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Aachen, Germany

Leibniz Institute for Interactive Materials

Aachen, Germany
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News Article | May 22, 2017
Site: www.eurekalert.org

Plants can absorb nutrients through their leaves as well as their roots. However, foliar fertilization over an extended period is difficult. In the journal Angewandte Chemie, German researchers have now introduced an efficient delivery system for micronutrients based on biohybrid microgels. Special peptides anchor the "microcontainers" onto the leaf surface while binding sites inside ensure gradual release of the "cargo". Foliar fertilization is already commonly used in areas such as viniculture, when the leaves on the vines turn yellow due to a mineral deficiency. Yet, despite the use of detergents, adhesives, and humectants, controlled delivery of nutrients through foliar fertilization over several weeks is nearly impossible to achieve. Up to 80% of the nutrients are washed away, winding up in the soil and being converted into forms that the plant cannot use. In addition, they can be washed into bodies of water and cause environmental problems. An additional problem is that strong sunlight evaporates the water out of the applied fertilizer solution. This results in a high salt concentration that draws water out of the leaf and causes burn damage. A team from DWI-Leibniz Institute for Interactive Materials in Aachen, RWTH Aachen University, and the University of Bonn has now developed a foliar fertilization system based on biocompatible microgels that adhere selectively to leaves for a long period and slowly deliver nutrients in a controlled fashion. Microgels are tiny particles of cross-linked macromolecules that can bind water and other molecules, such as fertilizers very efficiently. Led by Ulrich Schwaneberg and Andrij Pich, the researchers equipped the interiors of gel particles with binding sites modeled on the iron-binding proteins of bacteria. These ensure that the iron ions are released slowly. The microgels are loaded with an iron-containing solution at a pH of 3. When the pH rises to 7, the microgels shrink, releasing water and binding the iron. The surface of the gel particles is equipped with anchor peptides from lactic acid bacteria. These bind securely to leaf surfaces to hinder rinsing away of the microgels. The water in the gel provides an aqueous microenvironment that allows the iron to diffuse into the leaves. Yellow leaves of iron-deficient cucumber plants rapidly turned green in spots where the new foliar fertilizer was applied. By incorporating different binding sites, the microgel "containers" can be loaded with a multitude of other metal ions or agents. A controlled delivery of agents as required would minimize the applied quantities as well as the release of fertilizers and pesticides into the environment. Low production costs, high levels of loading, easy application, and adjustable adhesive properties should make broad industrial applications possible. The goal is to make self-regulating delivery systems for sustainable agriculture. Dr. Andrij Pich is Lichtenberg Professor leading the Laboratory for Functional and Interactive Polymers at the Institute of Technical and Macromolecular Chemistry at RWTH Aachen and member of the scientific directors board at the DWI-Leibniz Institute for Interactive Materials. His research is focused on tailored synthesis of new macromolecules and their integration in complex functional polymer materials for applications in engineered plastics, biomaterials, catalysis and plant care.


News Article | May 22, 2017
Site: phys.org

Plants can absorb nutrients through their leaves as well as their roots. However, foliar fertilization over an extended period is difficult. In the journal Angewandte Chemie, German researchers have now introduced an efficient delivery system for micronutrients based on biohybrid microgels. Special peptides anchor the "microcontainers" onto the leaf surface while binding sites inside ensure gradual release of the "cargo". Foliar fertilization is already commonly used in areas such as viniculture, when the leaves on the vines turn yellow due to a mineral deficiency. Yet, despite the use of detergents, adhesives, and humectants, controlled delivery of nutrients through foliar fertilization over several weeks is nearly impossible to achieve. Up to 80% of the nutrients are washed away, winding up in the soil and being converted into forms that the plant cannot use. In addition, they can be washed into bodies of water and cause environmental problems. An additional problem is that strong sunlight evaporates the water out of the applied fertilizer solution. This results in a high salt concentration that draws water out of the leaf and causes burn damage. A team from DWI-Leibniz Institute for Interactive Materials in Aachen, RWTH Aachen University, and the University of Bonn has now developed a foliar fertilization system based on biocompatible microgels that adhere selectively to leaves for a long period and slowly deliver nutrients in a controlled fashion. Microgels are tiny particles of cross-linked macromolecules that can bind water and other molecules, such as fertilizers very efficiently. Led by Ulrich Schwaneberg and Andrij Pich, the researchers equipped the interiors of gel particles with binding sites modeled on the iron-binding proteins of bacteria. These ensure that the iron ions are released slowly. The microgels are loaded with an iron-containing solution at a pH of 3. When the pH rises to 7, the microgels shrink, releasing water and binding the iron. The surface of the gel particles is equipped with anchor peptides from lactic acid bacteria. These bind securely to leaf surfaces to hinder rinsing away of the microgels. The water in the gel provides an aqueous microenvironment that allows the iron to diffuse into the leaves. Yellow leaves of iron-deficient cucumber plants rapidly turned green in spots where the new foliar fertilizer was applied. By incorporating different binding sites, the microgel "containers" can be loaded with a multitude of other metal ions or agents. A controlled delivery of agents as required would minimize the applied quantities as well as the release of fertilizers and pesticides into the environment. Low production costs, high levels of loading, easy application, and adjustable adhesive properties should make broad industrial applications possible. The goal is to make self-regulating delivery systems for sustainable agriculture. More information: Richard A. Meurer et al, Biofunctional Microgel-Based Fertilizers for Controlled Foliar Delivery of Nutrients to Plants, Angewandte Chemie International Edition (2017). DOI: 10.1002/anie.201701620


LONDON--(BUSINESS WIRE)--Foliar fertilization, the process of applying a liquid fertilizer to the leaves of a plant rather than to the soil, can be beneficial to crops but presents challenges in terms of application and efficiency. Up to 80% of the nutrients provided by this type of fertilizer can be washed away, which is a significant waste of resources and can pollute nearby water sources. Infiniti Research notes that while foliar fertilization can be effective in specific situations, long-term applications are often not practical. However, German researchers are looking to change this. Researchers from DWI-Leibniz Institute for Interactive Materials in Aachen, RWTH Aachen University, and the University of Bonn have created a new system for foliar fertilization that allows the fertilizer to adhere to the leaves for a longer period of time, resulting in less waste. It is based on biocompatible microgels that deliver their nutrients in a slow, controlled manner. The microgels have so far been tested as a delivery method for iron, effectively and quickly restoring iron-deficient cucumber plants. Anchor peptides from lactic acid bacteria prevent the gels from being washed away, and the water in the gels allows nutrients such as iron to diffuse into the plant leaves. This allows for the use of smaller quantities of fertilizer, resulting in lower costs and less pollution and helping to make agriculture more sustainable. Looking for additional research and insights? Request a free proposal How can Infiniti Research Help You? Inefficiencies can be a major source of operational expenses. It is important to be aware of both the causes of inefficiencies and of potential solutions to them. Additionally, by keeping track of new developments in the market, it is possible to find new ways to improve your business and stay ahead of the competition. Market intelligence can inform you of developments that could impact your business, as well as keep you abreast of your competition’s activities. Infiniti Research recently undertook a project to assess the fall protection equipment market in Europe for a global manufacturer of safety products. The assessment provided an in-depth analysis of the market landscape, demand and technology trends, product developments, and competitive landscape, allowing the company to gain a better understanding of the market landscape, along with its latest trends and future requirements. Request a brochure and see how you can benefit from Infiniti’s services. Established in 2003, Infiniti Research is a leading market intelligence company providing smart solutions to address your business challenges. Infiniti Research studies markets in more than 100 countries to help analyze competitive activity, see beyond market disruptions, and develop intelligent business strategies. With 13 years of experience and offices across three continents, Infiniti Research has been instrumental in providing a complete range of competitive intelligence, strategy, and research services for over 550 companies across the globe.


Nishiguchi A.,Leibniz Institute for Interactive Materials | Singh S.,Leibniz Institute for Interactive Materials | Wessling M.,Leibniz Institute for Interactive Materials | Kirkpatrick C.J.,Johannes Gutenberg University Mainz | And 2 more authors.
Biomacromolecules | Year: 2017

In vitro reconstruction of an alveolar barrier for modeling normal lung functions and pathological events serve as reproducible, high-throughput pharmaceutical platforms for drug discovery, diagnosis, and regenerative medicine. Despite much effort, the reconstruction of organ-level alveolar barrier functions has failed due to the lack of structural similarity to the natural basement membrane, functionalization with specific ligands for alveolar cell function, the use of primary cells and biodegradability. Here we report a bipolar cultured alveolar-capillary barrier model of human primary cells supported by a basement membrane mimics of fully synthetic bifunctional nanofibers. One-step electrospinning process using a bioresorbable polyester and multifunctional star-shaped polyethylene glycols (sPEG) enables the fabrication of an ultrathin nanofiber mesh with interconnected pores. The nanofiber mesh possessed mechanical stability against cyclic expansion as seen in the lung in vivo. The sPEGs as an additive provide biofunctionality to fibers through the conjugation of peptide to the nanofibers and hydrophilization to prevent unspecific protein adsorption. Biofunctionalized nanofiber meshes facilitated bipolar cultivation of endothelial and epithelial cells with fundamental alveolar functionality and showed higher permeability for molecules compared to microporous films. This nanofiber mesh for a bipolar cultured barrier have the potential to promote growth of an organ-level barrier model for modeling pathological conditions and evaluating drug efficacy, environmental pollutants, and nanotoxicology. © 2017 American Chemical Society.


Rose J.C.,Leibniz Institute for Interactive Materials | Camara-Torres M.,Leibniz Institute for Interactive Materials | Rahimi K.,Leibniz Institute for Interactive Materials | Kohler J.,Leibniz Institute for Interactive Materials | And 3 more authors.
Nano Letters | Year: 2017

Injectable biomaterials provide the advantage of a minimally invasive application but mostly lack the required structural complexity to regenerate aligned tissues. Here, we report a new class of tissue regenerative materials that can be injected and form an anisotropic matrix with controlled dimensions using rod-shaped, magnetoceptive microgel objects. Microgels are doped with small quantities of superparamagnetic iron oxide nanoparticles (0.0046 vol %), allowing alignment by external magnetic fields in the millitesla order. The microgels are dispersed in a biocompatible gel precursor and after injection and orientation are fixed inside the matrix hydrogel. Regardless of the low volume concentration of the microgels below 3%, at which the geometrical constrain for orientation is still minimum, the generated macroscopic unidirectional orientation is strongly sensed by the cells resulting in parallel nerve extension. This finding opens a new, minimal invasive route for therapy after spinal cord injury. © 2017 American Chemical Society.


Wessling M.,RWTH Aachen | Wessling M.,Leibniz Institute for Interactive Materials | Morcillo L.G.,RWTH Aachen | Abdu S.,RWTH Aachen
Scientific Reports | Year: 2014

Electro-convective vortices in ion concentration polarization under shear flow have been of practical relevance for desalination processes using electrodialysis. The phenomenon has been scientifically disregarded for decades, but is recently embraced by a growing fluid dynamics community due its complex superposition of multi-scale gradients in electrochemical potential and space charge interacting with emerging complex fluid momentum gradients. While the visualization, quantification and fundamental understanding of the often-chaotic fluid dynamics is evolving rapidly due to sophisticated simulations and experimentation, little is known whether these instabilities can be induced and affected by chemical topological heterogeneity in surface properties. In this letter, we report that polyelectrolyte layers applied as micropatterns on ion exchange membranes induce and facilitate the electro-osmotic fluid instabilities. The findings stimulate a variety of fundamental questions comparable to the complexity of today's turbulence research.


Home > Press > Physicists come up with a way to make cleaner fuel cells: An international group of scientists from Russia, France, and Germany have developed ion-exchange synthetic membranes based on amphiphilic compounds that are able to convert the energy of chemical reactions into electrical Abstract: An international group of scientists from Russia, France, and Germany have developed ion-exchange synthetic membranes based on amphiphilic compounds that are able to convert the energy of chemical reactions into electrical current. The new development described in the journal Physical Chemistry, Chemical Physics could potentially be used in fuel cells, and in separation and purification processes. The study was conducted by MIPT's Laboratory of Functional Organic and Hybrid Materials, which was opened in 2014. Fuel cells consist of separate galvanic cells and their closest relatives are batteries (primary cells) and accumulators (secondary cells). Batteries convert the energy of the reaction between an oxidizing agent and a reducing agent, and stop working when these agents are used up. An accumulator is able to store electrical energy applied to it from an external source, convert it to chemical energy, and release it again, thus reversing the process. A fuel cell on the other hand, which is also an electrochemical generator, gets the materials that it needs to function from an external source. These materials are a reducing agent (usually hydrogen, methanol or methane) and an oxidizing agent, oxygen. Providing these materials from an external source means that electricity can be obtained from a fuel cell continuously without having to stop to recharge for as long as the parts of the cell are in working order. The main elements of this generator are a cathode and an anode, separated by an ion-exchange membrane. At the cathode, the reducing agent is dissociated - an electron is separated from a hydrogen molecule (or another fuel) and thus a positively charged hydrogen ion, a proton, is formed. The membrane allows protons to pass through, but retains the electrons - these particles are forced to take the "long route" through an external circuit. Only once they have passed through this circuit (the device that the fuel cell is powering) can they reach the anode where they find oxygen and the protons that passed through the membrane to combine and form water. The electrons, which are forced to go around the membrane, create a current in the external circuit that can be utilized. Why do we need fuel cells and why are they not used more widely? Fuel cells use the same fuel that can be burned in conventional internal combustion engines producing the same basic products - water vapour in the case of hydrogen and water vapour with carbon dioxide in the case of organic fuel. However, compared to a traditional engine, a fuel cell has at least two advantages: first, the process takes place at a lower temperature without a number of harmful emissions such as nitrogen oxides; secondly, fuel cells can have a much higher level of efficiency. Petrol and diesel generators are limited by thermodynamic laws (they do not allow an efficiency coefficient of more than 80% for example), but such laws do not apply to fuel cells. In a number of technological applications, fuel cells stand a good chance of replacing internal combustion engines at least. Before this happens however, special infrastructure will need to be put in place (the hydrogen needs to be stored somewhere, it will require special filling stations, pipes designed for high pressures, fuel tanks) and a number of improvements will need to be made to fuel cells themselves. Choosing the correct membrane will play a very important, if not essential, role in improving fuel cells - the material that the membrane is made from must be as inexpensive as possible, chemically stable, technologically advanced, and its pores must provide adequate selectivity. Chemists and physicists are not simply going through materials at random, but conducting targeted experiments to create nanostructures with predetermined properties. Molecular engineering Scientists from MIPT, the Institute of Problems of Chemical Physics, Moscow State University, Institut de Sciences des Matériaux de Mulhouse, and DWI - Leibniz Institute for Interactive Materials of RWTH Aachen University have learned how to form pores from certain molecules for membranes of a fuel cell so that the opening is exactly the diameter required for the optimum functioning of the cell. The molecules in question with the working names A-Na and Azo-Na are promising substances that are classified as benzenesulfonates. They are wedge-shaped (see image above) and can independently assemble themselves into supramolecular structures - complex organized groups of multiple molecules. Depending on the conditions set by the scientists, the molecules form discs, which, in turn, form columns with ion channels inside. This self-assembly of complex structures of individual molecules is possible due to their electrical properties. At one end of these molecules is a polar chemical group, i.e. a group with an electric charge, and in a solution it naturally turns towards charged water molecules. At the other end of these molecules there are non-polar hydrocarbon "tails" that again due to their electrical properties try to stay as far away from water molecules as possible - this mechanism is what causes the formation of soap film, a cell membrane, and a fat droplet on the surface of cooking stock. Scientists were able to predict the formation of these discs with pores and cylinders based on information on the structure of the benzenesulfonates being investigated, their geometry and physical and chemical properties. Using this information, the scientists first made a mathematical model based on the properties of complex supramolecular structures formed by A-Na and Azo-Na and only then did they begin their experiments. During these experiments, they obtained various different forms of ion channels maintaining the substances at a certain humidity and temperature, and then irradiating them with UV light for polymerization. The polymers created with this method were tested for selective permeability of ions and this enabled the scientists to identify which conditions of the synthesis of polymer membranes are best suited for making potential fuel cells. From catalyst to molecules The modern approach to producing structures that are ordered at a molecular level does not only involve computer models and logically choosing conditions to synthesize the required polymers. Researchers are now able to control the results of their work by directly observing the shape of the molecules or supramolecular structures they produce. The structure of the complexes obtained was confirmed by X-ray scattering analysis of a synchrotron radiation source. This method is used when scientists need to find out the structure of something at a scale that cannot be seen with an optical microscope: the nanopores created by the researchers in their study were only a few nanometres wide; this is more than ten times smaller than a visible light wave. At the European Synchrotron Radiation Facility in Grenoble (France) polymers were studied using X-ray analysis. X-rays were scattered over the samples and the analysis of the resulting diffraction pattern enabled the researchers to establish the exact size of the pores in the new polymers. The pore size is directly related to the efficiency of the fuel cell. The selective permeability of these pores, which resemble the aperture of a camera, determines how efficiently ions are screened, and consequently how efficiently energy is converted in a fuel cell. Global warming and molecular engineering The new study, which MIPT specialists were actively involved in, does not only show how a promising material can be obtained from certain molecules and the methods that are used to do this. It allows us to look from an unexpected angle at a problem that at first glance may seem entirely unrelated to organic chemistry or X-ray analysis - the problem of global warming, a subject that came up once again in the news recently after an international agreement was signed in Paris on the reduction of carbon emissions. Today, it is almost unanimously recognized by the scientific community that the average temperature on the planet is rising and this is happening because of the increased concentration of carbon dioxide in the atmosphere. This gas, which traps heat, is mainly released by burning organic fuels - therefore an effective measure to prevent a further rise in temperature would be to switch to technologies that do not use oil, coal, and gas. However, radically redesigning virtually all technological infrastructure is not possible without an acceptable alternative to internal combustion engines: either electric accumulators and electric motors, or fuel cells with electric motors. Fuel cells themselves of course will not solve the problem of rising temperatures on the planet. But they are part of a possible solution: and this means that self-organization of supramolecular structures from two promising substances codenamed A-Na and Azo-Na can also be considered part of a global task. Even if it is not stated explicitly by the authors of a particular study, many scientific results can often influence people's lives in rather unexpected ways. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


News Article | January 1, 2016
Site: phys.org

Fuel cells consist of separate galvanic cells and their closest relatives are batteries (primary cells) and accumulators (secondary cells). Batteries convert the energy of the reaction between an oxidizing agent and a reducing agent, and stop working when these agents are used up. An accumulator stores electrical energy applied to it from an external source, converts it to chemical energy, and releases it again, thus reversing the process. A fuel cell, on the other hand, which is also an electrochemical generator, gets the materials that it needs to function from an external source. These materials are a reducing agent (usually hydrogen, methanol or methane) and an oxidizing agent, oxygen. Providing these materials from an external source means that electricity can be obtained from a fuel cell continuously without having to stop for recharging as long as the parts of the cell are in working order. The main elements of this generator are a cathode and an anode, separated by an ion-exchange membrane. At the cathode, the reducing agent is dissociated—an electron is separated from a hydrogen molecule (or another fuel) and thus, a positively charged hydrogen ion, a proton, is formed. The membrane allows protons to pass through, but retains the electrons—these particles are forced to take the "long route" through an external circuit. Only once they have passed through this circuit (the device that the fuel cell is powering) can they reach the anode, where they find oxygen and the protons that passed through the membrane to combine and form water. The electrons, which are forced to go around the membrane, create a current in the external circuit that can be utilized. Why do we need fuel cells and why are they not used more widely? Fuel cells use the same fuel that can be burned in conventional internal combustion engines producing the same basic products—water vapour in the case of hydrogen, and water vapour with carbon dioxide in the case of organic fuel. However, compared to a traditional engine, a fuel cell has at least two advantages: First, the process takes place at a lower temperature without a number of harmful emissions such as nitrogen oxides; secondly, fuel cells can have a much higher level of efficiency. Petrol and diesel generators are limited by thermodynamic laws (they do not allow an efficiency coefficient of more than 80 percent, for example), but such laws do not apply to fuel cells. In a number of technological applications, fuel cells stand a good chance of replacing internal combustion engines at least. Before this happens, however, special infrastructure is necessary (the hydrogen needs to be stored somewhere, it requires special filling stations, pipes designed for high pressures, fuel tanks) and a number of improvements need to be made to fuel cells themselves. Choosing the correct membrane is essential for improving fuel cells—the material that the membrane is made from must be as inexpensive as possible, chemically stable, technologically advanced, and its pores must provide adequate selectivity. Chemists and physicists are not simply going through materials at random, but conducting targeted experiments to create nanostructures with predetermined properties. Scientists from MIPT, the Institute of Problems of Chemical Physics, Moscow State University, Institut de Sciences des Matériaux de Mulhouse, and DWI - Leibniz Institute for Interactive Materials of RWTH Aachen University have learned how to form pores from certain molecules for membranes of a fuel cell so that the opening is exactly the diameter required for the optimum functioning of the cell. The molecules in question, A-Na and Azo-Na, are promising substances that are classified as benzenesulfonates. They are wedge-shaped (see image) and can independently assemble themselves into supramolecular structures—complex organized groups of multiple molecules. Depending on the conditions set by the scientists, the molecules form discs, which form columns with ion channels inside. This self-assembly of complex structures of individual molecules is possible due to their electrical properties. At one end of these molecules is a polar chemical group, i.e. a group with an electric charge, and in a solution, it naturally turns towards charged water molecules. At the other end of these molecules, there are non-polar hydrocarbon "tails" that, due to their electrical properties, try to stay as far away from water molecules as possible—this mechanism is what causes phenomena such as the formation of soap film, a cell membrane, and a fat droplet on the surface of cooking stock. Scientists were able to predict the formation of these discs with pores and cylinders based on information on the structure of the benzenesulfonates being investigated, their geometry and physical and chemical properties. Using this information, the scientists first made a mathematical model based on the properties of complex supramolecular structures formed by A-Na and Azo-Na, and only then did they begin their experiments. During these experiments, they obtained various forms of ion channels, maintaining the substances at a certain humidity and temperature, and then irradiating them with UV light for polymerization. The polymers created with this method were tested for selective permeability of ions and this enabled the scientists to identify which conditions of the synthesis of polymer membranes are best suited for making potential fuel cells. The modern approach to producing structures that are ordered at a molecular level does not only involve computer models and logically choosing conditions to synthesize the required polymers. Researchers can now control the results of their work by directly observing the shape of the molecules or supramolecular structures they produce. The structure of the complexes obtained was confirmed by X-ray scattering analysis of a synchrotron radiation source. This method is used when scientists need to find out the structure of something at a scale that cannot be seen with an optical microscope. The nanopores created by the researchers in their study were only a few nanometres wide; this is more than ten times smaller than a visible light wave. At the European Synchrotron Radiation Facility in Grenoble (France) polymers were studied using X-ray analysis. X-rays were scattered over the samples and the analysis of the resulting diffraction pattern enabled the researchers to establish the exact size of the pores in the new polymers. The pore size is directly related to the efficiency of the fuel cell. The selective permeability of these pores, which resemble the aperture of a camera, determines how efficiently ions are screened, and consequently how efficiently energy is converted in a fuel cell. The new study, which MIPT specialists were actively involved in, does not only show how a promising material can be obtained from certain molecules and the methods that are used to do this. It allows us to look from an unexpected angle at a problem that at first glance may seem entirely unrelated to organic chemistry or X-ray analysis—the problem of climate change, a subject in the news recently after an international agreement was signed in Paris on the reduction of carbon emissions. Today, it is almost unanimously recognized by the scientific community that the average temperature on the planet is rising and this is happening because of the increased concentration of carbon dioxide in the atmosphere. This gas, which traps heat, is mainly released by burning organic fuels. Therefore, an effective measure to prevent a rise in atmospheric carbon would be to switch to technologies that do not use oil, coal, and gas. However, radically redesigning virtually all technological infrastructure is not possible without an acceptable alternative to internal combustion engines, either electric accumulators and electric motors, or fuel cells with electric motors. Fuel cells themselves, of course, will not solve the problem of atmospheric carbon. But they are part of a possible solution, and this means that self-organization of supramolecular structures from A-Na and Azo-Na can also be considered part of a global task. Even if it is not stated explicitly by the authors of a particular study, many scientific results can often influence people's lives in rather unexpected ways. Explore further: Chemical distribution and bonding states in fuel cell membranes More information: K. N. Grafskaia et al. Designing the topology of ion nano-channels in the mesophases of amphiphilic wedge-shaped molecules, Phys. Chem. Chem. Phys. (2015). DOI: 10.1039/C5CP05618G


Gendel Y.,Leibniz Institute for Interactive Materials | Rommerskirchen A.K.E.,RWTH Aachen | David O.,Leibniz Institute for Interactive Materials | Wessling M.,RWTH Aachen | Wessling M.,Leibniz Institute for Interactive Materials
Electrochemistry Communications | Year: 2014

We report batch and continuous electrochemical desalination utilizing the ion adsorption capacity of a slurry containing carbon particles. Two carbon suspensions and the feed water are fed into the electrochemical cell operated according to the principle of membrane assisted capacitive deionization (MCDI). In a batch mode operation after the desalination step is complete the adsorbed ions are discharged from flowing electrodes to the same portion of water using polarity reversal. Operation with 15 g NaCl/l water solution resulted in extremely high apparent salt adsorption capacity (SAC) value of 260 mg/g dry carbon. This value is much higher than the highest value of SAC reported until now - 14.3 mg/g. The reason for this phenomenon is not clear and further research is currently performed. In a new truly continuous process, both slurry streams are continuously recirculated between the desalination module and a regeneration/concentration module operated with the same functionality but with reversed potential. Ions desorb from the flowing electrodes and concentrate through the membranes into a purge stream. We prove continuous operation with desalination rate of more than 99% for an initial salt concentration of 1 g NaCl/l. Concentration factors depend on the recovery, with 90% water recovery being demonstrated easily. © 2014 Elsevier B.V.


Rommerskirchen A.,Leibniz Institute for Interactive Materials | Rommerskirchen A.,RWTH Aachen | Gendel Y.,Leibniz Institute for Interactive Materials | Wessling M.,Leibniz Institute for Interactive Materials | Wessling M.,RWTH Aachen
Electrochemistry Communications | Year: 2015

Abstract The search for novel desalination technologies has recently led to the introduction of flow-electrodes to capacitive deionization (CDI) processes, named as flow-electrode capacitive deionization (FCDI). Unlike classical CDI, which is a discontinuous or semi-continuous process due to the need for regeneration of the electrodes within the same module, flow-electrodes offer new design opportunities which enable fully continuous desalination processes as well as easily scalable systems. Here, we describe a novel system for the continuous desalination of water based on FCDI using a single flow-electrode and a single module. The flow-electrode is based on activated carbon powder suspended in water. During continuous operation of the system, a desalination rate of a 1 g/L NaCl solution of up to 70% is achieved at water recoveries of up to 80%. Additionally we report very good current efficiencies: in case of 80% water recovery, the current efficiency is 0.93. The single flow-electrode single module process might reduce energy and investment costs and lower the threshold to a large scale implementation. © 2015 Elsevier B.V.

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