Study of the adsorption of copper, nickel and zinc ions on a zeolite-containing sorbent synthesized from thermal power plant waste

Abstract

The study investigated the possibility of using ash and slag waste from thermal power plants as an alternative raw material source to obtain an inexpensive zeolite-containing sorbent, which was synthesized by hydrothermal synthesis by adding 20% sodium hydroxide at a temperature of 120оC for 24 hours. Using X-ray diffraction, it was established that the synthesized material mainly consists of the framework aluminosilicate mineral hydrosodalite. Using the obtained material, the sorption of copper, zinc, and nickel cations from aqueous media was studied using the Langmuir, Freundlich, and Dubinin-Radushkevich models. The constants of these equations were determined, the values of the isobaric-isothermal potential and the free energy of ion adsorption were calculated. It has been established that the sorption of metal ions is of a physical nature. It was found that the Dubinin–Radushkevich equation better describes the process of adsorption of zinc and nickel, and the Langmuir equation better describes the sorption of copper ions. The decrease in the degree of affinity of sorbed ions to the surface of the synthesized zeolite-containing sorbent was determined as follows: . Thus, based on the obtained values of sorption of copper, zinc, and nickel ions, the fundamental possibility of using ash and slag waste as a raw material source for obtaining inexpensive and effective zeolite-containing sorbents for extracting the above metal ions from aqueous media was established.