Faculty Publications

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    New polymeric and inorganic membrane materials for water separation
    (Elsevier, 2023) Nayak, S.; Isloor, A.M.; Maddodi, B.S.
    Overuse and exploitation of water resources have caused the global water crisis. To overcome the problem, wastewater reuse has become essential for the survival of humankind. Hence, humans must depend on technologies that efficiently separate contaminants from water and make it reusable for domestic, agricultural, and industrial utilization. To achieve this, membrane technology is the ideal technology, so it has been pursued for the same reason over many decades. It has undergone extensive research and development in its materials processing, fabrication, and applications. In order to achieve a high degree of efficiency in the separation process, there is a need for new membrane materials as conventional materials are not sustainable and efficient enough to separate pollutants like heavy metals, pathogens, dyes, natural organic matter, inorganic salts, and other emerging contaminants from the water. This chapter presents different classifications of membranes and mainly discusses the development of new polymeric and inorganic membrane materials, their performance, application, and the challenges that need to be addressed for their usage in membrane technology-based water separation. © 2024 Elsevier Inc. All rights reserved.
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    Studies on copper coated polysulfone/modified poly isobutylene alt-maleic anhydride blend membrane and its antibiofouling property
    (2013) Isloor, A.M.; Ganesh, B.M.; Isloor, S.; A.F., A.F.; Nagaraj, H.S.; Pattabi, M.
    As nanofiltration is gaining more and more importance in the field of desalination, one has to address the many obstacles in order to achieve effective/efficient filtration. One such issue is biofouling and microbial attack to the membrane. This paper describes about the study on copper coating onto the membrane surface as biofouling protective layer. This is an attempt to come up with a new approach for desalination and an antimicrobial membrane. The work indicates that, the copper coated membrane can resist the possible microbial attack to some extent while maintaining good salt rejection and appreciable flux. SEM and EDX studies had shown the distribution of copper on the membrane surface. The copper coated membrane had shown the maximum salt rejection of about 96% for 3500ppm NaCl solution and also it had shown the pure water flux of 36Lm-2h-1. © 2012 Elsevier B.V.
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    Permeation, Antifouling and desalination performance of TiO2 nanotube incorporated PSf/CS blend membranes
    (2013) Kumar, R.; Isloor, A.M.; A.F., A.F.; Abdul Rashid, S.A.; Ahmed, A.A.
    Polysulfone (PSf) and chitosan (CS) blend membranes were prepared by incorporating titanium dioxide nanotubes (TiO2NT) in different compositions. The proper blending of PSf and CS in the PSf/CS/TiO2 membranes was confirmed by ATR-IR spectroscopy. The influence of nanotubes on morphology of membranes was investigated by Field Emission Scanning Electron Microscopy (FESEM). The effect of nanotubes on hydrophilicity of the membranes was studied by water swelling and contact angle measurements. The distribution of TiO2NT on the membrane surface was determined by Transmission Electron Microscope (TEM) analysis. The permeation property of PSf/CS/TiO2NT membranes was carried out by measuring the time dependent pure water flux (PWF). Bovine serum albumin (BSA) protein rejection studies were performed to know the antifouling properties. The rheological percolation threshold of PSf/CS/TiO2NT solutions was measured by viscosity studies. The nanotubes incorporated PSf/CS membranes showed enhanced permeation and antifouling properties compared to PSf/CS and nascent PSf ultrafiltration membranes. Membranes prepared well above rheological percolation threshold showed drastic reduction in pore size and acted as nanofiltration (NF) membranes. © 2013 Elsevier B.V.
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    Modification of PSf/PIAM membrane for improved desalination applications using Chitosan coagulation media
    (2013) Kumar, R.; A.F., A.F.; Kassim, M.A.; Isloor, A.M.
    Polysulfone (PSf)/poly (isobutylene-alt-maleic anhydride) (PIAM) nanofiltration membranes were modified by changing the coagulation bath with various concentrations of glutaraldehyde cross-linked Chitosan solutions. Further the membranes were treated with 0.1N NaOH solution in order to achieve the hydrolysis of PIAM. The morphological changes of the membranes were determined using scanning electron microscope. The blending of PSf/PIAM membrane, the incorporation of Chitosan (CS) molecules in membrane matrix and the hydrolysis of PIAM in the membrane upon alkali treatment were studied by Attenuated Total Reflectance Infra Red (ATR-IR) spectroscopy. The hydrophilicity of modified membranes was measured using the contact angle analyzer. The pressure and time dependent pure water flux of modified PSf/PIAM/CS membranes were measured and compared with PSf/PIAM membranes (after alkali treatment). The antifouling property of membranes was determined using Bovine Serum Albumin (BSA) protein rejection studies. The modified membranes showed improved hydrophilicity and reduced pore size. The order of rejection of membranes for various electrolytes was Na2SO4>MgSO4>NaCl at minimum pressure of 0.2MPa TMP. The antifouling property of modified membranes increased with an increase in the composition of Chitosan in coagulation bath and membrane M-0.8 showed a maximum fouling resistance ratio of 74%. © 2013 Elsevier B.V.
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    Performance improvement of polysulfone ultrafiltration membrane using N-succinyl chitosan as additive
    (2013) Kumar, R.; Isloor, A.M.; A.F., A.F.; Matsuura, T.
    A water soluble chitosan derivative, N-succinyl chitosan (NSCS), was blended with polysulfone (PSf) in three different compositions to fabricate PSf/NSCS blend membranes. The blending of polymers was confirmed by Attenuated Total Reflectance Infra-Red (ATR-IR) spectroscopy. The membranes were characterized by Scanning Electron Microscopy (SEM) images for their cross-sectional morphology. Pure water flux, water uptake and contact angle of the PSf/NSCS blend membranes were measured and compared with the pristine polysulfone membrane. The PSf/NSCS blend membranes showed enhanced hydrophilicity and permeation fluxes compared to the pristine polysulfone membrane. The membrane antifouling property was determined by filtering the bovine serum albumin (BSA) solution. The maximum flux recovery ratio (FRR) of 70% was observed by the PSf/NSCS blend membrane with 20% NSCS content. The PSf/NSCS membranes with the PSf:NSCS ratios of 80:20 and 90:10 showed nearly the same fluxes as those of polysulfone/polyethylene glycol (PSf/PEG) blend membranes with the same compositions. The hydrophilic derivative of chitosan NSCS acted as an excellent additive in improving PSf ultrafiltration properties. © 2013 Elsevier B.V.
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    Antifouling and performance enhancement of polysulfone ultrafiltration membranes using CaCO3 nanoparticles
    (2013) Nair, A.K.; Isloor, A.M.; Kumar, R.; A.F., A.F.
    Calcium carbonate nanoparticles were synthesized from calcium nitrate via chemical precipitation method. The nanoparticles were characterized using scanning electron microscope (SEM), Attenuated total reflectance infra red (ATR-IR) spectrum and by X-ray diffraction (XRD). These nanoparticles were used as additive for polysulfone (PSf) ultrafiltration membrane along with polyethylene glycol (PEG) as pore forming agent. The PSf hybrid membranes were characterized by ATR-IR, XRD, and SEM studies. ATR-IR and XRD results indicated the successful incorporation of the nanoparticles in the membranes. Cross sectional images of the membranes along with the elemental mapping of calcium on the membrane surface were assessed using SEM. Hydrophilicity of the membranes was evaluated in terms of contact angle measurements. The permeability of the membranes was determined by measuring the pure water flux (PWF). Membranes were also subjected to antifouling studies using bovine serum albumin (BSA) as the standard protein for rejection. The membranes showed better permeability and antifouling property with the increased addition of CaCO3 nanoparticles. © 2013 Elsevier B.V.
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    Preparation and antifouling properties of PVDF ultrafiltration membranes with polyaniline (PANI) nanofibers and hydrolysed PSMA (H-PSMA) as additives
    (Elsevier, 2014) Pereira, V.R.; Isloor, A.M.; Bhat, K.U.; A.F., A.F.
    Polyaniline (PANI) nanofibers were used as hydrophilic additives to study their effect on the performance of polyvinylidene fluoride (PVDF) ultrafiltration (UF) membranes. PVDF UF membranes were prepared by the phase inversion method with hydrolyzed polystyrene-co-maleic anhydride (H-PSMA) and PANI nanofibers as additives. PANI nanofibers were synthesized by rapid mixing reaction and were used as a hydrophilic modifying agent with varying concentrations (0-1.5 wt.%) in the membranes. The synthesized PANI nanofibers were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM) analysis. Hydrolyzed PSMA was prepared by the hydrolysis of PSMA and was used as a novel pore forming additive. The addition of PANI nanofibers into the membranes increased the membrane hydrophilicity, porosity, water uptake and permeability. The membranes also showed good antifouling nature during BSA (bovine serum albumin) filtration when compared to the pristine membrane without PANI nanofibers. Membrane with 1.0 wt.% PANI content showed highest permeability among the synthesized membranes. The membrane having highest permeability was subjected to heavy metal ion rejection which showed high rejection of 98.52% and 97.38% for heavy metal ions Pb2+ and Cd2+ respectively. © 2014 Elsevier B.V.
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    Performance enhancement of polysulfone ultrafiltration membrane using TiO2 nanofibers
    (Taylor and Francis Inc. 325 Chestnut St, Suite 800 Philadelphia PA 19106, 2016) Nair, A.K.; Shalin, P.M.; JagadeeshBabu, P.E.
    Titanium dioxide nanofibers were synthesized via alkaline hydrothermal method using TiO2 nanopowder. The hydrothermal method was optimized by studying the operating variables to obtain nanosized TiO2 fibers. These nanofibers were used to make composite polysulfone ultrafiltration membranes along with polyethylene glycol as pore forming agent. The obtained samples were characterized using scanning electron microscope, X-ray diffraction, and attenuated total reflectance infrared spectroscopy. Contact angle measurements were used to estimate hydrophilicity of the membrane. Performance of the membrane was analyzed using pure water flux studies and antifouling studies with bovine serum albumin as the standard protein for rejection. The composite membranes exhibited better performance in both permeability and antifouling property. © 2015 Balaban Desalination Publications. All rights reserved.
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    The effect of glycine betaine additive on the PPSU/PSF ultrafiltration membrane performance
    (Taylor and Francis Inc. dwt@deswater.com, 2016) Moideen K, I.; Isloor, A.M.; Garudachari, B.; A.F., A.F.
    A series of new ultrafiltration (UF) membranes were prepared by blending polyphenylsulfone and polysulfone with glycine betaine (GB) and polyethylene glycol-1000 (PEG-1000) as additive. GB of varying concentrations (0–2 wt.%) were dissolved in N-Methyl-2-pyrrolidone to prepare the membranes by phase inversion method. The membranes were characterized by Scanning Electron Microscope and dispersive X-ray analysis to study the asymmetric nature of membranes and the retention of GB in membranes, respectively. The stability tests were conducted to study the stability of additives in the membranes. The membrane hydrophilicity was determined by contact angle, porosity, water uptake, and permeability studies. The addition of GB additives enhanced the membrane performance like permeability, antifouling property, and heavy metal rejection. Also, the antifouling property improved with the addition of GB. The antifouling nature was calculated by flux recovery ratio, reversible and irreversible fouling. Polymer-enhanced UF of heavy metals like Pb2+ and Cd2+ was performed and rejection of 80.23 and 71.45%, respectively, was exhibited by the GB 1 membrane with agreeable permeability and antifouling property. © 2016 Balaban Desalination Publications. All rights reserved.
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    TiO2 nanosheet incorporated polysulfone ultrafiltration membranes for dye removal
    (Desalination Publications dwt@deswater.com, 2018) Nair, A.K.; Kumar, B.V.; Kalaiarasan, G.; JagadeeshBabu, J.B.
    Incorporation of nanomaterials in polymeric membranes is an effective means to improve membrane performance. In the present work, a novel additive TiO2 nanosheet was incorporated in polysulfone membrane. TiO2 nanosheets were synthesised by hydro-thermal method and blended with polysulfone to give nanocomposite membranes. The membranes performance was evaluated via pure water flux, bovine serum albumin rejection and anti fouling studies. Further the membranes were subjected to dye rejection application using Congo red and Rhodamine-B dyes. The membranes were characterised using scanning electron microscopy; X-ray diffraction and contact angle measurement. The nanocomposite membranes exhibited superior permeation, anti fouling and dye rejection traits. © 2018 Desalination Publications. All rights reserved.