Siberian Federal University Scientists Innovate Sorbent from Ash Microspheres for Liquid Toxic Waste
Scientists from SibFU and the Krasnoyarsk Research Center, SB RAS have studied the processes of material synthesis based on volatile ash microspheres that are produced as a result of coal combustion. These materials can be effectively used as industrial sorbents to absorb heavy metals, particularly lead and cadmium, from liquid industrial waste.
Lead and cadmium are priority toxicants, which are found, among other things, in liquid waste from chemical and metallurgical industries. Currently, sorption processes are often used to treat wastewater contaminated with heavy metals. In this process, inorganic materials such as zeolites are used as sorbents.
Zeolites can selectively absorb various organic substances, as well as metal cations due to ion exchange processes. The advantages of zeolite-based sorbents are that they can perform two important functions. Firstly, they can concentrate heavy metals thanks to their ion-exchange properties. Secondly, they can promote the crystallization of extracted toxicants -in this case, cadmium and lead -when heated.
“Currently, activated carbon and carbon nanotubes, sulfocationites based on plant materials, natural biopolymer chitosan, and zeolites are used to remove heavy metals from liquid waste. It is more cost-effective to use zeolites obtained from cheap and readily available raw materials, such as volatile ash from coal combustion. We have synthesized monophasic zeolite materials that can absorb and fix lead and cadmium ions in a mineral-like (crystalline) form”, said Tatiana Vereshchagina, Dr. Sc. (Chemistry), the author and leading researcher of the study, Head of the Department of Chemistry, Polytechnic School, SibFU.
The scientists studied the conditions for the synthesis of monozeolite materials — future sorbents, as well as how the composition of microspheres obtained from volatile ash from coal combustion affects the structural type of the resulting zeolite and, consequently, the efficiency of lead and cadmium ion extraction.
“We were able to demonstrate that most zeolite-based products are highly effective for removing lead and cadmium ions from industrial solutions, with a recovery rate reaching 99%. In this case, the best sorbents are based on the zeolite phases of gismondine and analcime”, — continued Tatiana Vereshchagina.
In addition to cleaning water from heavy metal ions, the proposed technology allows for the conversion of zeolites containing toxicants into a stable mineral-like form. This form acts as a retaining matrix, preventing the spread of heavy metals into the environment.
The work was carried out within the framework of the state task of the Institute of Chemistry and Chemical Technology, SB RAS, “Development of the scientific basis for the creation of functional materials with specific properties based on complex oxide systems and energy ash microspheres”.