Abstract
A zeolite-carbon sorbent based on natural zeolite from the Shankhanay deposit and biochar obtained from walnut shells was synthesized for the purification of aqueous solutions from organic dyes. The composite material was obtained using acid-base treatment and hydrothermal action, which ensured the formation of a porous structure and a stable combination of mineral and carbon components. The physicochemical and structural characteristics of the synthesized sorbent were studied using scanning electron microscopy, X-ray diffraction analysis, and low-temperature nitrogen adsorption. It was found that the synthesis process preserves the zeolite's crystalline framework while simultaneously expanding the pore space, increasing the availability of active adsorption sites and improving mass transfer conditions. The adsorption properties of the zeolite-carbon composite were studied using the extraction of methylene blue from aqueous solutions under batch conditions. The experimental kinetic data are satisfactorily described by a pseudo-second-order model, indicating the significant role of chemical interaction between the adsorbent and adsorbate. The equilibrium adsorption data are in good agreement with the Langmuir model, indicating a predominantly monolayer nature of the adsorption process. The maximum adsorption capacity of the synthesized sorbent was 26.17 mg g⁻¹. These results confirm the potential of using zeolite-carbon sorbents for the removal of cationic organic pollutants from aqueous media.