In this research work, the synthesis of anion exchanges membranes (AEMs) from brominated poly (2, 6-dimethyl-1, 4-phenylene oxide) (BPPO) and dimethyethanolamine (DMEA) has been investigated for electrodialysis (ED) application. Fourier transform infrared spectroscopy was used to confirm the functional groups in the membranes. The morphology of the prepared membranes was investigated by scanning electron microscopy. Physiochemical and electrochemical properties of the prepared membranes were studied in detail. The membranes possess ion exchange capacity of 0.66 mmol/g to 1.38 mmol/g, water uptake of 11.60 % to 48.50 %, volume expansion ratio of 8.58 % to 20.21 %, tensile strength of 32.52 MPa to 49.22 MPa and transport number of 0.94 to 0.98. These membranes have higher chemical stability in alkaline medium than QPPO membrane (quaternized with trimethylamine) at room temperature. The membranes DMEA-10 and DMEA-15 were selected for NaCl desalination by ED with a lab-scale electrodialysis cell at constant applied voltage. The prepared membranes DMEA-10

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.

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The corresponding poly(AMPS-co-CEA) based membrane which showed high base permeability and proper separation factor in alkali recovery via DD process.