scholarly journals Pressure Dependency of the Membrane Structure Parameter and Implications in Pressure Retarded Osmosis (PRO)

2018 ◽  
Author(s):  
Torleif Holt ◽  
Edvard Sivertsen ◽  
Willy R. Thelin ◽  
Geir Brekke
Keyword(s):  
Membrane Structure ◽  
Structure Parameter ◽  
Pressure Retarded Osmosis ◽  
Pressure Dependency

Influence of pretreatment on AMWD (apparent molecular weight distribution) of dissolved organics in the secondary effluent and membrane structure parameter model analysis for ultrafiltration

2006 ◽  
Vol 6 (4) ◽  
pp. 99-106
Author(s):  
L. Wang ◽  
X.D. Wang ◽  
J.T. Chai ◽  
Y. Kang
Keyword(s):  
Molecular Weight ◽  
Pore Size ◽  
High Molecular Weight ◽  
Membrane Structure ◽  
Apparent Molecular Weight ◽  
Low Molecular Weight ◽  
Secondary Effluent ◽  
Structure Parameter ◽  
Pore Density ◽  
The Mean

This study analyzed the characteristics of the apparent molecular weight distribution (AMWD) of the secondary effluent organic matter and investigated the effect of various applicable pretreatment technologies for ultrafiltration (UF), including coagulation, powdered activity carbon (PAC) adsorption and O3-PAC process, on the AMWD of effluent and the flux decline. The influence of molecular size distribution on the mean pore size and pore density of membrane was then evaluated with the model of membrane structure parameter. The results showed: (1) after different pretreatments, the AMWD of raw water changed, coagulation could effectively remove high molecular weight organics, PAC adsorption was effective in removing low molecular weight organics, due to ozonization and PAC adsorption and O3-PAC pretreatment could remove both high molecular weight and low molecular weight organics; (2) the AMWD had great influence on membrane permeation, after different pretreatments, the AMWD of raw water changed and the variation of membrane permeation was also different; (3) the influence factors a1and a2 of the mean pore size and the membrane pore density of different pretreatment water samples were used as indexes which calculated through experiment and the model of membrane structure parameter. The influence of AMWD in water samples on the membrane mean pore size and pore density were then evaluated, which showed that low molecular weight organics could easily cause interior adsorption, and high molecular weight organics could easily cause membrane surface blocking.

Determination of a constant membrane structure parameter in forward osmosis processes

2011 ◽  
Vol 375 (1-2) ◽  
pp. 241-248 ◽  
Author(s):  
Minkyu Park ◽  
Ji Jung Lee ◽  
Sangho Lee ◽  
Joon Ha Kim
Keyword(s):  
Membrane Structure ◽  
Forward Osmosis ◽  
Structure Parameter

Bimolecular and Monomolecular Lipid Films: Selected Area Electron Diffraction

1969 ◽  
Vol 27 ◽  
pp. 338-339
Author(s):  
Robert M. Glaeser ◽  
David W. Deamer
Keyword(s):  
Electron Diffraction ◽  
Membrane Structure ◽  
Molecular Organization ◽  
Membrane Material ◽  
X Ray Diffraction ◽  
Membrane Systems ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Lipid Films ◽  
Ultimate Objective

In the investigation of the molecular organization of cell membranes it is often supposed that lipid molecules are arranged in a bimolecular film. X-ray diffraction data obtained in a direction perpendicular to the plane of suitably layered membrane systems have generally been interpreted in accord with such a model of the membrane structure. The present studies were begun in order to determine whether selected area electron diffraction would provide a tool of sufficient sensitivity to permit investigation of the degree of intermolecular order within lipid films. The ultimate objective would then be to apply the method to single fragments of cell membrane material in order to obtain data complementary to the transverse data obtainable by x-ray diffraction.

Cellulose Acetate Reverse Osmosis Membrane Structure

1972 ◽  
Vol 30 ◽  
pp. 528-529
Author(s):  
H. K. Plummer ◽  
E. Eichen ◽  
C. D. Melvin
Keyword(s):  
Cellulose Acetate ◽  
Reverse Osmosis ◽  
Membrane Structure ◽  
Freeze Drying ◽  
Dense Layer ◽  
Water Removal ◽  
Reverse Osmosis Membrane ◽  
Correct Interpretation ◽  
Electron Image ◽  
Scanning Electron

Much of the work reported in the literature on cellulose acetate reverse osmosis membranes has raised new and important questions with regard to the dense or “active” layer of these membranes. Several thickness values and structures have been attributed to the dense layer. To ensure the correct interpretation of the cellulose acetate structure thirteen different preparative techniques have been used in this investigation. These thirteen methods included various combinations of water substitution, freeze drying, freeze sectioning, fracturing, embedding, and microtomy techniques with both transmission and scanning electron microscope observations.It was observed that several factors can cause a distortion of the structure during sample preparation. The most obvious problem of water removal can cause swelling, shrinking, and folds. Improper removal of embedding materials, when used, can cause a loss of electron image contrast and, or structure which could hinder interpretation.

Warm and freeze-fracture of cotton seed radicles

1987 ◽  
Vol 45 ◽  
pp. 984-985
Author(s):  
E. L. Vigil ◽  
E. F. Erbe
Keyword(s):  
Thin Film ◽  
Water Vapor ◽  
Fracture Surface ◽  
Membrane Structure ◽  
Room Temperature ◽  
Freeze Fracture ◽  
Longitudinal Axis ◽  
Fracture Plane ◽  
Cotton Seeds ◽  
Condensed Water

In cotton seeds the radicle has 12% moisture content which makes it possible to prepare freeze-fracture replicas without fixation or cryoprotection. For this study we have examined replicas of unfixed radicle tissue fractured at room temperature to obtain data on organelle and membrane structure.Excised radicles from seeds of cotton (Gossyplum hirsutum L. M-8) were fractured at room temperature along the longitudinal axis. The fracture was initiated by spliting the basal end of the excised radicle with a razor. This procedure produced a fracture through the tissue along an unknown fracture plane. The warm fractured radicle halves were placed on a thin film of 100% glycerol on a flat brass cap with fracture surface up. The cap was rapidly plunged into liquid nitrogen and transferred to a freeze- etch unit. The sample was etched for 3 min at -95°C to remove any condensed water vapor and then cooled to -150°C for platinum/carbon evaporation.

The ultrastructure of the double membrane-bound bodies and endoplasmic reticulum in serial sections of wheat spot mosaic-affected wheat plants

1990 ◽  
Vol 48 (3) ◽  
pp. 694-695
Author(s):  
M. H. Chen ◽  
C. Hiruki
Keyword(s):  
Endoplasmic Reticulum ◽  
High Resolution ◽  
Membrane Structure ◽  
Mosaic Disease ◽  
Serial Sections ◽  
Thin Sections ◽  
Double Membrane ◽  
Southern Alberta ◽  
Membrane Bound ◽  
Scanning Em

Wheat spot mosaic disease was first discovered in southern Alberta, Canada, in 1956. A hitherto unidentified disease-causing agent, transmitted by the eriophyid mite, caused chlorosis, stunting and finally severe necrosis resulting in the death of the affected plants. Double membrane-bound bodies (DMBB), 0.1-0.2 μm in diameter were found to be associated with the disease.Young tissues of leaf and root from 4-wk-old infected wheat plants were fixed, dehydrated, and embedded in Spurr’s resin. Serial sections were collected on slot copper grids and stained. The thin sections were then examined with a Hitachi H-7000 TEM at 75 kV. The membrane structure of the DMBBs was studied by numbering them individually and tracing along the sections to see any physical connection with endoplasmic reticulum (ER) membranes. For high resolution scanning EM, a modification of Tanaka’s method was used. The specimens were examined with a Hitachi Model S-570 SEM in its high resolution mode at 20 kV.

Sign in / Sign up

Export Citation Format

Share Document