Sorption Materials Research Articles

Application of the Organic Waste-Based Sorbent for the Purification of Aqueous Solutions

The effective purification of large-capacity wastewater from heavy non-ferrous metals and organic pollutants using inexpensive sorption technology remains a crucial task. Analyzing the current objectives of sustainable development, biochar obtained from chicken manure has prospects as a source for sorption purification of industrial wastewater. To determine the characteristics of organic material and the composition of the initial and equilibrium phases, the following analysis methods were used: volumetric, complexometric, pH-metric, X-ray fluorescence, chromatographic, spectrophotometric, luminescence-photometric and X-ray diffraction. The thermal nitrogen desorption method was used for determining the specific surface area and pore sizes with the Quantachrome Nova 1000e automatic analyzer. The sorption properties of the reprocessing product of the fresh poultry manure were investigated in relation to organic and inorganic compounds: phenols, benzene, ketones, cations of lead, mercury, manganese and iron. Based on the results obtained, technical conditions were developed for the use of the reprocessed organic waste-based product as a sorption material for household, industrial and technological wastewater purification from organic and inorganic components.

Monitoring the effectiveness of selected sorption materials in removing diclofenac from water

One of the contemporary problems is the widespread use of medicaments, which leads to an increased occurrence of these substances in the environment. The efficiency of conventional treatment processes for removing drugs from water is in most cases very little, if not zero. Treatment processes for removal of drugs include adsorption on activated carbon, membrane processes, and advanced oxidation processes. Within a specific university research project, a laboratory test was performed at the Institute of Municipal Water Management of the Faculty of Civil Engineering, Brno University of Technology, to monitor the effectiveness of diclofenac removal by selected sorption materials. Diclofenac was chosen for this experiment as a representative of one of the most widespread groups of drugs - non-steroidal anti-inflammatory drugs. The removal of diclofenac from water was performed using columns filled with sorption materials Filtrasorb F100, GEH and Bayoxide E33. The aim of the test was to compare the selected sorption materials in terms of their effectiveness in removing diclofenac from water. From analyses of water taken at predetermined time intervals after filtration through said materials, it was found that the most suitable material for removing diclofenac from water is Filtrasorb F100.

Removal of selected pesticides from water using granular activated carbon

Pesticides are intensively used for the protection of field crops, orchards and vineyards, but they are also used in the removal of undesirable stands on non-agricultural land (railway embankments, playgrounds, handling areas, etc.), in water management (in coastal management, destruction of growths in irrigation canals), in forestry, etc. Regular application of pesticides increases their content in the aquatic environment and agricultural products. Their occurrence in water is relatively common and it follows that these substances are used in large quantities. Residues of these substances can persist in soils for 2 to 12 weeks. Due to their good solubility in water, they are easily transported from the soil to aquifers.Several methods can be used to remove pesticides from water, e.g., coagulation, filtration, precipitation, ozonation, adsorption, ion exchange, nanofiltration, reverse osmosis and advanced oxidation processes. Their effectiveness varies considerably and depends mainly on the chemical nature of the pesticide being removed.This article studies adsorption on two granular activated carbons Filtrasorb 400 and Norit 1240. Mixture of the pesticide standards (acetochlor, alachlor, dimethachlor, propachlor, metazachlor and metolachlor) was added to drinking water with concentration of approximately 1 µg/L. The experiments were performed in the glass bottles with the volume of 200 mL of water. The granular activated carbons (200 mg) were added to the bottles. Subsequently these bottles were regularly stirred, and the samples were taken out at times 0, 30, 60, 90, 120, 180, 240 and 360 minutes. Samples were taken by pipette into the 40 ml glass vials with added thiosulphate for preservation. Analyses of target pesticides were performed in laboratories of ALS Czech Republic in Prague. LC-MS using the internal standard method was used to determine chlorinated pesticides in water samples. The adsorption efficiency of pesticides removal and the adsorption capacity of granular activated carbon depends on the time of contact of water with the material. The results showed that the efficiency of selected pesticides removal and adsorption capacity for two granular activated carbons used varied. Filtrasorb F400 proved to be a better sorption material than Norit 1240. The efficiency of this material ranged from 18 to 60%, while the efficiency of Norit 1240 was significantly lower.Adsorption capacity of activated carbons for selected pesticides and reaction kinetics of 0th, 1st, 2nd and 3rd order was also studied.

Potential of Kale and Lettuce Residues as Natural Adsorbents of the Carcinogen Aflatoxin B1 in a Dynamic Gastrointestinal Tract-Simulated Model.

Adsorption of the carcinogen aflatoxin B1 (AFB1) onto agro-waste-based materials is a promising alternative over conventional inorganic binders. In the current study, two unmodified adsorbents were eco-friendly prepared from kale and lettuce agro-wastes. A dynamic gastrointestinal tract-simulated model was utilized to evaluate the removal efficiency of the sorptive materials (0.5%, w/w) when added to an AFB1-contaminated diet (100 µg AFB1/kg). Different characterization methodologies were employed to understand the interaction mechanisms between the AFB1 molecule and the biosorbents. Based on adsorption results, the biosorbent prepared from kale was the best; its maximum adsorption capacity was 93.6%, which was significantly higher than that of the lettuce biosorbent (83.7%). Characterization results indicate that different mechanisms may act simultaneously during adsorption. Non-electrostatic (hydrophobic interactions, dipole-dipole interactions, and hydrogen bonding) and electrostatic interactions (ionic attractions) together with the formation of AFB1-chlorophyll complexes appear to be the major influencing factors driving AFB1 biosorption.

Modification of Magnetite Nanoparticles with Triazine-Based Dendrons and Their Application as Drug-Transporting Systems.

The following research aims at the synthesis of magnetite nanoparticles functionalized with triazine-based dendrons and the application of the obtained materials as effective sorptive materials dedicated to acidic bioactive compounds. The adopted synthetic approach involved: (1) the synthesis of nanosized Fe3O4 particles via classic co-precipitation method, (2) the introduction of amine groups on their surface leading to materials’ precursor, and (3) the final synthesis of branched triazine-based dendrons on the support surface by an iterative reaction between cyanuric chloride (CC) and piperazine (p) or diethylenetriamine (DETA) via nucleophilic substitution. The characterized materials were tested for their adsorptive properties towards folic acid, 18β–glycyrrhetinic acid, and vancomycin, showing high adsorption capacities varying in the ranges of 53.33–401.61, 75.82–223.71, and 68.17–132.45 mg g−1, respectively. The formed material–drug complexes were also characterized for the drug-delivery potential, performed as in vitro release studies at pH 2.0 and 7.4, which mimics the physiological conditions. The release profiles showed that the proposed materials are able to deliver up to 95.2% of the drugs within 48 h, which makes them efficient candidates for further biomedical applications.

Functionalized Metal-Organic Framework Toward Colorimetric CO2 Sensing in Indoor Air Environment

Carbon dioxide (CO2) has been shown to contribute to human health consequences indoors, such as shortness of breath, nasal and optic irritation, dizziness, and nausea. Given these precarious conditions for human health, various efforts have emerged toward development of CO2 monitors for indoor deployment. The chief problem in gas sensing is the design of a sensor that is highly-sensitive and selective to targeted species, energy-efficient, inexpensive to fabricate, stable, and convenient for users. One of the most popular CO2 sensors in commercial operations is the nondispersive infrared (NDIR) CO2 sensor. While boasting high accuracy and longevity, the CO2 NDIR sensor has traditionally been challenged by power consumption, cost, and bulky dimensions. In contrast to the NDIR sensing technology, colorimetric sensing retains several advantages, including easy preparation, user convenience, and obvious responses detectable by the human eye.In this work, we situate metal–organic frameworks (MOFs) as highly-porous, crystalline sorbents for sensitive colorimetric CO2 detection. In particular, a zeolitic imidazolate framework (ZIF) is chosen as the sorptive material due to its chemical stability and tunable CO2 affinity. The colorimetric gas sensor is developed by incorporating a CO2-affinative basic function and a pH indicator into the ZIF. The developed colorimetric CO2 sensor exhibits an obvious response to a wide range of CO2 levels of interest to indoor air detection (with a lower limit of detection below 1,000 ppm CO2). Powder X-ray diffraction confirms its chemical stability over one month in ambient conditions. Ultraviolet-visible spectroscopy reveals quantitative differences in colorimetric responses across a span of CO2 concentrations (700 – 7,500 ppm CO2). The color response is attributed to a two-step reaction mechanism whereby the pH indicator deprotonates the reaction intermediate between the adsorbed CO2 reacting with the basic function, shifting the pH and inducing a color change. Given its simple fabrication, rapid and obvious response, and stability in ambient environment, the ZIF-based colorimetric sensor provides a promising route for an improved indoor air quality monitoring. Acknowledgements We would like to thank the National Science Foundation for support in the form of a Graduate Research Fellowship (GRF) and Grant # 1903188, as well as the Bakar Fellows Program.

Use of Garlic Processing By-Products to Remove Pollutants from Aqueous Media

The paper summarized the literature data on using ground peels, outer leaves, and garlic roots (Allium sativum L.) as sorption materials to remove various metal ions, dyes, and antibiotics from aqueous media. This paper provides brief information on the amount of waste generated from processing garlic, its chemical composition, and ways of reuse. It gives the adsorption processes parameters and the values of sorption parameters for the studied pollutants. It was shown that garlic residue sorption characteristics for various pollutants could be increased by chemical modification with various chemical reagents. It was determined that the Langmuir model more accurately describes the pollutant’s adsorption isotherms in most cases, and the kinetics of the process more accurately describes the pseudo-second-order model. It was shown that garlic peels and steam are good precursors for activated carbons production.

Biosorbents for wastewater treatment

Biosorption is a promising technology for removing various pollutants from industrial wastewater, which consists in the use of secondary plant raw materials (e.g., agro-industrial waste) to solve environmental pollution problems. The purpose of this study is to evaluate the potential of nut shells as a biosorbent, to study the effect of alkaline modification of shells on their properties and to study the use of spent biosorbents as additives in cement. The influence of the fractional composition of the initial material on its sorption capacity and the influence of the modification of shells with alkaline solution on the properties of the obtained biosorbents are investigated. The yield of the final products was determined gravimetrically as the ratio of the mass of the product to the mass of the raw material. The sorption capacity was studied using model solutions. The concentration of sodium hydroxide solutions was determined by titration, and the cationic dye by spectrophotometric method. Methylene blue was used as a test dye. The studies have shown that the fractional composition of the material largely determines its sorption properties. Reducing the particle size of the nut shells leads to an increase in the sorption efficiency of methylene blue from 17.2% for the fraction with a size of 1.5-2.0 mm to 39.2% for the fraction with a size of 0.5-1.0 mm. The static exchange capacity increases by an average of 30 % for each subsequent fraction. To improve the sorption properties of the initial material, along with grinding, it is advisable to use chemical modification. The method of alkaline modification was used, which is accompanied by partial destruction of the aromatic component of raw materials and low molecular weight polysaccharides and by removal of extractives of different nature, which leads to the formation of a more porous structure. The maximum sorption efficiency of methylene blue (80 %) corresponds to the biosorbent obtained from nut shells (fractional composition 0.5-1.0 mm) by modifying with 5 % NaOH solution for 180 min at a temperature of 100 oC. Alkaline treatment significantly improves the adsorption capacity of the biosorbent to the cationic dye compared to the initial material. The sorption capacity of nut shells and biosorbent based on shells was studied as a function of pH of aqueous dye solution and duration of contact. It was found that pH of the aqueous solution had a significant effect on the sorption of the dye and the maximum value was reached at pH 6. This is due to the electrokinetic properties of the surface of lignocellulosic materials - the ability to change charge depending on pH (positive in acidic, negative in neutral and alkaline), due to the presence of different functional groups. The study of kinetics showed that the maximum rate of absorption of methylene blue corresponded to the first 30 minutes of contact. Sorption equilibrium is achieved within 240 minutes of contact. Sorption kinetics was also studied using pseudo-first and pseudo-second order models, as well as a diffusion model. The pseudo-second order kinetic model (R2 = 0.99) best describes the absorption kinetics of the cationic dye and suggests that the fixation of methylene blue on the surface of the biosorbent occurs due to various mechanisms. The problem of further use of spent sorption materials is no less important than the efficiency of sorbents in creating an effective integrated water treatment technology. Spent biosorbent was used as an additive to the composition of cement type I/500. The use of plant material in the amount of 5% will not lead to a significant deterioration of the physical and mechanical properties of cement. This indicates the prospects of such an approach in the utilization of spent sorbents. In further research, it is planned to investigate various modification options for plant materials for obtaining highly effective biosorbents of multipurpose function for the solution of environmental problems.

REMOVAL OF POLLUTANTS FROM SEWAGE WITH GRINDED SHELLS OF APRICOT KERNELS

A review of the literature data on the use of biomass components of apricot trees (Prunusarmeniaca) as a sorption material for the extraction of various pollutants from waste and natural waters is carried out. The parameters of the sorption interaction at which the highest degree of removal of pollutants is achieved are given. It has been shown that it is possible to increase the sorption capacity of apricot biomass components by modifying it with various chemical reagents. It has been determined that the most studied sorption material is the shell of apricot kernels. It is determined that the largest number of publications is devoted to the use of the latter as raw materials for the production of activated carbons. It was revealed that the surface area and the total pore volume of activated carbons from the kernels of apricot fruits depend on the modes of carbonization and activation of raw materials. It is shown that activated carbons are effective sorbents for removing various pollutants (metal ions, dyes, oil and oil products) from aqueous media. It was found that the adsorption isotherms of pollutants are most adequately described in most cases by the Langmuir and Freundlich models, and the kinetics of the process is most often described by the pseudo-second order model.

Selection of sorption materials for the extraction of nickel and cobalt from the ore of the Gornostaevskoye deposit

Oxidized nickel ores account for the majority of industrial ores suitable for nickel production. The processing of such ores using traditional pyrometallurgical technology is not economically viable due to the low nickel content. One of the most cost-effective methods of processing oxidized nickel ores is sulfuric acid leaching technology followed by sorption extraction. The aim of this work is to establish the kinetic and thermodynamic parameters of the sorption extraction of nickel and cobalt using iminodiacetate chelating ion-exchange sorbents from various manufacturers, to select a desorbing solution and to determine the degree of desorption. The sorption of nickel and cobalt was carried out in a weakly acidic medium from a model solution containing impurities of other metals in static and dynamic modes. The limiting sorption capacity for the studied sorbents is 18-26 mg/g for nickel and 1-2 mg/g for cobalt in the static mode. The sorption capacity in the dynamic mode for nickel is equal to 25.5 g/L for Purolite S 930, 29.2 g/L for Lewatit TP 207, 1.4 g/L, and 1.8 g/L for cobalt, respectively. The best desorption parameters are achieved when using a 2 M sulfuric acid solution. The degree of desorption for sorbents Purolite S 930 and Lewatit TP 207 exceeds 90%. The use of the Lewatit TP 207 sorbent for the extraction of nickel from the leaching solution of nickel ore of the Gornostaevskoye deposit in 5 cycles made it possible to obtain a commercial desorbate with a nickel content of 18 g/L. The use of a part of the commercial desorbate obtained in the previous cycle, further strengthened to the initial concentration of sulfuric acid, for re-extracting nickel from the saturated sorbent during a cyclic process leads to a deterioration in desorption characteristics. It is recommended to remove the commercial desorbate from the process after several cycles of desorption and supply new solution of sulfuric acid for desorption to restore the sorption parameters.

Sorption of petroleum products by chemically modified agricultural waste

The work investigated the physical, mechanical and sorption properties of cellulose-containing wastes of agro-industrial production, formed as a result of manufacturing activities of one of the large agricultural enterprises in the Republic of Tatarstan. To improve the sorption properties, the wastes were chemically modified via treating them with sodium hydroxide solutions with 0.5, 1, and 3% concentrations at a temperature of (20 ± 2) ° C. Standard and operating diesel oils were used as sorbates. As a result of alkaline treatment, there is an increase in the maximum oil absorption of sorption materials in relation to engine oils, an increase in the sorption activity with respect to iodine, which characterizes the material porosity, as well as a decrease in the bulk density of the modified samples. The best physical, mechanical and sorption properties were found in cellulose-containing waste treated with a 3% sodium hydroxide solution.

Сорбция и удерживающая способность модифицированных волокнисто-пористых материалов по отношению к нефти и нефтепродуктам

Purpose. Investigation of the effect of electric polarization of polymeric fibrous materials on the sorption of oil and petroleum products. Methods. Melt blowing of Borealis brand polypropylene. Polarization of samples in a corona discharge field of positive and negative polarity with a strength of 25 kV/cm. Sample processing in low-temperature oxygen plasma of a glow discharge with a frequency of 35 kHz. Weighting method for determining sorption characteristics. Scanning electron microscopy method. Electret thermal analysis method. Findings. The dependence of sorption parameters of materials on the type of physical modification – corona discharge of different polarity and low-temperature plasma of a glow discharge – has been established. It is shown that the modification of fibrous-porous materials in a corona discharge field to impart electret properties to them somewhat reduces the sorption characteristics of these materials in relation to oil. In the manufacture of sorption materials for the collection of crude oil, the original unmodified fibrous-porous material should be used. It has been experimentally established that in the manufacture of sorption materials for the collection of light oil fractions, the preferred method is the modification of fibers in a corona discharge field of negative polarity. Electrization has a significant effect on the processes of sorption by fibers of its lipophilic components. A physical model of the sorption of petroleum products by electret samples of polymeric fibrous-porous materials is proposed. Application field of research. Fibrous-porous polymeric materials subjected to physical modification with the formation of an electret state can be used for: sorption of some oil fractions, filtration of liquids from contaminants of a dielectric nature, purification of air from ionized dust containing radioactive particles, targeted separation of biological fluids containing dielectric and (or) electret components.

Solvent-free processing of eco-friendly magnetic and superhydrophobic absorbent from all-plant-based materials for efficient oil and organic solvent sorption

The unique features of bioresources such as cellulose and bio-wax include renewability, biodegradability, low cost, and abundance on Earth. Therefore, their efficient use is essential for a sustainable economy. Herein, we report a facile method for the surface modification of pretreated cotton with a bio-wax emulsion in water and Fe3O4 nanoparticles to fabricate a green, durable, magnetic, and superhydrophobic/superoleophilic absorbent for the sorption of oil and organic solvents. Magnetic superhydrophobic cotton (MSC) was successfully prepared via a simple two-step dip-coating method without using any toxic organic reagents. The as-prepared MSC was used to selectively absorb various types of oils and organic solvents up to approximately 20–50 times its own weight. Furthermore, it exhibited a stable magnetic responsivity and high reusability in oil/water separation cycles. In addition, the removal and collection of the absorbed oil/organic solvents were easily achieved with distillation and a vacuum air pump. Moreover, the as-prepared MSC was used in a heavy oil/water gravity-separation filter system and in the continuous collection of a light oil from water surfaces using a pump. The proposed concept may provide a green and sustainable strategy for fabricating superhydrophobic/superoleophilic materials for efficient sorption of oils and organic solvents.

Onion (Allium Cepa) Processing Waste as a Sorption Material for Removing Pollutants from Aqueous Media

The paper summarizes the literature data on the use of onion (Allium cepa) processing waste as sorption materials to remove various pollutants (metal ions, dyes, antibiotics) from aqueous media. It provides brief literature data on the structure, volume of cultivation, and chemical composition of some components of onion biomass. It was found that onions contain many amino acids, vitamins, polyphenolic compounds, and other biologically active compounds that have various functional groups in their composition. This contributes to the removal of various metal ions (Ca2+, Cd2+, Cr(VI), Cu2+, Hg2+, Mg2+, Ni2+, Pb2+, Zn2+) from aqueous media with native and modified onion processing waste (onion skin). The work shows the possibility of increasing the sorption characteristics of pollutants by treating the Allium cepa biomass with various chemical reagents. It was found that the pollutant adsorption isotherms on onion skin are most often more accurately described by the Langmuir and Freundlich models, less often by other models. The kinetics of the process predominantly corresponds to the pseudo-second-order model. It was shown that the use of onion skin extracts modified with various chemical compounds is promising for removing heavy metal ions. The work also shows the possibility of using onion skin modified by plasma and microwave radiation to remove the Methylene blue dye from simulated solutions.

ON THE POSSIBILITY OF USING CARBON ENTEROSORBENTS TO NORMALIZE CHOLESTEROL METABOLISM

The creation of effective drugs for the prevention and treatment of atherosclerosis is one of the urgent interdisciplinary tasks for modern chemistry and pharmacology. Given the role of hypercholesterolemia in the development of this disease, it is necessary to remove excess amounts of cholesterol from the body. As an alternative to means of lowering total cholesterol and low-density lipoprotein (LDL) cholesterol, the possibility of using carbon enterosorbents for efferent therapy is considered. Aim. The purpose of the study was to evaluate the sorption capacity of the adsorbents developed by authors in terms of the possibility of cholesterol adsorption. Methods. Using the spectrophotometric method, the sorption of cholesterol on samples of adsorbents obtained by chemical activation of waste from the processing of lignocellulosic raw materials — dogwood and coffee residue has been studied. Results. A comparison of sorption isotherms with the isotherm obtained on the industrial adsorbent SORBEX has been performed. It was shown that the adsorption capacity of carbon adsorbents is primarily determined by their porous structure. The highest sorption values (7,3 mg/g) have been revealed by the sorption material obtained by chemical activation of cornel seed, an intermediate position (6,3 mg/g) is occupied by the adsorbent obtained from the coffee residue. Industrial carbon SORBEX has the lowest sorption values (5,3 mg/g). Conclusions. Calculations by Langmuir’s and Freundlich’s models testify about the accordance of the experimental data to Langmuir’s model. The use of the obtained activated carbons may be one of the effective alternative ways to lower blood cholesterol.

Recyclable Functionalized Material for Sensitive Detection and Exceptional Sorption of Hexavalent Chromium and Permanganate Ions with Biosensing Applications.

Environmental remediation with a single platform for selective sensing and removal of toxic analytes with recyclability of the material has always been a desirable system for sustainability. However, materials comprising all the abovementioned advantages are rarely known for oxoanions. We herein developed a fluorogenic napthalimide-based functionalized mesoporous silica material (SiO2@NBDBIA) as a signaling and remediation system for oxoanions (CrO42-, Cr2O72-, and MnO4-) from a pool of several anions. The fluorescence quenching of the SiO2@NBDBIA material in the presence of CrO42-, Cr2O72-, and MnO4- ions gives the limit of detection (LOD) values of 6.23, 25.2, and 20.32 ppb, respectively, which are well below the maximum contaminant level demarcated by the United States Environmental Protection Agency. The maximum adsorption capacities of the material for the abovementioned oxoanions are found to be 352, 363, and 330 mg/g, respectively, which are well above those mentioned in the literature reports. Contrary to the literature-dominated irreversible ion-exchange mechanism, the reversible hydrogen-bonded binding of the material with the oxoanions leads to the recyclability of the material easily, which is very rare in the literature. The DFT calculations were performed to examine the interactions between the material and oxoanions. For real applications, this material was also used as a fluorescence probe to detect these oxoanions in the actual water samples, and more interestingly, used as a biosensing probe for these oxoanions in the living organism Artemia salina through fluorescence imaging. Thus, the SiO2@NBDBIA material is a unique example of recyclable material for detecting and remediating oxoanions.

Ecological Aspects of Clay Sorption Materials Usage in Leather and Fur Production Technologies

The work is devoted to solving the current problem of increasing the level of environmental safety of treatment industrial wastewater of leather production from chromium ions (III) through the use of natural and modified bentonite. The studies of natural and modified bentonite use in the adsorption of Cr3 + ions were conducted. The influence of the process duration on the sorption efficiency of chromium ions was studied. Studies were conducted to use spent bentonite in tanning and filling processes. The efficiency of modification of montmorillonite has been proved and the expediency of using mineral dispersion for qualitative formation of the structure and properties of the leather during tanning has been established.

Wastewater purification from copper and nickel ions by means of thermally modified organo-mineral wastes and their combinations

Wastewaters, which contain heavy metals, are one of the main sources of environment pollution. This paper presents the data of research findings concerning the combined use of thermally modified organo-mineral waste products of sugar production and brewing industry for purifying test solutions from copper and nickel ions. The most efficient is the sorption material, obtained by heat treatment of brewing industry’s kieselguhr sludge KS450 (94% for nickel ions and 95% for copper ions); the next efficient is the material, obtained from sugar industry’s carbonaceous sludge CS600; the application of combined sorbents showed no increase in wastewater purification efficiency.

A Study of Zn2+ ions adsorption by native and chemically modified pea (Pisum sativum) pods

The paper deals with a study of Zn2+ ions adsorption by native and modified fine-cut pea (Pisumsativum) pod shells. The sorption material under study was treated using 1%, 2% and 3% NaOH or H2SO4 solutions. Isotherms of Zn2+ ions adsorption by native and treated pea pod shells were plotted and calculated using the Langmuir, Freundlich, Tyomkin, and Dubinin-Radushkevich models. It was determined that the isotherm of zinc ions adsorption by native shells of pea pods is most accurately described by the Langmuir model, by modified shells – by the Freundlich model. According to the values of the adsorption energy and the Gibbs energy, the adsorption is a physical process. The paper provides data on the degree of crystallinity, elemental analysis, and IR spectra of native and treated pea pods.

Thermal utilization of spent sorptive material from phythogenic waste

The thermal utilization of spent sorptive materials based on phythogenic waste in a pulsating combustion unit is proposed. The combustion temperature was determined based on the method of differential scanning calorimetry and derivatography. The hazard class of the produced ash is calculated on the basis of elemental analysis.