羧甲基纤维素—聚丙烯酰胺接枝絮凝剂的制备及对污染废水的处理研究
发布时间：2018-06-27 04:23
本文选题：羧甲基纤维素 + 聚丙烯酰胺 ； 参考：《长安大学》2015年硕士论文
【摘要】：我国水资源问题日趋严重,水资源匮乏与污染现状正不断加剧,近年来,工业污水成为水资源污染的主要来源,其成分复杂,含有多种难降解有机污染物,给人们的生活带来严重威胁。尤其是污染废水的化学需氧量,处理难度大,治理费用高。因此寻求低成本、高效率的水污染处理方法是我们迫切解决的问题之一,也是可持续发展的必然要求。聚丙烯酰胺作为一种常用水处理剂,是一种水溶性线性高分子有机物,在实际应用中易吸潮结块,且成本较高,因此设想将聚丙烯酰胺引入到羧甲基纤维素大分子结构中,制备一种高效率、低成本的兼具两者优良性质的水处理剂。本课题将聚丙烯酰胺接枝到羧甲基纤维素分子骨架上,在一定条件下,经过硫酸钾-亚硫酸氢钠双引发剂引发,通过自由基聚合过程形成有机高分子聚合物。以接枝率为主要参考指标,研究了物料比、引发剂用量、起始温度、反应时间和pH等因素的影响。在此基础上还选取影响接枝率较大的四个因素进行正交实验,并以丙酮为溶剂对粗产品进行回流提纯,对接枝絮凝物进行了红外和核磁分析。最终确定了合成羧甲基纤维素-聚丙烯酰胺接枝絮凝剂的最佳条件:CMC为1g时,CMC:AM=1:8,初始pH=9,K2S2O8-NaHSO3双引发剂用量为1mL,接枝温度为40℃,反应时间3.5h,此时接枝率达到60.12%。影响接枝因素的强弱顺序为:pH㧐引发剂用量㧐接枝温度㧐反应时间。反应得到的羧甲基纤维素-聚丙烯酰胺接枝聚合产物为白色粉末,在水中形成疏松的海绵结构,性质较稳定,兼具了羧甲基纤维素和聚丙烯酰胺的性质。配置实验室模拟废水,采用重铬酸钾法测定其初始的CODcr=519.792mg/L。将制备的CMC-PAM絮凝剂用于处理废水,以CODcr为参考指标,持续曝气条件下考察了CMC-PAM用量、絮凝时间、pH的影响,并设计正交实验确定其影响大小。得到的最佳处理条件为:CMC-PAM用量150mg/L,pH=9,絮凝1.5h,COD的最大去除率为49.27%。各因素的影响顺序为:pH㧐投加量㧐絮凝时间。CMC-PAM降解废水COD的机理主要包括:压缩双电层、吸附电中和、吸附架桥、沉淀物卷扫等。
[Abstract]:In recent years, industrial sewage has become the main source of water resources pollution, its composition is complex, and it contains a variety of refractory organic pollutants. It poses a serious threat to people's lives. In particular, the chemical oxygen demand (COD) of polluted wastewater is difficult to treat and the cost of treatment is high. Therefore, to seek low cost and high efficiency water pollution treatment method is one of the urgent problems we solve, and is also the inevitable requirement of sustainable development. As a common water treatment agent, polyacrylamide is a kind of water-soluble linear polymer organic matter, which is easy to absorb moisture and agglomerate in practice, and its cost is high. Therefore, it is envisaged to introduce polyacrylamide into the macromolecular structure of carboxymethyl cellulose. A water treatment agent with high efficiency and low cost was prepared. In this paper, polyacrylamide was grafted onto the molecular skeleton of carboxymethyl cellulose. Under certain conditions, organic polymer was formed by radical polymerization through potassium sulfate and sodium bisulfite double initiator. The effects of material ratio, initiator dosage, initial temperature, reaction time and pH were studied. On this basis, four factors affecting the grafting rate were selected for orthogonal experiments. The crude products were purified by reflux with acetone as solvent, and the grafted flocculants were analyzed by IR and NMR. Finally, the optimum conditions for the synthesis of carboxymethyl cellulose-polyacrylamide graft flocculant were determined. The optimum conditions were as follows: 1 g CMC: AMN: 1 8, initial pH 9 K2S2O8-NaHSO3 double initiator dosage 1 mL, grafting temperature 40 鈩，
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