Reverse osmosis membranes studies

Durability Study of Cellulose Acetate Reverse-Osmosis Membrane Under Adverse Circumstances for Desalting... 

Intrinsic Membrane Compaction and Aqueous Solute Studies of Hyperfiltration (Reverse-Osmosis) Membranes Using Interferometry ... 

This study was conducted in an effort to learn more about the interaction of halogens with commercial reverse osmosis membranes under a variety of experimental conditions. Membranes used in this work representing several different polymer systems were pro-... 

The aim of this study is to investigate the ability of ortho-phosphoric acid to function as the pore-producing additive for the preparation of CA reverse osmosis membranes. Ortho-phosphoric acid (PA) is known to be a strongly hydrogen bonded liquid, and it has been claimed ( ) to be a promising additive for the asymmetric CA membrane formation. To our knowledge, there has not been a thorough study on the problem. 

This paper has provided the reader with an introduction to a class of polymers that show great potential as reverse osmosis membrane materials — poly(aryl ethers). Resistance to degradation and hydrolysis as well as resistance to stress Induced creep make membranes of these polymers particularly attractive. It has been demonstrated that through sulfonation the hydrophilic/hydrophobic, flux/separation, and structural stability characteristics of these membranes can be altered to suit the specific application. It has been Illustrated that the nature of the counter-ion of the sulfonation plays a role in determining performance characteristics. In the preliminary studies reported here, one particular poly(aryl ether) has been studied — the sulfonated derivative of Blsphenol A - polysulfone. This polymer was selected to serve as a model for the development of experimental techniques as well as to permit the investigation of variables... 

Bacterial cells for the laboratory studies were prepared by growing V. alginolyticus in a M9 minimal salts bacterial growth medium with 8mM glucose as the carbon and energy source (70). The standard M9 medium was modified by addition of 21 g/L of NaCl (SWM9). Water used for all studies was deionized and passed through a reverse osmosis membrane (Milli-Q). 

The most extensive studies of plasma-polymerized membranes were performed in the 1970s and early 1980s by Yasuda, who tried to develop high-performance reverse osmosis membranes by depositing plasma films onto microporous poly-sulfone films [60,61]. More recently other workers have studied the gas permeability of plasma-polymerized films. For example, Stancell and Spencer [62] were able to obtain a gas separation plasma membrane with a hydrogen/methane selectivity of almost 300, and Kawakami et al. [63] have reported plasma membranes... 

Kucera-Gienger, Studies on Halogen Interaction with Polyamide Type Reverse Osmosis Membranes, Master s Thesis, UCLA, March, 1984. 

Much effort has been expended in attempting to use membranes for separations. Reverse osmosis membranes are used worldwide for water purification. These membranes are based on size selectivity depending on the pores used. They do not have the ability to selectively separate target species other than by size. Incorporation of carrier molecules into liquid membrane systems of various types has resulted in achievement of highly selective separations on a laboratory scale. Reviews of the extensive literature on the use of liquid membrane systems for carrier-mediated ion separations have been published [15-20]. A variety of liquid membranes has been studied including bulk (BLM), emulsion (ELM), thin sheet supported (TSSLM), hollow fiber supported (HFSLM), and two module hollow fiber supported (TMHFSLM) types. Of these liquid membranes, only the ELM and TMHFSLM types are likely to be commercialized. Inadequacies of the remaining... 

This section describes some case studies carried out by the authors, which are related to radioactive liquid waste treatment using membrane processes a study about the influence of radiation on reverse osmosis membranes, a practical case about concentration of I radioactive liquid wastes by ultrafiltration and reverse osmosis processes, and a practical experience about decontamination of Cs liquid waste by reverse osmosis, including a study of radiological protection during the treatment. 

Belfer, S., Purinson, Y., and Kedem, O., Surface modification of commercial polyamide reverse osmosis membranes by radical grafting An ATR-FT-IR study, Acta Polym., 49, 574, 1998. 

B. A. Winfield, A study of the factors affecting the rate of fouling of reverse osmosis membranes treating secondary sewage effluent. Water Research 13, 565-569 (1979). 

The conclusion which can be drawn from the above studies is that the skin layer in integrally-skinned reverse osmosis membranes consists of a single layer of consolidated Sol 2 type micelles. 

An effect not considered in the above models is the added resistance, caused by fouling, to solute back-diffusion from the boundary layer. Fouling thus increases concentration polarization effects and raises the osmotic pressure of the feed adjacent to the membrane surface, so reducing the driving force for permeation. This factor was explored experimentally by Sheppard and Thomas (31) by covering reverse osmosis membranes with uniform, permeable plastic films. These authors also developed a predictive model to correlate their results. Carter et al. (32) have studied the concentration polarization caused by the build-up of rust fouling layers on reverse osmosis membranes but assumed (and confirmed by experiment) that the rust layer had negligible hydraulic resistance. 

Abstract The processes of lactic acid production include two key stages, which are (a) fermentation and (h) product recovery. In this study, fiee cell of Bifidobacterium longum was used to produce lactic acid from cheese whey. The produced lactic acid was then separated and purified from the fermentation broth using combination of nanofiltration and reverse osmosis membranes. Nanofiltration membrane with a molecular weight cutofif of 100-400 Da was used to separate lactic acid from lactose and cells in the cheese whey fermentation broth in the first step. The obtained permeate from the above nanofiltration is mainly composed of lactic acid and water, which was then concentrated with a reverse osmosis membrane in the second step. Among the tested nanofiltration membranes, HL membrane from GE Osmonics has the highest lactose retention (97 1%). In the reverse osmosis process, the ADF membrane could retain 100% of lactic acid to obtain permeate with water only. The effect of membrane and pressure on permeate flux and retention of lactose/lactic acid was also reported in this paper. 

Hyung H and Kim JH, A mechanistic study on boron rejection by sea water reverse osmosis membranes. Journal of Membrane Science 2006, 286, 269—278. 

M. Herzberg, M. Elimelech, Physiology and genetic haits of reverse osmosis membrane biofihns A case study with Pseudomonas aeruginosa, ISME Journal 2008, 2, 180-194. 

The effect of the direction of flow on deposition rate distribution has received some attention. The effect of the position of the monomer inlet in a capacitively coupled bell-jar reactor has been studied [41, 52]. In the latter work, the position of the inlet was found to affect the efficacy of the resultant plasma polymer as a reverse osmosis membrane. 

Enomoto, H., Lujitsuka, M Hasegawa, T. et al. (2010) A feasibility study of pressure-retarded osmosis power generation system based on measuring permeation volume using reverse osmosis membrane. Electrical Engineering in Japan, 173 (2), 8-20. 

Xu, X. and Kirkpatrick, R.J. 2006. NaCl interaction with interfacially polymerized polyamide films of reverse osmosis membranes A solid-state Na NMR study. J. Membr. Sci. 280 226-233. 

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