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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 43 for “"salt rejection"”.
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Electrokinetic salt rejection in hyper-filtration through porous materials.
Massachusetts Institute of Technology. Dept. of Mechanical Engineering. Thesis. 1974. Ph.D.
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The effect of very high hydraulic pressure on the permeability and salt rejection of reverse osmosis membranes
… reverse osmosis membrane can maintain excellent rejection at pressures as high as 172 bar. However, it was also demonstrated that there was a significant drop in permeability at high pressures - likely due to membrane compaction. A simple visco-elastic model was shown to be able to model the …
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Effect of feed temperature on the performance and properties of the NF270 membrane
… passed through the membrane and water flux and salt rejection were measured. Results from fitting with experimental data show that water flux increased 23% and salt rejection changed minimally from 25°C to 40°C. A numerical fitting method used the experimental data to determine the parameters of …
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Superhydrophobic membranes for membrane distillation and crystallization
… lower operating temperature and pressures, high salt rejection and the ability to process high concentration feeds. However, inefficiencies exist in the form of low permeate flux and membrane wetting. Superhydrophobic modifications to the membrane surface could potentially overcome this issue. …
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Characterization and performance of vertically-aligned carbon nanotubes in capacitive deionization systems
… technology where adsorption capacity and salt removal rates into porous, tortuous carbon electrodes is still low. Previously, a breadth of carbon material electrodes have been investigated for CDI, due to their high surface area to volume ratio, high conductivity and non-corrosive property …
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Hybrid organic-inorganic pervaporation membranes for desalination
… independent of the concentration of the salt feed water. The pervaporation process combines the evaporation of volatile components of a mixture with their permeation through a nonporous polymeric membrane under reduced pressure conditions. In desalination applications, pervaporation has …
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Functionalized High Aspect Ratio Cellulose Nanocrystal Filled Composites for Gas and Liquid Separations
… exhibited an increase in water flux and sodium salt rejection up to a maximum when the m-phenylenediamine monomer to TOCN ratio was 20:1 followed by a decrease in both water flux and salt rejection with more TOCN added to the membrane. At the optimal loading level there was a 25% increase in the …
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Synthesis and Characterization of Linear and Crosslinked Mono-Sulfonated Poly(arylene ether sulfone)s for Reverse Osmosis Applications
… drawbacks that jeopardize effective levels of salt rejection in order to achieve high water flux. In mixed salt feed sources, monovalent salt rejection decreases when divalent cations such as Ca2+ bind with the anionic sulfonate groups to cause charge screening, and this can lead to too much …
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Engineering nanostructured selective layers for reverse osmosis membranes
… osmosis (RO), a process through which water is desalted via pressurized flow past a salt-selective membrane, is an energy-efficient method to generate freshwater from oceanic, brackish, and waste water sources. However, there are a number of challenges to scaling up RO processes to large scale …
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Investigating the adsorption and transport of water in MFI zeolite pores for water desalination
… a microporous active layer capable of rejecting salt ions while allowing for water transport would increase the permeability while maintaining high salt rejection. Zeolites provide a model porous network which is capable of performing this type of molecular sieve separation. However, a lack of …
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Novel thin film nanocomposite membranes with improved properties for enhanced desalination performance
… had higher water flux and comparable or higher salt rejection compared with the TFC membrane without nanoparticles. In addition, nanoparticle surface functionalization using epoxy and amine moieties facilitated the chemical interaction between SN and the TFC membranes, resulting in TFN membranes …
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Modification of polyamide thin film composite reverse osmosis membrane for water desalination
… better performance in term of water flux and salt rejection when compared to that of nanocomposite and composite membranes. As a concept, thin film quantum dots composite membrane may be used as an alternative for thin film composite reverse osmosis membrane.
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Synthesis and Characterization of Poly(arylene ether sulfone)s for Reverse Osmosis Water Purification and Gas Separation Membranes
… is an effective technique for increasing the salt rejection of water purification membranes and the selectivity of gas separation membranes. An abundance of monomers, telechelic oligomers, and novel polymers were synthesized for use as separation membranes. These materials were often imbued …
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Vertically-aligned carbon nanotube membranes for water desalination and ultrafiltration
… membranes were tested for water flux and salt rejection capabilities. The performance of VACNT membranes of densities 5×109, 1010, 5×1010 and 1011 cm-2 were 918, 1008, 1112 and 1202 LMH at 1 bar respectively. The permeance of 1202 LMH was around 30 times higher than traditional …
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Design of advanced reverse osmosis and nanofiltration membranes for water purification
… the water flux increased 5 - 6 times while the salt rejection almost kept constant. This membrane appears to provide a unique solution for hot water desalination and also a feasible way to improve the water productivity by increasing the operating temperature without any drop in salt rejection.
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Understanding the Impact of High Aspect Ratio Nanoparticles on Desalination Membrane Performance
… increase in water flux and an improvement in salt rejection to 98.98 ± 0.41 % compared to 97.53 ± 0.31 % for a plain polyamide control membrane. Likewise, a MOF nanorod membrane (0.01 wt% loading) with a high ratio of acid chain modification exhibited a 95% flux increase with maintained high …
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Design and fabrication of novel nanofiber membranes via electrospinning technique for membrane distillation
… with enhanced water vapor flux and stable salt rejection performances for the treatment of seawater, seawater RO brine and CSG RO brine by MD applications. The fabricated electrospun nanofiber membranes exhibited better performances than the commercial PVDF membranes due to their suitable …
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Effects of Multi-walled Carbon Nanotubes (MWCNTs) and Integrated MWCNTs/SiO2 Additives on Polymeric PVDF Membrane for Membrane Distillation
… great desalination potential with extremely high salt rejection (>99.98%). The incorporation of MWCNTs did not improve the tensile properties of the membrane.
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Synthesis, crosslinking and characterization of disulfonated poly(arylene ether sulfone)s for application in reverse osmosis and proton exchange membranes
… methanol permeability, water permeability and salt rejection. In general, all of the crosslinked membranes had lower water uptake and swelling relative to their uncrosslinked counterparts, and less water uptake and volume swelling were correlated with increasing gel fractions. It was possible …
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Nanoporous graphene as a desalination membrane : a computational study
… graphene can effectively filter NaCl salt from water. Using classical molecular dynamics, we report the desalination performance of such membranes as a function of pore size, chemical functionalization, and applied pressure. Our results indicate that the membrane's ability to prevent …
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