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Yan H.,Anhui University of Science and Technology | Yan H.,Hefei ChemJoy Polymer Materials Company | Xu C.,Georgia Institute of Technology | Li W.,Hefei ChemJoy Polymer Materials Company | And 3 more authors.
Industrial and Engineering Chemistry Research | Year: 2016

As a novel solvent, ionic liquids have been used in a series of industrial fields, in which large amounts of waste ionic liquids are generated and need to be concentrated and recycled rather than discharged. The disposal of aqueous ionic liquid solutions may cause environmental issues due to slow degradation and toxicity. Electrodialysis (ED) was proposed here to concentrate dilute aqueous solutions of ionic liquids. The effects of the membrane types, applied voltage drops across the ED membrane stack and operating modes, including partial cyclic operation mode, and changes in the volume ratio of concentrated solution to dilute solution (Vc/Vd) were investigated systematically. Results indicate that the membrane type and operating voltage drop across the membrane stack were optimized as CJMC/MA membranes and 10 V, respectively. Also, it shows that the concentration efficiency of the volume ratio of 1:8 is superior to that of partial cyclic operation mode because high concentration ratio (4.5), low energy consumption (9.46 kWh/m3), and low water transport (10.3%) can be achieved. In addition, membrane fouling was monitored, which showed that anion-exchange membranes were stable in the concentrating process. Nevertheless, the absorption of foulants on the membrane surface has some effect on the concentrating process, which should be overcome in industrial application. Overall, the ED process is a feasible technology to concentrate and recycle waste ionic liquids. © 2016 American Chemical Society.


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 | Year: 2015

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.


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 | Year: 2015

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.


Pan Q.,Hefei University of Technology | Hossain M.M.,Hefei University of Technology | Yang Z.,Hefei University of Technology | Wang Y.,Hefei University of Technology | And 4 more authors.
Journal of Membrane Science | Year: 2016

Solvent-free strategy has attracted a broad interest in preparation of ion exchange membranes in recent years stemming from the no need of organic solvents and facilitated construction of highly crosslinking networks. However, post-functionalization is commonly required for further introducing ion-exchange groups. In this study, we report a one-pot solvent-free synthesis of cross-linked anion exchange membranes (AEMs) without the need for post-functionalization. We firstly dissolved brominated poly (2, 6-dimethyl-1, 4-phenylene oxide) (BPPO) in liquid monomers mixture of 4-vinylbenzyl chloride (VBC) and styrene without any organic solvent, then added appropriate amount of N-vinylimidazole and N-methylimidazole to introduce imidazolium groups into both of polyelectrolyte and solvents. The transparent, robust and crosslinked AEMs were obtained by the thermal crosslinking of the unsaturated moieties during the membrane forming process. This approach, distinct from the classical post-functionalization processes, performs crosslinking and functionalization simultaneously. Particularly, imidazolium cations locating on cross-links endow the resultant membrane a high concentration of charge carriers (ion-exchange capacity) for target low resistance, while maintain a high mechanical stability. © 2016 Elsevier B.V.


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 | Year: 2016

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.


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 | Year: 2015

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.


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 | Year: 2015

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.


Wang Y.,Anhui University of Science and Technology | Wang Y.,Hefei ChemJoy Polymer Materials Co. | Pan S.,Hefei ChemJoy Polymer Materials Co. | Xu T.,Anhui University of Science and Technology
Huagong Xuebao/CIESC Journal | Year: 2015

Xylitol is an important sugar alcohol widely used as sweetener. A processing route to remove the residual acid from xylose hydrolyzed solution in industrial production of xylitol is the acid hydrolysis method. Conventional neutralization method with lime has many drawbacks such as high energy consumption, large consumption of chemicals and environmental pollution. To achieve a clean production of xylitol, a self-resemble electrodialysis stack was used for selective removal of residue acid. The influences of current density on the removal ratio of residue acid and recovery ratio of xylose were investigated. The residue acid removal rate was higher than 99% and xylose recovery rate reached 84.9% at a current density of 30 mA·cm-2. The total energy consumption for xylose hydrolyzed solution was 179 kW·h·t-1 and the deacidification process cost was estimated to be 139 ¥·t-1, indicating economic and ecological advantages of this technology. Thus the electrodialysis is a very promising technology for production of xylitol. © All right reserved.

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