羧甲基淀粉水处理絮凝剂的制备与应用研究

羧甲基淀粉水处理絮凝剂的制备与

应用研究

摘要

本文以淀粉为原料，系统研究了羧甲基淀粉制备过程中不同因素与取代度的关系、对产物的结构变化及其理化性质的影响。

采用溶剂法以淀粉（种类）为原料，以乙醇为溶剂，氢氧化钠为碱化剂，一氯乙酸为醚化剂，对羧甲基淀粉的制备工艺进行了研究。考察了一氯乙酸用量、氢氧化钠用量、乙醇用量、反应时间、反应温度对醚化反应的影响，采用络合滴定法测定羧甲基淀粉的取代度。实验结果表明：在一定的范围内，羧甲基淀粉的取代度随着一氯乙酸用量、氢氧化钠用量、乙醇用量、反应时间、反应温度的增加、延长、升高均呈现出先增后减的规律。在单因素实验的基础上，选取一氯乙酸用量、氢氧化钠用量、乙醇用量、反应时间、反应温度五个因素为变量，以羧甲基淀粉的取代度为控制指标，通过五因素四水平正交试验得出这五个因素与取代度的关系，确定了制备羧甲基淀粉的最佳制备条件为：一氯乙酸0.075mol、氢氧化钠0.2mol、反应温度50℃、反应时间90min、无水乙醇70ml。

用上面制备的羧甲基淀粉再进行絮凝实验。以高岭土悬浊液为处理体系，探讨了羧甲基淀粉的絮凝性能，烧杯絮凝评价实验表明：羧甲基淀粉投加量为4mg/L时，剩余浊度可降至3.2NTU。若以羧甲基淀粉为助凝剂，实验结果表明，当投加8mg/L 聚合氯化铝（PAC）以及1mg/L羧甲基淀粉(CMS)则浊度去除率可达90%以上。

关键字：淀粉，羧甲基，取代度

Abstract

In this paper，with starch as material，the factors which affect DS of Carboxymethyl starch 、the properties and the structure of Carboxymethyl starch were studied

Carboxymethyl starch was prepared in alcohol medium by chloroactic acid and sodium hydroxide. We studied the different factors in preparation on degree of substitution (DS) of Carboxymethyl starch，which include the dosage of chloractic acid，the dosage of sodium hydroxide，the concentration of ethanol，by the reaction temperature and the reaction time. The result indicated that at first the DS of Carboxymethyl starch increased then decreased in a range of dosage. On the basis of one-factor experiments ，we select the ration of starch，chloractic acid and sodium hydroxide，the concentration of ethanol，the reaction temperature and the reaction time as the variables，DS as the experiments index，using L16(45) orthogonal experiment，we obtain the optimum processing conditions for preparation starch：chloroactic acid 0.075mol，sodium hydroxide0.2mol，reaction temperature 50℃，ethanol 70ml.

The properties of carboxymethyl starch flocculation are studies in kaolinite containing suspension. The experimental results show that. The remaining turbidity in treated water decreased to 3.2NTU after adding 4mg/L carboxymethyl starch.. the flocculation experiment of carboxymethyl starch as coagulant aid indicated that

turbidity removal ratios are larger than 90%.after adding 8mg/L PAC within 1mg/L

carboxymethyl starch.

Key words：Carboxymethyl starch，orthogonal test，solvent method

目录

引言 (6)

1.1 淀粉 (6)

1.1.1 淀粉的化学结构与性质 (6)

1.2 改性淀粉 (11)

1.3 羧甲基淀粉的性质及应用 (15)

1.4 本课题研究的主要内容及意义 (18)

1.4.1溶剂法制备羧甲基淀粉影响因素的研究 (18)

1.4.2溶剂法制备羧甲基淀粉最佳工艺参数的确定 (18)

1.4.3羧甲基淀粉（做助絮凝剂）的应用试验 (18)

1.4.4本课题研究的目的意义 (18)

第二章制备 (20)

2.1 羧甲基淀粉的制备 (20)

2.1.1 干法工艺 (20)

2.1.2 湿法工艺 (21)

2.1.3 溶剂工艺 (21)

2．2单因素实验实验部分： (22)

2.2.1对氯乙酸单因素进行试验： (25)

2.2.2 NaOH用量单因素进行试验： (27)

2.2.3温度单因素进行试验： (28)

2.2.4.时间单因素进行试验： (29)

2.2.5无水乙醇（乙醇浓度） (31)

2.3正交实验： (33)

第三章性能分析 (37)

3.1试验的基本原理、仪器及操作步骤 (37)

3.1.1 主要药剂与仪器 (38)

3.1.2 实验方法及操作步骤 (38)

3.1.3 CMS的絮凝效果； (38)

3.1.5 影响因素pH对絮凝效果的影响 (42)

3.1.6 CMS作助凝剂的絮凝实验 (44)