Papers by Keyword: Sorption

Abstract: Borassus palm or aethiopium palmyra is a palm species tree, widely spread in sub-Saharan Africa but its fruits don’t have any economic value therefore considered as waste. This study investigated the potential of Borassus fruit fibers (BFF), extracted manually from the underutilized fruit, for various applications by examining their hygroscopic properties. Scanning electron microscopy (SEM) revealed the fibers' unique features, including a relatively large diameter and high affinity for water vapor. A Dynamic Vapor Sorption (DVS) analysis with exposure time varying from 1, 2, 4 until 72h and varied Relative Humidity (from 0 to 90%) with 10% increment was carried out to examine the Sorption-desorption behavior. The characteristic hysteresis behavior of natural fibers was observed, with significant moisture uptake, particularly above 70% RH. The sorption and desorption processes were quantified, revealing a linear relationship between mass change and relative humidity. Furthermore, an Ensemble learning approach, specifically a Gradient Boosting Regression (GBR) model, was developed to predict the hygroscopic behavior of BFF. Trained on the experimental sorption-desorption data, the GBR model demonstrated excellent predictive accuracy, achieving a high R² value of 91.7% and low CV, MSE, and RMSE values (6.9 and 2.6, respectively). These findings highlight the significant influence of relative humidity on BFF moisture content and demonstrate the effectiveness of GBR as a powerful tool for accurately predicting the complex hygroscopic behavior of these fibers.

Abstract: The article analyzes the systems for generation, purification, transportation and storing of gaseous hydrogen as the alternative renewable energy source for ensuring of level of ecological safety of power plants with reciprocation internal combustion engines exploitation process. Purpose of the study is to improve the description of the process of purifying gaseous hydrogen from associated impurities during its production, storage and transportation based on the results of mathematical modeling analysis using improved mathematical apparatus based on modified thermodynamic perturbation theory. Problem of the study is the imperfection of the existing mathematical apparatus for describing the processes of purification of gaseous hydrogen as a commercial product and renewable ecological safe energy carrier using sorption metal hydride technologies based on TiMn_1,5. Idea of the study is to develop a list of recommendations and organizational and technical measures for obtaining ultra-high purity gaseous hydrogen in environmental protection technologies by improving the adequacy of the mathematical description of the processes of its sorption-desorption by intermetallic compounds based on TiMn_1,5. Task of the study is to adapt the mathematical apparatus of the modified thermodynamic perturbation theory to describe the process of selective sorption of hydrogen by metal hydrides of the type TiMn_1,5 from gas mixtures obtained during its production, storage and transportation. Object of the study is sorption processes in metal hydride technologies for the purification of gaseous hydrogen as an alternative fuel and a useful commercial product based on TiMn_1,5. Subject of the study is mathematical description of the course of hydrogen sorption processes by intermetallic compounds of the type TiMn_1,5 when purified from gas impurities. Methods of the study are literature analysis, modified thermodynamic perturbation theory, mathematical modeling. Scientific novelty of results of the study is for the first time, an apparatus for mathematically describing the processes of hydrogen sorption by intermetallic compounds of the type has been suggested TiMn_1,5 from gas mixtures during its production, storage and transportation based on the improvement of the modified thermodynamic perturbation theory. Practical value of results of the study is the improved mathematical apparatus and the results of its application which are suitable for developing a list of recommendations and organizational and technical measures for obtaining ultra-high purity gaseous hydrogen as an ecologicale safe renewable fuel in environmental protection technologies both during the times of armed aggression and during the post-war reconstruction of critical infrastructure and economic potential of our country. The main part of the research is devoted to the adaptation of the mathematical apparatus of the modified perturbation theory to describe the sorption processes of the interaction of hydrogen, which is in the state of a gas mixture, and intermetallic compounds of the type TiMn_1,5. It has been shown that based on sorption metal hydride technologies of the type TiMn_1,5 it is possible to achieve ultra-high purity of gaseous hydrogen as a commercial product when using it as an environmentally safe, renewable type of motor fuel. Mathematical modeling of hydrogen sorption by intermetallic compounds, performed on the basis of the mathematical apparatus of the thermodynamic perturbation theory improved in the study and on the example of the intermetallic hydride TiMn_1,5, based on the application of the lattice gas model for metal hydrides. A list of recommendations and organizational and technical measures has been developed for the implementation of this type of environmental protection technologies in the practice of the units of the State Emergency Service of Ukraine, in particular the operation of fire and emergency rescue equipment with internal combustion piston engines, both during armed aggression and during the post-war reconstruction of critical infrastructure and the economic potential of our country and ensuring the fulfillment of the requirements contained in the Order of the State Emergency Service of Ukraine No. 618 (on the main activity) dated September 20, 2013. «On Approval of the Regulations on the Organization of Environmental Support of the State Emergency Service of Ukraine» and in the historical perspective of achieving the sustainable development goals contained in the Decree of the President of Ukraine No. 722/2019 of September 30, 2019 «About the Goals of Sustainable Development of Ukraine for the Period up to 2030».

Abstract: This study investigates the impact of chemical and thermal activation on the sorption capacity of Transcarpathian clinoptilolite from the Sokyrnytsky deposit. The chemical activation of natural clinoptilolite was performed using aqueous solutions of 5% HCl and 25% H₂SO₄ at a solid-to-liquid phase ratio of 1:10. Thermal activation was conducted at a temperature of 300°C. The sorption capacity of both natural and activated clinoptilolite was evaluated for water vapor in this thermal analysis. The ability of activated clinoptilolite to absorb direct blue dye was determined through spectrophotometric analysis. The partial degradation of clinoptilolite due to acid modification was confirmed by X-ray phase analysis and electron microscopy. The sorption isotherms of direct blue dye were modeled using the Langmuir equation, and the corresponding constants were determined. Clinoptilolite activated with a 25% aqueous H₂SO₄ solution is recommended for use in sorption technologies for wastewater treatment from direct dyes.

Abstract: The object of the study was the Ukrainian bentonite clays of the Cherkasy deposit (layer II of the Dashukivska area) and the Ilnytske deposit of the Transcarpathian region. Enrichment of clays with montmorillonite was carried out by the method of sedimentation of the coarsely dispersed phase. The natural type of montmorillonite and the nature of isomorphic substitutions in its structure were confirmed by X-ray diffractometric and complex thermal analyses. Activation of bentonite clay enriched with montmorillonite was carried out by the action of ultrasonic waves. The sorption capacity of activated and montmorillonite-enriched clays with respect to Cu²⁺ ions was assessed by the results of energy dispersive X-ray analysis. The ion exchange mechanism of sorption of Cu²⁺ ions was confirmed by the data of diffractometric X-ray analysis. The prospects for the use of enriched bentonite clays activated by ultrasonic waves are outlined.

Abstract: Buckwheat grain processing produces a significant amount of buckwheat hulls, which are usually stored or incinerated, posing a threat to the environment, particularly to soil and air. The solution to this problem may lie in the production of biochar from buckwheat husks. Buckwheat husks have a favourable composition for biochar production. The resulting biochar can be used as an additive to compost to improve its characteristics, ensure a high-quality composting process and adsorb pollutants. Since the mechanisms of sorption of biochar produced from buckwheat husk are not yet well understood, the aim of this study is to investigate the sorption properties of biochar on the example of lead ion sorption. Comparison of the efficiency of lead ion sorption by different modified forms of raw materials shows that the method of biochar production significantly affects its sorption activity. An increase in the pyrolysis temperature has a positive effect on the sorption properties; the highest sorption is achieved at an initial concentration of lead ions of 1.00 mg/ml. The analysis of adsorption isotherms indicates a type L, which indicates minimal interaction between the adsorbed molecules. The kinetic parameters of the sorption process show that the system reaches equilibrium within a few hours, and the maximum sorption values are observed after 2.5-3 hours of incubation.

Abstract: The ionic mechanism of copper ion sorption from an aqueous medium has been confirmed. The study has elucidated the regularities of the process within a stirred bed reactor, where kinetics are limited by the internal diffusion region. Initial sorption curves under dynamic conditions have been obtained.

Abstract: An algorithm for predicting the intensity of sorption of gaseous materials released into the atmosphere as a result of an accident is proposed. The algorithm consists of three hierarchical levels: monitoring the parameters of gaseous material emission, predicting the consequences of gaseous material emission before and after sorption, and making a management decision. The first hierarchical level includes 4 blocks: obtaining information from the chemical reconnaissance group and the facility representative on the type, amount of hazardous gaseous materials, release intensity and scale of the accident; obtaining information from the hydrometeorological service on temperature, atmospheric pressure, wind direction and speed in the accident area; processing the information received; information on the availability of forces and means for sorption of hazardous gaseous materials. The second hierarchical level also includes 4 blocks: readiness of forces and means for sorption of hazardous gaseous materials; calculation with sorption; calculation without sorption; determination of the boundaries of the chemical damage zone according to the established criteria. At the third hierarchical level, there is 1 block: making a management decision. The software implementation of the proposed algorithm was carried out. The use of the developed algorithm and its software implementation will increase the speed and accuracy of predicting the consequences of the release of hazardous gaseous materials in an accident.

Abstract: The aim of the research was to establish and produce unfamiliar magnetic absorbents based on a commonly accessible specimen containing crown ethers via iron nanoparticles (magnetite), investigation their structural, magnetic, and absorbance properties, and analyze the possible utilization of these sorbents for the sorption and accumulation of tetracyclines. New crown complexes with biological prop ethers have been created, and the structure of the produced crown complexes has been determined using elemental analysis data from studies of these samples' IR, mass, and NMR spectra. According to the contact duration between the phases, the pH and solution's composition, the structure of tetracyclines, and their concentration, an organized research of the sorption of tetracycline on a magnetic composite with crown ethers was conducted as a component of the study. Crown ethers and Fe₃O₄ (CE@Fe₃O₄NPs) nanoparticles were produced under certain conditions, and the composites' magnetic and structural characteristics were evaluated. Tetracyclines were evaluated for their ability to bind to the nanostructures produced by CE@Fe₃O₄ NPs. These structures have no negative effects and remain safe for consumption. Crown ethers are currently produced using novel techniques, and new magnetic sorbents made with crown ethers and Fe₃O₄ nanoparticles have also been developed. It has been shown that magnetic sorbents composed of Fe₃O₄ nanoparticles and crown ethers have superparamagnetic characteristics. The research in consideration identifies and discusses the characteristics of tetracyclines' sorption behavior. There are several methods for concentrating tetracyclines for sorption onto a magnetic sorbent using Fe₃O₄ nanoparticles and crown ethers from aqueous solutions. Our research has demonstrated, using the example of produced CE@Fe₃O₄ NPs nanostructures, that mixing the nanotechnological approach with the methods of supramolecular chemistry offers a large adsorption effectiveness.

Abstract: This article focuses on the moister sorption by laminated composites. Moisture sorption was carried out on layered polymer composite materials consisting of layers of basalt fabric and fiberglass based on epoxy-diane resin. It is shown that the process of moisture absorption for glass fiber-reinforced polymers is more intense and with a higher concentration of moisture in comparison with basalt fiber-reinforced polymer. Curves of the sorption processes of moisture absorption and water absorption are obtained. The diffusion coefficients for the corresponding processes are calculated. Alteration in the surface structure of polymer composite materials were recorded using surface topography and REM images before and after exposure in the climate of Yakutsk (Russia).

Abstract: A technique for starch modification by graft polymerization of acrylamide has been developed. The obtained copolymer is soluble in a wide range of pH 2 - 12. The modification of starch made it possible to freely combine it with aqueous acid solutions of chitosan, in order to achieve a synergistic effect of their properties. A porous material based on modified starch and its mixtures with chitosan, which has high sorption characteristics, has been developed. The resulting material is promising as a sorbent of heavy metal ions and packing materials for transportation and storage.