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Item A review on RO membrane technology: Developments and challenges(Elsevier B.V., 2015) Shenvi, S.S.; Isloor, A.M.; A.F., A.F.Reverse osmosis (RO) based desalination is one of the most important and widely recognized technologies for production of fresh water from saline water. Since its conception and initiation, a significant development has been witnessed in this technology w.r.t. materials, synthesis techniques, modification and modules over the last few decades. The working of a RO plant inclusive of the pretreatment and post-treatment procedures has been briefly discussed in the article. The main objective of this review is to highlight the historical milestones achieved in RO technology in terms of membrane performance, the developments seen over the last few years and the challenges perceived. The material properties of the membrane dominate the performance of a RO process. The emergence of nano-technology and biomimetic RO membranes as the futuristic tools is capable of revolutionizing the entire RO process. Hence the development of nano-structured membranes involving thin film nano-composite membranes, carbon-nanotube membranes and aquaporin-based membranes has been focussed in detail. The problems associated with a RO process such as scaling, brine disposal and boron removal are briefed and the measures adopted to address the same have been discussed. © 2014 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 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.Item (2E)-3-(6-Methoxynaphthalen-2-yl)-1-[4-(methylsulfanyl)phenyl] prop-2-en-1-one(2012) Fun, H.-K.; Chia, T.S.; Padaki, M.; Isloor, A.M.; A.F., A.F.The asymmetric unit of the title compound, C21H 18O2S, consists of two crystallographically independent molecules (A and B). The molecules exist in a trans conformation with respect to the central C=C bond. The naphthalene ring system makes dihedral angles of 51.62 (12) (molecule A) and 52.69 (12)°(molecule B) with the benzene ring. In molecule A, the prop-2-en-1-one group forms dihedral angles of 22.84 (15) and 29.02 (12)°with the adjacent naphthalene ring system and benzene ring, respectively, whereas the corresponding angles are 30.04 (12) and 23.33 (12)°in molecule B. In the crystal, molecules are linked by intermolecular C - H?O hydrogen bonds into head-to-tail chains along the a axis. The crystal packing also features C - H?? interactions. The crystal studied was a pseudo-merohedral twin with twin law (100 01?0 001?) and a refined component ratio of 0.6103 (16):0.3897 (16). © 2012 International Union of Crystallography.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.Item Synthesis, characterization and desalination study of composite NF membranes of novel Poly[(4-aminophenyl)sulfonyl]butanediamide (PASB) and methyalated Poly[(4-aminophenyl)sulfonyl]butanediamide (mPASB) with Polysulfone (PSf)(2013) Padaki, M.; Isloor, A.M.; Kumar, R.; A.F., A.F.; Matsuura, T.In the present investigation, Poly [(4-aminophenyl)sulfonyl]butanediamide (PASB) and methylated Poly[(4-aminophenyl)sulfonyl] butanediamide (mPASB) polymers were synthesized, using succinyl chloride and substituted 4-amino-1-benzenesulphonamide. Polysulfone composite membranes were prepared by blending these novel polymers by Diffusion Induced Phase Separation (DIPS) method. The performance of the membrane was studied in terms of salt rejection, water flux and molecular weight cutoff. The prepared membranes were hydrophilic in nature, which was confirmed by water uptake studies and contact angle measurement. All the membranes showed 1000. Da molecular weight cutoff. A maximum NaCl rejection of 52% was observed in some of the membranes. The effect of feed NaCl concentration on the NaCl rejection was also studied. The resistance of the membranes in a wide pH range was studied by water uptake measurement. Antifouling properties of the membranes were also performed using Bovine Serum Albumin (BSA) solution. © 2012 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.Item Preparation and characterization of PPEES/chitosan composite nanofiltration membrane(2013) Shenvi, S.S.; Abdul Rashid, S.A.; A.F., A.F.; Kassim, M.A.; Isloor, A.M.Composite membrane having chitosan (CH) as the active layer supported on Poly(1,4-phenylene ether ether sulfone) (PPEES) membrane was synthesized in the current study. The chitosan layer was crosslinked by glutaraldehyde in two different concentrations. The scanning electron microscopic images and hydraulic permeability coefficient revealed the ultrafiltration (UF) nature of the neat PPEES membrane. This was used as a new support material for the casting of chitosan layer in order to get composite membranes. The composite nature of the PPEES/CH membranes was confirmed by FESEM and DSC analysis. The Infrared spectroscopy results confirmed the crosslinking of the chitosan surface by glutaraldehyde (GA). The changes in the hydrophobic nature of the PPEES membrane surface due to deposition of chitosan active layer followed by crosslinking were studied by their contact angle measurement and water flux study. From our studies, PPEES has proved to be a good support membrane for preparation of composite membranes. Increase in GA concentration increased the salt rejection of the membrane up to 34% for NaCl and 53% for MgSO4 on one hand with a simultaneous decrease in the flux values. The hydraulic permeability coefficient values confirmed that the prepared membranes are in nanofiltration range. © 2012 Elsevier B.V.