电渗析和离子交换耦合过程对苏氨酸发酵液脱盐处理

Desalination of threonine(THR)fermentation broth by electrodialysis and ion exchange coupling process

苏氨酸作为一种高附加值的精细化工产品,具有广泛的应用前景.本文采用电渗析(ED)和离子交换(IX)两种方法处理苏氨酸发酵液,并研究了将这两种方法进行耦合的电去离子技术(EDI)的脱盐效果.ED过程中,改变料液浓度和回收次数,结果表明,在30V工作电压下操作最为有利;料液稀释倍数越大,越快达到脱盐终点,苏氨酸回收率越高,过程能耗也越低;能耗和回收率的数据表明,进行一次回收ED后不适合再继续进行ED回收苏氨酸.对于IX过程,使用717型树脂,对硫酸盐的脱除率和吸附容量分别能达到44.02%和33.88mg/g;树脂用量越多,吸附率越高(31.92%~74.73%),但吸附容量逐渐降低(38.43~14.99mg/g);发酵液初始浓度增大,溶液中吸附质离子增多,树脂的吸附容量增加.对于EDI过程,达到脱盐终点的速度比ED过程更快,脱盐效率也更高.综合效果表明,混合添加5mL Na型和5mL Cl型树脂,采用EDI过程处理发酵液,在能耗(0.269kW·h/L)和脱盐速率方面都更有优势.

Threonine（THR）is a high-value fine chemical which has a wide application prospect.Two methods of electrodialysis（ED）and ion exchange（IX）were used to treat fermentation broth and the desalting effect of electrodeionization（EDI）technology was studied by coupling the two methods.Varying of the feed solution concentration and the recycling times during ED process showed that operation voltage at 30 V was more favorable;higher dilution ratio could lead to shorter time in reaching the end point of desalination,higher THR recovery rate and lower energy consumption.Energy consumption and recovery rate showed that,after recycling of one time,it was not appropriate to proceed with ED recovery of THR.For IX,the removal rate and adsorption capacity of the sulfate were 44.02% and 33.88 mg/g by 717 type resin,respectively.The more resin dosage,the higher adsorption rate（31.92%～74.73%）,but the lower adsorption capacity（38.43～14.99 mg/g）.As the initial concentration of sulfate increased,the adsorption capacity increased in the feed,and the adsorption capacity increased.For EDI,the rate of desalting as well as the desalination rate was higher than that of ED.Comprehensive results show that EDI process with the addition of 5 mL Na and 5 mL Cl type resins has advantages in energy consumption（0.269 kW·h/L）and desalination rates for treating the THR fermentation broth.