scholarly journals “Breakthrough” osmosis and unusually high power densities in Pressure-Retarded Osmosis in non-ideally semi-permeable supported membranes

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Andriy Yaroshchuk
Keyword(s):  
Cell Biology ◽  
Membrane Damage ◽  
Forward Osmosis ◽  
Solute Concentration ◽  
Supported Membranes ◽  
Porous Layers ◽  
Pressure Retarded Osmosis ◽  
Internal Concentration ◽  
Order Of Magnitude ◽  
Power Densities

Abstract Osmosis is the movement of solvent across a membrane induced by a solute-concentration gradient. It is very important for cell biology. Recently, it has started finding technological applications in the emerging processes of Forward Osmosis and Pressure-Retarded Osmosis. They use ultrathin and dense membranes supported mechanically by much thicker porous layers. Until now, these processes have been modelled by assuming the membrane to be ideally-semipermeable. We show theoretically that allowing for even minor deviations from ideal semipermeability to solvent can give rise to a previously overlooked mode of “breakthrough” osmosis. Here the rate of osmosis is very large (compared to the conventional mode) and practically unaffected by the so-called Internal Concentration Polarization. In Pressure-Retarded Osmosis, the power densities can easily exceed the conventional mode by one order of magnitude. Much more robust support layers can be used, which is an important technical advantage (reduced membrane damage) in Pressure-Retarded Osmosis.

scholarly journals On the understanding and feasibility of “Breakthrough” Osmosis

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jun Jie Wu ◽  
Robert W. Field
Keyword(s):  
High Power ◽  
Forward Osmosis ◽  
Solute Concentration ◽  
Pressure Retarded Osmosis ◽  
Permselective Membrane ◽  
Order Of Magnitude ◽  
Theoretical Paper ◽  
Salt Diffusion ◽  
Power Densities ◽  
Very High

Abstract Osmosis is the movement of solvent across a permselective membrane induced by a solute-concentration gradient. Now in ‘Forward Osmosis’ it is empirically observed that the diffusion of the solute is counter to that of the solvent i.e. there is so-called “reverse salt diffusion”. However it has been recently suggested, in a theoretical paper, that if allowance is made for minor deviations from ideal semi-permeability then operation in an overlooked mode of “breakthrough” osmosis would be possible and importantly it would yield relatively large rates of osmosis. A consequential prediction was that in “breakthrough mode”, Pressure-Retarded Osmosis (PRO) would generate very high power densities exceeding those in the conventional mode by one order of magnitude. The practicality of this suggestion was explored and necessarily questions were then raised regarding the foundation of the Spiegler-Kedem-Katchalsky model. Arising from: Yaroshchuk, A., Sci. Rep. 7, 45168 (2017); 10.1038/srep45168

Pressure retarded osmosis for energy production: membrane materials and operating conditions

2012 ◽  
Vol 65 (10) ◽  
pp. 1789-1794 ◽  
Author(s):  
H. Kim ◽  
J.-S. Choi ◽  
S. Lee
Keyword(s):  
Energy Production ◽  
Concentration Polarization ◽  
Forward Osmosis ◽  
Operating Conditions ◽  
Polarization Ratio ◽  
Pressure Retarded Osmosis ◽  
Fundamental Understanding ◽  
Internal Concentration ◽  
Membrane Type ◽  
Osmotic Pressure Difference

Pressure retarded osmosis (PRO) is a novel membrane process to produce energy. PRO has the potential to convert the osmotic pressure difference between fresh water (i.e. river water) and seawater to electricity. Moreover, it can recover energy from highly concentrated brine in seawater desalination. Nevertheless, relatively little research has been undertaken for fundamental understanding of the PRO process. In this study, the characteristics of the PRO process were examined using a proof-of-concept device. Forward osmosis (FO), reverse osmosis (RO), and nanofiltration (NF) membranes were compared in terms of flux rate and concentration polarization ratio. The results indicated that the theoretical energy production by PRO depends on the membrane type as well as operating conditions (i.e. back pressure). The FO membrane had the highest energy efficiency while the NF membrane had the lowest efficiency. However, the energy production rate was low due to high internal concentration polarization (ICP) in the PRO membrane. This finding suggests that the control of the ICP is essential for practical application of PRO for energy production.

scholarly journals Effect of fouling on performance of pressure retarded osmosis (PRO) and forward osmosis (FO)

2018 ◽  
Vol 565 ◽  
pp. 450-462 ◽  
Author(s):  
Endre Nagy ◽  
Imre Hegedüs ◽  
Emily W. Tow ◽  
John H. Lienhard V
Keyword(s):  
Forward Osmosis ◽  
Pressure Retarded Osmosis

Herbicidal Concentrations of Picloram in Cell Culture and Leaf Buds

Weed Science ◽  
1972 ◽  
Vol 20 (2) ◽  
pp. 185-188 ◽  
Author(s):  
F. S. Davis ◽  
A. Villarreal ◽  
J. R. Baur ◽  
I. S. Goldstein
Keyword(s):  
Cell Culture ◽  
Glycine Max ◽  
Gossypium Hirsutum ◽  
Cell Cultures ◽  
Tolerance Limit ◽  
Primary Leaf ◽  
Fresh Weight ◽  
Internal Concentration ◽  
Order Of Magnitude

Cell cultures of soybean(Glycine max(L.) Merrill ‘Acme’) were exposed to media containing 4-amino-3,5,6-trichloropicolinic acid (picloram) for 15 days. Picloram also was supplied once in droplets (water) to cotyledons of 10 to 13-day-old seedlings of cotton(Gossypium hirsutumL. ‘Champion’). The amounts of picloram necessary to reach and exceed the 50% tolerance limit (TL50) of the cell cultures (inhibition) and of the primary leaf buds (toxicity) were established, and internal picloram concentrations then were determined. Internal concentrations at the TL50were 0.17 nM/g fresh weight and 14.7 nM/g fresh weight for cell cultures and leaf buds, respectively. These values are approximately 10−7and 10−5molar. In leaf buds, concentrations increased rapidly for 36 hr after treatment and declined slowly thereafter. Primary leaf buds accumulated up to several times the lethal internal concentration of picloram when the dosage to the cotyledons was increased by one order of magnitude.

scholarly journals Nearfield trapping increases lifetime of single-molecule junction by one order of magnitude

2020 ◽  
Author(s):  
Albert C. Aragonès ◽  
Katrin F. Domke
Keyword(s):  
Molecular Electronics ◽  
Single Molecule ◽  
Fold Increase ◽  
Trapping Efficiency ◽  
Non Invasive ◽  
Order Of Magnitude ◽  
Molecule Junction ◽  
Single Molecule Junction ◽  
The Difference ◽  
Power Densities

Abstract Progress in molecular electronics (ME) is largely based on improved understanding of the properties of single molecules (SM) trapped for seconds or longer to enable their detailed characterization. We present a plasmon-supported break-junction (PBJ) platform to significantly increase the lifetime of SM junctions of 1,4-benzendithiol (BDT) without the need for chemical modification of molecule or electrode. Moderate far-field power densities of ca. 11 mW/µm2 lead to a >10-fold increase in minimum lifetime compared to laser-OFF conditions. The nearfield trapping efficiency is twice as large for bridge-site contact compared to hollow-site geometry, which can be attributed to the difference in polarizability. Current measurements and tip-enhanced Raman spectra confirm that native structure and contact geometry of BDT are preserved during the PBJ experiment. By providing a non-invasive pathway to increase short lifetimes of SM junctions, PBJ is a valuable approach for ME, paving the way for improved SM sensing and recognition platforms.

scholarly journals A Review of CFD Modelling and Performance Metrics for Osmotic Membrane Processes

Membranes ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 285
Author(s):  
Kang Yang Toh ◽  
Yong Yeow Liang ◽  
Woei Jye Lau ◽  
Gustavo A. Fimbres Weihs
Keyword(s):  
Performance Metrics ◽  
Forward Osmosis ◽  
Cfd Modelling ◽  
Membrane Processes ◽  
Pressure Retarded Osmosis ◽  
Multi Scale ◽  
Scale Modelling ◽  
Computational Fluid Dynamics Cfd ◽  
And Performance ◽  
Module Performance

Simulation via Computational Fluid Dynamics (CFD) offers a convenient way for visualising hydrodynamics and mass transport in spacer-filled membrane channels, facilitating further developments in spiral wound membrane (SWM) modules for desalination processes. This paper provides a review on the use of CFD modelling for the development of novel spacers used in the SWM modules for three types of osmotic membrane processes: reverse osmosis (RO), forward osmosis (FO) and pressure retarded osmosis (PRO). Currently, the modelling of mass transfer and fouling for complex spacer geometries is still limited. Compared with RO, CFD modelling for PRO is very rare owing to the relative infancy of this osmotically driven membrane process. Despite the rising popularity of multi-scale modelling of osmotic membrane processes, CFD can only be used for predicting process performance in the absence of fouling. This paper also reviews the most common metrics used for evaluating membrane module performance at the small and large scales.

Excitable Membrane Properties of Neurons

2020 ◽  
Author(s):  
Leonard K. Kaczmarek
Keyword(s):  
Action Potential ◽  
Action Potentials ◽  
Cell Biology ◽  
Neuronal Firing ◽  
Membrane Properties ◽  
Potassium Ions ◽  
Single Action ◽  
Sodium Calcium ◽  
Different Types ◽  
Order Of Magnitude

The intrinsic electrical properties of neurons are extremely varied. For example, the width of action potentials in different neurons varies by more than an order of magnitude. In response to prolonged stimulation, some neurons generate repeated action potential hundreds of times a second, while others fire only a single action potential or adapt very rapidly. These differences result from the expression of different types of ion channels in the plasma membrane. The dominant channels that shape neuronal firing patterns are those that are selective for sodium, calcium, and potassium ions. This chapter provides a brief overview of the biophysical properties of each of these classes of channel, their role in shaping the electrical personality of a neuron, and how interactions of these channels with cytoplasmic factors shape the overall cell biology of a neuron.

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