Chemists From St. Petersburg State University Find A Way To Speed Up Industrial Wastewater Treatment Sixfold

Chemists from St. Petersburg State University have developed reagents for the treatment of industrial wastewater. These compounds are several times more effective than those currently in use. Thanks to this development, enterprises will be able to treat larger volumes of water in less time, thereby reducing the cost of maintaining treatment equipment.

Almost all industrial enterprises use water in their technological processes and are therefore required to operate water treatment facilities. In Russia today, demand for such facilities is high. As the country moves towards import substitution, new enterprises are emerging and existing ones are constantly expanding their production capacity.

‘Modern water purification reagents do not always work effectively, which results in harmful substances being released into the environment. Some of these substances can seriously damage ecosystems. For example, iron compounds in wastewater can cause oxygen depletion in bodies of water and, consequently, lead to fish mortality,’ said Ksenia Meshina, a first-year master’s student in Chemistry and a member of the Research Team ‘Synthesis and Investigation of Nanoparticles and Nanostructured Materials’.

Ksenia Meshina explained that the scientists from St. Petersburg State University have developed reagents capable of improving wastewater treatment, preventing negative environmental impacts and extending the service life of modern treatment facilities.

The researchers created composite materials with a sodium alginate polymer matrix containing hydroxyapatite or zinc oxide nanoparticles. These materials interact with substances that pollute wastewater, including metal ions, pharmaceutical compounds, hormones, and dyes. They can either absorb these substances or break them down into carbon dioxide and water, which are safe for the natural environment.

The mechanism of action depends on the purification method and the main component of the material.

Ksenia Meshina, a first-year master’s student in Chemistry and a member of the Research Team ‘Synthesis and Investigation of Nanoparticles and Nanostructured Materials’

For example, composites containing hydroxyapatite are suitable for sorption (the selective absorption of substances — Editor’s note). They outperform other compounds in terms of sorption capacity and, in particular, adsorb certain metals more effectively.

‘For example, many sorbents used today have very low activity against arsenic, for example. The nanoparticles we have developed remove it effectively,’ said Olga Osmolovskaya, Associate Professor in the Department of General and Inorganic Chemistry at St. Petersburg State University and Head of the Research Team ‘Synthesis and Investigation of Nanoparticles and Nanostructured Materials’.

Nanoparticles containing zinc oxide have a dual action. ‘They can both absorb pollutants and decompose them under the influence of visible or ultraviolet light, which means they can be used for water purification by photocatalysis,’ explained Ksenia Meshina.

According to Olga Osmolovskaya, the main advantage of the developed materials is that they can be rapidly modified to neutralise both known and newly emerging pollutants.

All the components of the composites created by the scientists are safe in themselves: sodium alginate is a natural polymer; hydroxyapatite is a natural component of human bones and teeth; and zinc oxide is a safe compound used in children’s cosmetics. Unlike some aggressive reagents, the nanoparticles do not damage equipment, and even if they accidentally enter natural water bodies, they will not harm the ecosystem.

The researchers studied the properties of the developed materials in detail at the resource centres of the St. Petersburg State University Research Park. In one experiment, they tested their effectiveness and found that the nanoparticles purified the same volume of water in just one hour that competing materials require two to six hours to treat. ‘Nanoparticles work faster and more effectively than other materials because they are extremely small and can therefore be used in large quantities. For example, one gram of nanoparticle powder can have a total surface area of up to 300 square metres (approximately the size of two volleyball courts — Editor’s note),’ noted Ksenia Meshina.

The nanomaterials developed by the scientists can be used at all types of enterprises, from cosmetics factories to metallurgical plants. Using these composites will reduce water treatment time while also lowering equipment depreciation and utility costs. Because nanoparticles are more effective than other reagents, the number of purification stages can be reduced, eliminating the need for additional steps and reducing overall costs.

Furthermore, when combined with existing technologies, the materials developed by the scientists from St. Petersburg State University could increase the degree of water purification from the current maximum of 98% to nearly 100%.

Scientific research in chemistry and materials science contributes to the implementation of the national project ‘New Materials and Chemistry’. The goal of the project is to achieve technological independence and to create conditions for the development of new markets and technological leadership in key sectors of manufacturing, including chemical and biotechnological products, novel and advanced materials, and rare and rare earth metals.

About St. Petersburg State University
St. Petersburg State University, the oldest university in Russia, was founded on 28 January (8 February) 1724. This is the day when Peter the Great issued a decree establishing the University and the Russian Academy of Sciences. St. Petersburg State University today is a major centre for education and research. More than 20,000 students study here, and more than 15 major laboratories and 23 resource centres have been established as part of the country’s leading Research Park. Graduates of the University have been recipients of the Nobel and Fields Prizes on multiple occasions.

Recently, St. Petersburg, the Northern Capital of Russia, officially introduced a new holiday—Day of St. Petersburg State University—which has been included in the St. Petersburg Law ‘On holidays and commemorative days in St. Petersburg’.