Abhishek N. Mondal

Click mediated high-performance anion exchange membranes with improved water uptake

We acquired herein a novel pendant type anion exchange membrane by grafting brominated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO) with HLTEI (1-(2-(hexylthio)ethyl)-1H-imidazole), a monomer synthesized via click chemistry. The membrane shows improved hydroxide conductivity because of the flexible side chain induced microphase-separated morphology. Low water uptake is the added benefit of the synthesized membrane.

Preparation of pyrrolidinium-based anion-exchange membranes for acid recovery via diffusion dialysis

ABSTRACT In this manuscript, the preparation of pyrrolidinium-based anion-exchange membranes (AEMs) from brominated poly(2,6-dimethyl-1,4-phenyleneoxide) (BPPO) is reported. Prepared membranes were completely characterized in terms of Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), atomic force microscopy (AFM), ion-exchange capacity (IEC), water uptake (WR), linear expansion ratios (LER), mechanical stability, acid stability, etc. Excellent thermal, mechanical and acid stability can be observed for prepared membranes. Prepared membranes were used in diffusion dialysis (DD) process for acid recovery from model waste HCl/FeCl2 solution. The dialysis coefficient of HCl (UH) is found to be in the range of 0.018–0.049 m/h, whereas the separation factor (S) was obtained as 36.24–66.39. Prepared membranes show much better DD performance than that of commercial fibre–supported DF-120B membrane (0.004 m/h for UH, 24.3 for S at 25°C). Prepared membranes got the potential to be used as a promising candidate for acid recovery via DD.

Effect of novel polysiloxane functionalized poly(AMPS-co-CEA) membranes for base recovery from alkaline waste solutions via diffusion dialysis

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.

Preparation and characterization of click-driven N-vinylcarbazole-based anion exchange membranes with improved water uptake for fuel cells

A novel side-chain-type anion exchange membrane (AEM) is synthesized using thiol-ene click chemistry and the Menshutkin reaction. The prepared membranes are fully characterized and successfully mitigate the trade-off between conductivity and water uptake. Side-chain-type polymer electrolyte membranes with moderate hydroxide conductivity and improved water uptake are obtained. The thiol-ene click reaction is employed for the synthesis of active monomer 9-(2-((3-(triethoxysilyl)propyl)thio)ethyl)-9H-carbazole (TESPTEC). Using the Menshutkin reaction, TESPTEC is introduced into the brominated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO) backbone. The NVC-50 membrane shows a maximum hydroxide conductivity of 19.84 ± 1.81 mS cm−1 at 20 °C, and 54.69 ± 2.91 mS cm−1 at 60 °C. However, at 20 °C, the water uptake of the membrane NVC-50 is only about 18.36 wt%. After 12 days of alkaline treatment, the NVC-50 membrane shows better alkaline stability than the conventional QPPO membrane.

Fabrication of cation exchange membrane from polyvinyl alcohol using lignin sulfonic acid: Applications in diffusion dialysis process for alkali recovery

ABSTRACT We report polyvinyl alcohol (PVA)-based hybrid membranes composed of salt of lignin sulfonic acid (LSA) and tetraethyl orthosilicate. The concentration of LSA with respect to PVA varied from 10% to 40%. The hybrid membranes showed water uptake (WU) in the range of 122–210%, ion exchange capacities in the range of 0.32–0.75 mmol g−1, dialysis coefficient (UOH) from 0.0068 to 0.0119 m h−1, and selectivity (S) from 15 to 26. The hybrid membranes also showed thermal and mechanical stability.