；而接枝长链烷烃的絮凝剂则对含油量较高的油田废水有着良好的絮凝效果。对比发现，疏水基团烷烃较长的疏水性强，但不宜接枝，处理有机成分较多的污水效果较好，短烷烃的疏水基团有一定的疏水性，接枝效果好，适于对各种水质废水的絮凝处理。更多还原

【Abstract】 For their efficient flocculation, the grafted starch-modified polymerflocculants were developed rapidly in recent years.Because there is amulti-hydroxyl structure in the starch molecular, the monomer withflocculation effect and variety of function can be introduced in the starchmolecules by free radical reactions, and then the starch can not only showgood flocculation effect, but also can show other effects. In this study, thestarch molecules is treated as the main, the functional monomer such asacrylamide, vinyl acetate is introduced by solution polymerization, andthe product is made cationic by the hydroxymethylation reaction, then anew hydrophobic association cationic starch graft flocculant issynthesized. The introduction of the hydrophobic monomer, not onlygreatly improve the flocculation efficiency, and the oily wastewater canbe emulsion breaking easily by using of the characteristics of thelipophilic of the hydrophobic groups, and the better adsorption andflocculation effect can be made on the larger oil content wastewater, onthe other hand, the hydrophobic group can improve the dewateringcapacity of the flocculant, so that the cake’s strength is increased, and canbe easily flocculation and sedimentation.In this study, the effect of the monomer ratio, initiator concentration,reaction temperature, reaction time and other factors on the flocculationproducts is studied by single factor experiments, then the optimumconditions is determined by orthogonal text: the ratio of the weight of thestarch and monomer is1:2.5, the amount of solvent is92%of the totalsystem, the amount of the initiator is1.25%of the amount of monomer, the reaction time is3hours at60℃, the amount of hydrophobicmonomers is10%of the total monomer amount, the amount of mutualsolvent ethanol is1ml; in the cationic experiment, the optimal conditionsis determined by the single factor method: the mass ratio of acrylamide:formaldehyde and Dimethylamine is1:1:1.5, the reaction temperature is60°C, the time is2h, the grafting rate of the hydrophobically associatingcationic starch flocculant can reach125.91%, the grafting efficiency canreach92.47%, the degree of amination was68.7%, The molecular weightis about384,000, and the structure of the graft copolymer is characterizedby infrared spectroscopy and the existence of a graft copolymer.is provedA test of the flocculation performance of the flocculant products ismade, and the results show that: the amount of the products is small inwastewater treating, and the flocculation efficiency is higher, it adapt to awider range of the pH, and performance better in an alkaline environment,but the temperature and ion concentration have a certain impact on theflocculation performance, high temperatures make the flocculationefficiency dropped significantly; then the flocculant products are used inpulp and paper effluent, oilfield wastewater, electroplating wastewaterand domestic wastewater, and is compared with the flocculant productsgrafting with different hydrophobic monomers, and the result show thatthe removal efficiency of turbidity and SS of the flocculant is superior toother products, so it has a better treatment effect on pulp and papereffluent and electroplating wastewater; while the flocculant productsgrafting with long-chain alkanes does a good job in the oilfieldwastewater. The result of the comparison show that the hydrophobicity ofthe flocculant products grafting with long-chain alkanes is strong, but it ishard to synthesis, and the flocculant products grafting with short alkanehas a better grafting efficiency and suitable for many kinds of waterquality of wastewater flocculation.更多还原