Composite Sorbent Research Articles

Efficient Selective CO2 Composite Sorbent from Amino Acid Ionic Liquids and Silica Gel: 2H NMR Spectroscopy Provides Insight on the CO2-Binding Mechanism and in-Pore Microscopic Viscosity.

A promising CO2 sorbent based on the [Emim][Gly] (1-ethyl-3-methylimidazolium glycinate)/silica gel composite has been studied. CO2 sorption experiments have shown that the optimum loading of [Emim][Gly] ionic liquid in silica gel is 40 wt.%. The 2-step process CO2 binding mechanism in [Emim][Gly] has been proposed based on the results of sorption experiments, 2H NMR spectroscopy and ab-initio calculations. The impact of CO2 on the microscopic viscosity and the dynamical melting of ionic liquid has been thoroughly investigated. 2H NMR spectroscopy has revealed that CO2 strongly binds cation and anion in [Emim][Gly], forcing them to move in a correlated fashion.

COMPARATIVE EVALUATION OF SORBENTS BASED ON NATURAL MATERIALS FOR CLEANING OIL-POLLUTED SOILS IN THE KOLA NORTH

The article presents the results of using sorbents based on natural materials as soil reclamation agents in the Arctic zone of the Russian Federation to reduce the negative impact of oil and oil product spills. It has been established that the most effective are composite sorbents based on sphagnum moss and peat in various combinations with excess activated sludge. The effectiveness of sorbents based on natural materials is compared with the commercial sorbent OilSorb. High dynamics of reducing the content of oil products in the first days in soil samples with the addition of composite sorbents, including natural sorption material and activated sludge, is noted.

Enhancement of Water Productivity and Energy Efficiency in Sorption-based Atmospheric Water Harvesting Systems: From Material, Component to System Level.

To address the increasingly serious water scarcity across the world, sorption-based atmospheric water harvesting (SAWH) continues to attract attention among various water production methods, due to it being less dependent on climatic and geographical conditions. Water productivity and energy efficiency are the two most important evaluation indicators. Therefore, this review aims to comprehensively and systematically summarize and discuss the water productivity and energy efficiency enhancement methods for SAWH systems based on three levels, from material to component to system. First, the material level covers the characteristics, categories, and mechanisms of different sorbents. Second, the component level focuses on the sorbent bed, regeneration energy, and condenser. Third, the system level encompasses the system design, operation, and synergetic effect generation with other mechanisms. Specifically, the key and promising improvement methods are: synthesizing composite sorbents with high water uptake, fast sorption kinetics, and low regeneration energy (material level); improving thermal insulation between the sorbent bed and condenser, utilizing renewable energy or electrical heating for desorption and multistage design (component level); achieving continuous system operation with a desired number of sorbent beds or rotational structure, and integrating with Peltier cooling or passive radiative cooling technologies (system level). In addition, applications and challenges of SAWH systems are explored, followed by potential outlooks and future perspectives. Overall, it is expected that this review article can provide promising directions and guidelines for the design and operation of SAWH systems with the aim of achieving high water productivity and energy efficiency.

Transformations of Critical Lithium Ores to Battery-Grade Materials: From Mine to Precursors

The escalating demand for lithium has intensified the need to process critical lithium ores into battery-grade materials efficiently. This review paper overviews the transformation processes and cost of converting critical lithium ores, primarily spodumene and brine, into high-purity battery-grade precursors. We systematically examine the study findings on various approaches for lithium recovery from spodumene and brine. Dense media separation (DMS) and froth flotation are the most often used processes for spodumene beneficiation. Magnetic separation (MS) and ore gravity concentration techniques in spodumene processing have also been considered. To produce battery-grade lithium salts, the beneficiated-concentrated spodumene must be treated further, with or without heat, in the presence of acidic or alkaline media. As a result, various pyro and hydrometallurgical techniques have been explored. Moreover, the process of extracting lithium from brine through precipitation, liquid–liquid extraction, and polymer inclusion membrane separation employing different organic, inorganic, and composite polymer sorbents has also been reviewed.

Composite Sorbent with Honeycomb Structure for Capturing Platinum Catalyst Aerosols

Composite Sorbent with Honeycomb Structure for Capturing Platinum Catalyst Aerosols

Bifunctional Portable Powder for Freshwater Production With Moisture Harvesting and Undrinkable Water Purification.

Freshwater scarcity threatens human survival, particularly in extreme environments like deserts, oceans, and space. Compatible atmospheric water harvesting and undrinkable water purification offer an affordable approach to solving freshwater scarcity in these extreme environments. Nonetheless, developing composite sorbent to attain efficient atmospheric water harvesting and undrinkable water purification remains challenging. Hence, a portable hybrid hygroscopic powder (HLC powder) consisting of hydroxypropyl chitosan, dibenzaldehyde-functional poly(ethylene glycol), lithium chloride (LiCl), and nano carbon black is proposed. The HLC powder with optimized LiCl load can capture moisture from the air, showing a high water uptake of 1.76g g-1 at 34% relative humidity (RH) and appropriate over a wide humidity from 34% to 75% RH. pH-responsive sol-gel transition induced by Schiff base bonds transforms the HLC solution into hydrogel, inhibiting hydrated salt leakage. Meanwhile, to achieve efficient undrinkable water purification, the LiCl-free hybrid powder is utilized to convert the undrinkable water, including seawater, dye water, and human urine, to photothermal hydrogel evaporators with low evaporation enthalpies and high evaporation rates ranging from 1.81 to 2.05 kg m-2 h-1 under one sun. This strategy establishes a new path to conveniently obtaining freshwater, breaking hydrological restrictions.

Covalent organic framework composite hydrogel sorbent beads for vortex-assisted dispersive miniaturized solid phase extraction of parabens and synthetic phenolic antioxidants in foodstuffs

A covalent organic framework composite hydrogel sorbent beads was fabricated for the vortex-assisted dispersive miniaturized-solid phase extraction and determination of parabens and synthetic phenolic antioxidants from food matrices. The covalent organic framework was entrapped into alginate hydrogel beads. This composite sorbent effectively adsorbs analytes through hydrophobic, π-π and hydrogen bonding interactions. Under optimal extraction conditions, the developed method demonstrated good linearity from 1.00 to 100 µg kg−1 for methyl paraben and 2.00 to 100 µg kg−1 for tertiary butylhydroquinone, propyl paraben, butyl paraben and butylated hydroxyanisole. Limits of detection ranged from 0.25 to 0.50 µg kg−1. The developed sorbent was applied to the extraction of parabens and synthetic phenolic antioxidants from tomato paste, mayonnaise, infant milk powder and coffee creamer samples. The analytes were separated and quantified by high-performance liquid chromatography, achieving recoveries ranging from 89 to 98 % with RSDs lower than 7 %. The vortex-assisted extraction approach was efficient, and the fabricated sorbent could be reused for up to eight cycles. The greenness of the methodology was also evaluated.

Valorization of Eggshell as Renewable Materials for Sustainable Biocomposite Adsorbents—An Overview

The production and buildup of eggshell waste represents a challenge and an opportunity. The challenge is that uncontrolled disposal of generated eggshell waste relates to a sustainability concern for the environment. The opportunity relates to utilization of this biomass resource via recycling for waste valorization, cleaner production, and development of a circular economy. This review explores the development of eggshell powder (ESP) from eggshell waste and a coverage of various ESP composite sorbents with an emphasis on their potential utility as adsorbent materials for model pollutants in solid–liquid systems. An overview of literature since 2014 outlines the development of eggshell powder (ESP) and ESP composite adsorbents for solid–liquid adsorption processes. The isolation and treatment of ESP in its pristine or modified forms by various thermal or chemical treatments, along with the preparation of ESP biocomposites is described. An overview of the physico-chemical characterization of ESP and its biocomposites include an assessment of the adsorption properties with various model pollutants (cations, anions, and organic dyes). A coverage of equilibrium and kinetic adsorption isotherm models is provided, along with relevant thermodynamic parameters that govern the adsorption process for ESP-based adsorbents. This review reveals that ESP biocomposite adsorbents represent an emerging class of sustainable materials with tailored properties via modular synthetic strategies. This review will serve to encourage the recycling and utilization of eggshell biomass waste and its valorization as potential adsorbent systems. The impact of such ESP biosorbents cover a diverse range of adsorption-based applications from environmental remediation to slow-release fertilizer carrier systems in agricultural production.

Efficient removal of aqueous ciprofloxacin antibiotic by ZnO/CuO-bentonite composites synthesized via carbon-bed pyrolysis of bentonite and metal co-precipitation

Antibiotics are of emerging concern due to their widespread use, lack of adequate treatment, and for their potential to threaten human health and the environment. Here, a facile fabrication approach for synthesizing ZnO/CuO-bentonite composites was investigated via carbon-bed pyrolysis of bentonite followed by ZnO/CuO co-precipitation. Sorbents were synthesized using a range of bentonite pyrolysis temperatures, metal oxide contents, and ZnO:CuO mass ratios. The ZnO/CuO-bentonite composites exhibited diverse functional groups, excellent mesoporosity, and high specific surface area (135.0 m2 g−1, four times that of pyrolyzed bentonite-only control). Ciprofloxacin removal was maximized at a bentonite pyrolysis temperature of 450 °C, a total metal oxide content of 25 %, and a Zn/Cu ratio between 95:5 and 93:7, and this material had an observed experimental CIP adsorption of 451 mg g−1 and a calculated maximum adsorption capacity of 1249.3 mg g−1. This excellent CIP sorption ability was attributed to its abundant surface active sites and multiple sorption mechanisms, including hydrogen-bond interaction, ion exchange, and electrostatic interaction. These results illustrate that ZnO/CuO-bentonite composite sorbents have excellent potential for use in environmental remediation and water treatment applications.

A novel membrane-based absorber for sorption heat transformers: A comparative experimental study of a thin-film absorbent and salt-impregnated adsorbents

The present study proposes a novel membrane-based sorber bed with stationary solution film for oscillatory sorption heat transformers. A custom-built gravimetric large pressure jump setup is used to experimentally compare the performance of the novel membrane-based sorber bed with a Lithium Bromide/Silica gel solid composite sorbent synthesized using the salt-impregnation method. It is shown that the current membrane-based sorber bed provides up to about four times the specific cooling power and more than twice the cooling power density of solid sorbents, demonstrating the capability of the present sorber bed as a promising alternative to solid sorbents. The specific cooling power, cooling power density, and energy storage density of about 2.8 kW/kg, 470 kW/m3, and 269 MJ/m3 are experimentally obtained, respectively. According to experimental results, it is observed that the film thickness plays a significant role in sorption dynamics, while the effect of membrane mass transfer resistance on sorption dynamics is less than 10%. In addition, the present membrane-based sorber bed is analytically modeled, and the results are validated with present experimental data. The present analytical model is also used to investigate the effects of design parameters on the performance metrics.

Sugarcane bagasse derived composite sorbent for sorption based atmospheric water harvesting

The escalating global concern surrounding water scarcity is significantly impacting the quality of life, particularly in arid and land-locked regions. Sorption-based atmospheric water harvesting (AWH), employing a sorbent to capture atmospheric moisture, emerges as a sustainable solution to mitigate the global water crisis. However, developing efficient, eco-friendly, easily synthesised, and cost-effective sorbents poses a challenge. Herein, an efficient composite sorbent derived from waste sugarcane bagasse-based activated carbon (SBAC), impregnated with a low-cost hygroscopic CaCl2 salt, has been prepared. The composite SBAC/CaCl2 showed good performance across a wide working range between 10–90 % relative humidity, with water uptake ranging from 0.24 to 2.44 g/g. At moderate temperature and humidity (25 °C, 60 % RH), SBAC/CaCl2 exhibited a water uptake of 1.2 g/g and achieved over 80 % of its equilibrium water uptake within 90 min. Also, the sorbent showed excellent solar driven desorption with desorption efficiencies reaching over 93 % and 85 % for 1 sun and 0.5 sun illumination, respectively, within 60 min. The sorption kinetics and adsorption isotherm showed excellent fit with the linear driving force model and Dubinin Astakhov isotherm model. The practical solar-driven atmospheric water harvesting performance of the SBAC/CaCl2 composite was also successfully demonstrated using a custom-built device under outdoor conditions and the harvested water met the quality standards of drinking water. Furthermore, the prepared sorbent exhibited cyclic stability and storage reliability with no performance degradation even after repeated cycles. This work highlights the significant potential of waste biomass derived sorbents for sustainable AWH applications.

A Super-Hygroscopic Solar-Regenerated Alginate-Based Composite for Atmospheric Water Harvesting.

Global water scarcity is leading to increasingly tense competition across populations. In order to complement the largely fast-depleting fresh water sources and mitigate the challenges generated by brine discharge from desalination, atmospheric water harvesting (AWH) has emerged to support long-term water supply. This work presents a novel alginate-based hybrid material comprised of porous silico-aluminophosphate-34 (SAPO-34) as fast-transport channel medium as well as hydrophilicity and stability enhancer, and graphene-based sheets as light absorber for solar-enabled evaporation, both optimally incorporated in an alginate matrix, resulting in a composite sorbent capable of harvesting water from the atmosphere with a record intake of up to 6.85 gw gs -1. Natural sunlight is solely used to enable desorption achieving increase of the temperature of the developed network up to 60°C andresulting in release of the sorbed water, with impurities content well below the World Health Organization (WHO) upper limits. After 30 cycles of sorption and desorption, the composite hydrogel displayed unchanged water uptake and stability. This work provides an impactful perspective toward sustainable generation of water from humidity without external energy consumption supporting the emergence of alternative water production solutions.

Composite sorbent based on Fe3O4 with Fe(N2H4)xCly for the removal of Chromium(VI) from wastewater

Composite sorbent based on Fe3O4 with Fe(N2H4)xCly for the removal of Chromium(VI) from wastewater

Polystyrene infused with functionalized reduced graphene oxide as a reusable oil sorbent

Adsorption has been reported to be optimal among oil spill cleanup methods due to its simplicity, low capital and operational cost, high removal efficiency and environmental friendliness. However, its continuous usage has been linked to generation of enormous waste, after oil spill cleanup, to which use of reusable oil sorbents has been proposed as a possible solution. Synthetic organic oil sorbents have high mechanical properties compared to other categories of oil sorbents, but they suffer low adsorptive capacities. To address this problem, among other nanoparticles, rGO have been infused in polymeric materials to produce composite oil sorbents characterized with high adsorptive capacities. In this research, surface modified rGO was infused in waste expanded polystyrene, to produce electrospun PS/FrGO composite sorbents by solution blending and electrospinning method. Adsorptive capacities of produced composites were evaluated in four oil samples. Functionalization of rGO was found to cause removal of residual oxygen containing functional groups such as hydroxyl (–OH), and resulted in more hydrophobic surface. Infusion of FrGO, in waste expanded polystyrene resulted into composites with increased surface area, from 71.50 m2/g for pure PS20 to 353.45 m2/g, 429.18 m2/g, 456.14 m2/g for PS20 infused with 1, 2 and 4wt% of FrGO. Increase in oil sorption capacities of the composite, observed in four oil samples corresponds to improved surface area. Produced composites show good recyclability in the four oil samples, at least up to the third sorption cycle.Graphical

Hierarchical porous MOF-199 mediated cellulosic paper for selective CO2 capture

MOF-199 is considered to be an excellent CO2 adsorbent owing to its substantial specific surface area, suitable pore structure and abundant sorption sites. However, powdered MOF-199 is prone to agglomeration and has poor recyclability. Herein, we proposed a MOF-199-based adsorbent by combining the MOF synthesis process with traditional papermaking process. Through such a design, MOF-199 particles are adhered on the surface of wood pulp fiber. The sufficient hydroxyl groups and electrostatic forces of cellulose facilitates the homogeneous and tight adhesion of MOF crystals. The optimal MP-4 sample demonstrated a high CO2 adsorption capacity (1.80 mmol·g‐−1 at 25 °C) and good CO2/N2 selectivity (30.06). Moreover, the composite sorbent can be easily regenerated. The adsorption mechanism was analyzed by the density functional theory approach. The simulation results showed that the carboxyl functional groups with a large number of oxygen atoms and active metal sites are the key to boost the CO2 adsorption performance.

Investigation of multiple cyclic pressure loading on the service life and sorption performance of a composite sorbent

Investigation of multiple cyclic pressure loading on the service life and sorption performance of a composite sorbent

A porous composite sorbent incorporating a metal organic framework and zinc oxide in cryogel to extract carbamate pesticides

A composite sorbent was designed and fabricated by incorporating the Materials of Institute Lavoisier (MIL-101) and zinc oxide (ZnO) into polyvinyl alcohol (PVA) cryogel. The composite sorbent was produced to extract carbamates (carbofuran, carbaryl, isoprocarb and diethofencarb) by in-syringe solid phase extraction (SPE). MIL-101 and ZnO enhanced the adsorption of the carbamates by creating π-π stacking and hydrogen bonding, while porous PVA cryogel acted as a solid support which helped to reduce backpressure in the system. The extraction of the target carbamates was optimized by varying the amount of MIL-101 and ZnO used in the sorbent fabrication, desorption conditions, sample pH, ionic strength, sample flow rate and sample volume. The extracted target carbamates were quantitatively determined using high performance liquid chromatography technique. The developed method exhibited linearity from 1.0 to 150.0 μgL−1 for all four target carbamate pesticides with a limit of detection 0.3 µg/L. The method identified carbamates in fruit juice and white wine, obtaining recoveries from 78.1 to 108.2 % and the relative standard deviation (RSD) lower than 6.3 %. The developed composite sorbent showed good accuracy, is simple to fabricate, works rapidly and can be used for 17 extraction-regeneration cycles.

Concentration of heavy metal ions from aqueous media under dynamic conditions using a composite sorbent based on chitosan and silica

Objectives. The study set out to investigate the sorption, toxicological, and regeneration properties of a composite sorbent based on chitosan hydrogel and unsuspended silicon dioxide (chitosan–colloidal silica), which manifest themselves under dynamic conditions of purification of aqueous solutions, as a means of removing heavy metal ions.Methods. The total dynamic exchange capacity of a chitosan–colloidal silica composite sorbent was evaluated under dynamic sorption conditions by passing solutions containing Zn(II), Cd(II), Cu(II), and Cr(III) ions having a concentration of 240–251 mg/L through a fixed sorption bed. The method for determining acute toxicity using daphnia (Daphnia magna Straus) is based on the direct calculation of the mortality of daphnia exposed to toxic substances contained in the test aqueous extract in comparison with a reference culture in samples that do not contain toxic substances. The regeneration ability of the sorbent was assessed by counting the number of sorption–desorption cycles using 0.1 M NaOH and 0.1 M NaHCO3 eluents, as well as aqueous solutions of H2O2 (1 and 3%).Results. The effectiveness of the chitosan–colloidal silica composite sorbent in the process of dynamic purification of aqueous media to remove Cu(II), Zn(II), Cd(II), and Cr(III) ions was established. After determining the times of ion breakthrough and saturation of the developed sorbent, its dynamic exchange capacity was calculated by processing the kinetic curves of sorption of heavy metal ions under dynamic conditions. The results of regeneration of the sorbent were presented in the context of the possibility of its reuse. It is shown that the sorbent can withstand up to five sorption–desorption cycles while maintaining a level copper cation extraction above 90%.Conclusions. Analysis of the kinetic curves demonstrated that the driving force behind the removal of heavy metals from aqueous media by means of the obtained sorbent is the external diffusion mass transfer of ions from the mobile phase of the solution. Biotesting of samples showed that the developed chitosan-based sorbent does not have acute toxicity.

Sorption kinetics of vermiculite-K2CO3 in thermochemical energy storage: Model evaluation and mechanism exploration

Thermal energy storage technology is crucial for building heating and domestic hot water supply, playing an essential role in optimizing energy utilization. Hydrated salts have emerged as prominent materials for thermochemical energy storage (TCES), with their sorption kinetics directly impacting thermal energy conversion efficiency. This study experimentally analyzes the microstructure and sorption performance of the EV/K2CO3 composite sorbent. Numerical analysis methods are employed to evaluate the validity of various sorption kinetics models and to elucidate the sorption mechanism and potential limitations of the composite sorbent. The findings indicate that EV can disperse K2CO3 salt particles while preserving a porous structure, thereby improving the sorption kinetics efficiency and stability of the EV/K2CO3 composite sorbent. At low relative pressure, EV/K2CO3 demonstrates a chemical adsorption mechanism, with nucleation models accurately predicting its sorption behavior, primarily limited by the nucleation and growth of hydrated salt crystals. At moderate relative pressure, EV/K2CO3 exhibits a mechanism involving both chemical adsorption and solution absorption, with diffusion models and the first-order model showing higher prediction accuracy, primarily limited by diffusion within or outside the product layer. At high relative pressure, EV/K2CO3 primarily undergoes solution absorption, with geometric contraction models and the first-order model displaying good predictive performance, primarily limited by the reaction phase interface. This study enhances comprehension of the sorption mechanism of the EV/K2CO3 composite, providing a scientific foundation for the development of high-performance TCES materials suitable for building and environmental applications.

Electrospun polystyrene/asphaltene fiber for selective separation of oil from water surface

To deal with the challenges of oil spills and their harms, fabricating superhydrophobic adsorbents with high sorption properties is a significant issue. For the first time, asphaltene was involved in polystyrene polymer using the electrospinning method to produce efficient fibers for oil adsorption from water. The polystyrene-asphaltene composite fibers showed a considerable increase in the porosity, surface area, water contact angle, and hydrophobic-lipophilic nature compared to polystyrene fibers. The maximum adsorption capacity of polystyrene-asphaltene fibers was 50–120% higher than that of polystyrene fibers. The oil adsorption on the composite sorbents was fast, and the steady state condition was reached in 22 min. The kinetic data fit the intraparticle kinetic model well, representing three stages of the adsorption process. Asphaltene, as a cost-effective, abundant component, induces unique properties in the polystyrene-asphaltene fibers and can be considered a proper choice for oil spill cleanup.