@article { ISI:000251722700028, title = {Assessing feasibility of polyarylate-clay nanocomposites towards improvement of gas selectivity}, journal = {Journal of Membrane Science}, volume = {306}, number = {1-2}, year = {2007}, month = {DEC}, pages = {277-286}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Polymer-clay nanocomposites are well known to reduce the penetrant permeability by following tortuous path. Effects of such reduction in gas permeability on variation in selectivity of nanocomposites prepared using a high permeability polymer were examined. The polyarylate: poly (tetramethyl bisphenolA-iso/terephthalate) that exhibits high permeability and moderate selectivity was chosen for making nanocomposites with two organically modified clays (Cloisite 6A and 10A) by solution intercalation method. The nanocomposite formation for various clay loadings (3, 5 and 7\% w/w) in polyarylate was ascertained by change in physical properties (X-ray diffraction, DMA, TEM). Behavior of solution viscosity and nanocomposite density indicated existence of polymer-clay layer interactions. As anticipated, though the gas permeability of pure gases, viz., He, N-2, CH4 and CO2 exhibited decrease, it was not monotonous. This decrease was more for larger gases (N-2, CH4 and CO2) in comparison to the decrease for smaller gas (He) permeability. This led to a decrease in CO2/N-2 and CO2/CH4 selectivities and increase in He/CO2 selectivity; while He/CH4 selectivity was increased substantially at 7\% clay loading. This variation indicated feasibility of nanocomposites formation as a tool for improving selectivity of certain gas pairs. (c) 2007 Elsevier B.V. All rights reserved.

}, keywords = {Gas permeation, Nanocomposites, polyarylates, selectivity, solution intercalation}, issn = {0376-7388}, doi = {10.1016/j.memsci.2007.09.001}, author = {Bhole, Yogesh S. and Wanjale, Santosh D. and Kharul, Ulhas K. and Jog, Jyoti Prakash} } @article { ISI:000280021000011, title = {Artificially designed membranes using phosphonated multiwall carbon nanotube-polybenzimidazole composites for polymer electrolyte fuel cells}, journal = {Journal of Physical Chemistry Letters}, volume = {1}, number = {14}, year = {2010}, month = {JUL}, pages = {2109-2113}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

The ability of phosphonated carbon nanotubes to offer an unprecedented approach to tune both proton-conductivity and mechanical stability of hybrid polymer electrolytes based on the polybenzimidazole membrane is demonstrated for fuel cell applications. The covalent attachment between the amino group of the 2-aminoethylphosphonic acid precursor and CNTs has been confirmed by NMR and IR experiments, while EDAX analysis indicates that one out of every 20 carbon atoms is in the CNT is functionalized. Proton conductivity of the composite membrane shows a remarkable 50\% improvement in performance while a maximum power density of 780 and 600 mW cm(-2) is obtained for the composite and pristine membranes, respectively. Finally, the ultimate strength determined for the composite and pristine membranes is 100 and 65 MPa, respectively, demonstrating the superiority of the composite. This study opens up a new strategy to systematically tune the properties of polymer electrolytes for special applications by using appropriately functionalized CNTS.

}, issn = {1948-7185}, doi = {10.1021/jz1007005}, author = {Kannan, Ramaiyan and Aher, Pradnya P. and Palaniselvam, Thangavelu and Kurungot, Sreekumar and Kharul, Ulhas K. and Pillai, Vijayamohanan K.} } @article {48353, title = {Addressing challenges in sealing of scalable multifiber module for O-2 enrichment using LSCF membranes}, journal = {International Journal of Applied Ceramic Technology}, volume = {19}, year = {2022}, month = {MAY}, pages = {1561-1571}, type = {Article}, abstract = {

Scalable and multifiber modules in oxygen separation face huge challenges due to difficulty in integrating all the necessary components, especially in sealing the fibers in a gas tight module. Here, we report our findings on design and fabrication of a multifiber La0.6Sr0.4Co0.2Fe0.8O3-delta (LSCF)-based module, which can be scaled up. The focus is on sealing ceramic-metal interfaces by layering of sealants of varying thermal properties. We have also incorporated the use of dead ended fibers to minimize ceramic-metal interfaces in the hot zones and present a new method for dead ending by flame melting. Pressurizing the air inlet feed from either bore side or shell side is detrimental to the structural integrity of the fibers. A thorough characterization of the fresh and spent fibers is also carried out using X-ray tomography and electron microscopy, which indicates effect of temperature and pressure on the fibers.

}, keywords = {Characterization, permeability, Perovskites}, issn = {1546-542X}, doi = {10.1111/ijac.13967}, author = {Jogdand, Shunottara M. and Bedadur, Prachiti R. and Torris, Arun and Agrawal, Ravi and Kharul, Ulhas K. and Devi, R. Nandini} } @article {49302, title = {ABPBI-based hollow fiber membranes for forward osmosis (FO) possessing low reverse salt flux}, journal = {Desalination and Water Treatment}, volume = {320}, year = {2024}, month = {OCT}, pages = {100641}, type = {Article}, abstract = {

The poly(2,5-Benzimidazole), known for its excellent thermochemical stability, was evaluated as a membrane material for forward osmosis. The dope in methane sulfonic acid was used to make hollow fiber membranes. The availability of bound MSA in HFMs was compared with its neutral form. Aqueous solutions of two common salts reported for FO (NaCl and MgCl2) were used as a draw solution at varying concentrations. The performance was determined in terms of water flux and reverse salt flux. The long-term performance of the membrane was assessed. The heat pretreatment of membranes was beneficial in offering low reverse salt flux, a crucial parameter in FO. The heat treatment at 350 degrees C exhibited excellent performance of low-RSF, irrespective of the draw solute used. The presence of MSA in the membrane matrix was found to be beneficial. Present HFMs exhibited reverse salt flux as low as 0.003 mol m-2 h-1 using 2 mol L-1 MgCl2 as a draw solution. The water flux of present membranes was lower than that of reported FO-membranes, which is attributable to the larger thickness of the present membranes. The findings will be used to make ABPBI-based membranes in thin form to elevate the fluxes and their practical applicability.

}, keywords = {ABPBI, Forward osmosis, Hollow fiber membrane, Low reverse salt flux}, issn = {1944-3994}, doi = {10.1016/j.dwt.2024.100641}, author = {Thorat, Nitin M. and Lele, Ashish K. and Kharul, Ulhas K.} }