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Mondal A.N.,Hefei University of Technology | Zheng C.,Hefei Chemjoy Polymer Materials Co. | Cheng C.,Hefei University of Technology | Hossain M.M.,Hefei University of Technology | And 4 more authors.
RSC Advances

In the modern arena of separation science and technology, cation exchange membrane (CEM) based diffusion dialysis (DD) has attracted remarkable attention due to its unique ion transport phenomena during applications for base recovery. In this manuscript, for the first time we reveal novel disodium 4-formylbenzene-1,3-disulfonate modified polysiloxane (FSP) induced poly(AMPS-co-CEA) based CEMs with polyvinyl alcohol (PVA) as a binder and tetraethoxysilane (TEOS) acting as a crosslinker for base recovery via diffusion dialysis. Synthesis of poly(AMPS-co-CEA) involved classical free radical polymerization with azobisisobutyronitrile (AIBN) acting as an initiator. By regulating the dosage of FSP in the membrane matrix, the physiochemical as well as the electrochemical properties of the prepared membranes can be modified. The prepared membranes were investigated comprehensively in terms of water uptake (WR), ion exchange capacity (IEC) along with thermo-mechanical measurements like DMA and TGA. The effect of FSP was discussed in brief to correlate the base recovery behaviour of the prepared membranes. The prepared CEMs have water uptakes (WR) in the range 204.0-248.7%, ion exchange capacities (IEC) between 0.58 and 0.76 mmol g-1, tensile strengths (TS) between 9.3 and 15.9 MPa as well as elongations at break (Eb) of 125.6-236.7%. At 25°C, the dialysis coefficient (UOH) values appeared as high as 0.0078-0.0112 m h-1 and the separation factors (S) ranged from 10.32 to 14.19. The membranes described in this manuscript could be a promising contender for base recovery via diffusion dialysis. © 2015 The Royal Society of Chemistry. Source

Mondal A.N.,Hefei University of Technology | Zheng C.,Hefei Chemjoy Polymer Materials Co. | Cheng C.,Hefei University of Technology | Miao J.,Hefei University of Technology | And 7 more authors.
Journal of Membrane Science

The progress in diffusion dialysis (DD)-based separations provides an effective platform for the development of suitable materials for cation exchange membranes (CEM), as CEM-based DD processes aimed at alkali recovery have generated much interest due to their unique ion transport phenomena. Here, for the first time, we report the use of novel silica-functionalized aminoisophthalic acid (AIPA)-based CEMs with polyvinylalcohol (PVA) used as a binder for DD applications (base recovery). The synthesis of the active material AIPA involved a classic nucleophilic reaction between 5-aminoisophthalic acid and 3-glycidoxypropyltrimethoxysilane. By varying the amount of AIPA inside the membrane matrix, the properties of the prepared membranes can be altered. The prepared AIPA membranes were investigated systematically in terms of water uptake (WR), ion exchange capacity (IEC) and thermomechanical measurements, such as DMA and TGA. The influence of AIPA on the base recovery behaviour of the membranes was investigated in detail. The prepared AIPA membranes displayed water uptake values (WR) within 44.2-47.5%, ion exchange capacity (IEC) values between 0.48 and 0.93 mmol/g, initial decomposition temperatures (IDTs) of 193 to 219 °C, tensile strength (TS) values of 50.1 to 58.4 MPa and elongation at break (Eb) values of 6.6 to 224.9%. At 25 °C, the dialysis coefficient (UOH) values were between 0.0068 and 0.0097 m/h, whereas the separation factors (S) ranged from 17.86 to 31.79. The membranes have great potential for base recovery via diffusion dialysis. © 2016 Elsevier B.V. Source

Wang Y.,Anhui University of Science and Technology | Li W.,Hefei Chemjoy Polymer Materials Co. | Xu T.,Anhui University of Science and Technology
Huagong Xuebao/CIESC Journal

Sarcosine is a high-value fine chemical which has many significant applications. Now there is a separation process to remove the inorganic salts from the target product during the production of sarcosine. Multistage fractional crystallization is the conventional separation technology for sarcosine production which has many drawbacks such as high energy consumption, large consumption of chemicals and environmental pollution. To achieve cleaner production of sarcosine, a self-made electrodialysis stack was used in the separation and purification of the target product. The influences of current density and initial pH value in the feed solution on the production of sarcosine were investigated. Results indicated that salt removal rates higher than 99% and a product recovery ratio of 71.5% can be obtained at a current of 2 A and initial feed solution of pH 6.5. The total energy consumption for sarcosine production was 26.4 kW·h·t-1 and the total process cost was estimated at 311 ¥·t-1, which is much less than the conventional separation technologies. It can be seen that electrodialysis is not only energy-saving but also environment-friendly for the industrial production of sarcosine. ©, 2015, Chemical Industry Press. All right reserved. Source

Mondal A.N.,Hefei University of Technology | Dai C.,Hefei University of Technology | Pan J.,Hefei University of Technology | Zheng C.,Hefei Chemjoy Polymer Materials Co. | And 4 more authors.
ACS Applied Materials and Interfaces

To reconcile the trade-off between separation performance and availability of desired material for cation exchange membranes (CEMs), we designed and successfully prepared a novel sulfonated aromatic backbone-based cation exchange precursor named sodium 4,4′-(((((3,3′-disulfo-[1,1′-biphenyl]-4,4′-diyl)bis(oxy)) bis(4,1-phenylene))bis(azanediyl))bis(methylene))bis(benzene-1,3-disulfonate) [DSBPB] from 4,4′-bis(4-aminophenoxy)-[1,1′-biphenyl]-3,3′-disulfonic acid [BAPBDS] by a three-step procedure that included sulfonation, Michael condensation followed by reduction. Prepared DSBPB was used to blend with sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO) to get CEMs for alkali recovery via diffusion dialysis. Physiochemical properties and electrochemical performance of prepared membranes can be tuned by varying the dosage of DSBPB. All the thermo-mechanical properties like DMA and TGA were investigated along with water uptake (WR), ion exchange capacity (IEC), dimensional stability, etc. The effect of DSBPB was discussed in brief in connection with alkali recovery and ion conducting channels. The SPPO/DSBPB membranes possess both high water uptake as well as ion exchange capacity with high thermo-mechanical stability. At 25°C the dialysis coefficients (UOH) appeared to be in the range of 0.0048-0.00814 m/h, whereas the separation factor (S) ranged from 12.61 to 36.88 when the membranes were tested for base recovery in Na2WO4/NaOH waste solution. Prepared membranes showed much improved DD performances compared to traditional SPPO membrane and possess the potentiality to be a promising candidate for alkali recovery via diffusion dialysis. (Chemical Equation Presented). © 2015 American Chemical Society. Source

Liu Y.,Hefei University of Technology | Pan Q.,Hefei University of Technology | Wang Y.,Hefei University of Technology | Wang Y.,Hefei Chemjoy Polymer Materials Co. | And 3 more authors.
Separation and Purification Technology

This study reports the preparation of the in-situ crosslinked anion exchange membrane that does not require the use of crosslinkers or catalysts. A polyelectrolyte bearing flexible unsaturated side chains was synthesized via the Menshutkin reaction with poly(2,6-dimethyl-1,4-phenylene oxide) and N,N-Dimethylvinylbenzylamine. The crosslinked derivatives were then prepared by the thermal crosslinking of the unsaturated side chains during the membrane formation process. This approach incorporates crosslinks, bearing quaternary ammonium cations, between the polymer chains in order to mitigate against excessive water swelling, and to enable the high ion contents to provide favorable low resistance of ion transport. Additionally, the resultant dense crosslinked network has the additional advantage of improving anion selective permeability of membrane. When being applied in ED application, the crosslinked membranes exhibit much higher desalination efficiency than commercial Neosepta AMX membrane, suggesting its potential application in ED. © 2015 Elsevier B.V. All rights reserved. Source

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