Abstract
The article describes the synthesis of an activated carbon-carbon/ash composite based on carbonized rice husk (CRH) and Ca-lignosulfonate. The obtained adsorbents were characterized by modern physicochemical research methods: scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS analysis), X-ray photoelectron spectroscopy (XPS), and low-temperature nitrogen adsorption. It was established that despite the presence of residual mineral impurities in an amount of about 15 wt. %, the synthesized CRH-lignosulf@850 composite exhibits a high specific surface area and a well-developed pore volume. These impurities are represented by the phases CaSiO3, MgSiO3, CaSO4 and SiO2, which proved to be resistant to alkaline leaching. The morphology of the obtained composites features a well-developed structure with both micro- and mesoporosity. According to calculations based on the Quenched solid density functional theory (QSDFT), the specific surface area of the obtained СRH-lignosulf@850 sample is 1144 m²/g, and the total pore volume is 0.947 cm³/g. Studies of methylene blue (MB) sorption under static conditions showed that the CRH-lignosulf@850 composite demonstrates high adsorption performance. According to the adsorption isotherms, the Toth model effectively describe the process, with the maximum sorption capacity of the material reaching 283.4 mg/g. The results obtained indicate the potential for using CRH-lignosulf@850 blocks to capture toxic compounds in emissions from enterprises producing organic products.