scholarly journals A Novel Anion Exchange Membrane for Bisulfite Anion Separation by Grafting a Quaternized Moiety through BPPO via Thermal-Induced Phase Separation

2020 ◽  
Vol 21 (16) ◽  
pp. 5782
Author(s):  
Md Mofasserul Alam ◽  
Yaoming Wang ◽  
Chenxiao Jiang ◽  
Tingting Xu ◽  
Yahua Liu ◽  
...  
Keyword(s):  
Phase Separation ◽  
Anion Exchange ◽  
Membrane Surface ◽  
Separation Performance ◽  
Anion Exchange Membranes ◽  
Transmission Electron ◽  
Alkali Medium ◽  
Core Elements ◽  
Anion Separation ◽  
Exchange Membrane

Ion-exchange membranes are the core elements for an electrodialysis (ED) separation process. Phase inversion is an effective method, particularly for commercial membrane production. It introduces two different mechanisms, i.e., thermal induced phase separation (TIPS) and diffusion induced phase separation (DIPS). In this study, anion exchange membranes (AEMs) were prepared by grafting a quaternized moiety (QM,2-[dimethylaminomethyl]naphthalen-1-ol) through brominated poly (2,6-dimethyl-1,4-phenylene oxide) (BPPO) via the TIPS method. Those membranes were applied for selective bisulfite (HSO3−) anion separation using ED. The membrane surface morphology was characterized by SEM, and the compositions were magnified using a high-resolution transmission electron microscope (HRTEM). Notably, the membranes showed excellent substance stability in an alkali medium and in grafting tests performed in a QM-soluble solvent. The ED experiment indicated that the as-prepared membrane exhibited better HSO3− separation performance than the state-of-the-art commercial Neosepta AMX (ASTOM, Japan) membrane.

scholarly journals Influential Mechanism of Natural Organic Matters with Calcium Ion on the Anion Exchange Membrane Fouling Behavior via xDLVO Theory

Membranes ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 968
Author(s):  
Zhun Ma ◽  
Lu Zhang ◽  
Ying Liu ◽  
Xiaosheng Ji ◽  
Yuting Xu ◽  
...  
Keyword(s):  
Organic Matter ◽  
Interaction Energy ◽  
Anion Exchange ◽  
Natural Organic Matter ◽  
Calcium Ions ◽  
Membrane Fouling ◽  
Membrane Surface ◽  
Anion Exchange Membrane ◽  
Anion Exchange Membranes ◽  
Exchange Membrane

The fouling mechanism of the anion exchange membrane (AEM) induced by natural organic matter (NOM) in the absence and presence of calcium ions was systematically investigated via the extended Derjaguin–Landau–Verwey–Overbeek (xDLVO) approach. Sodium alginate (SA), humic acid (HA), and bovine serum albumin (BSA) were utilized as model NOM fractions. The results indicated that the presence of calcium ions tremendously aggravated the NOM fouling on the anion exchange membrane because of Ca-NOM complex formation. Furthermore, analysis of the interaction energy between the membrane surface and foulants via xDLVO revealed that short-range acid–base (AB) interaction energy played a significant role in the compositions of interaction energy during the electrodialysis (ED) process. The influence of NOM fractions in the presence of calcium ions on membrane fouling followed the order: SA > BSA > HA. This study demonstrated that the interaction energy was a dominating indicator for evaluating the tendency of anion exchange membranes fouling by natural organic matter.

Fundamental characteristics study of anion-exchange PVDF–SiO2 membranes

2012 ◽  
Vol 66 (11) ◽  
pp. 2343-2348 ◽  
Author(s):  
Xingtao Zuo ◽  
Wenxin Shi ◽  
Shuili Yu ◽  
Jiajie He
Keyword(s):  
Anion Exchange ◽  
Vinylidene Fluoride ◽  
Membrane Surface ◽  
Exchange Capacity ◽  
Anion Exchange Membranes ◽  
Blending Method ◽  
Poly Vinylidene Fluoride ◽  
Potential Applications ◽  
Alkaline Membrane ◽  
Exchange Membrane

A new type of poly(vinylidene fluoride)(PVDF)–SiO2 hybrid anion-exchange membrane was prepared by blending method. The anion-exchange groups were introduced by the reaction of epoxy groups with trimethylamine (TMA). Contact angle between water and the membrane surface was measured to characterize the hydrophilicity change of the membrane surface. The effects of nano-sized SiO2 particles in the membrane-forming materials on the membrane mechanical properties and conductivity were also investigated. The experimental results indicated that PVDF–SiO2 anion-exchange membranes exhibited better water content, ion-exchange capacity, conductivity and mechanic properties, and so may find potential applications in alkaline membrane fuel cells and water treatment processes.

scholarly journals Highly conductive and chemically stable alkaline anion exchange membranes via ROMP of trans-cyclooctene derivatives

2019 ◽  
Vol 116 (20) ◽  
pp. 9729-9734 ◽  
Author(s):  
Wei You ◽  
Elliot Padgett ◽  
Samantha N. MacMillan ◽  
David A. Muller ◽  
Geoffrey W. Coates
Keyword(s):  
Anion Exchange ◽  
Random Copolymer ◽  
Chemical Degradation ◽  
Random Copolymers ◽  
Anion Exchange Membranes ◽  
Widespread Application ◽  
Imidazolium Cations ◽  
Transmission Electron ◽  
High Level ◽  
Exchange Membrane

Alkaline anion exchange membranes (AAEMs) are an important component of alkaline exchange membrane fuel cells (AEMFCs), which facilitate the efficient conversion of fuels to electricity using nonplatinum electrode catalysts. However, low hydroxide conductivity and poor long-term alkaline stability of AAEMs are the major limitations for the widespread application of AEMFCs. In this paper, we report the synthesis of highly conductive and chemically stable AAEMs from the living polymerization of trans-cyclooctenes. A trans-cyclooctene–fused imidazolium monomer was designed and synthesized on gram scale. Using these highly ring-strained monomers, we produced a range of block and random copolymers. Surprisingly, AAEMs made from the random copolymer exhibited much higher conductivities than their block copolymer analogs. Investigation by transmission electron microscopy showed that the block copolymers had a disordered microphase segregation which likely impeded ion conduction. A cross-linked random copolymer demonstrated a high level of hydroxide conductivity (134 mS/cm at 80 °C). More importantly, the membranes exhibited excellent chemical stability due to the incorporation of highly alkaline-stable multisubstituted imidazolium cations. No chemical degradation was detected by 1H NMR spectroscopy when the polymers were treated with 2 M KOH in CD3OH at 80 °C for 30 d.

scholarly journals Improved Physicochemical Stability and High Ion Transportation of Poly(Arylene Ether Sulfone) Blocks Containing a Fluorinated Hydrophobic Part for Anion Exchange Membrane Applications

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1400 ◽  
Author(s):  
Ji Chu ◽  
Kyu Lee ◽  
Ae Kim ◽  
Dong Yoo
Keyword(s):  
Phase Separation ◽  
Anion Exchange ◽  
Physical Stability ◽  
Exchange Capacity ◽  
Open Circuit ◽  
Anion Exchange Membranes ◽  
Arylene Ether ◽  
Atomic Force ◽  
Physicochemical Stability ◽  
Exchange Membrane

A series of anion exchange membranes composed of partially fluorinated poly(arylene ether sulfone)s (PAESs) multiblock copolymers bearing quaternary ammonium groups were synthesized with controlled lengths of the hydrophilic precursor and hydrophobic oligomer via direct polycondensation. The chloromethylation and quaternization proceeded well by optimizing the reaction conditions to improve hydroxide conductivity and physical stability, and the fabricated membranes were very flexible and transparent. Atomic force microscope images of quaternized PAES (QN-PAES) membranes showed excellent hydrophilic/hydrophobic phase separation and distinct ion transition channels. An extended architecture of phase separation was observed by increasing the hydrophilic oligomer length, which resulted in significant improvements in the water uptake, ion exchange capacity, and hydroxide conductivity. Furthermore, the open circuit voltage (OCV) of QN-PAES X10Y23 and X10Y13 was found to be above 0.9 V, and the maximum power density of QN-PAES X10Y13 was 131.7 mW cm−2 at 60 °C under 100% RH.

scholarly journals Highly Conductive and Water-Swelling Resistant Anion Exchange Membrane for Alkaline Fuel Cells

2019 ◽  
Vol 20 (14) ◽  
pp. 3470 ◽  
Author(s):  
Qianqian Ge ◽  
Xiang Zhu ◽  
Zhengjin Yang
Keyword(s):  
Fuel Cells ◽  
Ionic Conductivity ◽  
Anion Exchange ◽  
Microphase Separation ◽  
Anion Exchange Membranes ◽  
Alkaline Fuel Cells ◽  
Transmission Electron ◽  
Hyperbranched Poly ◽  
Water Swelling ◽  
Exchange Membrane

To ameliorate the trade-off effect between ionic conductivity and water swelling of anion exchange membranes (AEMs), a crosslinked, hyperbranched membrane (C-HBM) combining the advantages of densely functionalization architecture and crosslinking structure was fabricated by the quaternization of the hyperbranched poly(4-vinylbenzyl chloride) (HB-PVBC) with a multiamine oligomer poly(N,N-Dimethylbenzylamine). The membrane displayed well-developed microphase separation morphology, as confirmed by small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). Moreover, the corresponding high ionic conductivity, strongly depressed water swelling, high thermal stability, and acceptable alkaline stability were achieved. Of special note is the much higher ratio of hydroxide conductivity to water swelling (33.0) than that of most published side-chain type, block, and densely functionalized AEMs, implying its higher potential for application in fuel cells.

scholarly journals Phenolphthalein Anilide Based Poly(Ether Sulfone) Block Copolymers Containing Quaternary Ammonium and Imidazolium Cations: Anion Exchange Membrane Materials for Microbial Fuel Cell

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 454
Author(s):  
Aruna Kumar Mohanty ◽  
Young-eun Song ◽  
Jung-rae Kim ◽  
Nowon Kim ◽  
Hyun-jong Paik
Keyword(s):  
Fuel Cell ◽  
Microbial Fuel Cell ◽  
Anion Exchange ◽  
Quaternary Ammonium ◽  
Anion Exchange Membrane ◽  
Anion Exchange Membranes ◽  
Good Thermal Stability ◽  
Imidazolium Cations ◽  
Membrane Morphology ◽  
Exchange Membrane

A class of phenolphthalein anilide (PA)-based poly(ether sulfone) multiblock copolymers containing pendant quaternary ammonium (QA) and imidazolium (IM) groups were synthesized and evaluated as anion exchange membrane (AEM) materials. The AEMs were flexible and mechanically strong with good thermal stability. The ionomeric multiblock copolymer AEMs exhibited well-defined hydrophobic/hydrophilic phase-separated morphology in small-angle X-ray scattering and atomic force microscopy. The distinct nanophase separated membrane morphology in the AEMs resulted in higher conductivity (IECw = 1.3–1.5 mequiv./g, σ(OH−) = 30–38 mS/cm at 20 °C), lower water uptake and swelling. Finally, the membranes were compared in terms of microbial fuel cell performances with the commercial cation and anion exchange membranes. The membranes showed a maximum power density of ~310 mW/m2 (at 0.82 A/m2); 1.7 and 2.8 times higher than the Nafion 117 and FAB-PK-130 membranes, respectively. These results demonstrated that the synthesized AEMs were superior to Nafion 117 and FAB-PK-130 membranes.

scholarly journals Electrowinning of Iron from Spent Leaching Solutions Using Novel Anion Exchange Membranes

Membranes ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 137
Author(s):  
Wouter Dirk Badenhorst ◽  
Cloete Rossouw ◽  
Hyeongrae Cho ◽  
Jochen Kerres ◽  
Dolf Bruinsma ◽  
...  
Keyword(s):  
Current Efficiency ◽  
Anion Exchange ◽  
Mechanical Stability ◽  
Specific Energy Consumption ◽  
Flow Cell ◽  
Process Efficiency ◽  
Side Reactions ◽  
Anion Exchange Membranes ◽  
Acid Generation ◽  
Exchange Membrane

In the Pyror process, electrowinning (EW) is used to recover acid and iron from spent leaching solutions (SLS), where a porous Terylene membrane acts as a separator between the cathode and anode. In this study, a novel anion exchange membrane (AEM)-based EW process is benchmarked against a process without and with a porous Terylene membrane by comparing the current efficiency, specific energy consumption (SEC), and sulfuric acid generation using an in-house constructed EW flow cell. Using an FAP-PK-130 commercial AEM, it was shown that the AEM-based process was more efficient than the traditional processes. Subsequently, 11 novel polybenzimidazole (PBI)-based blend AEMs were compared with the commercial AEM. The best performing novel AEM (BM-5), yielded a current efficiency of 95% at an SEC of 3.53 kWh/kg Fe, which is a 10% increase in current efficiency and a 0.72 kWh/kg Fe decrease in SEC when compared to the existing Pyror process. Furthermore, the use of the novel BM-5 AEM resulted in a 0.22 kWh/kg Fe lower SEC than that obtained with the commercial AEM, also showing mechanical stability in the EW flow cell. Finally, it was shown that below 5 g/L Fe, side reactions at the cathode resulted in a decrease in process efficiency, while 40 g/L yielded the highest efficiency and lowest SECs.

scholarly journals Alkali Attack on Cation-Exchange Membranes with Polyvinyl Chloride Backing and Binder: Comparison with Anion-Exchange Membranes

Membranes ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 228 ◽  
Author(s):  
Shoichi Doi ◽  
Nobuya Takumi ◽  
Yuriko Kakihana ◽  
Mitsuru Higa
Keyword(s):  
Cation Exchange ◽  
Anion Exchange ◽  
Polyvinyl Chloride ◽  
Chemical Structure ◽  
Immersion Test ◽  
Ion Concentration ◽  
Membrane Properties ◽  
Anion Exchange Membranes ◽  
Alkali Solutions ◽  
Exchange Membrane

Systematic alkali immersion tests of cation-exchange membranes (CEM) with polyvinyl chloride (PVC) as their backing and binder were conducted to compare that of an Anion-exchange membrane (AEM) with the same PVC materials to investigate the mechanism of dehydrochlorination. In the immersion tests, originally colorless and transparent AEM turned violet, and chemical structure analysis showed that polyene was produced by the dehydrochlorination reaction. However, the CEM did not change in color, chemical structure or membrane properties during the test with less than 1M alkali solutions. According to the Donnan equilibrium theory and the experiments using CEM and AEM, the hydroxide ion concentration in the CEM was much lower than that in the AEM under the same conditions. However, when the alkali immersion test was performed using the CEM under more severe conditions (6 M for 168 h at 40 °C), there was a slight change in the color and chemical structure of the CEM, clearly indicating that not only AEMs, but also CEMs with PVC matrixes were deteriorated by alkali, depending on the conditions.

Dual exchange membrane fuel cell with sequentially aligned cation and anion exchange membranes for non-humidified operation

2020 ◽  
Vol 596 ◽  
pp. 117745 ◽  
Author(s):  
So Young Lee ◽  
Ji Eon Chae ◽  
Jieun Choi ◽  
Hyun Seo Park ◽  
Dirk Henkensmeier ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Anion Exchange ◽  
Anion Exchange Membranes ◽  
Exchange Membrane
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