CREATION OF SUSTAINABLE SORPTION MATERIALS FROM SECONDARY RESOURCES FOR THE PURIFICATION OF POLLUTED SOILS

Abstract

The development of effective sorbents for the purification of soils contaminated with heavy metals based on secondary resources is an urgent task of environmental safety of the Republic of Kazakhstan. Of particular interest in this area is the use of spent gas mask filters, the disposal of which allows us to simultaneously solve the problems of accumulation of hazardous waste and remediation of contaminated areas. In this work, the possibility of obtaining highly effective sorbents from spent gas mask filters for the extraction of Pb²⁺ Cd²⁺ and Cu ²⁺ ions from polluted media is investigated. The sorbents were obtained by combined thermal and chemical modification of the starting material. The physicochemical properties of the developed materials were studied using low-temperature nitrogen adsorption BET analysis and IR Fourier spectroscopy. It was found that the modification leads to a significant increase in the specific surface area of sorbents (from 200 to 610 m²/g), an increase in the total pore volume and the formation of oxygen-containing functional groups on the surface. Experimental studies of sorption have shown the high efficiency of the developed materials in relation to heavy metal ions. The maximum sorption capacity was 89 mg/g for Pb²⁺, 53 mg/g for Cd²⁺  and 40 mg/g for Cu²⁺ with a removal efficiency of up to 92%. Kinetic analysis showed that the sorption process quickly reaches equilibrium within 12-24 hours and is best described by a pseudo-second-order model (R² 0.97-0.99), which indicates the predominance of chemo sorption mechanisms.