海带浸取液中碘的分离纯化研究

发布时间：2018-04-25 15:08

  本文选题：碘 + 溶剂萃取　； 参考：《哈尔滨工业大学》2014年硕士论文

【摘要】：海洋被称为自然界的“碘库”，以海水或海藻为原料提取碘已成为该领域的趋势。本文以海带浸取液为原料，分别采用溶剂萃取法与活性炭吸附法从中提取碘。在溶剂萃取法中以氧化率、萃取率和分配比为考察指标，优化了萃取工艺条件；在活性炭吸附法中，以吸附率为考察指标，优化了吸附工艺条件。采用恒界面池法，探究了溶剂萃取碘过程的传质动力学。 试验过程中，采用氧化还原滴定法测定碘离子浓度，步骤参照国家标准；采用紫外分光光度法绘制测定碘浓度的标准曲线，其试验条件为：5mL碘酸钾标准溶液中加入1.0mol/L硫酸溶液2mL，10g/L碘化钾溶液3mL，5g/L淀粉溶液5滴，显色时间10min。 通过单因素试验和正交试验优化的萃取工艺条件为：原料液酸化至pH1.5，加入亚硝酸钠0.01g/20mL，，相比1:3，温度55℃，转速500r/min，反应25min，七级逆流萃取后萃取率达到98.7%，试验得出的萃取级数与通过McGabe-Thiele图解法得出的理论逆流萃取级数一致。反萃取的最优工艺条件为：温度35℃，搅拌速率500r/min，反萃取时间8min。 活性炭吸附试验的最优工艺条件为：活性炭用量0.14g/100mL，搅拌速度600r/min，吸附温度25℃，吸附50min。通过吸附等温试验，得出温度升高，对吸附过程不利，与单因素试验得出的的结论基本一致。解吸的最优工艺条件为：温度30℃，搅拌速度500r/min，解吸160min。 对萃取反应进行初步热力学研究得：反应焓变为11.89kJ/mol，反应熵变为71.38J/(mol·K)，反应自由能小于0，该萃取碘的反应可自发进行，升高温度有利于萃取。 采用恒界面池法研究了原料液起始浓度、搅拌强度、界面积、温度对萃取速率和传质过程的影响，得出萃取碘的过程属于扩散控制模式，萃取碘的速率方程为：R0.0001I2 2，萃取过程活化能2.19kJ/mol，得出了转速与传质系数及温度与传质系数的关系。
[Abstract]:The ocean is called the "iodine bank" in nature. It has become a trend in this field to extract iodine from sea water or seaweed. Iodine was extracted from kelp leaching solution by solvent extraction and activated carbon adsorption respectively. In the solvent extraction, the oxidation rate, the extraction rate and the distribution ratio were taken as the indexes to optimize the extraction process conditions, and in the activated carbon adsorption method, the adsorption rate was taken as the inspection index, and the adsorption process conditions were optimized. The mass transfer kinetics of solvent extraction of iodine was investigated by means of constant interface cell method. During the experiment, the iodine ion concentration was determined by oxidation-reduction titration, and the standard curve of iodine concentration was drawn by ultraviolet spectrophotometry. The experimental conditions were as follows: adding 2 mL 1.0mol/L sulfuric acid solution 2 mL 10 g / L potassium iodide solution into 1: 5 mL standard solution of potassium iodate, 3 mL Ki 5 g / L starch solution 5 drops, color reaction time 10 min. The extraction conditions optimized by single factor experiment and orthogonal test are as follows: acidification of raw liquid to pH 1.5, addition of sodium nitrite 0.01g / 20mL, compared with 1: 3, temperature 55 鈩

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