Russian Chemists Improve Seawater Desalination Membrane
A team of researchers of the HSE Faculty of Chemistry Joint Department of Inorganic Chemistry and Materials Science with the RAS Kurnakov Institute of General and Inorganic Chemistry have designed a novel type of hybrid ion-exchange membrane. Such membranes can be used to produce drinking water from seawater, which is particularly relevant for areas with access to the sea and a shortage of drinking water. The study is published in Desalination.
Membrane filters are used to filter drinking water and are considered the most advanced filtration systems today. However, modern membranes are not yet capable of entirely removing excess salts.
Seawater comprises various salts, including those which contain positively charged cations of sodium (Na+) and calcium (Ca2+) and negatively charged anions such as chlorides (Cl-) and sulphates (SO42-). Depending on the type of filtering membrane, either cations or anions can permeate it during desalination. In either case, membranes tend to be selective, eg by being more permeable to sodium than calcium.
Most anion exchange membranes are selective to doubly charged anions, ie sulphates (SO42-) or carbonates (CO32-). Such anions are more likely to cause a precipitation reaction. On an industrial scale, this can lead to failure of water treatment plants due to excessive saline deposits in their concentrate modules. Designing anion-exchange membranes which are selective to singly charged anions (chlorides Cl- and nitrates NO3-) is therefore an important R&D area in industrial water treatment.
A team of researchers from the HSE Faculty of Chemistry and the RAS Institute of General and Inorganic Chemistry have come up with a novel approach to obtaining anion-exchange membranes which are selective to singly charged ions. The researchers modified ready-made membranes by introducing cerium phosphate containing acidic phosphate groups to the membrane pores to improve its properties. Since cerium phosphate dissolves in water poorly, it helps filter out particles and increase membranes' lifetime.
First, the membrane surface is treated with a cerium salt solution and then with a phosphoric acid salt. A chemical reaction between the salts produces cerium phosphate nanoparticles with negatively charged surfaces. Colliding with other negatively charged particles in seawater, they repel each other. According to Coulomb's law, the higher the negative charge, the stronger the repulsive force. Since sulphates have a -2 charge, they will be repelled more strongly from membrane pores containing cerium phosphate particles than, for example, singly charged chloride ions. This, according to the researchers, is one of the reasons behind the modified membranes' increased selectivity to singly charged anions.
The researchers varied the number and duration of the membrane treatment cycles and the concentration of reagents. The team also experimented with desalinating a mixed sodium chloride and sodium sulphate solution to determine which of the modified membranes was more selective to singly charged ions. The most impressive results—a 55% increase in the Cl/SO4-selectivity compared to the original commercial membrane—was shown by a modified membrane treated in one cycle with each of the reagents for 10 minutes.
Andrey Manin, co-author of the paper and student of the HSE Faculty of Chemistry
'We propose a fairly efficient and affordable method for obtaining anion-exchange membranes, and we hope that they will be used in the future for seawater desalination. We have recently been working as part of the Composite Materials for Environmental Protection research and study group to modify a different type of membrane using a similar method.'
Russian researchers from HSE University and the Russian Academy of Sciences Nesmeyanov Institute of Organoelement Compounds have come up with a new method of enhancing the chemical reaction involved in producing gamma-aminobutyric acid (GABA) analogues used in sedative drugs. Adding fluoride to the catalyst more than doubled the yield of the pure product and increased the total reaction yield by 2.5 times. This approach is expected to make the production of certain drug components more efficient and less costly. The study has been published in the Journal of Organic Chemistry.
In 2023, the first Master's programme 'Chemistry of Molecular Systems and Materials' at the HSE Faculty of Chemistry will enrol students. Half of the study time will be devoted to research projects in the field of modern fundamental and applied research on the topics studied at five institutes of the Russian Academy of Sciences. Dmitrii Roitershtein, Academic Supervisor of the programme and Associate Professor at the Joint Department of Organic Chemistry with the RAS Zelinsky Institute of Organic Chemistry, spoke about the programme to the HSE News Service.
The HSE University Faculty of Chemistry opened three years ago, and its first intake of undergraduate students is set to graduate in 2023. These students have already demonstrated impressive results in their research—half of second and third-year students have publications in journals indexed in WoS and Scopus, almost a third of which are in Q1 journals. Andrey Yaroslavtsev, Head of the Chemistry programme and Academic of the Russian Academy of Sciences (RAS), told the HSE University News Service about the secret of this success.
The Journal of Alloys and Compounds has published an article coauthored by the Institute of Solid State Chemistry and Mechanochemistry (the Ural Branch of the Russian Academy of Sciences), the Donostia International Physics Centre, and the HSE Tikhonov Moscow Institute of Electronics and Mathematics on the characteristics of cubic double perovskite oxides. To date, experimental measurements of the minerals’ characteristics have not corresponded to the results of theoretical modelling. The work marks the first time that researchers have set themselves the task of explaining this disparity. The data obtained will allow researchers to improve low-temperature fuel cell technologies—one of the main alternatives to current sources of electricity.
Yury Belousov, Associate Professor at the HSE Faculty of Chemistry, joined his colleagues from Moscow State University, Lebedev Physical Institute, and the University of Camerino, Italy, to work on a review, in which they compared and analysed over 200 lanthanide azolecarboxylates. The scholars were the first to systematize the scattered published information in a single source, which will be useful for technology developments in electronics, metallurgy and nuclear medicine, as well as in the chemical and nuclear industries. The review was published in Coordination Chemistry Reviews.
RAS Institute of Problems of Chemical Physics Launches Joint Department with HSE Faculty of Chemistry
The new Department will prepare students for careers in cutting edge research and engineering, as well as entrepreneurial and commercial development. They will be able to promote their own innovative projects and projects developed by their colleagues. The Department is headed by Professor Sergey Aldoshin, full member of Russian Academy of Sciences.
A group of Moscow scientists has discovered and explained the activity mechanism of a new anti-cancer molecule — diphenylisoxazole. This molecule has been shown to be effective against human cancer cells. The research, published in the journal Bioorganic & Medicinal Chemistry Letters, makes it possible to produce an affordable cancer treatment drug.
A team of chemists from HSE University and the Zelinsky Institute of Organic Chemistry used molecular modelling to find out that two medications that have been known for a long time can be used to fight SARS-CoV-2. One of them is used to treat alcohol addiction, and the other is for cancer.
The HSE News Service attended the first workshop held at a new laboratory that has been equipped for chemistry students. In the new laboratory, first-year students will be able to conduct experiments and learn how to work with different substances.
The HSE Department of Chemistry will begin accepting applications this year for its new Bachelor’s Programme in Chemistry. Programme Director and Russian Academy of Sciences (RAS) Corresponding Member Andrey Yaroslavtsev explains how the programme will be organised and why HSE is an excellent option for anyone planning to pursue a career in chemistry.