Selective Adsorption Research Articles

Fabrication of ultrasound/microwave co-assisted ruthenium temperature-sensitive ion-imprinted polymer microspheres and evaluation of its selective adsorption performances

Ruthenium recovery from secondary sources is necessary to secure the supply of ruthenium because of the increasing demand for ruthenium in industrial applications and the generation of ruthenium-containing secondary sources. In this work, a integration technique that combining imprinted technology, temperature-sensitivity technology, multi-field coupling technology and Pickering emulsion technology was proposed to prepare a green and efficient ruthenium temperature-sensitive ion-imprinted polymer microsphere under ultrasound/microwave co-assisted conditions for the specific separation and purification of ruthenium in complex environments. The structures and morphologies of the obtained hollow temperature-sensitive imprinted microspheres were characterized. Their adsorption/desorption performances, reusability and application in secondary resources were also studied and evaluated. The adsorption mechanism was studied by adsorption kinetic studies and isothermal adsorption studies. The results showed that the structure of US/MW-Ru(IV)-TIIPM was responsive to external temperature changes, reaching a maximum adsorption of 16.2105 mg/g at 33 °C and a maximum desorption rate of 76.30 % at 25 °C. US/MW-Ru(IV)-TIIPM has good reusability and demonstrates good separation and purification capabilities when applied to platinum catalyst leach solutions.

Enhanced adsorption of radioactive cesium from nuclear wastewater using ZIF-67 laminated 2D MXene Ti3C2

Development of nuclear industry has caused severe water pollution. Adsorptive removal of radionuclides from wastewater has been regarded as effective solution for environment. However, developing adsorbents with high adsorption capacity and selectivity for removal of radionuclides (such as 137Cs) is still a challenge. Herein, we adopted an in situ assemble strategy to construct a novel composite, in which zeolitic imidazolate framework (ZIF-67) was grafted into two-dimension (2D) layers of transition metal carbides/nitrides (MXenes) Ti3C2, and used it in adsorptive removal of Cs+ from wastewater. Laminated and pillaring effect of ZIF-67 increased interlayer spacing and specific surface area of Ti3C2, significantly enhancing Cs+ adsorption. MXenes matrix provided the main adsorptive sites and interaction to stabilize Cs+, while the hybrid ZIF-67 assisted adsorption. The adsorbent achieved 96.2 % removal for 5 mg·L-1 of Cs+ within 6 h, and 50.0 mg·g−1 of maximum adsorption capacity, with good recyclability for 4 times. Ion competition, kinetics and thermodynamics were studied in detail to obtain the behavior of Cs+ adsorption. Finally, adsorption mechanism was proposed that [Ti − O] − H+ and [Ti − O] groups of 2D Ti3C2 were main adsorptive sites to participate in ion exchange and complexation with Cs+, respectively, while 2-methylimidazole (2-MI) ligands in ZIF-67 were synergetic adsorption sites.

Plant extract mediated in-situ synthesis of iron/manganese alginate hydrosphere and its excellent recovery of rare earth elements in mine wastewater

The recovery of rare earth elements (REEs) is a major issue based on environmental governance and sustainable resource utilization. In this study, we developed a novel hydrogel material (Fe/Mn@ALG) by anchoring Fe/Mn NPs on alginate spheres, where Fe/Mn NPs were in-situ synthesized using Euphorbia cochinchensi leaf extract as reduced and protection agents. The Fe/Mn@ALG was applied directly to real mine wastewater, generating efficient and selective recovery of REEs with the coexistence of numerous competing metal ions. As results have shown, Fe/Mn@ALG was a useful adsorbent for REEs with an adsorption efficiency 78.62 % achieved, which was also confirmed by distribution coefficients (Kd), up to 2451.66 mL·g−1. Furthermore, Fe/Mn@ALG exhibited preferential response to REEs over other metal ions with the separation factor (SF) being up to 240. This great adsorption performance and selectivity toward REEs were attributed to its specific surface area, oxygen-rich functional groups and negatively charged surface in acid wastewater. Furthermore, REEs could be greatly desorbed from Fe/Mn@ALG with output concentration being three times higher than the initial concentration. Additionally, Fe/Mn@ALG maintained its good adsorption performance with efficiency reaching 72.24 % after five reuses. Overall, Fe/Mn@ALG can be considered as a promising candidate for wastewater remediation and sustainable management of resources.

Mechanism investigation on selective adsorption of fabric loaded with calcium silicate for organic dyes

Mechanism investigation on selective adsorption of fabric loaded with calcium silicate for organic dyes

Unveiling Inequality of Atoms in Ultrasmall Pt Clusters: Oxygen Adsorption Limited to the Uppermost Atomic Layer

The concept of preferential atomic and molecular adsorption site is of primary relevance in heterogeneous catalysis. In the case of ultrasmall size‐selected clusters, distinguishing the role played by each atom in a reaction is extremely challenging due to their reduced size and peculiar structures. Herein, it is revealed how the inequivalent atoms composing graphene‐supported Pt12 and Pt13 clusters behave differently in the photoinduced dissociation of O2, with only those in the uppermost layer of the clusters being involved in the reaction. In this process, the epitaxial graphene support plays a fundamental active role: its corrugation and pinning induced by the presence of the clusters are crucial for defining the preferential adsorption site on the Pt atomic agglomerates, facilitating the lateral diffusion of physisorbed oxygen at a distance that induces its selective adsorption in the topmost layer of the clusters, and inducing an inhomogeneous charge distribution within the clusters which directly affects the O2 adsorption. The inhomogeneous oxidation of the clusters is resolved by means of synchrotron‐based X‐ray photoelectron spectroscopy and supported by ab initio density functional theory calculations. The possibility to identify the active sites on Pt clusters induced by cluster–support interactions has the potential to enhance the experimentally supported design of nanocatalysts.

High-Performance Polyamidoxime Porous Membrane Prepared by the In Situ Modification/Nonsolvent-Induced Phase Separation Strategy for Uranium Extraction from Seawater.

The abundance of uranium (U(VI)) reserves in seawater makes it crucial to develop economically efficient methods for uranium extraction from seawater. In this work, an enhanced polyamidoxime porous membrane (PAOM) was fabricated by pre-in situ amidoxime modification combined with nonsolvent-induced phase separation (NIPS). The strategy of in situ modification of the polyacrylonitrile (PAN) solution served to enhance the homogeneity of the reaction and avoid the destruction of the membrane matrix and pore structure. Compared with the control sample (AOPM), PAOM possessed better mechanical strength and hydrophilicity. The introduction of polyvinylpyrrolidone (PVP) formed a porous structure in PAOM, improving spatial accessibility and facilitating the diffusion transport and capture of UO22+ inside the membrane. The more uniform and abundant distribution of amidoxime groups in PAOM gave it ultrahigh adsorption capacity and selectivity. The equilibrium adsorption capacity and Kd value of PAOM were 1.72 and 5.51 times higher than those of AOPM. Meanwhile, PAOM also demonstrated good recyclability, with only a 6.15% decrease in adsorption capacity after seven cycles. Additionally, PAOM exhibited excellent dynamic adsorption performance, and after 14 days of continuous filtration and adsorption, PAOM could extract 2.03 mg·g-1 U(VI) from natural seawater.

Fast Perfluorooctanoic Acid (PFOA) Removal with Honeycomb-like Nitrogen-Doped Carbon Nanosheets: Mechanisms for the Selective Adsorption of PFOA over Competing Contaminants/Water Matrix

Fast Perfluorooctanoic Acid (PFOA) Removal with Honeycomb-like Nitrogen-Doped Carbon Nanosheets: Mechanisms for the Selective Adsorption of PFOA over Competing Contaminants/Water Matrix

Fluorescence Light‐Up Electrospun Membrane Incorporated with PbBr2 as a Highly Selective Fluorescence Probe for the Detection of Cs+

AbstractThis study introduces a novel fluorescent light‐up electrospun membrane, integrating PbBr2, which serves as an exceptionally selective probe for the detection of cesium ions (Cs+). Leveraging the superior optical properties of CsPbBr3 perovskite nanocrystals (PNCs), the researchers employ electrospinning technology to fabricate a test strip, namely PbBr2@polyacrylonitrile (PbBr2@PAN) nanofiber membranes, capable of swiftly detecting Cs+ in water merely by observing changes in the nanocrystals' luminescence with the naked eye. By the introduction of NH4+‐modified montmorillonite (NH4+‐MMT), PbBr2‐MT@PAN nanofiber membranes is obtained. The selectivity and sensitivity to Cs+ can be further improved because NH4+‐MMT endows PbBr2‐MT@PAN nanofiber membranes with the hydrophilic property and selective adsorption toward Cs+ ions. The membrane's fabrication is simple, scalable, and cost‐effective, with high cesium selectivity and sensitivity down to 44 ppb. This innovation enables efficient, on‐site cesium monitoring critical for environmental safety and nuclear waste management.

Application of waste gypsum as novel selective depressant in the flotation separation of apatite from dolomite

The accumulation of gypsum slag not only causes resource wastage, but also poses serious environmental hazards, therefore, utilizing the resources of the main components in gypsum slag is an imperative task. In this study, gypsum was used as an inorganic depressant for the flotation separation of apatite from dolomite through the selective adsorption of gypsum on the surface of dolomite. Micro-flotation experiments showed that sodium oleate exhibited a good ability to collect apatite and dolomite, but poor ability to collect gypsum. At pH 9.5, when 3.75 g/L gypsum was added to the slurry, the recovery of dolomite decreased from 76.77 % to 18.34 %, whereas that of apatite was 86.45 %. Atomic force microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy were employed to elucidate the adsorption characteristics of gypsum on the apatite and dolomite surfaces. The results showed that gypsum was selectively adsorbed on the raised particles on the dolomite surface and combined with the active sites of Ca and Mg metal ions. However, the adsorption of gypsum on the surface of apatite was weak and had little effect on the flotation performance. Density functional theory calculations showed that the O in gypsum reacted easily with Ca and Mg metal ions on the mineral surface. The adsorption energies of gypsum at the Ca and Mg sites on the dolomite surface were −81.97 and −86.18 kJ/mol, respectively, whereas the adsorption energy on the apatite surface was only −34.20 kJ/mol. Gypsum is the main component of gypsum slag, and this study provides a potential recycling method for gypsum slag resources.

Mechanisms of mercury removal from water with highly efficient MXene and silver-modified polyethyleneimine cryogel composite filters

Safeguarding aquatic ecosystems and human health requires effective methods for removing pollutants. Mercury (Hg) is a very toxic pollutant with a global presence and is highly mobile and persistent. Here, innovative materials were prepared for separating Hg(II) from water, and the mechanisms underlying the efficient uptake of Hg species have been investigated. The sorbents include silver (Ag) nanoparticles and multilayered Ti3C2Tx MXene, both incorporated into the structure of a three-dimensional polyethyleneimine porous cryogel (PEI) that acts as a scaffold holding and exposing nano active sites involved in the removal of Hg. Specifically, Ag particles were deposited onto MXene phases, and the resulting composite was embedded in the macroporous PEI polymer (PEI/MXene@Ag cryogel). The composite has beneficial properties regarding Hg removal: 99% of Hg was separated from waste within 24 h in batch studies. The maximum removal capacity of Hg reached 875 mg/g from HgCl2, and 761 mg/g and 1280 mg/g from Hg(OAc)2 and Hg(NO3)2 salts by PEI/MXene@Ag. The Hg uptake stems from the composite’s relatively large specific surface area, layered porous channels, and highly dispersed Ag nanoparticles in the multilayered Ti3C2Tx MXene. The matrix in the water samples that were treated with the composite did not hinder the uptake of Hg by PEI/MXene@Ag. The high effectiveness achieved for the removal of Hg, combined with rapid adsorption kinetics, high efficiency, and selectivity, positions it as an efficient solution. Future work should address upscaling its preparation for increasing readiness towards mitigating Hg in surface water.

Carbon Dioxide Capture on Oxygen- and Nitrogen-Containing Carbon Quantum Dots.

To address global climate change challenges, an effective strategy involves capturing CO2 directly at its source using a sustainable, low-cost adsorbent. Carbon quantum dots (CQDs), derived from lignin, are employed to modify the internal surface of an activated carbon adsorbent, enabling selective adsorption based on electrostatic interactions. By manipulating charge distribution on CQDs through either doping (nitrogen) or functionalization (amine, carboxyl, or hydroxyl groups), the study confirms, through classical molecular dynamics simulations, the potential to adjust binding strength, adsorption capacity, and selectivity for CO2 over N2 and O2. For simulations with a single component gas, maximum selectivities of 3.6 and 6.7 are shown for CO2/N2 and CO2/O2, respectively, at 300 K. Simulations containing a wet flue gas indicate that the presence of water increases the CO2/N2 and CO2/O2 selectivities. The highest CO2/H2O selectivity obtained from a CQD/graphite system is 4.3. A comparison of graphite and lignin-based carbon composite (LBCC) substrates demonstrated that LBCC has enhanced adsorptive capacity. The roughness of the LBCC substrate prevents the diffusion of the CQD on the surface. This computational study takes another step toward identifying optimal CQD atomic architecture, dimensions, doping, and functionalization for a large-scale CQD/AC adsorbent solution for CO2 capture.

Waste biomass-derived activated carbons for selective oxygen adsorption

Activated carbons (ACs) derived from waste rice husk ash (RHA) exhibit remarkable potential for selective oxygen adsorption. The pore morphology of the prepared materials was characterized utilizing BET measurement, t-plot, and BJH-plot suggesting a linear relation between activation temperature and mesopore volume, whereas, micropore volume decreases at activation beyond 550 °C. FT-IR spectroscopy confirms their non-polar surface. Notably, AC-600 achieves an outstanding O2/N2 (0.21/0.78) of 152.7 at 0.01 bar at 25 °C, owing to the non-polar nature of the surface, favouring oxygen adsorption due to its low quadrupole moment. Additionally, the mixed micro and mesoporous structure of AC-600 significantly enhance the oxygen adsorption, showing an ∼18.4% (or 1.2-fold) increase compared to AC-500. However, a ∼32.3% decrease in oxygen uptake was observed for AC-800 due to excessive “burn-off”. Adsorption selectivity, assessed with Ideal Adsorption Solution Theory (IAST) and fitted to the Freundlich isotherm model, and adsorption kinetics, analysed using the pseudo-second-order Lagergren and Webber-Morris intraparticle diffusion models, highlighted the impact of activation temperature on the porosity of the material. Understanding the surface chemistry and pore morphology of activated carbon offers deeper insights to enhance oxygen uptake capacity, advancing the development of sustainable, industrially viable materials for oxygen production.

The Role of Fe(III) in Selective Adsorption of Pullulan on Calcite Surfaces: Experimental Investigation and Molecular Dynamics Simulation.

The floatability of fluorite and calcite exhibit similar properties, rendering their flotation separation challenging. Macromolecular polysaccharide reagents containing the polyhydroxyl group have shown broad promising application. The selectivity of polysaccharide is relatively low. In this study, the introduction of Fe3+ was employed to enhance the selective adsorption capacity of Pullulan polysaccharide towards fluorite and calcite minerals, thereby achieving effective flotation separation. Furthermore, the mechanism underlying intramolecular interactions was elucidated. The DFT calculation and XPS analysis revealed that the adsorption of Fe3+ on the calcite surface was more favorable, leading to the formation of a Ca-O-Fe structure. The MD simulation, XPS analysis, and Zeta potential analysis revealed that the Fe-OH groups on the surface of calcite reacted with the -OH groups in Pullulan and formed bonds, resulting in the formation of a Calcite-Fe-Pullulan structure. This facilitated the attachment of a significant number of Pullulan molecules to the calcite surface. The formation of a hydrophilic layer on the outer surface of calcite by Pullulan, in contrast to the absence of such layer on fluorite's surface, results in an increased disparity in surface floatability between these two minerals, thereby enhancing the efficiency of flotation separation.

Carbon Dioxide Adsorption over Activated Biocarbons Derived from Lemon Peel.

The rising concentration of CO2 in the atmosphere is approaching critical levels, posing a significant threat to life on Earth. Porous carbons derived from biobased materials, particularly waste byproducts, offer a viable solution for selective CO2 adsorption from large-scale industrial sources, potentially mitigating atmospheric CO2 emissions. In this study, we developed highly porous carbons from lemon peel waste through a two-step process, consisting of temperature pretreatment (500 °C) followed by chemical activation by KOH at 850 °C. The largest specific surface area (2821 m2/g), total pore volume (1.39 cm3/g), and micropore volume (0.70 cm3/g) were obtained at the highest KOH-to-carbon ratio of 4. In contrast, the sample activated with a KOH-to-carbon ratio of 2 demonstrated the greatest micropore distribution. This activated biocarbon exhibited superior CO2 adsorption capacity, reaching 5.69 mmol/g at 0 °C and 100 kPa. The remarkable adsorption performance can be attributed to the significant volume of micropores with diameters smaller than 0.859 nm. The Radke-Prausnitz equation, traditionally employed to model the adsorption equilibrium of organic compounds from liquid solutions, has been shown to be equally applicable for describing the gas-solid adsorption equilibrium. Furthermore, equations describing the temperature dependence of the Radke-Prausnitz equation's parameters have been developed.

Synthesis of Some Eco-Friendly Materials for Gold Recovery.

The aim of this study was to develop new materials with adsorbent properties that can be used for the adsorption recovery of Au(III) from aqueous solutions. To achieve this result, it is necessary to obtain inexpensive adsorbent materials in a granular form. Concomitantly, these materials must have a high adsorption capacity and selectivity. Other desired properties of these materials include a higher physical resistance, insolubility in water, and materials that can be regenerated or reused. Among the methods applied for the separation, purification, and preconcentration of platinum-group metal ions, adsorption is recognised as one of the most promising methods because of its simplicity, high efficiency, and wide availability. The studies were carried out using three supports: cellulose (CE), chitosan (Chi), and diatomea earth (Diat). These supports were functionalised by impregnation with extractants, using the ultrasound method. The extractants are environmentally friendly and relatively cheap amino acids, which contain in their structure pendant groups with nitrogen and sulphur heteroatoms (aspartic acid-Asp, l-glutamic acid-Glu, valine-Val, DL-cysteine-Cys, or serine-Ser). After preliminary testing from 75 synthesised materials, CE-Cys was chosen for the further recovery of Au(III) ions from aqueous solutions. To highlight the morphology and the functionalisation of the material, we physicochemically characterised the obtained material. Therefore, the analysis of the specific surface and porosity showed that the CE-Cys material has a specific surface of 4.6 m2/g, with a porosity of about 3 nm. The FT-IR analysis showed the presence, at a wavelength of 3340 cm-1, of the specific NH bond vibration for cysteine. At the same time, pHpZc was determined to be 2.8. The kinetic, thermodynamic, and equilibrium studies showed that the pseudo-second-order kinetic model best describes the adsorption process of Au(III) ions on the CE-Cys material. A maximum adsorption capacity of 12.18 mg per gram of the adsorbent material was achieved. It was established that the CE-Cys material can be reused five times with a good recovery degree.

The superior adsorption capacity of biogenic α-Mn2O3 in comparison to chemogenic α-Mn2O3 for five divalent heavy metal cations and the adsorption mechanism of biogenic α-Mn2O3: Experimental and DFT investigations

Manganese oxides play a crucial role in the adsorption of heavy metals in the environment. However, there is currently a lack of information regarding the comparative adsorption efficiency of heavy metals between biogenic and chemogenic manganese oxides. In this work, we compared the adsorption performance of biogenic and chemogenic α-Mn2O3 towards Pb(II), Cd(II), Cu(II), Zn(II) and Ni(II). Mineral characterization analyses revealed that biogenic α-Mn2O3 exhibited a polycrystalline nature, whereas chemogenic α-Mn2O3 displayed a monocrystalline nature with a lower impurity content compared to biogenic α-Mn2O3. Under acidic conditions, biogenic α-Mn2O3 demonstrated a significantly higher adsorption capacity, ranging from 3 to 6 times greater than its chemogenic counterpart, within an initial heavy metal concentration range of 0.2–1.0 mM. This superiority can be attributed to the presence of more abundant functional groups and a greater content of hydroxyl O species on the surface of biogenic α-Mn2O3 in comparison to chemogenic α-Mn2O3. During the adsorption process of biogenic α-Mn2O3, there were observed ionic exchanges between Mn(II) and these cations. More importantly, biogenic α-Mn2O3 bound with these cations probably through the formation of -O/OH/S complexes. The adsorption selectivity of biogenic α-Mn2O3 towards the five heavy metals was experimentally determined to follow the order of Ni(II) > Pb(II) > Cu(II) > Zn(II) > Cd(II). The electronic interaction between biogenic α-Mn2O3 and these cations indicated that Ni(II), Pb(II) and Cu(II) were more likely to share electrons with O atoms on the surface of biogenic α-Mn2O3 compared to Zn(II) and Cd(II).

Selective adsorption of divalent and trivalent cations in porous electrodes.

The capacitive deionization technology uses the electrochemical adsorption of ions in porous electrodes to desalinate seawater or brackish water. Recently, capacitive deionization has gained significant attention as a technology for selective adsorption of ionic species from multicomponent aqueous electrolytes. To investigate the mechanism of selective adsorption at the molecular level, we performed molecular dynamics simulations of aqueous electrolytes and porous electrodes with different divalent or trivalent ions, electrode pore sizes, and applied voltages. We calculated the free energy barriers preventing ions from entering the pores of the electrode and the structure of the water molecules near the ions and the electrode surface under various conditions. Our results suggest that, when the pore and ion sizes are comparable, the steric and electrostatic interactions between the hydrated ions and electrode pores are comparable in magnitude. Moreover, the relative importance of the two interactions can be reversed by slight changes in the external conditions, such as the ion size, valence of the ions, electrode pore size, and applied voltage. Thus, by finely tuning the electrode pore size and the applied voltage, it may be possible to selectively adsorb a particular ionic species from a multicomponent electrolyte through capacitive deionization using a porous electrode.

Hyper-Cross-Linked Polyindole for Selective Adsorption and Resource Utilization of Organic Pollutants in Water.

Efficient treatment and utilization of organic pollutants in water are difficult for environmental remediation. A new hyper-cross-linked polymer (PIn-HCP) with high specific surface area was constructed via polyindole (PIn) as building blocks. Rich pore structures and abundant adsorption sites in PIn-HCP were obtained by hyper-cross-linking. The specific surface area of PIn-HCP was enhanced from 14.85 to 431.89 m2/g. The adsorption capacities of PIn-HCP-2 for methylene blue (MB), methyl orange (MO), rhodamine B (RhB), and tetracycline hydrochloride (TH) are 902.0, 275.2, 16.0, and 0.0 mg/g, respectively. PIn-HCP also realized selective adsorption of MB, which can better separate MB/RhB and MB/TH. MB is adsorbed onto PIn-HCP via a synergistic mechanism including π-π stacking, electrostatic interaction, cation-π interaction, hydrogen bonding interaction, and ion exchange. The huge conjugated structure of PIn promotes PIn-HCP to selectively adsorb MB. In addition, PIn-HCP also retains the electrochemical properties of PIn. MB can improve the specific capacitance of PIn-HCP up to five times, and it has potential as a supercapacitor electrode. PIn-HCP offers a promising and practical solution for the efficient treatment and utilization of organic pollutants in water.

CO2 capture using functionalized MIL-101(Cr) metal–organic frameworks: Functionality nanoarchitectonics of nanospace for CO2 adsorption

In this study, we investigated the effect of functional groups of metal–organic frameworks (MOFs) on CO2 adsorption at low pressure through experimental and computational approaches. We compared the performance of −SO3H, –NO2, aryl –NH2, and alkyl –NH2 groups (in similar molar quantities) in CO2 adsorption under the same conditions. The adsorption efficiency followed in the order: alkyl –NH2 > -SO3H>aryl –NH2 > –NO2 because of the different adsorption mechanisms over the groups. The main mechanism over alkyl –NH2 was the formation of ammonium carbamate via the carbamic acid formation. The adsorption mechanism over −SO3H and aryl –NH2 groups was Lewis acid-base and H-bonding interactions, while that over –NO2 group was solely Lewis acid-base interaction. The alkyl amine exhibited the best performance (in adsorption capacity, selectivity, and adsorption heat) due to its ability to form carbamate readily. On the contrary, aryl amine demonstrated lower performance than −SO3H groups, attributed to their low capability to form carbamate. These findings underscore the importance of amine type in CO2 adsorption, highlighting that aryl amines, different from alkyl amines, perform worse than other functional groups, such as −SO3H.

Additive-free synthesis of house-of-card NaX zeolite for supporting amine: An efficient adsorbent for SO2 removal

The efficient adsorption of sulfur dioxide (SO2) is crucial for purifying exhaust gases, and zeolites are promising adsorbents due to their low cost and excellent stability. However, developing FAU-type zeolites with high adsorption capacities and selectivities remains challenging due to their narrow pores and limited adsorption sites. Herein, an additive-free synthesis strategy is proposed to facilely obtain NaX zeolites (X-HCL) with the house-of-card-like morphology. The hierarchical structure of X-HCL not only benefits the removal of SO2 through favorable spatial diffusion, but also promotes the loading of basic adsorption sites- [caprolactam] [tetrabutylammonium bromide] (CT) ionic liquid. The obtained CT/X-HCL adsorbent demonstrates remarkable SO2 adsorption capacity (10.58 mmol/g) and cyclic stability, as well as great selectivity of SO2/N2 (1673) and SO2/CO2 (219) due to the strong affinity of CT towards SO2. Moreover, co-feeding with water vapor benefits the adsorption of SO2 on CT/X-HCL owing to the enhanced chemisorption of hydrated CT for SO2. This research provides new insights into the construction of hierarchical zeolite for efficient adsorption and separation of SO2.