Amphiphilic poly(acrylonitrile)-co-poly(2-dimethylamino)ethyl methacrylate conetwork-based anion exchange membrane for water desalination

Abstract

We report the preparation of a novel cross-linked anion exchange membrane (AEM) from poly(acrylonitrile)-co-poly(2-dimethylamino)ethyl methacrylate (PAN-co-PDMA) copolymer by quaternizing the DMA moieties followed by cross-linking of -CN groups. This process avoids the use of the carcinogenic reagent, chloromethyl ether (CME) which is widely employed for the chloromethylation reaction in the preparation of AEMs. Key parameters were evaluated via electrodialysis (ED) during water purification and revealed that a copolymer containing 28 wt% PDMA possesses all the required properties of a high performance AEM, such as, reasonable water uptake (21%), good ion-exchange capacity (IEC ¼ 1.30 m eq g À1 ), high ionic conductivity (K m ¼ 2.22 mS cm À1 ), a high transport number (t À ¼ 0.88) and good mechanical properties (9.2 MPa of tensile stress at break and 2.4 Kg cm À2 of burst strength in the water wet state). The AEM was directly tested in an ED unit in the recirculation mode by varying the concentration of the NaCl feed and the applied potential, showing a current efficiency as high as 80%. Such combination of physical and electrochemical properties of the membrane is attributed to its co-continuous morphology and its low degree of phase separation as confirmed by swelling, differential scanning calorimetry, the homogeneous distribution of oppositely charged dye and by the transparency of the membrane in both the dry and swelled states.

Microwave-Assisted Synthesis of Highly-Crumpled, Few-Layered Graphene and Nitrogen-Doped Graphene for Use as High-Performance Electrodes in Capacitive Deionization

“…Note that regeneration of HCG and HCNDG electrodes and repeatability of the electrosorption process were realized in the unit cell. The electrosorption capacity decline of electrodes have not been observed in the unit cell after over 3 charge–discharge cycles, which is in agreement with recent studies 9 11 42 .…”

Degradable/cytocompatible and pH responsive amphiphilic conetwork gels based on agarose-graft copolymers and polycaprolactone

“…[4][5][6][7] These polymeric conetworks have diverse applications such as nanotemplates for organic/inorganic nanohybrids, 8 pervaporation membranes, 9 membranes for water desalination via electrodialysis, 10,11 supports for high efficiency enzyme catalysis, 12 antifouling/antimicrobial coatings, [13][14][15] biomaterials, such as controlled drug release matrices, 16,17 and scaffolds for tissue engineering. 1-7 APCN gels are mostly prepared by radical polymerization of telechelic macro-monomers containing at least two polymerizable groups with a selected low molecular weight monomer.…”

Preparation of heterogeneous bipolar membranes and their performance evaluation for the regeneration of acid and alkali

“…21,22 Ionic conductivity (K m ) of the membranes Ionic conductivity measurements of AEM, CEM, AL, CL and BPM were determined aer equilibrating the samples in 0.1 N NaCl solutions for 24 h. For the measurement the membranes are sandwiched between two square piece graphite electrodes (1.0 cm 2 ). 21,22 Ionic conductivity (K m ) of the membranes Ionic conductivity measurements of AEM, CEM, AL, CL and BPM were determined aer equilibrating the samples in 0.1 N NaCl solutions for 24 h. For the measurement the membranes are sandwiched between two square piece graphite electrodes (1.0 cm 2 ).…”

“…23 The performances of the prepared membranes are analyzed in terms of current efficiency and energy consumption calculated by the following equations; 21,22 Power consumption (W in kW h kg À1 ) during BPED process is dened as the amount of energy needed during hydrolysis of one kg salt. Different salt solutions (500 mL) of concentration 0.5 M and 500 mL water were circulated in three compartments (compartments 2, 3 and 4) at ow rate 5 L h À1 .…”