Concentration Polarization Phenomena in Ion-exchange Membrane Electrodialysis. II. The Effect of the Condition of the Diffusion-boundary Layer on the Limiting-current Density and on the Relative Transport Numbers of Ions

Electrodialysis (ED) desalination performance of different conventional and laboratory-scale ion exchange membranes (IEMs) has been evaluated by many researchers, but most of these studies used their own sets of experimental parameters such as feed solution compositions and concentrations, superficial velocities of the process streams (diluate, concentrate, and electrode rinse), applied electrical voltages, and types of IEMs. Thus, direct comparison of ED desalination performance of different IEMs is virtually impossible. While the use of different conventional IEMs in ED has been reported, the use of bioinspired ion exchange membrane has not been reported yet. The goal of this study was to evaluate the ED desalination performance differences between novel laboratory‑scale bioinspired IEM and conventional IEMs by determining (i) limiting current density, (ii) current density, (iii) current efficiency, (iv) salinity reduction in diluate stream, (v) normalized specific energy consumption, and (vi) water flux by osmosis as a function of (a) initial concentration of NaCl feed solution (diluate and concentrate streams), (b) superficial velocity of feed solution, and (c) applied stack voltage per cell-pair of membranes. A laboratory‑scale single stage batch-recycle electrodialysis experimental apparatus was assembled with five cell‑pairs of IEMs with an active cross-sectional area of 7.84 cm2. In this study, seven combinations of IEMs (commercial and laboratory-made) were compared: (i) Neosepta AMX/CMX, (ii) PCA PCSA/PCSK, (iii) Fujifilm Type 1 AEM/CEM, (iv) SUEZ AR204SZRA/CR67HMR, (v) Ralex AMH-PES/CMH-PES, (vi) Neosepta AMX/Bare Polycarbonate membrane (Polycarb), and (vii) Neosepta AMX/Sandia novel bioinspired cation exchange membrane (SandiaCEM). ED desalination performance with the Sandia novel bioinspired cation exchange membrane (SandiaCEM) was found to be competitive with commercial Neosepta CMX cation exchange membrane.

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Cation-Exchange Membrane with Low Frictional Coefficient and High Limiting Current Density for Energy-Efficient Water Desalination

ACS Omega ◽

10.1021/acsomega.8b01403 ◽

2018 ◽

Vol 3 (8) ◽

pp. 10331-10340 ◽

Cited By ~ 6

Author(s):

Arindam K. Das ◽

Murli Manohar ◽

Vinod K. Shahi

Keyword(s):

Cation Exchange ◽

Current Density ◽

Energy Efficient ◽

Frictional Coefficient ◽

Water Desalination ◽

Cation Exchange Membrane ◽

Limiting Current ◽

Limiting Current Density ◽

Exchange Membrane

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Performance Enhancement in Proton-Exchange Membrane Fuel Cell for Cathode Pulsating Flow

ASME 2010 8th International Fuel Cell Science, Engineering and Technology Conference: Volume 1 ◽

10.1115/fuelcell2010-33283 ◽

2010 ◽

Author(s):

Yun Ho Kim ◽

Hun Sik Han ◽

Seo Young Kim ◽

Gwang Hoon Rhee

Keyword(s):

Fuel Cell ◽

Current Density ◽

Proton Exchange Membrane ◽

Performance Enhancement ◽

Proton Exchange ◽

Pulsating Flow ◽

Limiting Current ◽

Mean Flow ◽

Limiting Current Density ◽

Exchange Membrane

The effect of cathode flow pulsation on the performance enhancement of a 10-cell proton-exchange membrane fuel cell is investigated. We perform the experiment using two pulsation devices. One pulsation device, i.e., acoustic woofer, generates a pulsating flow, which is added to a unidirectional flow supplied from a compressed air tank. The other pulsation device is a crankshaft system that produces a pure oscillatory flow without mean flow. In the case of cathode pulsating flow with mean flow, the fuel cell power output and the limiting current density dramatically increase as pulsating frequency increases at given pulsating amplitude, while the fuel cell efficiency slightly decreases. This result is contributed that the pulsating flow enhances the dispersion inside the cathode channels, and then improving the oxygen and temperature distributions. This performance enhancement by cathode pulsating flow is more distinct at low cathode mean flow rates. In the case of cathode pulsating flow without mean flow, the fuel cell stack is operated despite cathode mean flow is absent. The limiting current density is extended as the pulsating frequency and swept distance (amplitude) increase. When the pulsating frequency and swept distance are 2.38Hz and 13.65mm respectively, the fuel cell performance is equal to that the cathode mean flow rate is 1.29 lpm. Also, the case of pulsating flow is more stable at the concentration loss region than the case of non-pulsating flow for the same performance conditions.

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