电渗析分离乙二醛与硝酸的过程研究

Separation process of glyoxal and nitric acid using electrodialysis technique

在硝酸氧化乙醛制备乙二醛的过程中,需要除去产品中未反应的硝酸。常规的处理工艺容易引起硝酸再次发生氧化反应,因此需要探索新的脱酸技术。文中对电渗析法分离乙二醛溶液中的硝酸进行了实验研究,筛选了3种均相离子交换膜进行实验,使用筛选出的J-1-18离子交换膜组装电渗析装置进行分离过程的工艺条件研究。实验研究了膜堆电压对硝酸脱除率的影响和操作电压对电流效率的影响,考察了硝酸初始质量分数对电渗析分离的影响。研究结果表明:电渗析在低电压下操作,电流主要用于硝酸根离子的迁移,可实现硝酸的有效分离,且分离硝酸所用时间短,还有利于分别回收硝酸和乙酸。

In the process of the glyoxal preparation by oxidizing acetaldehyde with nitric acid, the unreacted nitric acid should be removed. The traditional treatment processes often lead to the oxidation of nitric acid occurred once again, so the new deacidification technique should be explored. Nitric acid separation using electrodialysis technique was researched experimentally. Three different types of homogeneous ion exchange membranes were selected and compared experimentally. The separation experiments were conducted in electrodialysis （ED） equipment equipped with membrane J-l-18, which was selected experimentally. The effects of membrane stack voltage on the nitric acid removal rate and the effect of the operating voltage on the current efficiency were investigated. The effect of nitric acid initial concentration on ED separation was researched. The research results show that the current mainly assures the transfer of nitrate ion when the ED equipment is operated at low voltage. The nitric acid can be removed effectively in a short time. In addition, operating at low voltage is in favour of the recovery of nitrle n,-.icl ~,-,,.1 o~;~ .~：.J ：