Journal Articles

Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/19884

Browse

Subject: search.filters.subject.membrane

Search Results

Now showing 1 - 10 of 37
  • No Thumbnail Available
    Item
    Separation of dimethyl phenol using a spiral-wound RO membrane - Experimental and parameter estimation studies
    (2009) Srinivasan, G.; Sundaramoorthy, S.; Murthy, D.V.R.
    Reverse osmosis (RO) is increasingly used as a separation technique in chemical and environmental engineering for the removal of organics and organic pollutants present in waste water. Treatment of organics by RO is dependent on many factors and hence developing a viable RO system involves extensive pilot-plant studies. The removal of an organic compound, namely dimethyl phenol, using a polyamide membrane was investigated in this study. Experiments were conducted on a laboratory-scale spiral-wound RO module. The permeate concentrations and rejection coefficient values were measured for various transmembrane pressures and feed concentrations. A maximum rejection of 97% was observed. A mathematical model was developed for the RO module assuming a solution-diffusion mechanism for solute and solvent transport through the membrane and considering the concentration and pressure to be uniform on both permeate and retentate sides. The model has four parameters. A graphical method for estimating the model parameters was proposed. The model and the estimated parameter values were validated with the experimental data. The model was able to predict the permeate concentration within an error of 19% and rejection within 2% error. © 2009.
  • No Thumbnail Available
    Item
    Synthesis and desalination performance of Ar+-N+ irradiated polysulfone based new NF membrane
    (2011) Hegde, C.; Isloor, A.M.; Padaki, M.; Wanichapichart, P.; Liangdeng, Y.
    In the last few years, membrane technology has gained more attention from polymer chemists throughout the globe. Nowadays, surface modification of membrane is very useful in biotechnology and food science. In the present investigation, we have synthesized polysulfone based composite nanofiltration (NF) membranes, and characterized these membranes by FT-IR, SEM and membrane performance studies. Surface plasma treatment was carried out by irradiation with argon and nitrogen beams in suitable conditions. It was observed that nitrogen beam caused surface roughness that was more severe than the Ar beam. After irradiation, water contact angle was slightly increased. For pure water permeability, flux increased linearly with the operating pressure. However, for the salt solution, the flux was decreased marginally and salt rejection increased after irradiation due to surface modification. The modification effect was characterized in terms of contact angle, AFM employed roughness measurement and dielectric property. It revealed that irradiated NF membranes showed higher salt rejection and lower flux as compared to the nonmodified membranes. Accordingly, the roughness of the membrane surface intensively affected the performance of RO membrane. © 2010 Elsevier B.V.
  • No Thumbnail Available
    Item
    Conversion of microfiltration membrane into nanofiltration membrane by vapour phase deposition of aluminium for desalination application
    (2011) Padaki, M.; Isloor, A.M.; Nagaraja, K.K.; Nagaraja, H.S.; Pattabi, M.
    Preparation and modification of NF membrane are challenging aspects in research. In the present work, we have synthesised Polysulfone (PSf) microfiltration membrane and reduced the pore size to nano level by physical vapour deposition (PVD) of aluminium metal. Membrane pore size was reduced from micro pore to nano pore, which rejected 42.22% of NaCl from the solution with 164L/m2h. And also water permeation decreases from 1.10324-10-10 to the 9.141-10-12. The SEM and AFM pictures showed the surface modification and metal deposition in the pores. The performance of the membrane was studied by dead end flow cell using 3.5% of NaCl solution, in which PVD membrane showed 42.22% of rejection with 16.4L/m2h flux. Thermal analysis from DSC showed Tg of 265°C. Contact angle measurement, and water uptake were also reported. © 2011 Elsevier B.V.
  • No Thumbnail Available
    Item
    An analytical model for spiral wound reverse osmosis membrane modules: Part II - Experimental validation
    (2011) Sundaramoorthy, S.; Srinivasan, G.; Murthy, D.V.R.
    This paper presents the experimental studies carried out for validation of a new mathematical model [1] developed for predicting the performance of spiral wound RO modules. Experiments were conducted on a laboratory scale spiral wound RO module taking chlorophenol as a model solute. Experiments were carried out by varying feed flow rate, feed concentration and feed pressure and recording the readings of permeate concentration, retentate flow rate, retentate concentration and retentate pressure. A total of 73 experimental readings were recorded. The membrane transport parameters Aw (solvent transport coefficient) and Bs (solute transport coefficient) and the feed channel friction parameter b were estimated by a graphical technique developed in this work. The mass transfer coefficient k, estimated using the experimental data, was found to be strongly influenced by solvent flux and solute concentration apart from the fluid velocity. Taking the effects of solvent flux, solute concentration and fluid velocity, a new mass transfer correlation for Sherwood number is proposed in this work for the estimation of mass transfer coefficient. Comparison of model predictions with experimental observations demonstrated that the model was capable of predicting permeate concentration within 10% error, retentate rate flow within 4% error and rejection coefficient within 5% error. © 2011 Elsevier B.V.
  • No Thumbnail Available
    Item
    Polysulfone/N-phthaloylchitosan novel composite membranes for salt rejection application
    (2011) Padaki, M.; Isloor, A.M.; Wanichapichart, P.
    N-phthaloylchitosan (CS) was synthesized by the reaction of chitosan with phthalic anhydride in dimethyl formamide. Different compositions of polysulfone (PSf) and N-phthaloylchitosan were used to prepare novel polysulfone/N-phthaloylchitosan (PSf/CS) composite membranes by phase inversion method. The composition ratios between the former and the latter were 80:20, 85:15, 90:10, and 95:5. Water flux results revealed that, PSf:CS 80:20 membrane is found to have greatest effective pore area while PSf:CS 95:05 membrane has the smallest value. The pore area is found to be larger with the increase in CS composition. In addition, its water swelling property increases with the increase of CS composition. Water flux results are in consistent with dielectric constant value. Use of known molecular weight of polyethylene glycol rejection study, revealed that, PSf:CS 95:05 membrane possessed the smallest pore size among these membranes. In conclusion, change of ratio between PSf and CS, considerably affects membrane pore size and hydrophilicity. For salt filtration, membrane PSf:CS 95:05 showed 93%, 76.11% and 70.12% rejection of MgSO4, Na2SO4, and NaCl, respectively. © 2011 Elsevier B.V.
  • No Thumbnail Available
    Item
    Validation of an analytical model for spiral wound reverse osmosis membrane module using experimental data on the removal of dimethylphenol
    (2011) Srinivasan, G.; Sundaramoorthy, S.; Murthy, D.V.R.
    A new analytical model for spiral wound RO module has been recently proposed by Sundaramoorthy et al. [1] and the same has been validated [2] with experimental data obtained on a laboratory scale RO unit used for the removal of chlorophenol. In this paper, the need to check the validity of this model with solutes other than chlorophenol is addressed by conducting suitable experiments with dimethylphenol as solute and validating this experimental data with the model. The four model parameters namely solvent transport coefficient Aw, solute transport coefficient Bs, feed channel friction parameter b and the mass transfer coefficient k were estimated. The results show that the mass transfer coefficient is influenced not only by fluid velocity but also by the solvent flux and solute concentration. A new correlation for mass transfer coefficient k, proposed by Sundaramoorthy et al. [2] for experimental data taken with chlorophenol as solute is also shown to be consistent with the experimental readings recorded in this study taking dimethylphenol as solute. Comparison of model predictions with the experimental observations demonstrated the capability of the model in predicting permeate concentration within 12% error, retentate flow within 5% error and rejection coefficient within 2% error. © 2011 Elsevier B.V.
  • No Thumbnail Available
    Item
    An analytical model for spiral wound Reverse Osmosis membrane modules: Part I - Model development and parameter estimation
    (2011) Sundaramoorthy, S.; Srinivasan, G.; Murthy, D.V.R.
    A mathematical model for spiral wound Reverse Osmosis membrane module is presented in this work. The model incorporates spatial variations of pressure, flow and solute concentration in the feed channel and uniform conditions of pressure in the permeate channel. Assuming solution-diffusion model to be valid, explicit analytical equations were derived for spatial variations of pressure, flow, solvent flux and solute concentration on the feed channel side of the module. Analytical procedures for estimation of model parameters were presented. Graphical linear fit methods were developed for estimation of parameters Aw (solvent transport coefficient), Bs (solute transport coefficient) and b (feed channel friction parameter). The mass transfer coefficient k was assumed to vary along the length of the feed channel with varying conditions of flow, solute concentration and pressure. Explicit analytical equations for estimation of mass transfer coefficient were presented. In this paper (Part I), theoretical studies on development of mathematical model and methods for estimation of model parameters are presented. In Part II of this paper series [1], Studies on validation of this model with experimental data are presented. The studies cover experimental work on a spiral wound RO module with an organic compound namely chlorophenol as a solute. © 2011 Elsevier B.V.
  • No Thumbnail Available
    Item
    New polypropylene supported chitosan NF-membrane for desalination application
    (2011) Padaki, M.; Isloor, A.M.; Fernandes, J.; Prabhu, K.N.
    In the present study, a new NF membrane was prepared by coating chitosan on polypropylene fiber support, by the dissolution of chitosan in 2% acetic acid solution. The resulting membrane was characterized by thermo gravimetric analysis, water absorption, contact angle measurement and scanning electron microscopy. Prepared membrane showed two Tg peaks, one at ~90 °C that was due to chitosan and the other peak at ~170 °C that was corresponding to the supporting polypropylene membrane. The membrane showed a low swelling ratio at pH 7, 9, and 11 as compared with pH 5. The performance of the membrane was assessed out using dead end cell. Water flux was studied at different pressures. The salt rejection study was done using NaCl solution and the effect of pH on performance of the membrane was also examined. Newly prepared membrane showed improved water flux, and % of rejection is highest in acidic pH and lowest in basic pH. Hydrulic permeability coefficient and the dielectric constant confirms that the prepared membrane is nanofiltration membrane. © 2011 Elsevier B.V.
  • No Thumbnail Available
    Item
    Synthesis, characterization and desalination study of novel PSAB and mPSAB blend membranes with Polysulfone (PSf)
    (2012) Padaki, M.; Isloor, A.M.; A.F., A.F.; Abdullah, M.S.
    The present paper describes the synthesis of poly sulphonyl amino benzamide (PSAB) and methyalated poly sulphonyl amino benzamide (mPSAB) polymer, using terephthalic acid chloride and substituted 4-amino-1-benzensulphonmide in N-methyl-. 2-pyrrolidone. Polymers were characterized by FT-IR, NMR and GPC. Polysulfone composite membranes were prepared using these novel poymers by DIPS (Diffusion Induced Phase Seperation) method. These composite membranes are useful for water purification with special emphasis on sea water desalination. Newly prepared membranes were studied for salt rejection, water flux, molecular weight cut off by PEG solution, effect of the pH on water swelling and salt rejection and flux decline was also studied. 30 to 70% of the salt rejection was observed in all membranes. Effect of the dilution on salt rejection was studied using different concentration of NaCl solution varying from 1000. ppm to 3500. ppm. All the membranes showed 80% rejection for PEG having 1000. Da molecular weight. Contact angle and water swelling was measured to determine hydrophilicity of the membrane. Water swelling and salt rejection in different pH was also studied. © 2012 Elsevier B.V.
  • No Thumbnail Available
    Item
    Preparation and characterization of sulfonated polysulfone and N-phthloyl chitosan blend composite cation-exchange membrane for desalination
    (2012) Padaki, M.; Isloor, A.M.; Wanichapichart, P.; A.F., A.F.
    Sulfonated polysulfone (sPSf) was prepared and used as a polymer matrix for cation-exchange membranes (CEM). The sulfonation reaction was carried out at room temperature and the degree of sulfonation was calculated by titration method. Blend composite membranes were prepared using different ratios of sPSf and modified chitosan (CS). Membrane properties were studied in terms of water flux, water swelling ratio, molecular weight cut off (MWCO), ion-exchange capacity (IEC) and contact angle measurement. Charge on the membrane was confirmed by ionic diffusion potential (DP). It was observed that, DP increased with the increase in the concentration of sPSf. The membrane sPSf:CS 60:40 showed 1000Da MWCO, 14.6mV diffusion potential (DP) and 0.083mM/g of IEC. Similarly sPSf:CS 90:10 showed 10,000Da MWCO, 71.7mV diffusion potential (DP) and 0.176mM/g of IEC. Moreover, membrane sPSf:CS 60:40 showed 93%, 89% and 69% for MgSO 4, Na 2SO 4 and NaCl rejection respectively. © 2012 Elsevier B.V.