Faculty Publications
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Item Membrane technology—a promising approach for metal ion extraction(Elsevier, 2024) Antony, N.; Vijesh, A.M.; Isloor, A.M.Metal ion extraction using ion exchange membranes (IEM) receives much attention as it can find a solution to environmental problems to reduce emissions of heavy metals from wastewater contaminated with industrial effluents. Among the various IEM available, cation exchange membranes are widely used by researchers due to its enhanced ability to hold the metal ion and retain them in the organic phase. This review book chapter emphasizes the extraction of metal ions, specifically about the studies carried out in the field of iron, zinc, and copper metal ions using IEM. © 2024 Elsevier Inc. All rights reserved.Item Preparation and evaluation of heavy metal rejection properties of polysulfone/chitosan, polysulfone/N-succinyl chitosan and polysulfone/N-propylphosphonyl chitosan blend ultrafiltration membranes(Elsevier, 2014) Kumar, R.; Isloor, A.M.; A.F., A.F.Heavy metal rejection properties of chitosan based polysulfone/chitosan (PSf/CS), polysulfonef/N-succinyl chitosan (PSf/NSCS) and polysulfone/N-propylphosphonyl chitosan (PSf/NPPCS) ultrfiltration (UF) membranes were evaluated. The rejection of membranes towards the copper, cadmium and nickel ions was studied during ultrafiltration (UF) by polymer enhanced ultrafiltration (PEUF) processes. The flux change during the UF process and the effect of pH on the rejection were determined. The membrane recycling property was studied during PEUF process by filtering chelated CuSO4 solution. A maximum of 78% of Cu, 73% of Ni and 68% of Cd rejection for M-5 membrane, 75% of Cu, 71% of Ni and 66% of Cd rejection for M-8 membrane and 76% of Cu, 69% of Ni and 66% of Cd rejection for M-2 membrane with reasonably good flux was observed. Further improvement in heavy metal ion rejection was achieved by PEUF process. Membrane M-5 showed a maximum of 98%, 95% and 92% rejection for Cu, Ni and Cd respectively with steady state flux of 117L/m2h. An increase in membrane recycling property after the metal ion rejection was mainly attributed to the hydrophilicity of CS, NSCS and NPPCS. © 2014 Elsevier B.V.Item 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.Item Fabrication of polydopamine functionalized halloysite nanotube/polyetherimide membranes for heavy metal removal(Royal Society of Chemistry, 2016) Hebbar, R.S.; Isloor, A.M.; Kulal, K.; A.F., A.F.Polydopamine modified halloysite nanotubes (HNTs) were synthesised through a one step facile procedure and employed as a well dispersed hydrophilic additive to enhance the filtration properties of polyetherimide (PEI) membranes. The nanocomposite membranes were prepared by an immersion precipitation method with different amounts of modified HNTs (MHNTs) in the casting solution. The good dispersion of MHNTs throughout the membrane matrix was confirmed by elemental mapping analysis. The prepared nanocomposite membranes were extensively studied in terms of their porosity, morphology, membrane hydraulic resistance and hydrophilicity. The permeation experiments showed that the modified membranes exhibited higher water flux than a pristine PEI membrane. The antifouling and anti-biofouling behaviour of the modified membranes was investigated in detail. The results revealed that a membrane with a 3 wt% MHNT dosage showed a higher Fouling Resistance Ratio (FRR) of 74.5% with reversible membrane fouling of 64.3%. Moreover, the membrane showed excellent resistance to microbial growth on the membrane surface. The well performing membrane was subjected to heavy metal ion rejection. Results indicated that membranes had the capacity to adsorb Pb2+ and Cd2+. Overall, PEI-MHNTs nanocomposite membranes could have great potential to improve antifouling, anti-biofouling and filtration properties. © The Royal Society of Chemistry 2016.Item Synthesis and characterization of novel sulfanilic acid-polyvinyl chloride-polysulfone blend membranes for metal ion rejection(Royal Society of Chemistry, 2016) Nayak, V.; Jyothi, M.S.; Balakrishna, R.G.; Padaki, M.; Isloor, A.M.Near-complete removal of heavy metals, namely Cd(ii), Cr(vi) and Pb(ii), has been attempted by a membrane purification process using a blend of modified polyvinyl chloride (PVC) and polysulfone (PSf), prepared by the diffusion induced phase separation (DIPS) method. The prepared novel material was characterized by NMR, ATR-IR spectroscopy and DSC. The sulphonyl groups incorporated into PVC enhance the hydrophilicity and are substantiated by water uptake, contact angle (CA) and flux studies. The obtained properties of the blend membrane like increased surface roughness and porosity are observed from AFM and SEM analysis. An enhanced rejection of ?95% which is about 1.15, 1.41 and 1.37 times better than the commercially available NF 270 membrane was observed, for Cd(ii), Cr(vi) and Pb(ii) respectively. The work was further extended to study the antifouling property and the interference of other existing metal ions on the performance. An improved antifouling property with 98.5% rejection for bovine serum albumin (BSA) and a 75.6% flux recovery ratio (FRR) was achieved. The study gains significance in exploring the incorporation of sulphonyl groups in to polymers, to enhance membrane performance. © The Royal Society of Chemistry 2016.Item Favorable influence of mPIAM on PSf blend membranes for ion rejection(Elsevier B.V., 2017) Jyothi, M.S.; Soontarapa, K.; Padaki, M.; Balakrishna, R.G.; Isloor, A.M.The study reports the use of a novel membrane for heavy metal removal and salt rejection. Poly isobutylene alt maleic anhydride (PIAM) modified by sulfanilic acid is blended with polysulfone (PSf) in different concentrations. This induces surface charge and hydrophillicity in the otherwise hydrophobic PSf membranes. The so modified polymers and their blends are characterized by spectroscopic and microscopic techniques. Blend membranes show drastically enhanced performance with respect to water flux, water uptake and ion exchange capacity. SEM micrographs indicate the hydrophilic domains, –SO3H groups in the polymer to have formed cavities during phase inversion process, thus enhancing permeability. 100% rejection of PEG 2000 and 59% of NaCl rejection substantiated the nature of the membrane to be nanofiltration (NF) type. The prepared membranes were further evaluated for Cr (VI) removal, with removal efficiency reaching above 92%. The electronic coupling that occurs between SO3H? and Na+ and the electrostatic interaction between metal ions and the charge on membrane facilitates NaCl and Cr (VI) rejection respectively. The study gains significance in use of such modified PIAM as blend material with any other polymer to enhance the native properties of the blend membrane. © 2017 Elsevier B.V.Item Performance intensification of the polysulfone ultrafiltration membrane by blending with copolymer encompassing novel derivative of poly(styrene-co-maleic anhydride) for heavy metal removal from wastewater(Elsevier B.V., 2018) Gnani Peer Mohamed, G.P.S.; Isloor, A.M.; Siddique, I.; Asiri, A.M.; A.F., A.F.; Kumar, R.; Ahamed, M.I.A simple, scalable, novel polymer was synthesized by the aminolysis of poly(styrene-co-maleic anhydride) cumene terminated (PSMAC) using p-aminohippuric acid. The main objective was to perceive the effect of blend ratio of polysulfone (PSF) and poly[styrene-alt-(N-4-benzoylglycine-maleamic acid)] cumene terminated (PAH) on morphology and permeation properties of the membranes. The PSF/PAH blend membranes unveiled enriched hydrophilicity, porosity, zeta potential, water uptake and permeability owing to the existence of the hydrophilic PAH. However, the contact angle was not diminished over 20% of PAH ratio as there was an increase of hydrophobic alkyl group density. Differential scanning calorimetry (DSC) was employed for the determination of the glass transition temperature of the blends and the results revealed that the polymer blend is miscible in nature. Moreover, the M-3 membrane was screened for the heavy metal ion removal and achieved removal of 91.5% of Pb2+ and 72.3% of Cd2+ ions, respectively. The adsorption parameters indicated that the Langmuir isotherm model fits well for both Pb2+ and Cd2+ ions adsorption on M-3 membrane. The adsorption capacity attained from Langmuir isotherm model was 19.35 and 9.88 mg/g for Pb2+ and Cd2+ ions correspondingly. © 2018 Elsevier B.V.Item Integration of Zwitterionic Polymer Nanoparticles in Interfacial Polymerization for Ion Separation(American Chemical Society, 2020) Gnani Peer Mohamed, G.P.S.; Isloor, A.M.; Bavarian, M.; Nejati, S.A thin-film nanocomposite (TFN) membrane was developed by integrating zwitterionic polymeric nanoparticles into the active layer of the membranes. High surface area zwitterionic polymeric nanoparticles (370 m2/g) were developed through distillation-precipitation polymerization (DPP). Sodium 4-vinylbenzenesulfonate (SVBS) was used as the monomer and N,N?-methylenebis(acrylamide) (MBAAm) utilized as the cross-linking agent. l-cysteine (l-Cys) was tethered to these matrices through thiol-ene reaction. The as-synthesized zwitterionic P(MBAAm-co-SVBS)@l-Cys nanoparticles were dispersed into the organic solution of trimesoyl chloride (TMC) to be integrated into the polyamide (PA) selective layer of thin film nanofiltration membranes. The PA layer was synthesized by interfacial polymerization through the reaction of 2% (w/v) of piperazine (PIP) in the aqueous phase and 0.15% (w/v) of the TMC solution. The fabricated TFN membranes exhibited pure water permeability (Jw) of 11.4 L/m2h bar and salt rejection value of 97.6% and 16.9%, for sodium sulfate and sodium chloride, respectively. The fabricated membranes demonstrated metal ion removal efficiencies of 99.48% and 95.67% for Pb2+ and Cd2+ ions, respectively. © © 2020 American Chemical Society.Item Fabrication and incorporation of MIL-53(Fe)-zwitterionic brushes into PVDF thin film composite membranes for enhancing heavy metal/dye rejection from aqueous body(Elsevier B.V., 2025) Prabhakar, N.; Isloor, A.M.; Farnood, R.; Fauzi Ismail, A.The bioaccumulation of heavy metal ions is a serious concern for researchers. The dyes and heavy metal ions also aquatic life impacting the biodiversity adversely. Synthesis of novel MIL-53(Fe)-PSBMA particles, and its incorporation into PVDF-based thin-film composite membranes is the crux of this work. Firstly, H2N-MIL-53(Fe) was synthesized by metal displacement reaction which was then modified into MIL-53(Fe)-PSBMA brushes. The brushes were synthesized by atom transfer radical polymerization method. The amine groups of the NH2-MIL-53(Fe) help connecting the MOF to the polymeric moiety. The as-synthesized material and the fabricated TFCs were characterized by BET, FTIR, XRD, XPS, TGA, AFM, FE-SEM, zeta potential, and DLS particle sizer. The presence of sulphur groups on the XPS spectrum of modified MOF ensured the successful polymer grafting on it. Zwitterionic moieties have both positive and negative charges within a single molecule which gave a resultant zeta potential of ?13.1 mV for the brushes. A pure water flux of 26.32 Lm?2 h?1 and 97.33 %, 95.19 %, 82.06 %, and 78.47 % rejections for Pb2+, Hg2+, As3+, Cd2+ ions and 96.23 % and 94.04 % rejection for 100 ppm reactive black-5 and sunset yellow dyes respectively were obtained for the optimized membrane having 0.035 wt% loading of zwitterionic MOF. This result was attributed to the enhanced membrane hydrophilicity which was also correlated with contact angle and water uptake studies. © 2024 Elsevier B.V.Item A chicken egg white-based amyloid–graphitic carbon nitride composite-incorporated hollow fiber membrane for efficient removal of dyes and heavy metal ions present in water(Royal Society of Chemistry, 2025) Nayak, S.S.; Isloor, A.M.; A.F., A.F.Severe water pollution due to excessive industrialization is resulting in a pure water crisis for humans and other living beings. This growing crisis emphasizes the urgent need for advanced and efficient water purification technologies to mitigate pollution and ensure the availability of pure water. To address this issue, the current study focuses on the synthesis of a chicken egg white amyloid–graphitic carbon nitride composite (AM–CN) using graphitic carbon nitride (g-C3N4) and egg whites through environment friendly and simple techniques. These composites were further characterized using different analytical techniques such as BET, FTIR, XRD, SEM, and TEM to understand the structure of the composite. Furthermore, these composites were embedded into hollow fiber membranes, and later, these membranes were analyzed through AFM, SEM, and hydrophilicity studies to understand the character and structure of the membrane. The filtration performance of the membrane revealed that the membrane with the AM–CN composite demonstrated enhanced performance in both pure water permeability and pollutant removal capacity. Among the fabricated membranes, the neat membrane exhibited a pure water permeability of 81 L m?2 h?1 bar?1. In contrast, the highest permeability of 203 L m?2 h?1 bar?1 was exhibited by the M II membrane, therefore considering it as an optimized membrane. This optimized membrane also displayed the highest pollutant removal capacity of >99% for Congo red dye, >98% for Reactive black 5 and 88% for Reactive orange 16 dye. In the case of heavy metal ion removal, the same membrane displayed an impressive 99% removal of lead ions and 75% removal of mercury ions in the presence of humic acid. © 2025 The Royal Society of Chemistry.