One of the most pressing needs of our time is safe, sustainable access to fresh water. The dominant technology for desalination of water is membrane-based desalination, an energy-efficient, environmentally friendly process.
Scientists have now developed a new membrane material that, unlike current polyamide membranes, tolerates chlorinated water. A team headed by Ho Bum Park (University of Ulsan, South Korea), Benny D. Freeman (University of Texas at Austin, USA), and James E. McGrath (Virginia Polytechnic Institute, Blacksburg, USA) reported in the journal Angewandte Chemie on a membrane that is made of sulfonated copolymers.
Chlorine is the most commonly used biocide in water treatment because it is both inexpensive and very effective in small amounts. The disinfection of water headed into membrane-based desalination facilities is crucial to hinder the growth of biofilms, which reduce efficiency. Polyamide membranes do not tolerate chlorine. This means that the water must first be treated with chlorine, and then the chlorine must be removed before the water comes into contact with the membrane. Before being fed into the supply network, the water must be chlorinated again. This is a complex, costly procedure.
Membranes made of polysulfone, a sulfur-containing engineering thermoplastic, are being considered as an alternative. They are highly tolerant to chlorine. However, polysufones are hydrophobic and do not allow enough water to pass through them. By attaching additional charged sulfonic acid groups, the researchers hoped to make the polymer more water friendly without affecting its other valuable properties.
Whereas previous efforts focused on modification of the polysulfone after polymerization, the team now took a different route: the simultaneous polymerization of disulfonated monomers (a building block containing two hydrophilic sulfonic acid groups) and another type of monomer led to the formation of a copolymer. Undesired side-reactions, cross-linking or breaks in the polymer chains do not occur by this method. Most importantly, it is possible to precisely control how many water-friendly, charged sulfonic acid groups are in the polymer chain. This allows the targeted generation of chlorine-resistant membranes whose permeability for water and salts can be tailored to specific applications (e.g., nanofiltration, reverse osmosis).
Benny D. Freeman | Angewandte Chemie International
Minimized water consumption in CSP plants - EU project MinWaterCSP is making good progress
05.12.2017 | Steinbeis-Europa-Zentrum
Jena Experiment: Loss of species destroys ecosystems
28.11.2017 | Technische Universität München
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong
Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...
An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications
Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...
Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.
The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
11.12.2017 | Physics and Astronomy
11.12.2017 | Earth Sciences
11.12.2017 | Information Technology