一种阴离子交换树脂的制备及其对饮用水原水中硝酸盐的吸附效果

发布时间：2018-04-25 18:22

  本文选题：离子交换树脂 + 合成条件　； 参考：《西安建筑科技大学》2014年硕士论文

【摘要】：饮用水原水中的硝酸盐污染已引起全球广泛关注。为经济高效地去除饮用水中的硝酸盐，通过1,4-二氯甲氧基丁烷和三乙胺分别对聚苯乙烯交联微球进行氯甲基化和胺化反应，制得了一种大孔型强碱性阴离子交换树脂，并利用傅里叶红外光谱法对其化学结构进行了表征。通过控制反应条件，考察了各个影响因素对氯甲基化反应以及胺化反应的影响，得出了最佳合成工艺，并对合成出的离子交换树脂分别进行静态和动态硝酸盐的吸附行为研究，得到以下结论： (1)聚苯乙烯交联微球的氯甲基化反应最佳反应条件为：溶胀剂——二氯甲烷的量为10mL g-1，四氯化锡用量为1.125mL g-1，BCMB用量为1.798g g-1，反应时间为6小时，当白球交联度为4时，在上述条件下可以得到氯含量接近16%的氯球。 (2)氯甲基化的聚苯乙烯交联微球最佳的胺化反应条件为：溶胀剂选用甲酰胺，三乙胺的量为理论用量的3倍，反应温度控制为60℃，反应时间为8h。在此反应条件下可得到全交换容量为2.4mmol/g的强碱性阴离子交换树脂。 (3)此离子交换树脂的对硝酸盐的吸附在40min可达平衡状态；温度与溶液酸碱度对硝酸盐的吸附无显著影响；此吸附过程符合伪二级动力学和Langmuir等温方程，属于化学吸附，颗粒扩散是速度控制步骤，根据计算式可得吸附量为18.34mg·g-1；选择性系数表明，此离子交换树脂对硝酸根具有选择吸附效果；对树脂的静态再生结果表明，最佳再生液NaCl浓度为8%，再生时间为30min，再生10次后树脂的再生率扔可保持在98%以上。 (4)连续流试验中离子交换柱的穿透时间和泄露时间分别为10小时和12小时，连续试验三次穿透曲线无明显变化，说明此离子交换柱的对硝酸盐的去除效果良好，且再生性能优良；当分别用8%和4%的氯化钠对离子交换柱进行反冲再生时，再生时间分别为1小时和2小时，，综合工业生产需要，最佳再生液选用8%的氯化钠；根据公式计算出此离子交换树脂的动态吸附量为17.85mg·g-1，与静态试验所得吸附量18.34mg·g-1相差不多，但略有下降。
[Abstract]:Nitrate pollution in drinking water has attracted worldwide attention. In order to remove nitrate from drinking water economically and efficiently, a macroporous strongly basic anion exchange resin was prepared by chloromethylation and amination of crosslinked polystyrene microspheres by 1o 4-dichloromethoxybutane and triethylamine, respectively. The chemical structure was characterized by Fourier transform infrared spectroscopy (FTIR). By controlling the reaction conditions, the effects of various factors on chloromethylation and amination reaction were investigated, and the optimum synthesis process was obtained. The adsorption behavior of the synthesized ion-exchange resin was studied by static and dynamic nitrate adsorption, respectively. The following conclusions were drawn: The optimum reaction conditions for chloromethylation of crosslinked polystyrene microspheres were as follows: the amount of dilatant-dichloromethane was 10mL g-1, the amount of tin tetrachloride was 1.798g / g -1, the reaction time was 6 hours, and the crosslinking degree of white sphere was 4. Under the above conditions, chlorine balls with chlorine content of nearly 16% can be obtained. The optimum amination conditions for chloromethylated polystyrene crosslinked microspheres were as follows: formamide was used as swelling agent, triethylamine was 3 times of theoretical dosage, reaction temperature was 60 鈩

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