Influence of aqua-ethanol medium on properties of intermediate layer ofa bipolar membrane

doi:10.11949/j.issn.0438-1157.20151004

Abstract

Abstract:

A bipolar membrane (BPM) was composed of a cation and an anion ion-exchange layer joined together in series. The water dissociation in BPM was then considered as an electric field-enhanced (EFE) phenomenon and its magnitude depended critically on the structure and composition of the bipolar intermediate layer. By changing the different content of ethanol, three commercial bipolar membranes Neosepta BP-1, Fumasep FBM and CJ-BPM were tested by AC impedance spectra and their bipolar membrane solvent resistance were evaluated simultaneously. It was confirmed that BP-1 had good solvent resistance and FBM and CJ-BPM solvent resistances were relatively weak. The experimental results showed that the water dissociation phenomenon occurred in the LiCl water-ethanol mixed solutions, and the local effective value of the BPM resistance increased with an increase in the content of ethanol, while the water dissociation became less obvious. This phenomenon could be explained due to the fact that the dissociative ability of alcohol was weaker than that of water. Thus, the existence of ethanol decreased the concentration of water in the intermediate layer of a bipolar membrane and caused the decrease in the water dissociation effect. By simplifying the algorithm to calculate the intermediate layer thickness of the BP-1 and FBM membranes, it was more intuitive to know the influence of ethanol content on the water dissociation.

Key words: water-ethanol system, membrane, ion exchange, electrochemistry, AC impedance spectra

摘要：

选取Neosepta BP-1,Fumasep FBM,CJ-BPM三种商业标准双极膜作为研究对象,以水-乙醇为研究体系,通过改变不同乙醇含量,测定双极膜的交流阻抗谱,并且对双极膜的耐溶剂性能进行评价,结果表明BP-1具有良好的耐溶剂性,FBM,CJ-BPM耐溶剂性相对较弱;水解离现象发生在LiCl水-乙醇混合溶液中,随着乙醇含量的增加,双极膜的阻值增加,而水解离程度降低。这种现象可以解释为醇解离能力要远远小于水解离能力,因此乙醇的存在使得中间界面层区域的水浓度降低,进而降低了水解离程度;通过简化算法计算出了不同乙醇含量下,BP-1,FBM的中间界面层厚度,更直观地看出乙醇对双极膜水解离性能的影响。

关键词: 水-乙醇体系, 膜, 离子交换, 电化学, 交流阻抗谱

CLC Number:

TQ028.8

LIU Xiaohe, LI Qiuhua, GE Liang, XU Tongwen. Influence of aqua-ethanol medium on properties of intermediate layer ofa bipolar membrane[J]. CIESC Journal, 2016, 67(1): 309-314.

刘小菏, 李秋花, 葛亮, 徐铜文. 水-乙醇体系对双极膜中间界面层的影响[J]. 化工学报, 2016, 67(1): 309-314.

References 21

[1]	SIMONS R. A novel method for preparing bipolar membranes [J]. Electrochim Acta, 1986, 31 (9): 1175-1176.
[2]	MICHAEL B M, MICHAEL S F. Graphene oxide as a water dissociation catalyst in the bipolar membrane interfacial layer [J]. ACS Appl. Mater. Interfaces, 2014, 6 (16): 13790-13797.
[3]	UMEMURA K, NAGANUMA T, MIYAKE H. Bipolar membrane: US 5401408 [P]. 1995-03-28.
[4]	HUANG C H, XU T W. Electrodialysis with bipolar membranes (EDBM) for sustainable development [J]. Environ. Sci. Technol., 2006, 40: 5233-5243.
[5]	LIU G L, LUO H P, WANG H H, et al. Malic acid production using a biological electrodialysis with bipolar membrane [J]. J. Membrane Sci., 2014, 471: 179-184.
[6]	XU T W, YANG W H. Citric acid production by electrodialysis with bipolar membranes [J]. Chem. Eng. Process., 2002, 41: 519-524.
[7]	林晗, 汪群慧, 王丽娟, 等. 双极膜电渗析法分离发酵液中乳酸及离子迁移规律 [J]. 化工学报, 2014, 65 (12): 4823-4830.LIN H, WANG Q H, WANG L J, et al. Lactic acid recovery from fermentation by bipolar membrane electrodialysis and ionic migration [J]. CIESC Journal, 2014, 65 (12): 4823-4830.
[8]	TENG L, SHEE F, ARUL J, et al. Performing a three-step process for conversion of chitosan to its oligomers using a unique bipolar membrane electrodialysis system [J]. J. Agric. Food Chem., 2008, 56: 10019-10026.
[9]	LIU X H, LI Q H, JIANG C X, et al. Bipolar membrane electrodialysis in aqua-ethanol medium: production of salicylic acid [J]. J. Membrane Sci., 2015, 4: 76-82.
[10]	KRYSTYNA P, MARTA J W B. Recovery of fumaric acid from fermentation broth using bipolar electrodialysis [J]. J. Membrane Sci., 2014, 469: 428-435.
[11]	HOLDIK H, ALCARAZ A, RAMÍREZ P, et al. Electric field enhanced water dissociation at the bipolar membrane junction from AC impedance spectra measurements [J]. J. Electroanal. Chem., 1998, 442: 13-18.
[12]	KEMPERMAN A J B. Handbook on Bipolar Membrane Technology [M]. Enschede: Twente University Press, 2000.
[13]	SIMONS R, SAJKEWYCZ N. AC electrical properties in bipolar membranes: experiments and a model [J]. J. Membrane Biol., 1977, 34: 263.
[14]	CHILCOTT T C, COSTER H G L, GEORGE E P. AC impedance of the bipolar membrane at low and high frequencies [J]. J. Membrane Sci., 1995, 100: 77-86.
[15]	HURWITZ H D, DIBIANI R, MOUSSAOUI R E, et al. Water dissociation in bipolar membranes studied by impedance spectroscopy [C]//BATH U K. Proceedings of Euromembrane, 1995, 1: 89.
[16]	GERISCHER H. Wechselstrompolarisation von Elektroden mit einem potential bestimmenden Schritt beim Gleichgewichts potential [J]. I. Z. Phys. Chem., 1951, 198: 256.
[17]	CHOU T J, TANIOKA A. Current-voltage curves of composite bipolar membrane in alcohol-water solutions [J]. J. Phys. Chem. B, 1998, 102: 7866-7870.
[18]	SANDRA E K, ELANOR K, GEOFF W S, et al. Electrodialysis in aqueous-organic mixtures [J]. Separation & Purification Reviews, 2015, 44: 269-282.
[19]	ZHANG F, HUANG C H, XU T W. Production of sebacic acid using two-phase bipolar membrane electrodialysis [J]. Industrial & Engineering Chemistry Research, 2009, 48: 7482-7488.
[20]	ANTONIO A, PATRICIO R, JOSÉ A M, et al. Conductive and capacitive properties of the bipolar membrane junction studied by AC impedance spectroscopy [J]. J. Phys. Chem. B, 2001, 105: 11669-11677.
[21]	ANTONIO A, HANS H, THOMAS R, et al. AC impedance spectra of bipolar membranes: an experimental study [J]. J. Membrane Sci., 1998, 150: 43-56.