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Shaykhiev I.G.

Doctor of Engineering Sciences (Advanced Doctor), Head of the Department, Kazan National Research Technological University

Kinetics and mechanism of adsorption of methylene blue dye by crushed sunflower biomass

https://doi.org/10.58224/2619-0575-2024-7-3-78-92
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 78 – 92 p.
Abstract
Objectives: to study the kinetics and mechanism of dye adsorption by cellulose raw materials. Methods. As a sorbent, waste from crop production was used – ground sunflower stalks, initial and modified with 10% NaOH alkali, with a particle size from 1 to 2 mm. Methylene blue dye was selected as an adsorbate by preliminary tests. Adsorption isotherms were constructed to determine the maximum sorption capacity. Kinetic models of sorption of the pseudo-first and pseudo-second order are constructed. In order to determine the mechanism of the process, thermodynamic constants were determined: sorption energy (E), Gibbs energy (ΔG) and Bio coefficient (Bi).
Results. The maximum sorption capacity of the crushed biomass of sunflower stalks in relation to the dye is 0.52 mmol/g for the alkali-modified material, which is 48% higher than the initial content (0.35 mmol/g). Thus, the SP(NaOH) material showed improved sorption properties, and it was selected for further kinetic studies. The sorp-tion energy is 5.82 kJ/mol, which may indicate physical adsorption. The Gibbs energy is -6.3742 kJ/mol, less than zero, which indicates the spontaneity of this process. The adsorption equilibrium for the MG dye occurs after 120 minutes, the kinetic curve has a smooth character. The Bio coefficient is 1.812, therefore, the adsorption process is limited by mixed diffusion.
Conclusions. The analysis of the data obtained made it possible to determine the Bio coefficient reflecting the course of MG adsorption by a mixed–diffusion mechanism over the entire time range of adsorption. This indicates the complex character of the MG adsorption process and confirms the importance of taking into account various factors influencing this process when developing methods for cleaning aquatic environments from organic pollu-tants.
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REMEDIATION OF SOILS CONTAMINATED WITH Cd2+ IONS BY ZOO COMPOST AFTER CULTIVATION OF HERMETIA ILLUCENS FLY LARVAE

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 34-45 p.
Abstract
One of the most toxic substances entering the soil due to anthropogenic impact is cadmium (Cd). When growing agricultural plants on soils contaminated with cadmium, it is possible for cadmium to enter the human body through food chains, which can cause numerous disturbances in the work of various body systems. In order to reduce the adverse effects of heavy metals on environmental objects, soil remediation is necessary. One of the types of remediation is a decrease in the mobility of pollutants and a decrease in their activity. In this paper, the possibil-ity of reducing the mobility of Cd2+ ions by adding zoo compost to contaminated soils after cultivating larvae of the “Black Soldier” fly (Hermetia illucens) was investigated. It was found that the content of Cd2+ ions in the mobile form in soils with the addition of zookompost significantly decreases compared to the control (up to 73.3% with a zookompost content of 2.5%). The sorption capacity of the zoo compost with respect to Cd2+ ions was determined, which is 0.12 mmol/g. The resulting sorption isotherm was processed within the framework of the monomolecular sorption models of Langmuir, Freundlich, Dubinin-Radushkevich. The values of sorption energy and Gibbs energy are calculated, the values of which indicate the course of spontaneous physical adsorption with chemisorption ele-ments.
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THE USAGE OF VEGETABLE SORBENT FOR REMOVING CONGO RED DYE FROM TEST SOLUTIONS

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 44-55 p.
Abstract
The research findings of sorption purification of test water environment, containing Congo red dye, by using this crop farming waste as a sorption material have indicated that the maximum sorption capacity of its biomass amounts to 0.37 mmol/g. The electronic microscopy data and the research findings of physical-chemical and sorp-tion properties of a new vegetable sorption material, obtained from sunflower (Heliánthus ánnuus) stalks, are presented. The processing of the data demonstrated that the obtained adsorption isotherm of Congo red belongs to Type V isotherms according to classification by Brunauer-Deming-Deming-Teller (BDDT) or to the S-type, according to Giles’ classification. With that, adsorption process is the most accurately described by the Freundlich model, and the process proceeds on the heterogeneous surface of the sorption material.
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SORPTION PROPERTIES OF SYCAMORE LEAF LITTER IN RELATION TO METHYLENE BLUE DYE

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 5-13 p.
Abstract
Dyes are one of the widespread and hazardous contaminants that enter water bodies with wastewater. Reagent precipitation, ion exchange, coagulation, flotation, and other methods are used to remove dyes from aqueous environment. At the same time, sorption treatment is one of the most effective. The authors proposed to use sycamore leaves biomass for the dye "Methylene blue" extraction from aqueous environment. To investigate the process of adsorption of methylene blue by the leaves biomass, the sorption capacity of the material has been es-tablished; it is shown that the adsorption process is best described by the Freundlich model with a correlation co-efficient R2 = 0.9537.
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SULFURIC ACID MODIFIED SAWDUST OF ACACIA AURICULARIS (ACACIA AURICULIFORMIS) FOR THE PURIFICATION OF WASTEWATER FROM COPPER IONS (II)

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 12-23 p.
Abstract
Modified sorption materials based on acacia sawdust (Acacia Auriculiformis) were obtained by treating their surface with low-concentration sulfuric acid solutions with concentrations of 1%, 2% and 3%. According to IR spectra, diffractograms, micrographs and histograms of the distribution of surface roughness of native and sulfuric acid-modified acacia sawdust, it was found that surface treatment of the sawdust with acid solutions leads to a change in the structure of the sorption material, namely, leaching of low molecular weight components from the composition of acacia wood. The regularities of the processes of adsorption of Cu2+ ions by native and sulfuric acid modified acacia filings under static conditions were studied. Using the obtained values of the initial and equi-librium concentrations of copper (II) ions in solutions, the sorption capacities of the materials were calculated and the adsorption isotherms of Cu2+ ions were constructed using native and modified acacia filings. Processing acacia sawdust with sulfuric acid solutions leads to an increase in the sorption capacity for copper ions, while the greatest sorption capacity is observed in the case of acacia sawdust treated with a 3% sulfuric acid solution. By processing the obtained sorption isotherms in the framework of the monomolecular models of Langmuir, Freindlich, Dubinin-Radushkevich, Temkin, the regression equations and approximation coefficients are determined. It was revealed that the processes of adsorption of Cu2+ ions by native and modified acacia sawdust with a 3% sulfuric acid solu-tion are best described by the Langmuir model, and the processes of copper ion adsorption by acacia sawdust mod-ified by 1% and 2% sulfuric acid solutions are described by the Freindlich model. The thermodynamic constants of the adsorption processes are calculated, from the values of which it is determined that all the studied processes belong to the processes of physical adsorption. By processing the kinetic dependences of the processes within the framework of the diffusion adsorption model, we calculated the Bio coefficients for the sorption processes of Cu2+ ions by native and modified acacia filings, the values of which determined the limiting stages of the processes (mixed diffusion).
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COMPARISON OF SORPTION PROPERTIES OF NATIVE AND HEAT-TREATED PEANUT PEEL AGAINST NICKEL IONS

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 4-9 p.
Abstract
The paper presents the results of investigating the possibility of increasing the sorption capacity of peanut peel after heat treatment at 300°C for 30 minutes. World peanut production is about 40 million tons for 2017-2018. The peel remaining after peanut processing is not used and it is unused waste. For research peanuts were taken growing in the valley of Aleppo (Syria). It was established that after heat treatment, the peanut peel surface becomes more prominent, which improves its sorption properties. During the heat treatment, the charring of the plant fibers that make up the peel occurs, as a result of which the surface of the material is covered with a layer of soot and becomes black. The black color has the greatest intensity during heat treatment at 300 oC. At lower roasting temperatures, the carbonization of the fibers is insufficient.At higher temperatures, the carbon layer is burning with the formation of CO2.
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STUDYING THE PROCESS OF OIL-CONTAINING EMULSION PURIFICATION BY MEANS OF EXPERIMENT PLANNING METHOD

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 19-30 p.
Abstract
The process of oil-containing emulsion purification with chestnut tree waste (CTW) is considered. The factors influencing the process of purification with the application of a full factorial experiment are established. The mathematical model obtained under carrying out a full factorial experiment has the form of a linear equation. The results of the calculation are comparable with the results of the experiment. The data obtained allow conducting a process of water purification at optimal values of technological parameters.
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THE USE OF PEANUT PROCESSING WASTE AS A SORPTION MATERIAL

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 40-49 p.
Abstract
The paper presents the results of the study of the possibility of using peanuts waste processing as a sorption material. The literature data on the use of numerous materials as sorbents are given. Physico-chemical and structural-morphological features of peanut shells were investigated. The object of the study was methylene blue dye as a widely known and used substance, and the sorption capacity for methylene blue is an important characteristic of industrial sorbents. The adsorption capacity of the material is calculated and the adsorption isotherm is constructed. The sorption capacity of the original peanut shell by methylene blue was 0.22 mmol/g.
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