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.

All news
02 Mar
Highest recognition of scientific merits to the university: congratulations to the winners of RUDN University prize in the field of science and innovation

February 15, RUDN University annual award in the field of science and innovation was presented. The highest award of the university was received by associate professor of the Faculty of Science Fyodor Zubkov and the team of authors of the Law Institute: Aslan Abashidze, Alexander Solntsev and Denis Gugunsky.

23 Feb
Start of the Year of Science and Technology: RUDN is ready for the year of science

Mathematics, chemistry, physics, medicine and modern languages - there are five priority areas of development at RUDN University along the path of a research university. RUDN University has a developed laboratory base, it encourages publication activity, forms teams of scientists and educates talented young researchers.

18 Feb
RUDN University physicists analyzed the role of gravity in elementary particles formation

Gravity might play a bigger role in the formation of elementary particles than scientists used to believe. A team of physicists from RUDN University obtained some solutions of semi-classical models that describe particle-like waves. They also calculated the ratio between the gravitational interaction of particles and the interaction of their charges.