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Showing 1 to 20 of 27 for “"reverse osmosis membranes"”.
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Colloidal fouling of reverse osmosis membranes
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1985.
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Effects of hydrocarbon fouling on reverse osmosis membranes
Organic fouling in reverse osmosis (RO) has been studied using model hydrocarbons such as hexane and diesel. A large number of countries that use reverse osmosis to obtain drinking water also are producers and exporters of hydrocarbons. This makes seawater RO units particularly susceptible to …
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Engineering nanostructured selective layers for reverse osmosis membranes
… with poor access and sanitation in 2007. Reverse 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 …
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Improvements to Polyamide Reverse Osmosis Membranes for Removal of Small, Neutral, Hydrophilic Solutes
… water sources, such as municipal wastewater, is reverse osmosis (RO). RO uses permselective membranes to remove solutes from source water while allowing clean permeate to pass through. While RO facilities treating municipal wastewater for potable purposes are already in operation, selectivity …
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Evaluation of a Typical CIP Protocol to Control Bacterial Biofilms on Whey Reverse Osmosis Membranes
… performance and premature replacement of membranes. Bacterial biofilms developed on reverse osmosis membranes cause severe flux decline during whey process1ng. Our previous studies provided clear evidence of mixed species biofilms on the membranes obtained from a commercial whey processing …
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The effect of very high hydraulic pressure on the permeability and salt rejection of reverse osmosis membranes
A stirred-cell reverse osmosis setup was used to demonstrate that a seawater 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 …
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Experiments and modeling of multilayered coatings and membranes : application to thermal barrier coatings and reverse osmosis membranes
… polymers with a view towards application to reverse-osmosis. A systematic simulation plus experiment-based methodology is proposed in order to calibrate the material parameters of the theory. Finally, the process of reverse osmosis is studied in the context of water desalination. An …
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The study of pretreatment options for composite fouling of reverse osmosis membranes used in water treatment and production
Most common inorganic foulants in RO processes operating on brackish water are calcium carbonate, calcium sulphate and silica. However, silica fouling is the recovery limiting factor in RO system. Silica chemistry is complex and its degree of fouling strongly depends on the silica solubility and …
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Bench Scale Analysis Of Experimental Fouling-resistent Low Pressure Reverse Osmosis Membranes Using High Organic Surface Water And Synthetic Colloidal Water
… filtration experiments were conducted on various membranes to investigate the physical and chemical factors that influence fouling. The effects of both organic and colloidal fouling were explored by conducting research on various commercial membranes and experimental membranes by Saehan …
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Thermodynamics of Polyamide Separation Membrane in Contact With Aqueous Solutions
The absorption of water in reverse osmosis membranes FT30 and LF10 is investigated by a combination of measurements of water mass uptake and biaxial stress as a function of relative humidity. Water solubility in polyamide active layer is 12 wt% at a relative humidity of 95%. The slope of a water …
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The feasibility of reverse osmosis as a water reclamation process with special reference to the rejection of organic compounds
… to assess the potential role and feasibility of reverse osmosis as a water reclamation process. In order to achieve this objective a number of separate desk, laboratory and pilot plant studies were conducted. It was concluded from the first desk study that a significant potential role exists for …
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Control of the desupersaturation reactor used in the SPARRO process
… focuses on the Slurry Precipitation And Recycle Reverse Osmosis (SPARRO) process. The process was designed to treat calcium sulphate (gypsum) scaling mine waters by encouraging preferentlal crystal growth onto introduced seeds, rather than on the reverse osmosis membranes. The major problem faced …
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Causes and analysis of failures in in-situ microscopy observation for the characterization of scaling in membrane distillation membranes
… and membrane lifespan. In the case of reverse osmosis membrane distillation (MD) involving fluid mixtures of inorganic elements, inorganic foulants build up on membrane surfaces, and reduce the flux of fluids across a membrane. Inorganic fouling can degrade the quality of water produced …
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Nanoporous graphene as a desalination membrane : a computational study
… 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 the salt passage depends critically on pore diameter, with pores in the 0.7-0.9 nm range allowing for …
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Advanced characterization of transport and microstructural properties in membrane materials
Membranes are employed in a variety of sustainable water treatment and energy conversion technologies. Advancing membrane materials for new separations includes unraveling the complex structure-property relationships that govern water and salt transport in conjunction with scaling processing …
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Advances in membrane-based oil/water separation
… Yet, despite their technological predominance, membranes can become severely fouled and irreversibly damaged when bulk and small stabilized oil droplets, emulsions, are present in intake streams. In this thesis, we seek to mitigate these deleterious effects through several means. First we seek …
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Investigating the adsorption and transport of water in MFI zeolite pores for water desalination
The permeability of reverse osmosis membranes is limited by the diffusive transport of water across a non-porous polyamide active layer. Alternatively, fabricating a microporous active layer capable of rejecting salt ions while allowing for water transport would increase the permeability while …
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Layer-by-layer assembly in confined geometries
… was used to modify track etched polycarbonate membranes in an attempt to build composite membranes which exhibited high salt rejection and high water permeance. These membranes were compared with theoretical models and with commercially available reverse osmosis membranes.
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Desalination of water by vapor transport through hydrophobic nanopores
Although Reverse osmosis (RO) is the state-of-the-art desalination technology, it still suffers from persistent drawbacks including low permeate flux, low selectivity for non-ionic species, and lack of resistance to chlorine. This leaves ample rooms. for further improvement for RO technology by …
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