极化石墨毡电极膜电吸附去除并回收乙酸

Removal and recovery of acetic acid by electrosorption with polarized graphite felt electrode as electrodes

目的探讨电极极化膜电吸附技术去除并回收乙酸的技术可行性。方法采用石墨毡为吸附电极,均相离子透过膜置于两电极之间,施加合适的直流电压,选择性吸附乙酸部分解离的阴阳离子。吸附完成后,反接电压,进行脱附浓缩。电极预先极化作为实验组,未极化作为对照组,考察电极极化对吸附与脱附的影响。结果实验数据表明,在相同的3V吸附电压下,使用预先通过5V电压极化处理的石墨毡电极,吸附效果要比使用不做任何处理的石墨毡电极要好,且脱附速率有很大的提升。在对乙酸进行脱附浓缩的过程中,溶液的p H从4. 04降到3. 48,溶液的浓度从0. 120 g/L上升到0. 374 g/L,浓缩倍率高达3. 12倍。结论膜电吸附去除乙酸是可行的;电极预先极化可显著提高乙酸的去除速率,并有效提高脱附后的溶液浓度;研究结果对于含有机酸废水的处理和有机酸的回收具有重要意义。

Objective: To explore the feasibility of applying membrane capacitive deionization( MCDI) to removing and recollecting acetic acid by polarizing the electrodes before adsorption. Methods: Graphite felts were adopted as the electrodes for adsorption,and,with homogeneous ionic selective membranes arranged between the electrode pair,direct potential was applied to remove the electrolyzed ions from the bulk solution. After adsorption,the potential was reversed to carry out desorption to harvest concentration solution. Operation with pre-polarization of electrodes was performed as the experimental group,and the one without pre-polarization as the control group,to detect the effect of pre-polarization on the performance of MCDI. Results: The experimental data showed that,under the same 3 V adsorption voltage,the adsorption effect of graphite felt electrode,which was treated by 5 V voltage polarization,was better than that of graphite felt electrode without any treatment,and the desorption rate was greatly improved. During the concentration of acetic acid,the p H of the solution decreased from 4. 04 to 3. 48,the concentration of solution increased from 0. 12 to 0. 37 g/L,and the concentration rate reached 3. 12 times. Conclusion: MCDI is feasible for removing and recollecting acetic acid;pre-polarization of electrodes can significantly accelerate the rate of acetic acid removal and harvest a higher concentration solution after desorption;the results are significantly meaningful for the treatment of waste water containing organic acids and recollection of these acids.