Faculty Publications
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Item Synthetic polymer-based membranes for dye and pigment removal(Elsevier, 2020) Gnani Peer Mohamed, G.P.S.; Isloor, A.M.; Lakshmi, B.The use of synthetic polymeric membranes to remove dyes and pigments from industrial wastewater is a growing technology. The toxic and nonbiodegradable nature of dyes and pigments in industrial wastewater influences the importance of the removal of those dyes and pigments. Conventional methods such as coagulation, the photocatalytic process, adsorption, ozonation, plasma treatment, electrochemical treatment, etc., are proposed. However, these methods are very time-consuming, use expensive catalysts, are difficult to scale up, and need secondary treatment. In recent times, a substantial number of attempts have been put forward to advance the performance of polymeric membranes for dye and pigment wastewater treatment. In this chapter, the recent progress on the use of polymeric membranes in processes such as nanofiltration, membrane distillation, and ultrafiltration for effective dye and pigment removal are discussed. © 2020 Elsevier Inc. All rights reserved.Item Synthesis, characterization & impedance studies of some new nano filtration membranes(Trans Tech Publications Ltd ttp@transtec.ch, 2010) Padaki, M.; Hegde, C.; Isloor, A.M.In the recent years membrane technology has gained significant attention from polymer chemists all around the world due to their attractive features such as efficiency, low costs, low energy costs and as effective solutions to longstanding problems in the chemical industries. Membrane technologies have been widely applied in the separation of liquids and even gases. Many separation problems can be solved economically by nanofiltration alone or in combination with other separation processes. This study aimed to synthesize polysulfone based nanofiltration membranes using DIPS (diffusion induced phase separation) technique. Newly synthesized polymer membranes were subjected to Infra red spectral and water uptake studies. Membranes were also characterized using electrochemical spectroscopy for their proton conducting property. Their surface morphology is visualized by SEM. © (2010) Trans Tech Publications.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.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.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.Item New CPS-PPEES blend membranes for CaCl2 and NaCl rejection(Techno Press technop2@chollian.net, 2012) Hegde, C.; Isloor, A.M.; Padaki, M.; A.F., A.F.; Lau, L.W.Carboxylated polysulfone (CPS), poly (1,4-phenylene ether ethersulfone) (PPEES), membranes were prepared and used for the separation of NaCl and CaCl2 in efficient way with less energy consumption. In this work, nanofiltration and reverse osmosis membranes were employed to the salt rejection behavior of the different salt solutions. The influence of applied pressure (1-12 bar), on the membrane performance was assessed. In CM series of membranes, CM1 showed maximum of 97% water uptake and 36% water swelling, whereas, CM4 showed 75% water uptake and 28% water swelling. In RCM series, RCM1 showed 85% water uptake and 32% water swelling whereas, in RCM4 it was 68% for water uptake and 20% for water swelling. Conclusively reverse osmosis membranes gave better rejection whereas nanofiltration membrane showed enhanced flux. CM1 showed 58% of rejection with 12L/(m2h) flux and RCM1 showed 55% of rejection with 15L/(m2h) flux for 0.1wt.% NaCl solution. Whereas, in 0.1wt.% CaCl22 solution, membrane CM11 showed 78% of rejection with 12L/(m2h) flux and RCM1 showed 63% rejection with flux of 9L/(m2h).Item Preparation and characterization of polysulfone and modified poly isobutylene-alt-maleic anhydride blend NF membrane(2012) Ganesh, B.M.; Isloor, A.M.; Padaki, M.Recently nanofiltration (NF) is gaining more importance for water treatment. It is replacing the conventional method of water treatment due to advantages of NF membranes over RO system. In this work, we are discussing the preparation of NF membrane for desalination of sea water. We herein report the synthesis of polymer, by the reaction of p-amino benzoic acid (PABA) and poly isobutylene-alt-maleic anhydride (PIAM) and its blend membrane preparation with polysulfone (PSf). The new membranes were characterized by SEM images, surface wettability to investigate the hydrophilic nature of the membrane, water swelling, pure water flux, molecular weight cut-off and salt rejection of the membranes. The membranes showed nano size (<50nm) pores in SEM image, and the contact angle data revealed that membrane surface is moderately hydrophilic. Membrane with 70:30 (PSf:modified PIAM) composition has shown good salt rejection of 96% at 200kPa for 3500ppm of NaCl solution with a pure water flux of 38.36Lm -2h -1. © 2011 Elsevier B.V.Item 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.Item Enhanced hydrophilicity and salt rejection study of graphene oxide-polysulfone mixed matrix membrane(2013) Ganesh, B.M.; Isloor, A.M.; A.F., A.F.Graphene oxide (GO) dispersed polysulfone (PSf) mixed matrix membranes were prepared by wet phase inversion method. The morphology of membranes was studied using scanning electron microscope (SEM) images. The variation in hydrophilicity was studied by measuring surface wettability and water swelling experiments. The performance of membranes in terms of pure water flux and salt rejection was studied. SEM images depict enhanced macrovoids, while the contact angle data reveals that, GO incorporated membrane surface is moderately hydrophilic. Membranes exhibited improved salt rejection after GO doping. Membrane with 2000ppm GO loading has exhibited maximum of 72% Na2SO4 rejection at 4bar applied pressure. The salt rejection seems to depend on pH of the feed solution and it has been witnessed that the salt rejection showed an increasing trend with increase in the pH. © 2012 Elsevier B.V.Item 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.