Sorption Materials Research Articles

Approaches for filtrate utilization from synthetic gypsum production.

Waste recycling and industrial wastewater treatment have always been of interest. A green approach was developed for the filtrate of synthetic gypsum production from water treatment coagulation sediments and spent sulfuric acid. Due to the high concentration of iron sulfate, concentrated filtrate showed good coagulation results, which were 5% lower than pure iron sulfate. In addition, a high concentration of iron facilitates its use as a precursor for synthesizing magnetic sorbents and photocatalysts. Such materials were synthesized by the solution combustion synthesis method. Oil sorption capacity reached 1.8g/g, comparable to some synthetic materials and higher than sorption materials based on natural materials. Photodegradation of acid telon blue dye after 90min of irradiation time was 82.7% with catalyst derived from filtrate compared to the just dye solution with 17.6% efficiency. The reaction rate constant for the photocatalyst sample was up to 11.4-fold higher compared with only UV treatment. The neutralized filtrate containing sulfur, calcium, magnesium, and sodium has been tested as a complex fertilizer. The results of bioindication for oil radish showed up to a 15% increase in the shoot length. A number of techno-economic indicators show that such an approach is advantageous from a technological, environmental, and economic point of view.

Soya bean derived activated carbon as an efficient adsorbent for capture of valuable heavy metals from waste aqueous solution

Abstract The removal of hazardous metal ions from liquid waste effluents is very important for water as well as environmental safety. In this regard, this article discusses in detail the U(VI) uptake from aquatic environment using biomass-based Soya Bean activated carbon (labeled as AC-SB). XRD, SEM, FTIR, Raman, and BET analysis were used to characterize the synthesized AC-SB sorbent. Batch-type experiments were used to investigate the effect of various parameters on adsorption efficiency, including pH, metal-ion concentration, temperature, and contact time. The sorption experimental data have been described well with pseudo-second-order kinetic mathematical equations. The equilibrium state of the uptake reaction was 120 min. The Langmuir isotherm model accurately described the equilibrium process which declares that the uranium sorption is a monolayer and homogeneous process. The sorption capacity of the prepared AC was 32.7 mg g−1. Thermodynamic analysis explore that the U(VI) uptake process is endothermic, feasible and spontenous process. The displayed results demonstrate that the prepared AC-SB sorbent could be used as the proper material for uranium sorption from real matrix samples.

Modification of Natural Minerals with Technogenic Raw Materials

The presence of uranium-containing wastes from large provinces in the Republic of Kazakhstan significantly complicates the ecological situation, causing damage to the soil and hydrosphere due to the uncontrolled spread of large volumes of natural waters contaminated with radionuclides. They are usually utilized by the sorption method; however, the use of synthesized sorption materials is limited by their high price, and natural minerals are limited by low sorption characteristics. Many modification options are used in order to improve the sorption characteristics, but only a few methods have been found applied in industry. The main disadvantages include the complexity in the application and modification of reagents rarely used in industrial practice, which increases their cost, and is an obstacle to their widespread use. The authors of this research have studied the possibility of using technogenic raw materials—slags of phosphorus production—as a modifier of natural minerals. The methods of slag activation are investigated, the optimal conditions for the modification of the natural minerals zeolite and shungite by activated slag are determined, and the sorption properties of modified sorbents are studied.

Review of Pistachio (Pistacia) Shell Use to Remove Pollutants from Aqua Media

The paper summarizes literature data on using crushed pistachio shells (Pistacia vera L.) as sorption materials to remove ions of various metals, dyes, and antibiotics from aqueous media. It provides brief information on the amount of pistachio processing waste, its chemical composition, and its recycling methods. It gives the adsorption process parameters and the values of pistachio shell sorption parameters for the studied pollutants. It was shown that pistachio shells' sorption characteristics for various pollutants could be increased by chemical modification with various chemical reagents. The isotherms of pollutant adsorption with pistachio shells were found to be, in most cases, more accurately described by the Langmuir model, and the process kinetics to follow in most cases, the pseudo-second-order model. It is shown that the pistachio shell is a good precursor for activated carbons production, which can also be used for the adsorption of various pollutants from aqueous media.

Crystallographic Mapping and Tuning of Water Adsorption in Metal-Organic Frameworks Featuring Distinct Open Metal Sites.

Crucial steps toward designing water sorption materials and fine-tuning their properties for specific applications include precise identification of adsorption sites and establishment of rigorous molecular-level insight into the water adsorption process. We report stepwise crystallographic mapping and density functional theory computations of adsorbed water molecules in ALP-MOF-1, a metal-organic framework decorated with distinct open metal sites and carbonyl functional groups that serve as water anchoring sites for seeding the nucleation of a complex water network. Identification of an unusual water adsorption step in ALP-MOF-1 motivated the tuning of metal ion composition to adjust water uptake. These studies provide direct evidence that the identity of the open metal sites in MOFs can dramatically affect water adsorption behavior between 0 and ∼20% RH and that multiple proximal water anchoring sites along the MOF skeleton facilitate water uptake which could be potentially useful for applications requiring rapid and energetically facile water sorption.

Use of Reduced Graphene Oxide to Modify Melamine and Polyurethane for the Removal of Organic and Oil Wastes

Methods for obtaining efficient sorption materials based on highly porous melamine and polyurethane matrices modified with reduced graphene oxide were developed. These materials are promising for solving environmental problems such as water pollution with organic products by sorption treatment. Reduced graphene oxides (rGOs) were synthesized from graphene oxide suspensions using potassium hydroxide, ascorbic acid or hydrazine hydrate. Composites with obtained rGO and melamine and polyurethane foam were produced for further characterization. The composites demonstrate high sorption of organic pollutants (oil, diesel fuel and gasoline) and low sorption of water. The composites were comprehensively analyzed by physicochemical techniques (SEM, XPS, Raman spectroscopy, UV–Vis) to elucidate the mechanism of sorption.

Physical and Chemical Regularities of Phosphorus and Beryllium Recovery by the Sorbents Based on Acrylic Fiber Impregnated by Iron Hydroxide (III)

The paper investigates the physicochemical regularities (kinetics and isotherm) of phosphorus and beryllium recovery by sorbents based on polyacrylonitrile (PAN) fiber and Fe(OH)3 obtained by various methods: PAN or pre-hydrolyzed PAN with precipitation of FeCl3 with ammonia, using ready-made or electrochemically generated Na2FeO4, pre-hydrolyzed PAN treated with an alkaline solution of Na2FeO4, as well as their comparison with granular aluminum oxide. The Langmuir, Freudlich and Dubinin–Radushkevich models show high performance of materials for sorption of stable P and Be used as tracers for the release of 7Be, 32P, and 33P from seawater. The obtained kinetic data are processed using kinetic models of intraparticle diffusion and the pseudo-first-order, pseudo-second-order, and Elovich models. Optimal conditions for obtaining sorbents are established, namely, the effect of NaOH concentration at the stages of preparation on the properties of sorbents based on the PAN fiber and Fe(OH)3 obtained by various methods.

Simultaneously Enhanced Hydrophilicity and Stability of a Metal-Organic Framework via Post-Synthetic Modification for Water Vapor Sorption/Desorption.

With increasing demands for high-performance water sorption materials, metal-organic frameworks (MOFs) have gained considerable attention due to their high maximum uptake capacities. In many cases, however, high overall capacity is not necessarily accomplishing high working capacity under operating conditions, due to insufficient hydrophilicity and/or water stability. Herein, we present a post-synthetic modification (PSM) of MOF-808, with di-sulfonic acids enhancing simultaneously its hydrophilicity and water stability without sacrificing its uptake capacity of ≈30 mmol g-1 . Di-sulfonic acid PSM enabled a shift of the relative humidity (RH) associated with a sharp step in water vapor sorption from 35-40 % RH in MOF-808 to below 25 % RH. While MOF-808 lost uptake capacity and crystallinity over multiple sorption/desorption cycles, the di-sulfonic acid PSM MOF-808 retained >80 % of the original capacity. PSM MOF-808 exhibited good hydrothermal stability up to 60 °C and high swing capacity.

Simultaneously Enhanced Hydrophilicity and Stability of a Metal‐Organic Framework via Post‐Synthetic Modification for Water Vapor Sorption/Desorption

AbstractWith increasing demands for high‐performance water sorption materials, metal‐organic frameworks (MOFs) have gained considerable attention due to their high maximum uptake capacities. In many cases, however, high overall capacity is not necessarily accomplishing high working capacity under operating conditions, due to insufficient hydrophilicity and/or water stability. Herein, we present a post‐synthetic modification (PSM) of MOF‐808, with di‐sulfonic acids enhancing simultaneously its hydrophilicity and water stability without sacrificing its uptake capacity of ≈30 mmol g−1. Di‐sulfonic acid PSM enabled a shift of the relative humidity (RH) associated with a sharp step in water vapor sorption from 35–40 % RH in MOF‐808 to below 25 % RH. While MOF‐808 lost uptake capacity and crystallinity over multiple sorption/desorption cycles, the di‐sulfonic acid PSM MOF‐808 retained >80 % of the original capacity. PSM MOF‐808 exhibited good hydrothermal stability up to 60 °C and high swing capacity.

In Ukrainian

The paper considers an approach to the processing of waste of agro-industrial raw materials due to chemical activation. To obtain a sorption material, waste was used, which is the shell of Juglansregia walnuts. The aim of the work was to develop adsorbents from walnut shells with a large proportion of mesopores, to determine the parameters of the porous structure and to study their adsorption capability to absorb egg albumin as a marker of medium molecular toxins of a protein nature. Activated carbon samples with a high mesopore content (550 m2/g) were obtained by combined activation of the feedstock. The sorption of one of the obtained samples and, for comparison, the medical product SORBEX was studied by the spectrophotometric method, and its effectiveness was proved in the absorption of egg albumin from aqueous solutions. The significant capability of the obtained sample to sorb protein (35–38 mg/g) was shown, it has been assumed that in the process of sorption, macromolecules are concentrated near the inlets into the pores of the adsorbent. It can be stated that the adsorption of albumin increases in proportion to the increase in the specific surface area of the mesopore. Using the obtained sorption isotherms, the parameters of adsorption processes were calculated. Adsorption isotherms were calculated using the Langmuir and Freundlich equations. It is shown that the maximum adsorption values calculated using the Langmuir equation are in good agreement with the experimental data.

APPLICATION OF RICE PAD (ORYZA SATIVA) AS A SORPTION MATERIAL TO REMOVE POLLUTANTS FROM AQUATIC ENVIRONMENT

The use of rice husk (the waste in the production of seeded rice (Oryza sativa) as a sorption material for the removal of pollutants of various classes – inorganic (Cr, Ni, Co, Pb, Hg, As, Cd, Cu, Zn) and organic substances (synthetic and natural dyes, phenols, antibiotics, polycyclic aromatic compounds, humic acids, pesticides, chitosan) from aqueous media is generalized. The literature data on the structure of seeded rice, the volume of its cultivation, the chemical composition, and some components of rice husk are given.
 The methods of physical and chemical (the use of inorganic acids, salts, and alkalis) are described activation, as well as modification of rice husks using surfactants, Fe3O4 nanoparticles, functional agents, and monomers (polymerization reactions). Quantitative characteristics of the absorption of various pollutants (recoveries, equilibrium limit sorption) are given. The influence of pH, temperature, the concentration of pollutants, phase contact time, volume, and mass of rice husk on sorption and removal of pollutants from aqueous media is shown. Possible sorption mechanisms, kinetic and sorption models are described. It is revealed that the isotherms of the sorption of pollutants in most cases are most adequately described by Langmuir and Freundlich models, and the kinetics of the process is a pseudo-second-order model.

Usage of sorbents for diminishing the negative impact of substances leaking into the environment in car accidents.

BackgroundCar accidents are often accompanied by dangerous substances leaking into the environment. A proper reaction to the leaking substances, utilizing appropriate sorbents, is necessary for diminishing the negative impact of such events. Sorbents as substances of initial intervention in car accidents (as well as industrial and ecological accidents) are a crucial tool for solving crises connected with dangerous substances escaping into the environment. The risk resulting from the given realities is described in detail in the introduction of the article.The goalThe goal is describing elements of crisis management in dangerous substance leakage and an analysis of sorption resources for quick and efficient interception of leaking substances, water, ethanol, oil, and gasoline in particular, as a reaction to such events.MethodsThe quality of a sorption resource is determined by a parameter called the sorption capacity, which has been established according to the ASTM F716-18 standard. Loose nature-based sorbents (peat) and synthetic silicate-based SiO2, Al2O3, Fe2O3, and polypropylene-based ones were observed. The research has been realized on a water, oil, gasoline, and ethanol sorbate. Each experiment was repeated three timesThe resultsThe results attest to the diversity of sorption capacity in comparing nature-based, silicate-based, and polypropylene-based sorption materials. The highest sorption capacity values were reached with the Sorb 4 sample, which is based on 66% of silica and 18% of alumina. The stated ratio is important, because the Sorb 3 sample contains 85% of silica and 6% of alumina and its absorption capacity values are significantly lower.

Retention of phosphorus in soils receiving bunker silo effluent

The eutrophication of freshwater systems is a pervasive issue in North America and elsewhere, which has been linked to elevated phosphorus (P) loading from watersheds. Most excess P is thought to originate from non-point agricultural sources, and less attention has been given to small rural point sources, such as bunker silos on livestock farms. Sophisticated management practices are rarely used to attenuate nutrients from bunker silo effluent, leaving simple vegetated buffer strips or riparian zones to protect surface water; however, the efficacy of these systems or larger constructed treatment systems is unclear. This study compared two systems receiving bunker silo effluent, one a natural riparian system with a vegetated buffer strip that is the most common practice and the other a constructed treatment system with a forebay, slag filter, and swale. The study quantified P retention within various subsections of each system and characterized the forms of stored P to infer the potential for remobilization. Results indicate that soils receiving bunker silo effluent represent considerable stores of legacy P in the landscape (750 and 3400 kg ha−1), the majority of which is stored in labile forms that may be vulnerable to remobilization under the waterlogged conditions that often occur in management practices and riparian zones. Some areas of the systems were able to store considerably more P than others, with the slag filter showing the greatest treatment efficacy. Spatial variability in stored P was apparent, where sections of the systems that directly received effluent retained more P than sections located farther away from bunker silos (indirect inputs). Results indicate that passive treatment systems become P saturated over time, limiting their longterm P removal efficacy. The efficacy of these systems may be improved with the inclusion of sorptive materials as a slag filter within the constructed treatment system significantly increased the life expectancy of that system. Greater understanding of both quantity and forms of P retained in systems and soils receiving bunker silo effluent will help develop management strategies that are more effective and longer-lasting for reducing excess P losses to surface water bodies.

Polylactide-Based Nonwoven Materials for Sorption of Oils of Different Viscosity

Polylactide-Based Nonwoven Materials for Sorption of Oils of Different Viscosity

Synthesis and characterization of kaolinite-based granular adsorbents for the removal of Cu(II), Cd(II), Co(II), Zn(II), and Cr(VI) from contaminated water

The object of this study is granular adsorbents based on kaolinite and zero-valent iron. The ceramic mass for their preparation contained polyvinyl alcohol as a powder-forming additive. It was established that its addition in quantities of 1.8–3.3 % practically does not change the porosity of the granules but increases their strength. X-ray phase and chemical analyzes confirmed the presence of a layer of zero-valent iron on the surface of the granules. The structural and sorption characteristics of sorption materials have been studied and the calculations of the main parameters of their porous structure were carried out. It is shown that when modifying granules with zero-valent iron, there is a decrease in the specific surface area and micropores volume for samples without a powder-forming additive by almost 2 times compared to the original granules. Moreover, these values almost do not change for samples obtained with the addition of polyvinyl alcohol. It was found that the application of the reaction layer to the granules leads to a significant increase in their sorption capacity with respect to heavy metal ions Cu(II), Cd(II), Co(II), Zn(II), and Cr(VI). It has been shown that the resulting adsorbents can be used for wastewater treatment containing a mixture of these toxicants. It was found that the values of maximum sorption on modified samples are 10–20 times higher than those for the original granules. A feature of the obtained adsorbents is the ability to simultaneously remove metal ions, both in the form of cations and anions. A significant increase in the sorption values of Cr(VI) anionic forms, which are difficult to remove from water by natural ion exchangers, has been established. It has been shown that granules based on kaolinite and zero-valent iron are effective adsorbents for water purification from heavy metal ions. The resulting materials can be used for wastewater treatment of electroplating industries and hydrometallurgical industry

Efficient separation of butane isomers via ZIF-8 slurry on laboratory- and pilot-scale

n-butane and isobutane are important petrochemical raw materials. Their separation is challenging because of their similar properties, including boiling point. Here, we report a zeolitic imidazolate framework-8 (ZIF-8)/N,N-Dimethylpropyleneurea (DMPU)-water slurry as sorption material to separate butane mixtures. The isobutane/n-butane selectivity of ZIF-8/DMPU-water slurries is as high as 890 with high kinetic performance, which transcends the upper limit of various separation materials or membranes reported in the literature. More encouragingly, a continuous pilot separation device was established, and the test results show that the purity and recovery ratio of isobutane product are 99.46 mol% and 87%, respectively, which are superior to the corresponding performance (98.56 mol% and 54%) of the industrial distillation tower. To the best of our knowledge, the use of metal-organic frameworks (MOFs) for gas separation in pilot scale remains underexplored, and thus this work provides a step forward to the commercial application of MOFs in gas separation.

Sorption Material Based on Chitosan, Decorated With Graphene Oxide for Purification of Waste Water from Copper Cations

This paper considers promising sorption materials based on chitosan and graphene oxide. It is shown that this direction is rapidly developing and various materials based on graphene oxide are being created. In the experimental part, the technology of obtaining a nanocomposite from graphene oxide – chitosan using heat treatment is presented. Microstructural analysis of chitosan and fluffed graphene oxide was carried out. The obtained sorption material of the sorbent was tested for its ability to extract copper cations.

Covalent molecularly imprinted polymers for selective adsorption of plant growth stimulator 1-naphthaleneacetic acid

In this work, we present the development and testing of new sorption materials for the adsorption of 1-naphtaleneacetic acid (NAA). Covalently prepared molecularly imprinted polymers (MIPs) were prepared as suitable materials. Molecular imprinting was performed using two different NAA derivatives: 4-vinylbenzyl 2-(naphthalen-1-yl)acetate and N-methyl-2-(naphthalen-1-yl)-N-((4-vinylbenzoyl)oxy)acetamide. The prepared monomers bearing NAA fragment were subjected to polymerization, removal of template and the prepared MIPs were further characterized and tested. Both types were able of MIPs to catch out >98% NAA from solution (10−3 mol L−1) within 10 min and subsequently desorb it quantitatively. Both types of prepared MIPs can be used in at least 10 consecutive adsorption/desorption cycles. Ester-derived MIPs were also highly effective for continuous flow adsorption of 10−2 mol L−1 NAA and showed certain level of selectivity for NAA in a mixture with anthranilic acid and/or salicylic acid.

Synthesis and spark plasma sintering of solid-state matrices based on calcium silicate for 60Co immobilization

An effective sorption material for the immobilization of cobalt radionuclides into highly safe and reliable solid-state matrices is proposed. The resulting silicate sorbent СaSiO 3 had an amorphous mesoporous structure (A BET 53 m 2 /g) and a sorption capacity Co ions of 3.32 mmol/g. The physico-chemical characteristics of the СaCoSi 2 O 6 sample obtained after Co 2+ ions sorption were studied using XRD, N 2 and Ar adsorption-desorption, SEM-EDX and TG/DTA methods. Solid-state silicate matrices characterized by high density values (2.86–3.16 g/cm 3 ), compressive strength (150–637 MPa) and Vickers microhardness (1.80–5.25 GPa) were obtained by spark plasma sintering (SPS). The sample obtained at 1000 °C had the lowest values of Co 2+ ions leaching (R Co ~10 −7 g/(cm 2 ×day)) and diffusion coefficient (De 1.73 ×10 −17 cm 2 /s) from silicate matrices. Thus, the obtained СaCoSi 2 O 6 silicate matrices saturated with Co ions comply with the regulatory requirements of GOST R 50926–96 and ANSI/ANS 16.1 for 60 Co immobilization. • Amorphous CaSiO 3 with 3.32 mmol/g Co ions sorption capacity was prepared. • SPS method allowed to obtain the CaCoSi 2 O 6 matrices at 1000 °C for 2 min. • CaCoSi 2 O 6 solid-state matrices exclude Co 60 ions leaching and diffusion. • The characteristics of CaCoSi 2 O 6 matrices exceeded the GOST and ANSI/ANS 16.1 requirements.

Cellulose and its derivatives, coffee grounds, and cross-linked, β-cyclodextrin in the race for the highest sorption capacity of cationic dyes in accordance with the principles of sustainable development

In this study, seven different materials were analyzed and includes coffee grounds (CG), two types of cellulose (CGC and CC), two types of modified cellulose (CT and CTCD), and cross-linked β-cyclodextrin (CD-1 and CD-2) were tested as adsorbents for the removal of dyes from the wastewater. The composition, morphology, and presence of functional groups in the obtained sorption materials were characterized by elemental analysis, SEM, TG/DTA, and FTIR spectroscopy. The sorption processes of the model contaminant, crystal violet (CV), were studied by kinetics and equilibrium models. The results showed, that using CTCD, the dye was adsorbed rapidly in 1 min and the slowest adsorption occurred in 20 min by CG. The time evolution was adjusted using a two-model, pseudo second-order model (CG and CGC) and pseudo first-order model in the rest adsorbents. According to the Langmuir and Sips isotherm models, the maximum adsorption capacities were very high in each case ranging from 1092.24 to 1220.40 mg g-1. Moreover, the adsorption capacity of the near-natural materials remained even higher after five regeneration cycles. The regeneration is almost waste-free and the materials used can be decomposed during composting. In addition, almost complete removal of cationic dyes was observed during the treatment of real wastewater samples.