Monolithic Adsorbents Research Articles

Two-linker MOFs-based glass fiber paper monolithic adsorbent for atmospheric water harvesting in arid climates

With the increasing demand for freshwater resources, the sustainable and effective utilization of atmospheric water has become a critical issue. Herein, an efficient and stable monolithic water-adsorbent is designed via functionalizing glass fiber paper loaded with two-linker metal-organic frameworks (CGF-mixed-MOFs(Al)). Firstly, a chitosan (CTS) polyelectrolyte layer is constructed on glass fiber paper to improve the MOFs loading capacity (306.71%) through electrostatic interaction and hydrophilic interaction. Subsequently, a series of two-linker metal-organic frameworks (mixed-MOFs(Al)) composed of MIL-160(Al) and Al-fumarate are tailor-made on CGF surface through a situ synthesis self-assembly technology. The resultant mixed-MOFs(Al) monolith exhibits better water harvesting ability and faster adsorption kinetics at low humidity owing to possessing more active adsorption sites. Different from CGF-MIL-160(Al) and CGF-Al-fumarate, the water sorption of CGF-mixed-MOFs(Al)5 at 30% RH, 25% RH and 20% RH reaches 0.37 g/g, 0.31 g/g and 0.25 g/g, respectively. The lab-scale atmospheric water harvesting device based on CGF-mixed-MOFs(Al)5 confirms the feasibility of this work-tailored product as a potential water sorbent in low-humidity environments. The cyclability results (50 times) indicate that CGF-mixed-MOFs(Al)5 maintains good water capture performance, integrity (no MOFs leakage) and crystallinity, which guarantees its working reliability and sustainable benefits. Therefore, our customized water adsorption system provides a simple, long-effective, economical and advanced strategy to capture more fresh water from atmosphere in arid climates.

Sol-gel processing of a covalent organic framework for the generation of hierarchically porous monolithic adsorbents

Sol-gel processing of a covalent organic framework for the generation of hierarchically porous monolithic adsorbents

Fabrication of a lignin-dopped monolithic adsorbent and its properties for the extraction of hyperin from Senecionis Scandentis Hebra

In this work, a monolithic cartridge packed with lignin polymer (LiP)-dopped adsorbent was fabricated in a stainless steel tube via polymerization using divinyltetramethyldisilane as the monomer, which aimed for the extraction and separation of hyperin from Senecionis Scandentis Hebra (SSH). The fabricated monolithic cartridge used for the solid-phase extraction (SPE) method was characterized by scanning electron microscope, fourier transform infrared spectrometer, specific surface area measuring instrument and mercury intrusion porosimetry, which confirms a macro- and meso-porous structure with high specific surface area of 333.2 m2/g of the optimized adsorbent. An SPE-HPLC method was established by combining the prepared monolithic cartridge and a C18 analytical column via HPLC system for the online extraction, enrichment and quantitative determination of hyperin from SSH. The results indicate that the prepared monolithic cartridge shows not only specific selectivity for the target component of hyperin, but also outstanding removal ability for the sample matrix. Methodology validation was carried out to verify the proposed quantitative analytical method, including the regression equation and related data, the precision, the spiked recovery and the preparative repeatability of the SPE cartridge, which results confirm the feasibility of the present method for the extraction and quantitative determination of hyperin from SSH.

Extraction and Determination of Evodiamine from Euodia Fructus with SPE-HPLC Based on a Homemade Phenyl-Based Monolithic Cartridge.

A phenyl-based monolithic adsorbent was prepared in a 50-mm-long stainless steel tube, which was initiated by the redox system, using ethylene glycol phenyl ether acrylate as the monomer and ethylene glycol dimethacrylate as the crosslinker. The effects of monomer/crosslinker ratio and the porogens on the permeability and morphology of the resulting adsorbents were investigated, and the optimal adsorbent shows relatively uniform pore structure according to the characterizations of scanning electron microscopy and nitrogen adsorption-desorption method. The column that filled with the adsorbent was used as the solid-phase extraction (SPE) cartridge, exhibiting unique selectivity for the extraction of evodiamine from Euodia fructus (the fruits of Euodia rutaecarpa (Juss.)Benth.), which attributes to the interactions of π-π and hydrogen bonding between the adsorbent and evodiamine. Combined with a C18 analytical column via high-performance liquid chromatography (HPLC) system, an online SPE-HPLC method was established for extraction, enrichment and determination of evodiamine from Euodia fructus. Method validation demonstrates that the relative standard deviation of the precision is less than 0.66%, and the spiked recovery is in the range of 93.11-98.06%. Furthermore, it is worth noting that the prepared SPE cartridge can be reused for no less than 100 times. These results show that the developed method is simple and efficient for online extraction and enrichment of evodiamine from Euodia fructus.

Solar-driven smart ceramic fiber-based monolithic adsorbent for autonomous indoor humidity control

Even though designing new sustainable buildings has become a main consensus in mitigating the energy crisis, it is equally important to reduce energy consumption of established architectures. Herein, we present a simple and efficient strategy for low-energy management of indoor humidity in established buildings. Solar-driven humidity-controlled ceramic fiber is fabricated by layer-by-layer assembly of chitosan/CuS backbones and dual-ligand metal organic framework (DMOFs) layer on a substrate. The hydrangea-type DMOFs layer exhibits high-efficient water collection as well as rapid adsorption and transport kinetics, supporting the high atmospheric hygroscopicity (0.45 g/g) of resultant ceramic fiber at 90% relative humidity (RH). The photothermal CuS layer shows high solar thermal conversion and efficient thermal conduction, allowing that adsorbed-water water to rapidly ooze out from DMOFs under the solar energy. Relying on attaching super-hygroscopic DMOFs and CuS particles with high solar absorption, the customized ceramic fiber achieves moisture collection at night and adsorbed-water release during daytime, thereby maintaining stable indoor humidity (41.8%–52.8%). By uniting these two daytime and nighttime management pathways, the resulting closed-loop system will offer a promising and low-energy solution for indoor ambient regulation in existing architectures.

Megaporous monolithic adsorbents for bioproduct recovery as prepared on the basis of nonwoven fabrics.

Megaporous adsorbents were prepared based on nonwoven polyethylene terephthalate (PET) fabrics and functionalized by covalent modification with polyvinylamine (PVAm) or monotriazinyl-β-cyclodextrin-substituted polyvinylamine (PVAm-MCT-β-CD). Mechanical properties of the resulting fabrics were maintained, as judged by tensile strength tests and scanning electron microscopy. Exceptional porosity (≥82%) and preserved hydrodynamic characteristics (Pe≥63) indicated excellent structural stability when packed. The performance of the constructed adsorbents was evaluated with high molecular weight (proteins) and low molecular weight (dyes) model compounds. The static binding capacity (SBC) for bovine serum albumin (BSA) was 79.7±1.3 and 92.9±8.2mg/g for PVAm-modified and PVAm-MCT-β-CD-modified fabrics, respectively. The mentioned materials also adsorbed Orange II, an acidic dye (92.4±2.6 and 101.9±2.6mg/g, respectively), indicating that the hydrophobicity was a prevailing binding mechanism operating at a pH close to isoelectric point. SBC for lysozyme and toluidine blue O (TBO, a basic dye) onto PVAm-MCT-β-CD functionalized PET was 52.7±5.1 and 73.3±0.6mg/g, respectively. TBOs have also shown some affinity for PVAm functionalized PET, but this was most likely to be mediated by hydrophobicity. On the other hand, operating at a superficial velocity of 90cm/h, dynamic binding capacity for BSA was 11.4±3.5 and 2.5±0.6mg/g indicating the importance of possible aggregation mechanisms during protein binding at equilibrium. Thus, PET-based adsorbents require further functional improvement for chromatography applications. However, the easy-to-construct, scalable nonwoven adsorbents deserve further attention as a potential alternative to packed-bed-chromatography adsorbents.

Selective adsorption of anionic dye from wastewater using polyethyleneimine based macroporous sponge: Batch and continuous studies

Dyes are well known for their hazardous impacts on public health and the environment. Dye removal using monolithic adsorbents is an attractive approach for industrial applications and process design owing to their utilization in both static and dynamic adsorption experiments. In the present work, polyethyleneimine (PEI) based macroporous monolithic sponge (S100) was engineered by ice-templating method and used as an adsorbent. Both batch and continuous operations for dye removal were studied. The effect of various parameters such as pH, adsorbent amount, flow rate, influent dye concentration, and adsorbent bed height on adsorption performance of S100 was studied and modelled using Langmuir/Freundlich isotherms for static operations and Adam-Bohart/Thomas model in packed-bed column experiments. Under optimum conditions, the adsorbent showed a remarkably higher adsorption capacity towards CR (1666.67 mg/g), which is considerably higher than most PEI-based adsorbents. Amine groups in S100 offered exceptional selectivity for anionic Congo red (CR) against cationic Methylene blue (MB) dye (separation factor of 208 and 87 in absence and presence of sodium chloride, respectively). It can be easily regenerated in alkaline medium without a significant loss in percent adsorption capacity and shows good thermal and mechanical stability. Notably, in column studies, a relatively smaller percentage of unused bed height (32.3%) was observed with higher dye uptake for 16 mg S100 at flow rate 10 mL/h and inlet concentration 300 mg/L. Thus, the adsorbent displays an outstanding physiochemical characteristic, excellent selectivity for anionic dye, ease of regeneration and high adsorption performance in both batch and continuous studies.

Two-Linker Mofs-Based Chitosanized Glass Fiber Paper Monolithic Adsorbent for Atmospheric Water Harvesting in Arid Climates

Two-Linker Mofs-Based Chitosanized Glass Fiber Paper Monolithic Adsorbent for Atmospheric Water Harvesting in Arid Climates

Hierarchically Structured Components: Design, Additive Manufacture, and Their Energy Applications

AbstractPursuing high energy efficiency and reaction rate is an effective direction in mitigating the energy and climate crisis. Mass transfer intensification is a powerful approach to enhance the energy efficiency and reaction rate in the energy conversion and storage processes. The nature‐inspired channels are outstanding tools to uniformly distribute the reactants, fast remove products, and reduce the diffusion distance for mass transfer intensification in monolithic adsorbents, structured catalysts, and electrodes. Besides, hierarchical pores are also a contributor to improve the reactant diffusion rate in the matrix. Additive manufacturing, combining the design of printing material and post‐treatment, provides a promising opportunity to accurately control the channels and adjust the pores in electrodes, catalysts, and adsorbents. This review summarizes the main state‐of‐the‐art methods to design ideal channels and to control the sizes and amounts of pores for the optimum hierarchical structure design, as well as the techniques to realize the hierarchical structure by additive manufacturing. In addition, this review also communicates the recently unlocked advantages of the designable channels and hierarchical pores in applications of adsorptions, chemical reactions, and electrochemical energy storage. Lastly, a new approach to design and fabricate the hierarchical structures is proposed, along with its potential benefits.

Extraction and determination of tussilagone from Farfarae Flos with online solid‐phase extraction–high‐performance liquid chromatography using a homemade monolithic cartridge doped with porous organic cage material

A solid-phase extraction cartridge was fabricated using diallyl isophthalate as the monomer with the addition of porous organic cage material via in situ free-radical polymerization in a stainless-steel column. The resulting monolithic adsorbent exhibited a relatively uniform porous structure, a high specific surface area of 113.98 m2 /g, and multiple functional chemical groups according to the characterization results. An online solid-phase extraction-high-performance liquid chromatography procedure was fabricated to extract and determine tussilagone from Farfarae Flos. The results show that the complex sample matrices can be removed in the solid-phase extraction procedure. Simultaneously, tussilagone can remain, which can be subsequently switched to an octadecylsilane bondedanalytical column. The methodological validation showed that the correlation coefficient was 0.9999 with a linear range of 0.6-200.0µg/mL, the limit of detection was 0.2µg/mL, the limit of quantification was 0.6µg/mL, accuracy was 100.3-100.6%, and relative standard deviation of precision was ≤1.9%. The present monolithic cartridge exhibits good reusability of not more than 100 times. The real sample of Farfarae Flos was determined with a tussilagone content of 0.74mg/g.

A highly efficient adsorbent constructed by the in situ assembly of Zeolitic imidazole framework-67 on 3D aramid nanofiber aerogel scaffold

• ZIF-67 was in situ assembled onto ANF aerogel to get 3D monolith adsorbent. • ANF/ZIF-67 aerogel showed stable and competitive structural features. • ANF/ZIF-67 aerogel demonstrated high adsorption capacity for Cu 2+ and Cr 6+ . • ANF/ZIF-67 aerogel displayed excellent adsorption capacity for CV and MO. • The adsorption capacity maintained up to 80% after five times of usage. The fabrication of a high-efficiency adsorbent, as a promising candidate for removing metal ions and organic dyes from aqueous solution, is a research hotspot but remains challenging. Aramid nanofibers (ANFs) are emerging building blocks that have realized multifunctional applications in various fields because of their intrinsic mechanical and chemical stability. In this research, three-dimensional (3D) ANF aerogel was assembled and applied in for in situ assembly of zeolitic imidazole framework-67 (ZIF-67). The aim, was to fully exploit the structural advantages of this composite’s ultra-low bulk density, large specific surface area, and high porosity, as well as provide more available adsorption sites by ZIF-67 polyhedrons, to facilitate pollutant adsorption from waste water. The prepared 3D ANF/ZIF-67 composite aerogel possessed favorable adsorption performance for heavy metal ions (250.95 and 183.29 mg/g for Cu 2+ and Cr 6+ , respectively) and organic dyes (199.36 and 65.98 mg/g for CV and MO, respectively), greatly exceeding that of the corresponding 3D ANF aerogel. Desorption experiments further demonstrated that up to 80% adsorption performance for heavy metal ions and organic dyes could be maintained after five times of usage. Hence, this research can provide new insights into the preparation of highly efficient adsorbents for water treatment.

Synthesis, characterization, and selective CO2 capture performance of a new type of activated carbon-geopolymer composite adsorbent

Surface modification of activated carbon is an effective strategy to enhance its adsorption performance. However, most studies have focused on the use of chemical modifiers, and the products are usually in a powder form. Herein, we report the effective surface modification of activated carbon through geopolymer chemistry via simultaneous alkali-activated functionalization and polycondensation, thus yielding a monolithic adsorbent. The CO2 adsorption capacity of the optimized adsorbent was 2.25 times higher than that of the average of the constituents. Moreover, geopolymers can also function as efficient binders to supply a sufficient compressive strength of 22.3 MPa for the resultant adsorbent. Under different conditions, significant surface texture reconstruction of activated carbon was observed and confirmed via systematic XRD, FESEM, BET, XPS, and Raman spectrum characterisations combined with density functional theory (DFT) calculations. The effective surface modification was associated with the high alkaline environment during the geopolymerization reaction, which intercalates –CO, -OK, and -COOK functional groups on the activated carbon surface. These groups exhibited stronger CO2 affinity than that of pure activated carbon and thus endowed the high-strength adsorbent with enhanced CO2 adsorption capacity.

Utilization of a double-cross-linked amino-functionalized three-dimensional graphene networks as a monolithic adsorbent for methyl orange removal: Equilibrium, kinetics, thermodynamics and artificial neural network modeling

Herein, it is aimed to develop a high-performance monolithic adsorbent to be utilized in methyl orange (MO) adsorption. Therefore, amino-functionalized three-dimensional graphene networks (3D-GNf) fulfilling the requirements of reusability and high capacity have been fabricated via hydrothermal self-assembly approach followed by a double-crosslinking strategy. The potential utilization of 3D-GNf as an adsorbent for removal MO has been assessed using both batch-adsorption studies and an artificial neural network (ANN) approach. Graphene oxide sheets have been amino-functionalized and cross-linked, by ethylenediamine (EDA) during hydrothermal treatment, following the glutaraldehyde has used as a double-crosslinking agent to facilitate the crosslinking of architecture. The successful fabrication of 3D-GNf has been confirmed by field-emission scanning electron microscopy (FESEM), Fourier transform infrared (FT-IR), Raman and X-ray photoelectron spectroscopy (XPS). Moreover, N2 adsorption/desorption isotherms have revealed the high specific surface area (1015 m2 g−1) with high pore volume (1.054 cm3 g−1) and hierarchical porous structure of 3D-GNf. The effect of initial concentration, contact time, and temperature on adsorption capacity have been thoroughly studied, and the kinetics, isotherms, and thermodynamics of MO adsorption have been modelled. The MO adsorption has been well defined by the pseudo-second-order kinetic model and Langmuir isotherm model with a monolayer adsorption capacity of 270.27 mg g−1 at 25 °C. The thermodynamic findings have revealed MO adsorption has occurred spontaneously with an endothermic process. The Levenberg-Marquardt backpropagation algorithm has been implemented to train the ANN model, which has used the activation functions of tansig and purelin functions at the hidden and output layers, respectively. An optimum ANN model with high-performance metrics (coefficient of determination, R2 = 0.9995; mean squared error, MSE = 0.0008) composed of three hidden layers with 5 neurons in each layer was constructed to forecast MO adsorption. The findings have shown that experimental results are consistent with ANN-based data, implying that the suggested ANN model may be used to forecast cationic dye adsorption.

Modular monolith adsorbent systems for CO2 capture and its parameterized optimization

A key challenge for power plant carbon capture systems is operating economically under varying load conditions. Daily variations may be handled through control systems with reduced economic performance, but longer term seasonal cycles will require different solutions to enable robust and economic operation. We propose to use modular monolith adsorbent (MMA) designs whose capacity and configuration can be altered to respond to variations in flue gas flow. The configuration of the blocks is defined by the pattern of their serial and parallel connection. The ability to present a shorter, but wider, bed at different flue gas flowrates can then be exploited to improve performance and continuing to meet constraints on product purity and recovery. This additional degree of freedom afforded by the modular nature of the design allows an active response to the flowrate conditions and increases the flexibility of the system over the space of flowrate and concentration. In order to compare the proposed MMA systems and the conventional passive design method, case studies with varying flue gas amounts in a power plant are carried out. Simulation results show that the proposed MMA systems have improved optimal solutions because of their design flexibility, compared to the conventional passive design approach. Lastly, the optimized solutions are presented as a parametric map with different CO2 capture fractions and flowrate of flue gas. These parametric off-line solutions can be a guideline for the process implementation and reduce the operating complexity even if the MMA systems are used.

Efficient capture of carbamate and triazole pesticides in environmental waters by functional groups-rich monolithic fibers prior to chromatographic quantification

Efficient capture of carbamate and triazole pesticides in environmental waters is challenging because of their low contents, high water-solubility and complex sample matrices. In the present study, according to the chemical features of carbamates and triazoles, a functional groups-rich monolithic adsorbent (FRMA) was fabricated and employed as the extraction phase of multiple fibers solid phase microextraction (MF-SPME) using 4-vinylphenylboronic acid and vinylimidazole as mixed functional monomers. Results well evidenced that multiple forces such as B-N coordination, H-bonding, π-π and hydrophobic interactions co-contributed the efficient enrichment of FRMA/MF-SPME towards studied pesticides (extraction efficiencies ranged from 76.8% to 91.7%). Under the optimized parameters, sensitive and reliable method for measurement of trace carbamate and triazole pesticides in a variety of water samples was developed by the combination of FRMA/MF-SPME with high performance liquid chromatography (HPLC) equipped with diode array detector (DAD). The limits of detection varied from 0.0049 μg/L to 0.015 μg/L, and the RSDs for precision were below 10%. The recoveries for different fortified contents (1.0 μg/L and 100 μg/L) were in the range of 82.0–119%, and the RSDs for repeatability varied from 2.1% to 9.2%. Compared with existing approaches, the established approach presents some attractive merits such as minimal labor required, good sensitivity, high cost-effectiveness and eco-friendliness. Thus, the introduced approach can serve as a promising alternative method for routine monitoring of carbamate and triazole pesticides in environmental waters.

Adsorption of Iron (II) Ion by Using Magnetite-Bentonite-Based Monolith from Water

In this study, iron removal was carried out by the adsorption process as a well-known method of removing heavy metal. Natural bentonite with magnetic properties in a monolithic form or Magnetite-Bentonite-based Monolith (MBM) adsorbent was used as an adsorbent to remove Iron (II) ion from the aqueous solution. The magnetic properties of adsorbents are obtained by adding magnetite (Fe3O4), which is synthesized by the coprecipitation process. The characterization of magnetic properties was performed using the Vibrating Sample Magnetometer (VSM). VSM results showed that the magnetic particles were ferromagnetic. Adsorption efficiency, isotherm model, and adsorption kinetics were investigated in a batch system with iron solution concentration varied from 2 to 10 mg/L and magnetite loading at 2% and 5% w/w. The highest removal efficiency obtained reached 89% with a 5% magnetite loading. The best fit to the data was obtained with the Langmuir isotherm (non-linear) with maximum monolayer adsorption capacity (Qo) at 5% magnetic loading MBM adsorbent is 0.203 mg/g with Langmuir constants KL and aL are 2.055 L/g and 10.122 L/mg respectively. The pseudo-first-order (non-linear) kinetic model provides the best correlation of the experimental data with the rate of adsorption (k1) with magnetite loading 2% and 5%, respectively are 0.024 min-1 and 0.022 min-1.

Field sample preparation of trace inorganic anions in environmental waters with in-tip microextraction device based on anion-exchange monolithic adsorbent followed by ion chromatography quantification

In this study, a new field preparation method for the quantification of inorganic anions (including F−, BrO3−, Cl−, NO2− and Br−) at trace levels in environmental waters was proposed and developed. Glycidyl methacrylate was copolymerized with ethylene dimethacrylate in a pipette tip to obtain epoxy group-rich monolith, and then trimethylamine was employed to perform ring-opening reaction and got anion-exchange monolithic adsorbent (AMA). The resultant adsorbent was used as the extraction medium of three-channel in-tip microextraction device (TCMD) which was employed to conduct field sample preparation of inorganic anions in different water samples followed by analysis with ion chromatography with conductivity detector (IC/CD). The AMA exhibited satisfactory capture capability to studied anions through anion-exchange interaction. After optimization of extraction parameters, a method with low limits of detection (LODs, 0.019–0.33 μg/L), satisfactory coefficients of correlation (0.9925–0.9985) and good precision (RSDs ≤ 10%) was developed. The introduced approach was successful applied to detect studied anions in environmental waters, and the fortified recoveries varied from 77.3 to 113%. Additionally, the accuracy of suggested method was inspected by confirmatory testing. Compared with reported methods, the current approach displays some attractive features such as semi-automation, high throughput and low LODs. The suggested AMA/TCMD for on-site preparation of inorganic anions not only circumvents the storage and transportation of a great quantity of waters, but also ensures the quantification accuracy.

Fabrication of a monolithic adsorbent with multi-sites and its application in the extraction of active components from traditional Chinese medicine formula

A vinylic functionalized covalent organic framework (V-COF) was introduced to the preparation of a porous organic polymer (POP)/V-COF monolithic cartridge, via one-step polymerization reaction in a 50-mm-long and 4.6-mm-inner diameter stainless steel column. The fabricated POP/V-COF monolith was characterized with scanning electron microscope, Fourier transform infrared spectrometer and specific surface area measuring instrument, which indicate that the monolithic material in the cartridge occupies porous structure, multiple functional groups and high specific surface area of 188.2 m2 g−1. The POP/V-COF monolith was used as a solid-phase extraction (SPE) cartridge, which was online combined with an octadecyl-silane analytical column of high-performance liquid chromatography (HPLC) to extract, enrich and detect dihydrotanshinone Ⅰ, cryptotanshinone, tanshinone I and tanshinone ⅡA from traditional Chinese formula of POP/V-COF adsorbent. Furthermore, the POP/V-COF cartridge was used to extract and enrich the bornyl acetate from the Salvia Miltiorrhiza Drink by offline SPE procedure, and the extractive solution was subsequently analysed using capillary-gas chromatography method. These results show that the POP/V-COF SPE cartridge can remove the matrices of the Salvia Miltiorrhiza Drink, and simultaneously can extract the target active components with specific selectivity. Quantitative methodology validation indicates the applicable of this method for determination of the four active components in Salvia Miltiorrhiza Drink with the fabricated online SPE-HPLC. It is worth noting that the present cartridge can be reused for at least 100 times, with the RSD values based on the peak areas of the four components are less than 6.3% (n = 100).

3D-printed monolithic porous adsorbents from a solution-processible, hypercrosslinkable, functionalizable polymer

Solid adsorbents have been actively developed for energy-efficient gas separations including carbon capture and air purification. However, conventional particulate adsorbents often show ineffective mass transfer and significant pressure drop in practical operations, leading to a limited overall performance. As a potential solution to these issues, the development of three-dimensionally (3D) structured adsorbents has been proposed. Herein, we report a novel approach to design 3D monolithic adsorbents for CO2 separation via 3D printing of a processible polymer, which in turn can be transformed into a functional porous material via hypercrosslinking and amine-grafting. Importantly, such structure can be realized without an aid from binders or mechanical supports. Our adsorbents demonstrated a promising CO2 adsorption performance without experiencing any pressure drop under dynamic flow condition. The stability and regenerability, which are also important requirements for practical operations, were also successfully demonstrated through a repetitive adsorption–desorption cycling test in the presence of water vapor. We envisage that our approach can be applied in the development of structurally versatile adsorbents for various gas separation processes.

Adsorption of Mercury(II) Ion in Aqueous Solution by Using Bentonite-Based Monolith

The removal of mercury from the waterbody remains a severe challenge in ensuring environmental safety due to its highly toxic and non-biodegradable properties. Adsorption is an evidently effective method for heavy metal removal in water. This research aims to study the mercury (II) ion adsorption behavior in aqueous solution onto extruded natural bentonite in monolithic structure, bentonite-based monolith (BBM) adsorbent. BBM was characterized by XRD, BET, and SEM, the results verify BBM could improve adsorption performance assumed on its structure. Adsorption efficiency, isotherm model, and adsorption kinetic were investigated. Experiments were performed in a lab-scale batch reactor with mercury solution concentration varied from 1 to 5 mg/L. The maximum adsorption efficiency discovered to be 63,9%. The experimental data fitted well to Langmuir isotherm (non-linear) and kinetic model pseudo first order (non-linear), revealing the maximum monolayer capacity (Qo) of BBM to be 0,187 mg/g with Langmuir constants KL and aL are 0,215 L/g dan 1,151 L/mg respectively. These value confirms that BBM adsorbent encompasses tremendous potential for mercury (II) ion removal in a solution.