INVESTIGATION OF THE ADSORPTION PROPERTIES OF ACTIVATED CARBON DERIVED FROM FRUIT PITS

Аннотация

This study investigates the adsorption properties of activated carbon derived from fruit pit waste, specifically walnut, apricot, and peach pits. Activation was conducted at 800– 850°C using both thermal and thermochemical methods, including steam treatment and chemical agents such as 10% ZnCl₂ and H₂SO₄ solutions. Benzene vapor was used as the adsorbate to evaluate the adsorption efficiency of the produced carbon adsorbents. Key parameters such as monolayer capacity (αₘ), saturation volume (Vs), specific surface area (S), micropore volume (W₀), and mesopore volume (Wme) were calculated using BET theory and micropore volumefillingequations. The results revealed that thermochemical activation significantly enhances the structural and adsorption characteristics compared to thermal activation. For instance, FC-WP-136 showed a 3.2-fold increase in pore volume under thermochemical conditions, with surface area reaching up to 1397.11 m²/g. Adsorption isotherms were classified as Type I, indicating microporous structures with high initial benzene uptake. The average pore radius was found to decrease with increased microporosity. These findings demonstrate the effectiveness of utilizing agricultural waste as a raw material for producing high-performance, selective carbon adsorbents. The study supports the development of cost-effective, import-substituting technologies for environmental purification andindustrial applications. Key words: Activated carbon, Fruit pit waste, Thermochemical activation, Benzene adsorption, Specificsurface area, Micropore structure, BET analysis. Introduction: Nowadays, the rapid development of industrial and agricultural sectors in our Republic and across the globe, along with the expanding application fields of activated carbon, has led to an increasing demand for selective adsorbents. One of the urgent challenges is the development of efficient, import-substituting technologies based on local raw materials. In this context, the production of low-cost activated carbon from domestic resources remains a topical issue. The third priority area of the Action Strategy for the Further Development of the Republic of Uzbekistan outlines important tasks aimed at the development of high-tech industrial processing sectors, primarily through the deep processing of local raw materials into high- quality end products. In this regard, scientific research into the production of selective carbon- based adsorbents from local raw materials—specifically, fruit pits—and the determination of page540 INTERNATIONAL JOURNAL OF ARTIFICIAL INTELLIGENCE ISSN:2692-5206,ImpactFactor:12,23 AmericanAcademicpublishers,volume05,issue06,2025 Journal: https://www.academicpublishers.org/journals/index.php/ijai their adsorption properties is of great importance. There is also a pressing need to develop energy-efficient technologies for theproduction ofselectivecarbon adsorbents. Literature review: Several methods are used to enhance the adsorption properties of carbon- based adsorbents. These include thermal activation, steam activation, and chemical activation techniques. Upon activation, thespecific surface area ofcarbon adsorbents can reach up to 1000 m²/g,significantly improving theiradsorption efficiency. [1;340-p]. In our country, scientific studies have mainly focused on the adsorption of organic compounds onto natural mineral compounds such as bentonites [2; p. 68], and on the adsorption of both organic and inorganic substances onto synthetic zeolites [3; p. 64, 4; p. 64, 5; p. 48, 6; p. 48]. However, the effect of thermal treatment temperatures on the adsorption capacity of carbon adsorbents derived from fruit pits has not been thoroughly investigated. Therefore, it is essential to conduct a fundamental study on the adsorption of organic vapor molecules onto carbon- based adsorbents activated bythermal and steam treatment at various temperatures. Methodology: Studying the effect of different thermal treatment temperatures on the adsorption capacity of carbon-based adsorbents, including those derived from fruit pits, is of great importance in adsorption processes. For this purpose, carbon adsorbents were prepared from waste fruit pits of walnut, apricot, peach, and bitter almond trees grown in the territory of Uzbekistan. The activation was carried out thermally at 400–500°C and using steam at 800– 850°C for 3hours. Theadsorption of benzenevapors ontheobtained carbon adsorbents was investigated. Before being used as the adsorbate, benzene was purified and dried under vacuum conditions. To ensure the vapor pressure matched the tabulated values for pure benzene, it was first cooled and then heated to remove dissolved gases. After this preparation, adsorption measurements were carried out. Results: As seen from the adsorption isotherms of benzene vapors (Figure 1), carbon adsorbents derived from fruit pit waste and activated at 800–850°C using 10% aqueous ZnCl₂ solution (thermochemical activation) demonstrated varying a