Қазақ ұлттық қыздар педагогикалық университеті / Казахский национальный женский педагогический университет

Постоянный URI для этого сообществаhttps://cris.qyzpu.kz/handle/123456789/1

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2024 - 20265

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Язык: АнглийскийТема: search.filters.subject.KOH activation

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    Electrochemical Performance of Biomass-Derived AC and CNTs-Based Supercapacitors
    (IGI Global, 2024-11-22)
    Meiram K. Atamanov
    ;
    Tolganay Atamanova
    ;
    Azamat Taurbekov
    ;
    Zulkhair Aimukhametovich Mansurov
    This study investigates the electrochemical performance of activated carbon (AC) derived from two biomass sources, rice husk (RH) and walnut shell (WS), utilizing two activation methods: chemical activation with potassium hydroxide (KOH) and physical activation with carbon dioxide (CO2). The aim is to evaluate the potential of these bio-derived carbon materials in energy storage applications, particularly for supercapacitors. The electrochemical behavior of the activated carbon electrodes was assessed using cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) techniques, along with electrochemical impedance spectroscopy (EIS), to evaluate the specific capacitance, energy density, charge transfer resistance, and ion diffusion properties.
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    Production and optimization of activated carbon from plant waste with high specific surface area for moisture-saving applications in agriculture
    (2024-10-20)
    Yerlan Doszhanov
    ;
    Aitugan Sabitov
    ;
    Karina Saurykova
    ;
    Zulkhair Aimukhametovich Mansurov
    ;
    М С Курманбаева
    In conditions of water shortage, sustainable agricultural development requires the use of water-saving technologies, including the use of water-retaining substrates based on activated carbon. In this work, the textural and adsorption characteristics of activated carbon obtained from plant waste were studied at different mass ratios of the sorbent and KOH (1:1, 1:2, 1:3 and 1:4). The aim of the study was to determine the optimal activation conditions for creating a material with a high specific surface area and a developed porous structure. The results showed that the largest pore volume (1.6 cm3/g) and a high degree of microporosity are achieved at a ratio of 1:3, which is confirmed by the analysis of pore distribution using the DFT and BJH methods. FTIR spectroscopy revealed the presence of functional groups (O–H, C=O and C–O) that contribute to water conservation. The differential pore volume distribution (dv(r), cm3/Å/g) also demonstrated that at a ratio of sorbent and KOH (1:3), the sample structure optimally combines micropores and mesopores, which increases the adsorption capacity of carbon.
    Цитирования (OpenAlex) 1
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    1-Carboxy-2-phenylethan-1-aminium Iodide 2-Azaniumyl-3-phenylpropanoate Crystals: Properties and Its Biochar-Based Application for Iodine Enrichment of Parsley
    (Multidisciplinary Digital Publishing Institute, 2025-10-06)
    Aitugan Sabitov
    ;
    Seitzhan Turganbay
    ;
    Almagul Kerimkulova
    ;
    Yerlan Doszhanov
    ;
    Karina Saurykova
    Iodine deficiency remains a significant nutritional problem, which stimulates the search for sustainable approaches to biofortification of vegetable crops. The aim of the work was to develop a "smart" bio-iodine fertilizer based on the organoiodide complex 1-carboxy-2-phenylethan-1-aminium iodide 2-azaniumyl-3-phenylpropanoate (PPI) and highly porous biochar from agro-waste, assessing its efficiency on the parsley model. PPI was synthesized and characterized (IR/UV spectroscopy, thermal analysis), biochar was obtained by KOH activation and studied by low-temperature nitrogen adsorption (S_BET) methods, as well as standard physicochemical characterization. The granulated composition PPI + biochar (BIOF) was tested in pot experiments in comparison with KI and control; The biomass of leaves and roots, iodine and organic nitrogen content, and antioxidant indices (ascorbic acid, total polyphenols, antioxidant activity) were assessed. BIOF provided a significant increase in yield and nutrition: leaf mass reached 86.55 g/plant versus 77.72 g/plant with KI and 65.04 g/plant in the control; root mass — up to 8.25 g/plant (p<0.05). Iodine content in leaves and roots increased to 11.86 and 13.23 mg/kg (d. w.), respectively, while organic nitrogen levels increased simultaneously (57.37 and 36.63 mg/kg). A significant increase in the antioxidant status was noted (ascorbic acid 36.46 mg/100 g dry weight; antioxidant activity 44.48 mg GA/g; polyphenols 23.79 mg GA/g). The presented data show that the combination of PPI with activated biochar forms an effective platform for controlled supply of iodine to plants, increasing the yield and functional qualities of products; the prospects for implementation are associated with field trials and dosage optimization.
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    Synthesis of Biomass-Derived Graphene Nanomaterials by Chemical Activation with KOH
    (Multidisciplinary Digital Publishing Institute, 2025-11-21)
    Makpal Seitzhanova
    ;
    Zhanar B. Kudyarova
    ;
    Bibigul B. Rakhimova
    ;
    Lyaila Tugelbayeva
    ;
    Жандос Турегулович Тауанов
    This work introduces an environmentally sustainable and cost-effective strategy for synthesizing graphene nanomaterials from agricultural residues—walnut shells and apricot stones. The synthesis pathway combines desilication, controlled pre-carbonization, chemical activation with KOH, and mild exfoliation to produce few-layer graphene with a high degree of structural order. The process, conducted at 523–573 K for pre-carbonization and 1123 K for activation, enables the formation of graphene sheets with a specific surface area of approximately 1300 m2/g, carbon content of 80–90%, and average pore diameter below 100 nm. The materials were comprehensively characterized using SEM, TEM, Raman spectroscopy, and BET analysis. Raman spectra revealed an IG/I2D ratio of ~1.5–2 a.u., confirming the presence of 4–5 graphene layers. Compared to conventional biomass-derived graphene routes, the developed approach ensures enhanced porosity, higher graphitic ordering, and improved purity, demonstrating its strong potential for energy storage, adsorptive purification, and environmentally benign nanotechnology applications.
    Цитирования (OpenAlex) 8Цитирования (OpenCitations) 1
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    Comparative Study of the Structural and Adsorptive Performance of Biomass-Derived Graphene Materials
    (Multidisciplinary Digital Publishing Institute, 2026-02-08)
    Makpal Seitzhanova
    ;
    Zhanar Kudyarova
    ;
    Yerlan Doszhanov
    ;
    Bibigul B. Rakhimova
    ;
    Svetlana Aleshkova
    This study presents the development of an environmentally benign and economically viable methodology for the synthesis of graphene-containing carbon materials derived from renewable agricultural residues, specifically walnut shells, rice husks, and apricot stones. The proposed synthesis route involves sequential stages of controlled pre-carbonization, desilicification, chemical activation with potassium hydroxide (KOH), and subsequent mild exfoliation, resulting in the formation of few-layer graphene with a high degree of structural ordering. Pre-carbonization carried out at 523–573 K, followed by activation at 1123 K, yields graphene sheets exhibiting a specific surface area of 1300–1800 m2/g, a carbon content of 60–90%, and an average pore diameter below 100 nm. The synthesized materials were subjected to comprehensive physicochemical characterization using BET surface area analysis, Raman spectroscopy, FTIR spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic absorption flame emission spectrophotometry. Raman spectroscopic analysis revealed an I_G/I_2D intensity ratio of approximately 1.5–2.0, indicating the presence of graphene structures consisting of approximately four to five layers. To enhance adsorption performance, the graphene-containing carbon materials were further functionalized with sulfuric acid, and the successful incorporation of surface functional groups was confirmed by FTIR spectroscopy. The adsorption properties of the functionalized graphene-containing carbon materials were evaluated in aqueous solutions containing sodium, potassium, calcium, and magnesium salts, demonstrating adsorption efficiencies of up to 80%. Compared to conventional biomass-derived graphene synthesis methods, the developed approach produces materials with enhanced porosity, higher graphitic ordering, and improved chemical purity. These characteristics highlight the strong potential of the synthesized graphene-containing carbon materials for applications in energy storage systems, adsorption-based water purification technologies, and environmentally sustainable nanotechnological applications.
    Цитирования (OpenAlex) 4