Faculty Publications
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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 Hydrophilic polydopamine/polyvinylpyrrolidone blended polyphenylsulfone hollow fiber membranes for the removal of arsenic-V from water(Elsevier Ltd, 2023) Kumar, M.; Isloor, A.M.; Nayak, M.C.S.; Todeti, S.R.; Padaki, M.; A.F., A.F.The demand for fresh drinking water is sky rocketing with the world's increasing population, urbanization and various industrial growth. However, toxic heavy metals and metalloids like arsenic is contaminating the drinking water. Arsenic is poisonous, carcinogenic and mutagenic for millions of population. We hereby proposing in-house fabricated novel hollow fiber membranes using polyphenylsulfone (PPSU) and pore-forming agent polyvinylpyrrolidone (PVP) along with increased concentrations of bio-inspired hydrophilic additive polydopamine (PDA) for removal of arsenic-V from the drinking water. The crystallinity of PDA was interpreted by X-ray diffraction. The morphology, topology and membrane surface chemistry of fabricated membranes were evaluated by scanning electron microscopy, atomic force microscopy, thermogravimetric analysis, fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy. The results indicated that, for the PDA-contained membranes overall performance was increased in terms of membrane hydrophilic characteristics and rejection efficacy. A 3 wt% of PDA in PPSU/PVP (PDA-3) executed enhanced arsenate (As-V) removal as high as 87.15% with flux of 31.80 L/m2h, which was higher than the neat membrane (PDA-0) as 67.70% with flux of 15.07 L/m2h for 5 mL/L arsenic-V aqueous solution at 0.2 MPa transmembrane pressure. Improved antifouling properties were observed from PDA-contained hollow fiber membranes, as evidenced by the improved flux recovery ratio and superior thermal stability. The mechanical properties (tensile strength) of pristine and PDA-contained membranes was also investigated. © 2023