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The international research group and RUDN University chemists proposed new reagents for the removal of lead from wastewater

The international research group and RUDN University chemists proposed new reagents for the removal of lead from wastewater

RUDN University chemists together with colleagues from other countries synthesized new compounds that effectively bind lead ions and can be used to remove it from wastewater and even from the living organism, that is, to play the role of an antidote for lead poisoning. The article is published in the journal Crystals.

Complex compounds of lead are widely used for the synthesis of polymers and compounds necessary for the production of semiconductors, materials for nonlinear optics and ferroelectrics. The large radius of the divalent lead ion Pb (II) allows you to change the number of bound atoms, ions or molecules (ligands) from 4 to 9. Thus, it is possible to obtain a wide range of substances based on lead, that combine organic and inorganic components in a single molecule. The widespread use of lead compounds in production leads to the accumulation of toxic waste, what stimulates the solution to the problem of removing lead from wastewater.

Fedor Zubkov, an employee of the Organic Chemistry Department of RUDN University, together with colleagues from Iran, Spain, Italy, and Croatia have obtained compounds that can effectively bind lead in wastewater, as well as in human and animal body. Chemists have created it on the basis of nicotinic and picolinic acids hydrazides. Nitrate, chloride, and perchlorate-anions serve as counterions to positively charged lead ions and stabilize the complex due to strong electrostatic interactions.

To study the obtained complexes, chemists had to design a special device for the synthesis and simultaneous selective crystallization of reaction products. To do this, alcohol solution of a mixture of lead nitrate (II), the corresponding ligand, and sodium perchlorate was placed in the main part of the tube as a donor of counterions. The mixture was heated at 60 °C so that the side branch of the tube, also filled with alcohol, remained at room temperature. The crystals of the complex formed in the side vessel after several days of synthesis were filtered, washed with ether and dried in air. The yield of metal complex ranged from 67 to 87 % of the theoretically possible.

According to x-ray diffraction analysis, one of the complexes turned out to be binuclear, that is, it contains two lead ions bound by a common ligand. Using computer simulations, it was shown that all complexes form supramolecular ensembles with different types of intermolecular interactions. In the formation of such structures, anions of inorganic acids play an important role, which experiences a strong electrostatic attraction to the internal coordination sphere of the lead complex. As a result, metal organic coordination polymers (metal organic frameworks, MOFs) are formed, which are promising metal organic catalysts and selective acceptors of heavy-metal ions.

The resulted substances — supramolecular ensembles — allow to bound and precipitate even trace amounts of lead in wastewater. They can be used for drinking water treatment and even as an antidote for lead poisoning.

The article is published in the journal Crystals.

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15 Nov 2017
RUDN University scientists publish results of their scientific researches in highly-recognized in whole world and indexed in international databases journals (Web of Science, Scopus ect.). That, of course, corresponds to the high status of the University and its international recognition. Publications of June-September 2017 ( In Journals of categories Q1-Q3)
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30 Dec
Biologists from RUDN University discovered the secret of flaxseed oil with long shelf life

Biologists from RUDN University working together with their colleagues from the Institute of Molecular Biology of the Russian Academy of Sciences and the Institute of Flax studied the genes that determine the fatty acid composition in flaxseed oil and identified polymorphisms in six of them. The team also found out what gene variations could extend the shelf life of flaxseed oil. This data can be used to improve the genetic selection of new flax breeds. The results were published in the BMC Plant Biology journal.

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19 Apr
Dentists from RUDN University Presented a New Classification of Root Canal Shape Changes

Individual characteristics of the shape and cross-section of the root canal are one of the main issues for dentists. When treating a root canal, a doctor needs to properly clean it, fill it, and carry out a rebuilding procedure so that a canal is sealed. The first stage of endodontic treatment requires detailed knowledge of root canal anatomy. A team of dentists from RUDN University studied and classified various changes in root canal shapes. The new classification will help doctors avoid diagnostic errors, better select their tools, and treat patients more efficiently.

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19 Apr
A chemist from RUDN developed a green catalyst for pharmaceutical and industrial chemistr

Many production facilities (e.g. plastic manufacturers, pharma companies, and others) use nanocatalysts that contain palladium—an expensive component that is not sustainably produced. A chemist from RUDN University found a way to reduce palladium consumption and to make its manufacture more eco-friendly. He developed a catalyst based on a substance that comes from plant waste. Using his invention, manufacturers could cut palladium consumption in half. Moreover, new catalysts can be reused multiple times without any decrease in efficiency.

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