Search results for " Membranes"
showing 10 items of 276 documents
Investigation of Reverse ElectroDialysis Units by Multi-Physical Modelling
2016
Reverse electrodialysis (RED) is an electrochemical membrane process that converts the salinity gradient energy between two solutions into electric current, by using ion exchange membranes. A novel multi-physical approach for RED modelling is proposed. 2-D simulations of one cell pair with tertiary current distribution (Nernst–Plank equation and local electroneutrality) were performed. Moreover, the Donnan exclusion theory was implemented for simulating double layer phenomena. Transport phenomena and electrochemical behavior were well described. The influence of membrane/channel configuration, dilute concentration and feeds velocity on the process performance was assessed. For a dilute conc…
Electrodialysis Applications in Wastewater Treatment for Environmental Protection and Resources Recovery: A Systematic Review on Progress and Perspec…
2020
This paper presents a comprehensive review of studies on electrodialysis (ED) applications in wastewater treatment, outlining the current status and the future prospect. ED is a membrane process of separation under the action of an electric field, where ions are selectively transported across ion-exchange membranes. ED of both conventional or unconventional fashion has been tested to treat several waste or spent aqueous solutions, including effluents from various industrial processes, municipal wastewater or salt water treatment plants, and animal farms. Properties such as selectivity, high separation efficiency, and chemical-free treatment make ED methods adequate for desalination and othe…
Lipid and phase specificity of α-toxin from S. aureus
2013
AbstractThe pore forming toxin Hla (α-toxin) from Staphylococcus aureus is an important pathogenic factor of the bacterium S. aureus and also a model system for the process of membrane-induced protein oligomerisation and pore formation. It has been shown that binding to lipid membranes at neutral or basic pH requires the presence of a phosphocholine-headgroup. Thus, sphingomyelin and phosphatidylcholine may serve as interaction partners in cellular membranes. Based on earlier studies it has been suggested that rafts of sphingomyelin are particularly efficient in toxin binding. In this study we compared the oligomerisation of Hla on liposomes of various lipid compositions in order to identif…
Noise driven translocation of short polymers in crowded solutions
2008
In this work we study the noise induced effects on the dynamics of short polymers crossing a potential barrier, in the presence of a metastable state. An improved version of the Rouse model for a flexible polymer has been adopted to mimic the molecular dynamics by taking into account both the interactions between adjacent monomers and introducing a Lennard-Jones potential between all beads. A bending recoil torque has also been included in our model. The polymer dynamics is simulated in a two-dimensional domain by numerically solving the Langevin equations of motion with a Gaussian uncorrelated noise. We find a nonmonotonic behaviour of the mean first passage time and the most probable tran…
Chemically driven phase separation in black lipid membranes and its coupling to membrane functions
1992
Abstract We analysed the single-channel current fluctuations of gramicidin in bimolecular lipid membranes in order to demonstrate (i) the influence of protein binding to the lateral organisation of a mixed membrane, and (ii) how this couples to the function of the ionophore. Examples of phase separations induced by synthetic polyelectrolytes, as models for peripheral membrane proteins, and specific ligand-receptor interactions are presented and discussed in view of the important lateral order-function relationship in biomembranes.
Influence of total solids concentration on membrane permeability in a submerged hollow-fibre anaerobic membrane bioreactor.
2012
The main aim of this work was to study the influence of the mixed liquor total solids (MLTS) concentration on membrane permeability (K 20) in a submerged anaerobic membrane bioreactor (SAnMBR) pilot plant, which is equipped with industrial hollow-fibre membranes and treats urban wastewater. This pilot plant was operated at 33°C and 70 days of SRT. Two different transmembrane fluxes (13.3 and 10 LMH) were tested with a gas sparging intensity of 0.23 Nm 3 m -2 h -1 (measured as Specific Gas Demand referred to membrane area). A linear dependence of K 20 on MLTS concentration was observed within a range of MLTS concentration from 13 to 32 g L -1 and J 20 of 10 LMH. K 20 was maintained at sustai…
Thermal potential of ion-exchange membranes and its application to thermoelectric power generation
2016
The low efficiency and high price of thermoelectric semiconductors has generated interest in unconventional forms of thermoelectric materials. In this article, ionic thermoelectricity has been studied with commercial ion-exchange membranes for different aqueous 1:1 electrolytes. The theory of thermal membrane potential has been derived taking into account the ionic heats of transport, the non-isothermal Donnan potentials, the temperature polarization, and the thermally-induced concentration polarization of the electrolyte. Also the generated thermoelectric power has been experimentally studied. The experiments show good agreement with the theory, and suggest ways for systematic improvement …
An ultrathin suspended hydrophobic porous membrane for high-efficiency water desalination
2017
Abstract An ultrathin highly fluorinated porous membrane was designed for a large production of desalted water at very low energy consumption. Imprinting water droplets were used through a low thermally conductive tetra-fluoroethylene (TFE)/2,2,4-trifluoro-5-tri-fluorometoxy-1,3-dioxol (TIT) (HYFLON AD 60) solution and the generated porous nanofilm was suspended onto a polyethersulfone (PES) honeycomb texture. The very tiny fluorinated thickness together with a large number of small-shaped pores provided the membrane for enhanced anti-wetting surface properties, extremely reduced resistance to water vapor transfer and outstanding thermal efficiency. Fine materials structure-transport relati…
Nanoporous alumina membranes filled with solid acid for thin film fuel cells at intermediate temperatures
2004
Thin film fuel cells have been fabricated by impregnation of inorganic porous membranes with inorganic proton conductor. Anodic alumina membranes (50 μm thick and pore diameter of 200 nm), filled with CsHSO4 salt have been used as protonic conductor in a hydrogen-oxygen fuel cell working between 423 and 443 K in dry atmosphere. Polarization curves at 433 K showing ohmic control with open circuit values near 0.8 V and short circuit current around 8 mA cm−2 have been obtained. Possible causes of degradation as well as alternative routes to overcome some of the problems encountered with this approach will be reported. Keywords: Solid acid, Anodic alumina membranes, Pore filling, Thin film fuel…
Photocatalytic membranes based on TiO2 catalysts and fluorinated polymers for CO2 conversion
2015
In this work, prepared TiO2–Nafion™-based membranes were used in a photocatalytic membrane reactor, operated in continuous mode, for converting CO2 to methanol.