Selective Adsorption Research Articles

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.

Enhanced removal of lead ions from wastewaters by electrochemical adsorption using nitrogen-doped Ti3C2Tx MXene

As a two-dimensional material containing transition metal carbides and nitrides, MXene is often used in capacitive deionization for its excellent hydrophilic and pseudocapacitive properties. Nitrogen doping is widely used to improve the adsorption properties of certain materials. However, the effect of nitrogen doping on the electrochemical adsorption properties of MXene remains unclear. In this work, nitrogen-doped Ti3C2Tx MXene was synthesized using a simple hydrothermal method to achieve highly selective and efficient removal of Pb(II) at a constant cell voltage. The concentration of Pb(II) decreased from 4.95 to 0.02 mg L−1 in a 100 mg L−1 NaCl supporting electrolyte after electrosorption. The removal efficiency of Pb(II) reached 99.5%, whereas it was only 15.2% for Na+. The introduction of nitrogen functional groups increased the electrical conductivity and layer spacing of MXene, thereby improving the pseudocapacitive adsorption performance in the presence of Pb(II). The complexation function of the Ti-OH group on nitrogen-doped Ti3C2Tx surface increased and contributed to the selective adsorption of Pb(II). The removal efficiency of Pb(II) increased with increasing solution pH and cell voltage, reaching the maximum value at pH 5.0 and 1.5 V, respectively. The effect of supporting electrolyte type on the removal of Pb(II) was negligible. In addition, the removal efficiency for mixed heavy metal ion solutions, including Cu(II), Ni(II), and Pb(II), exceeded 79.0%. It exhibited the highest removal efficiency for Pb(II) at 97.9%. After five cycles of electrochemical adsorption–desorption, the nitrogen-doped Ti3C2Tx maintained a stable Pb(II) removal efficiency of 97.0%. This work provides a promising material for the electrochemical removal of low-concentration heavy metal ions from wastewaters.

Selective adsorption of indole on mesoporous carbon in an aqueous system

Selective adsorption of indole on mesoporous carbon in an aqueous system

Recent advances in MXene nanomaterials: Fundamentals to applications in environment sector

AbstractMXenes are a new type of 2D transition metal carbon/nitride or carbonitride, which are composed of Mn+1AXn phase material (MAX phase) through single‐layer or thin‐layer nanosheets obtained by exfoliation. Owning to unique two‐dimensional layered structure, large specific surface area, excellent electrical conductivity and mechanical stability, the MXenes have quickly become a research hotspot due to their magnetic and other properties, and have been widely used in many fields such as electrochemical sensors, energy storage, catalysis, and adsorption. This article summarizes and introduces preparation methods of two‐dimensional materials MXenes, and focus on reviewing their application research progress in the electrochemical sensors and environmental field in recent years, including detection of biomarkers and environmental pollutants, adsorption of heavy metals, adsorption of radiation metals, adsorption of organic matter, selective adsorption of carbon dioxide, membrane separation, sensors, electrocatalysis, photocatalysis, electromagnetic absorption and shielding, etc. A summary and review were conducted, and finally the existing problems and future development at this stage were analyzed.

Chitosan-amidated lignin aerogel beads efficiently loaded with lanthanum hydroxide for phosphate removal from aqueous solutions

Developing phosphorus removal adsorbents with high adsorption performance and excellent structural stability remains a challenge. Herein, a chitosan (CS) - amidated lignin (AL) gel-bead adsorbent with high efficiency in immobilizing lanthanum hydroxide (La(OH)3) was fabricated via an in situ precipitation and freeze-drying strategy (abbreviated as La@ALCSx). The abundant hydroxyl and amino groups in CS promoted excellent loading of La(OH)3 on the surface and inside of the adsorbent. The introduction of lignin enhanced the structural stability of the beads along with the mass transfer efficiency. Owing to the porous structure and high La utilization, the adsorption capacity of La@ALCS2 reached 130.52 mg P g−1. Intra-sphere complexation of La(OH)3 with phosphate resulted in high adsorption selectivity of La@ALCS2. Moreover, the millimeter-sized of La@ALCS2 has favourable recoverability and maintains high adsorption performance after five adsorption-desorption cycles. Characterization analysis indicated that electrostatic attraction and ligand exchange were the main adsorption mechanisms. The excellent phosphorus removal efficiency, separation efficiency and recyclability of La@ALCSx provide a viable solution for the remediation of phosphate contaminated waters.

Effective purification of phosphate from water using ultra-small hydrated cerium oxides encapsulated inside gel-type polymer

Deep removing phosphate from waters is crucial in managing eutrophication, and adsorption has been widely regarded as an effective option. However, it is still lack of adsorbents with high reactivity and applicability. Herein, a novel nanocomposite HCO@N201 was introduced by impregnating hydrated cerium oxides (HCO) NPs inside a gel-type polymer N201. Due to the unique pore structure of N201 that contained plenty of micropores of <5 nm, the in-situ generated HCO NPs were regulated to sub-5 nm level (with the average size of 3.99 ± 0.06 nm), much smaller than the HCO NPs formed inside the widely-used macroporous host D201 (27.64 ± 2.55 nm). Adsorption isotherms demonstrated that HCO@N201 exhibited the saturated adsorption capacity of 218.43 mg/g toward phosphate, reaching to 1.52 times that of the macroporous analogue HCO@D201 (144.04 mg/g). In addition, HCO@N201 exhibited highly enhanced decontamination performance in terms of adsorption selectivity, stability, and reusability. XPS analyses of O 1s and Ce 3d spectra indicated that HCO@N201 possessed elevated proportions of surface hydroxyl groups (−OH, 53.35 %) and Ce(III) species (38.13 %) than HCO@D201 (37.31 % and 29.13 % for –OH and Ce(III) species, respectively). Various techniques including FT-IR, SEM-EDS, and STEM-HAADF have also been applied to deeply explore the internal mechanism of decontamination. In cyclic fixed-bed operations, HCO@N201 could consistently produce approximately 1150 bed volumes (BV) of clean water from the influent containing ∼2 mg/L of phosphate, exceeding twice that of HCO@D201. This study may provide a promising phosphate purifier with high reactivity and applicability.

Synergistic Coordination in Cu Single-Atom Catalysts Enhances High-Valent Copper-Oxo Species for Efficient PMS Activation.

In the domain of heterogeneous catalytic activation of peroxymonosulfate (PMS), high-valent metal-oxo (HVMO) species are widely recognized as potent oxidants for the abatement of organic pollutants. However, the generation selectivity and efficiency of HVMO are often constrained by stringent requirements for catalyst adsorption sites and electron transfer efficiency. In this study, a single-atom catalyst, CuSA/CNP&S, is synthesized featuring multiple types (planar/axial) of heteroatom coordination via an H-bond-assisted self-assembly strategy. It isconfirmed that CuN3 active centers with axial S coordination are uniformly distributed in a carbon matrix modified by planar P atoms. CuSA/CNP&S activated PMS to selectively generate Cu(III)═OH species as the primary reactive oxygen species (ROS). The pseudo-first-order kinetic rate for bisphenol A degradation reached 1.51min-1, a 17.57-fold increase compared to the unmodified CuSA/CN catalyst. Additionally, the CuSA/CNP&S catalyst demonstrates high efficiency and durability in removing contaminants from various aqueous matrices. Theoretical calculations and experimental results indicate that the intrinsic electric field generated by distal planar P atoms enhances electron transfer efficiency within the carbon matrix. Meanwhile, axial S coordination elevates the d-band center and tunes the eg * band broadening of Cu, thereby enhancing the adsorption selectivity for the terminal oxygen of PMS. This multitype coordination synergistically mitigates the issues of low selectivity and yield of HVMO species.

Poly(ionic liquids-acrylic acid)-modified MIL-101(Cr) metal−organic frameworks: Preparation and efficient adsorption of europium☆

A novel composite material, Poly(IL-AA)@MIL-101(Cr), combining metal-organic framework, polymeric ionic liquid and acrylic acid, was synthesized for the selective and efficient adsorption of rare earths europium(III) (Eu3+). Characterization of the materials was carried out using techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), thermogravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET). The results demonstrate successful incorporation of the polymeric ionic liquid onto the material surface while preserving the crystal structure and morphology of MIL-101(Cr). Adsorption experiments were conducted to explore parameters including solution pH, initial Eu3+ concentration, and duration, with comprehensive analyses of adsorption kinetics, isotherms, and mechanisms. Findings reveal that Poly(IL1-AA)@MIL-101(Cr), Poly(IL3-AA)@MIL-101(Cr), and Poly(IL5-AA)@MIL-101(Cr) achieve adsorption equilibrium for Eu3+ at approximately 9 h with an equilibrium pH of 6.2. The adsorption of Eu3+ predominantly follows a pseudo-second-order kinetic model and Langmuir isotherm adsorption model. Moreover, the prepared composite material exhibits superior adsorption selectivity for Eu3+ over other metal ions in the mixture (K+, Mg2+, Ni2+, Co2+, Zn2+, La3+, and Nd3+). Even after five adsorption-desorption cycles, the composite material maintains satisfactory adsorption performance.

Rare earth europium recovery using selective metal-organic framework incorporated mixed-matrix membrane

Rare-earth elements (REEs) play a crucial role in state-of-the-art technologies and sustainable energy generation. However, conventional production methods of REE often instigate detrimental impacts on environment. Hence, the development of efficient and sustainable hydrometallurgical methods for REE recovery from complex solution has become a crucial research focus. This study investigates a mixed-matrix membrane composed of a highly europium selective metal-organic framework-based adsorbent, Cr-MIL-PMIDA, embedded in sulfonated poly(ether ketone) (SPEK) polymer membrane matrix to preferentially concentrate europium (Eu3+) ions in the presence of other competing cations. The activated membrane notably reduced ionic conductivity for Eu3+ compared to other multivalent ions. Membrane extraction experiments further confirmed the selective behavior, demonstrating slower diffusion for Eu3+ compared to Mg2+ and Zn2+ cations. Especially, at pH 5, Mg2⁺ and Zn2⁺ recovery was greater than 30%, whereas Eu³⁺ recovery remained lower than 4%. We propose that the strong chemical affinity between the phosphate group and Eu3+ help partition of the Eu3+ ions in the membrane phase and inhibit the diffusion and further partitioning of the Eu3+ ion from bulk solution. Furthermore, we demonstrate the stability of the composite membrane and the embedded MOF particles in aqueous solution for up to 12 days without degradation, attributing it to the robust chemical stability of the MOF structure.

Three-dimensional linker-promoted hierarchical porous metal–organic framework for natural gas purification

The purification of methane from natural gas is extremely important for industrial applications. In this study, hierarchical porous material LIFM-Z1 with microporous cages and mesoporous hexagonal one-dimensional channels was successfully synthesized and evaluated. The results show that LIFM-Z1 can effectively separate CH4 from the mixed gas containing CH4, C2H6, C3H8 and n-C4H10. Single-component adsorption experiments revealed the selective adsorption ability of LIFM-Z1 for C2H6, C3H8, and n-C4H10, enabling a clear distinction between these components and CH4. This selectivity was further verified by dynamic breakthrough experiments. Theoretical analysis shows that the interaction between LIFM-Z1 and gas molecules mainly depends on the synergistic effect of C–H⋯O hydrogen bond and C–H⋯C van der Waals force. The results highlight the potential of utilizing 3D linkers to enhance the inner wall interaction with CH4 and its related gases in MOF construction. These characteristics of LIFM-Z1 not only successfully demonstrate the potential of separation and purification of natural gas with high efficiency, but also show its broad application prospects in the actual natural gas processing.

Selective adsorption of indole on mesoporous carbon in an aqueous system

Selective adsorption of indole on mesoporous carbon in an aqueous system

Stable hierarchical ionic liquid nanochannels for highly efficient CO2 adsorption, separation and conversion

Constructing stable nanochannels and nanoconfined environments for ionic liquids holds significant application value in gas separation, ion channels, and related fields. The functional polyionic liquid synthesized in this study exhibits a controllable assembly structure and demonstrates liquid crystal properties. Through heating and water treatment, the polyionic liquids crosslink to form multi-hierarchical nanopores, including sub-nanochannels with pore sizes similar to CO2, without the need for a catalyst. The specific surface area and pore size of the polyionic liquid network (PILC) were adjusted by regulating the self-assembly of polyionic liquids in water. The unique PILC, combining ionic liquid nanopores and liquid crystal structure properties, shows high CO2 adsorption performance and excellent CO2/N2 selectivities, surpassing commonly reported ionic liquid porous materials. Furthermore, PILC-2 exhibits good catalytic performance for CO2 cycloaddition, and its catalytic activity and selectivity did not significantly decrease after five cycles. This study successfully introduces hierarchical ionic liquid nanochannels into porous networks without involving any inorganic ordered nanomaterials. This provides a simple and effective approach for the highly selective adsorption and separation of CO2, as well as for the preparation of catalytic materials.

Adsorption of tryptophan by covalent organic frameworks

Abstract Hemoperfusion based on adsorption has been widely used to remove the blood toxins of patients with hepatic encephalopathy. It is important to develop adsorbents with high adsorption capacity, and specific adsorption performance for toxins is highly desired for hemoperfusion. Herein, we evaluate the tryptophan adsorption performance of four kinds of covalent organic frameworks (COFs) by powder X-ray diffraction (PXRD), high-performance liquid chromatography (HPLC), and so on. Benefitting from the abundant pore, suitable pore size, and attractive effect between tryptophan and hydroxy groups in COFs, TAPB-DHTA-COF and TAPT-DHTA-COF with abundant hydroxy groups show remarkable adsorption performance for tryptophan, which is superior to commercial activated carbon. Furthermore, the selective adsorption of COF does not affect other components in the blood, thus avoiding the occurrence of other diseases. Therefore, COFs offer a promising platform for the adsorption of toxins in hemoperfusion.