Nanoporous Adsorbents Research Articles

The Role of Nanoporous Adsorbents in the Circular Economy—Closing the Loop of Critical Materials Recovery

AbstractDue to the increase in the global population, industrialization, and the transition to climate neutrality through low‐emission technologies, the pressure on critical materials (CMs) continues to grow. CMs are defined as materials with a significant risk of supply chain disruption and limited substitutability. In this context, rare‐earth elements, platinum group metals, lithium, and cobalt are particularly crucial for the shift to carbon‐free economy and sustainability. One of the important strategies to endorse the goal of carbon reduction is to promote the recycling of resources. As a solution, effective recovery strategies have been developed, such as solid‐phase separation technologies based on advanced functional sorbents. This perspective article aims to provide a general assessment of the role of porous materials in closing the loop of critical materials recycling. Here, comprehensive insights are provided into recent development, design, and application of porous adsorbents commonly applied in solid‐phase extraction systems. Their current research status and problems related to their future application are also highlighted. This review covers recent advances in porous and hierarchical silica‐based materials, aerogels, covalent organic frameworks, metal–organic frameworks, and carbon‐based adsorbents.

A Review on Adsorption in Nanoporous Adsorbents for Gas Decontamination: Space Applications and Beyond

A Review on Adsorption in Nanoporous Adsorbents for Gas Decontamination: Space Applications and Beyond

Nanomaterial Texture-Based Machine Learning of Ciprofloxacin Adsorption on Nanoporous Carbon

Drug substances in water bodies and groundwater have become a significant threat to the surrounding environment. This study focuses on the ability of the nanoporous carbon materials to remove ciprofloxacin from aqueous solutions under specific experimental conditions and on the development of the mathematical model that would allow describing the molecular interactions of the adsorption process and calculating the adsorption capacity of the material. Thus, based on the adsorption measurements of the 87 carbon materials, it was found that, depending on the porosity and pore size distribution, adsorption capacity values varied between 55 and 495 mg g−1. For a more detailed analysis of the effects of different carbon textures and pores characteristics, a Quantitative nano-Structure–Property Relationship (QnSPR) was developed to describe and predict the ability of a nanoporous carbon material to remove ciprofloxacin from aqueous solutions. The adsorption capacity of potential nanoporous carbon-based adsorbents for the removal of ciprofloxacin was shown to be sufficiently accurately described by a three-parameter multi-linear QnSPR equation (R2 = 0.70). This description was achieved only with parameters describing the texture of the carbon material such as specific surface area (Sdft) and pore size fractions of 1.1–1.2 nm (VN21.1–1.2) and 3.3–3.4 nm (VN23.3−3.4) for pores.

Molecular Simulation of Cyclohexane in Nanoporous Materials: Adsorption of Conformers and Coadsorption with Water and Carbon Dioxide.

Molecular simulation is used to investigate the adsorption of an organic molecule and its different conformers into various nanoporous adsorbents. In more detail, we perform grand canonical Monte Carlo simulations to determine the adsorption isotherms for cyclohexane with its three conformers (chair, boat, and twisted boat) at three different temperatures into a molecular model of active carbons and two metal-organic frameworks (MOFs) (Cu-BTC and Al-Fum). By considering the adsorption of each conformer separately, we show that the adsorption isotherms are weakly dependent on the molecular conformation. When considering the concomitant adsorption of the three conformers under realistic conditions (to verify the population of each conformer in bulk mixtures), we show that the chair conformer is predominantly adsorbed in each material. However, such favorable adsorption mostly reflects the fact that this conformer has the largest population in the bulk mixture under the same thermodynamic conditions. On the contrary, with an increase in the cyclohexane gas pressure, the adsorption of boat and twisted boat conformers increases, while that of the chair conformer decreases as packing (entropy) effects become predominant during confinement. The adsorption of cyclohexane in the active carbon and MOF materials is also considered in the presence of water and CO2 atmospheres. In the case of the Al-fumarate material, the material is found to be strongly organophilic so that water and CO2 adsorption are negligible, and cyclohexane adsorption is not affected by competitive adsorption under any considered thermodynamic condition. On the contrary, for the active carbon and Cu-BTC material, competitive adsorption between cyclohexane and water or CO2 is observed even if cyclohexane adsorption remains preferred. While the different molecules coexist in the adsorbed phase at low pressures, increasing the cyclohexane pressure beyond 103 Pa promotes cyclohexane adsorption concomitantly with water and/or CO2 desorption.

Fabrication of a cost-effective metal oxide-based adsorbent from industrial waste slag for efficient CO2 separation under flue gas conditions

Efficient and affordable adsorbents for CO2 capture are essential in implementing carbon capture technology to mitigate the negative impact of greenhouse gas emissions. This study focuses on synthesizing new nanoporous adsorbents from industrial waste slag using a simple and cost-effective coprecipitation method. In this method, raw slag was milled for 48 h and used as a benchmark for comparing two newly synthesized adsorbents. Selectivity and pure gas isotherm experiments were conducted for all adsorbents in the 25–65°C temperature range and under harsh industrial conditions of 65°C and 15 % CO2. This study utilized the response surface methodology (RSM) to optimize the CO2 adsorption parameters. Specifically, the optimized adsorption conditions were determined for the 15/85 % CO2/N2 condition, and the optimal values for pressure and temperature were found to be 5 bar and 45°C, resulting in CO2/N2 selectivity of 5.65. The NH3-slag adsorbent was identified as the superior choice based on its selectivity and maximum adsorption capacity. The maximum adsorption capacity and cyclic efficiency were determined to be 4.15 mmol/g and 98.1 %, respectively, at a temperature, pressure, and composition of 45°C, 5 bar, and 15 % CO2. Isotherm and thermodynamic models were employed to further investigate the adsorption process. The isotherm results indicated that the adsorption of CO2 by adsorbents occurred heterogeneously in patch-wise sites. Meanwhile, the thermodynamic parameters showed that the process was exothermic and spontaneous, with ΔH° falling below 20 (kJ/mol), showing physisorption phenomena.

Methylene blue adsorption on Y-zeolite as a nano-porous adsorbent: equilibrium and kinetic studies

ABSTRACT The elimination of dye pollutants from industrial wastewaters, notably from sectors such as textiles and dyeing, remains a pivotal aspect of pollution mitigation endeavours. This research introduces an innovative strategy employing Y zeolite as a nano-porous adsorbent for eliminating methylene blue (MB), a prevalent cationic dye. Y zeolite was synthesised via hydrothermal technique. Through methodical experimentation, the impact of temperature, contact time, concentration, pH and adsorbent quantity on removal efficiency were examined with optimal conditions achieving 93.83% MB removal. The synthesised Y zeolite underwent characterisation utilising diverse techniques, including SEM, TEM, XRD, BET, and FTIR, which elucidated the structural and chemical characteristics. The surface area and pore diameter of Y zeolite were determined to be 229.1 m2/g and 20.3 Å, respectively. Utilisation of Response Surface Methodology (RSM) using design expert software facilitated the exploration of influential parameters, such as pH, temperature, contact time, adsorbent quantity, and MB concentration. The optimal conditions of pH = 7, temperature = 43°C, contact time = 85 min, adsorbent dosage = 0.5 g/L, and initial concentration = 30 ppm were obtained. Furthermore, reusability and durability of Y zeolite through multiple cycles of MB adsorption was assessed, revealing a retained efficiency of ~ 70% after 5 consecutive cycles. Kinetic studies confirmed pseudo-2nd-order model, emphasising chemisorption as the rate-limiting step. Equilibrium data fitting to the Langmuir isotherm highlighted the homogeneity of active adsorption sites on the zeolite surface, emphasising a high adsorption capacity. In conclusion, this study offers a promising solution for the removal of MB from aqueous solutions using Y zeolite as a nano-porous adsorbent. The findings underscore the importance of zeolite’s porosity and surface characteristics in enhancing adsorption efficiency, providing valuable insights for future applications in water treatment and environmental remediation efforts. This research showed that Y Zeolite is effective, low cost, eco-friendly, and can be regenerated as an adsorbent to eliminate MB from aqueous systems.

Mind the Gap: The Role of Mass Transfer in Shaped Nanoporous Adsorbents for Carbon Dioxide Capture.

Adsorptive separations by nanoporous materials are major industrial processes. The industrial importance of solid adsorbents is only expected to grow due to the increased focus on carbon dioxide capture technology and energy-efficient separations. To evaluate the performance of an adsorbent and design a separation process, the adsorption thermodynamics and kinetics must be known. However, although diffusion kinetics determine the maximum production rate in any adsorption-based separation, this aspect has received less attention due to the challenges associated with conducting diffusion measurements. These challenges are exacerbated in the study of shaped adsorbents due to the presence of porosity at different length scales. As a result, adsorbent selection typically relies mainly on adsorption properties at equilibrium, i.e., uptake capacity, selectivity and adsorption enthalpy. In this Perspective, based on an extensive literature review on mass transfer of CO2 in nanoporous adsorbents, we discuss the importance and limitations of measuring diffusion in nanoporous materials, from the powder form to the adsorption bed, considering the nature of the process, i.e., equilibrium-based or kinetic-based separations. By highlighting the lack of and discrepancies between published diffusivity data in the context of CO2 capture, we discuss future challenges and opportunities in studying mass transfer across scales in adsorption-based separations.

Heavy metals removal from wastewater using nanoporous adsorbent: Separation analysis via machine learning model

This paper presents a comprehensive analysis of three predictive models, namely Multi-Layer Perceptron (MLP), LASSO, and Extreme Gradient Boosting (XGB) for estimating concentration (C) of a substance in a given dataset. Adsorption separation was considered for water treatment, and the models were employed for tracking the concentration variations of solute in the process. With x(m) and y(m) as input variables which are the location, and concentration (C) measured in mol/m³ as output, the dataset comprises more than 19,000 data points. The Fireworks Algorithm (FWA) was employed to perform hyper-parameter optimization for the models. Different metrics were utilized to gauge the proficiency of each model, such as the R2 (coefficient of determination) for both the training and testing datasets, RMSE, and MAE. Results indicate that the MLP model obtained the highest score in terms of R2, with values of 0.99751 for the training data and 0.99756 for the testing data, suggesting excellent predictive accuracy. The MLP model also demonstrated the lowest error rates, with an RMSE of 1.3937 E+00 and an MAE of 8.81875E-01. The results revealed that the employed machine learning models are well capable of predicting adsorption process when combined with mass transfer modeling and great accuracy can be obtained.

Highly efficient removal of MTBE using natural nanoporous adsorbents

Highly efficient removal of MTBE using natural nanoporous adsorbents

Treatment of carbamazepine and other structurally-related pharmaceuticals in water and wastewater by nanoporous adsorbents and photocatalysts: a critical review

Abstract Carbamazepine (CBZ) is a contaminant of emerging concern that is persistent in water and wastewater. At low concentrations, prolonged exposure to CBZ-containing water causes detrimental health effects to humans and may also have negative impacts on the environment. Here we critically review new treatment approaches to decrease CBZ concentrations in water and wastewater. First, we summarize the transformation pathways of CBZ in the aquatic environment and identify the corresponding products. Then, we describe the removal of CBZ and structurally-related pharmaceuticals by phototransformation, biotransformation, and adsorption processes, with an emphasis on the application of naturally- and biologically-derived nanoporous adsorbents, such as agricultural wastes, natural polymers, activated carbon, metal organic frameworks, silicas, and molecularly imprinted polymers. Biologically-derived activated carbons exhibited the highest adsorption capacities for CBZ, with adsorption predominantly occurring through hydrophobic and π–π interactions. CBZ was also effectively treated using titanium dioxide and other inorganic photocatalysts. This review not only provides a critical synthesis of state-of-the-art adsorption and degradation processes for CBZ and structurally-related pharmaceuticals, but also proposes knowledge gaps and future research directions.

Anisotropic Deformation in a Polymer Slab Subjected to Fluid Adsorption.

Nanoporous adsorbents can mechanically swell or shrink once upon the accumulation of guest fluid molecules at their internal surfaces or in their cavities. Existing theories in this field attribute such sorption-induced swelling to a tensile force, while shrinkage is always associated with a contractive force. In this study, however, we propose that the sorption-induced deformation of a porous architecture is not solely dictated by the stress conditions but can also be largely influenced by its mechanical anisotropy. In more detail, the sorption-induced deformation of a polymeric slab is investigated using a hybrid molecular dynamics and Monte Carlo algorithm. When subjected to water loading, the slab is found to swell along its normal direction and display an overall positive volumetric strain. Moreover, the surface roughness is enhanced as a response to the surface energy decrease induced by the water covering the slab external surface. Unexpectedly, the in-plane deformation of the slab material seems to be highly constrained, so that it is far below its normal counterpart. This anisotropy is enhanced when the slab thickness decreases. With a thickness of around 1.35 nm, an in-plane shrinkage is observed throughout the entire hygroscopic range. A theoretical analysis based on a poromechanical model suggests that the anisotropic mechanical properties, which are common for a slab material, are the essence of the constrained in-plane swelling or even shrinkage under the isotropic sorption-induced tensile forces. This study, unveiling overlooked mechanisms of sorption-induced shrinkage in mechanically anisotropic materials, provides new insights into this field.

Aspects of Gas Storage: Confined Geometry Effects on the High-Pressure Adsorption Behavior of Supercritical Fluids.

During the last decades, major progress was made concerning the understanding of subcritical low-pressure adsorption of fluids like nitrogen and argon at their boiling temperatures in nanoporous materials. It was possible to understand how structural properties affect the shape of the adsorption isotherms. However, within the context of gas storage applications, supercritical high-pressure gas adsorption is important. A key feature here is that the experimentally determined surface excess adsorption isotherm may exhibit a characteristic maximum at a certain pressure. For a given temperature and adsorptive/adsorbent system, the surface excess maximum (and the corresponding adsorbed amount) is related to the storage capacity of the adsorbent. However, there is still a lack of understanding of how key textural properties such as surface area and pore size affect details of the shape of supercritical high-pressure adsorption isotherms. To address these open questions, we have performed a systematic experimental study assessing the effect of pore size/structure on the supercritical adsorption isotherms of pure fluids such as C2H4, CO2, and SF6 over a wider range of temperatures and pressures on a series of model materials exhibiting well-defined pore sizes, i.e., ordered micro- and mesoporous materials (e.g., NaY zeolite, KIT-6 silica, and MCM-48 silica). A fundamental result of our experiments is a unique fluid-independent correlation between the pressure of the surface excess maximum pmax (at a given temperature) and the pore size (by taking into account the kinetic diameter of the fluid and the underlying effective attractive fluid-wall interaction). Summarizing, our results suggest important structure-property relationships, allowing one to determine, for given thermodynamic conditions, important information related to the optimal operating conditions for supercritical adsorption applications. The insights may also serve as a basis for optimizing and tailoring the properties of nanoporous adsorbent materials for gas storage applications.

A Novel Nanoporous Adsorbent for Pesticides Obtained from Biogenic Calcium Carbonate Derived from Waste Crab Shells

A novel nanoporous adsorbent was obtained through the thermal treatment and chemical wash of the wasted crab shells (BC1) and characterized by various techniques. The structure of BC1 at the end of the treatments comprised a mixture of calcite and amorphous CaCO3, as evidenced by X-ray diffraction and Fourier transform infrared absorption. The BET surface area, BET pore volume, and pore diameter were 250.33 m2 g−1, 0.4 cm3 g−1, and <70 nm, respectively. The point of zero charge of BC1 was determined to be around pH 9. The prepared adsorbent was tested for its adsorption efficacy towards the neonicotinoid pesticide acetamiprid. The influence of pH (2–10), temperature (20–45 °C), adsorbent dose (0.2–1.2 g L−1), contact time (5–60 min), and initial pesticide concentration (10–60 mg L−1) on the adsorption process of acetamiprid on BC1 was studied. The adsorption capacity of BC1 was 17.8 mg g−1 under optimum conditions (i.e., 20 mg L−1 initial acetamiprid concentration, pH 8, 1 g L−1 adsorbent dose, 25 °C, and 15 min contact time). The equilibrium data obtained from the adsorption experiment fitted well with the Langmuir isotherm model. We developed an effective nanoporous adsorbent for the recycling of crab shells which can be applied on site with minimal laboratory infrastructure according to local needs.

Adsorption of aniline from aqueous solutions onto a nanoporous material adsorbent: isotherms, kinetics, and mass transfer mechanisms

Abstract MCM-48, which is particulate and nanoporous, was formulated to actively remove aniline (AN) (i.e., benzenamine) from wastewater. MCM-48 was characterized by several methods. It was found that the MCM-48 was highly active in adsorbing aniline from wastewater. The Langmuir, Freundlich, and Temkin isotherms were employed to evaluate the adsorption equilibrium. At 100 and 94 mg g−1, the maximum theoretical and experimental absorption of aniline, respectively, fit with a Type I Langmuir isotherm. The Langmuir model was optimal in comparison to the Freundlich model for the adsorption of AN onto the mesoporous material MCM-48. The results of these kinetics adsorption models were investigated using model kinetics that employed both pseudo-first- and pseudo-second-order models as well as models utilized intraparticle diffusion. The kinetics adsorption models demonstrated that the absorption was rapid and most closely agreed with the pseudo-first-order model. The kinetic studies and the adsorption isotherms revealed the presence of both physical adsorption and chemisorption. The potential adsorption mechanisms include the following: (1) hydrogen bonding, (2) π-π interactions, (3) electrostatic interaction, and (4) hydrophobic interactions. The solution's pH, ionic strength, and ambient temperature also played essential roles in the adsorption.

Adsorptive desulphurization of fuels by hypercrosslinked nanoporous polymers derived from polycyclic aromatic hydrocarbons

A sustainable method is employed to remove polycyclic aromatic sulphur heterocycles (PASHs) from fuels by using a series of high surface area nanoporous adsorbents synthesized from polycyclic aromatic hydrocarbons (PAHs). The hypercrosslinking of PAHs has been used to synthesize high surface area (SABET of 620–1565 m2 g−1) nanoporous polymeric materials via a microwave assisted method. The adsorbent poly-naph (highest SABET, i.e., 1565 m2 g−1) display best performance for desulphurization of fuels from batch to fixed bed column mode. In batch mode, the adsorption capacity of 12.1 (up to 9 ppm sulphur) and 8.9 mgS g−1 (up to 43 ppm sulphur), has been estimated for model (100 ppm sulphur) and real fuels (110 ppm sulphur), respectively. Furthermore, from ultra-low sulphur model (10 ppm sulphur) and real fuel (9 ppm sulphur), the adsorption capacity of 16.1 (up to 0.3 ppm sulphur) and 10 mgS g−1 (up to 3 ppm sulphur) has been estimated. In fixed-bed column mode, the high concentrated model and real fuel have been desulphurized to final concentration of 1 and 12 ppm, respectively. While, at low concentrations, the final concentration of 100 ppb and 1 ppm is achieved for model and real fuels, respectively. The adsorption mechanism revealed that π-electron density in the polymeric framework plays prominent role in the adsorption process apart from high surface area. This approach to control carcinogenic aromatic pollutants like PAHs and PASHs can be sustained over time through technological advancement, financial assistance and governmental regulation.

Magnetic oxide nano-porous adsorbents: a highly efficient approach for acid Fuchsin removal from medical laboratory effluents via adsorption process

Magnetic oxide nano-porous adsorbents: a highly efficient approach for acid Fuchsin removal from medical laboratory effluents via adsorption process

Enhanced removal of Cu(II) ions from aqueous solution by in-situ synthesis of zeolitic imidazolate framework-67@wood aerogel composite adsorbent

ABSTRACT Zeolitic imidazolate frameworks (ZIFs) were considered to be one of the most promising emerging nanoporous adsorbents capable of efficiently removing a variety of heavy metals ions from wastewater. However, due to the powdered crystalline state, easy aggregation and instability of ZIFs materials, their actual large-scale applications in water matrices are significantly hindered. Compounding ZIFs with self-supporting porous wood aerogel (WA) to obtain advanced composites is excepted to further enhance their adsorption performance with higher practicability. Herein, a novel Zeolitic Imidazolate Framework-67 (ZIF-67)@wood aerogel (denoted as ZIF-67@WA) adsorbent for efficient capture of Cu(II) ions was successfully fabricated via in situ growth of Cobalt-based ZIF-67 particles onto the WA scaffold. Benefiting from the integration of unique three-dimensional porous structures and abundant accessible active sites, the obtained ZIF-67@WA hybrids exhibited fast adsorption kinetics and the maximum adsorption capacity towards Cu(II) calculated from the Langmuir model was 254.84 mg g−1. The adsorption kinetic and isotherm studies were consistent with pseudo-second-order model (R 2 = 0.991) and Langmuir model (R 2 = 0.973), indicating the adsorption of Cu(II) was a monolayer chemisorption process. This work proposed a new route for designing and constructing functionalized MOF@biomass hybrid materials for heavy metal wastewater treatment.

In Situ Dilatometry Measurements of Deformation of Microporous Carbon Induced by Temperature and Carbon Dioxide Adsorption under High Pressures

Adsorption-based carbon dioxide capture, utilization, and storage technologies aim to mitigate the accumulation of anthropogenic greenhouse gases that cause climate change. It is assumed that porous carbons as adsorbents are able to demonstrate the effectiveness of these technologies over a wide range of temperatures and pressures. The present study aimed to investigate the temperature-induced changes in the dimensions of the microporous carbon adsorbent Sorbonorit 4, as well as the carbon dioxide adsorption, by using in situ dilatometry. The nonmonotonic changes in the dimensions of Sorbonorit 4 under vacuum were found with increasing temperature from 213 to 573 K. At T > 300 K, the thermal linear expansion coefficient of Sorbonorit 4 exceeded that of a graphite crystal, reaching 5 × 10−5 K at 573 K. The CO2 adsorption onto Sorbonorit 4 gave rise to its contraction at low temperatures and pressures or to its expansion at high temperatures over the entire pressure range. An inversion of the temperature dependence of the adsorption-induced deformation (AID) of Sorbonorit-4 was observed. The AID of Sorbonorit-4 and differential isosteric heat of CO2 adsorption plotted as a function of carbon dioxide uptake varied within the same intervals of adsorption values, reflecting the changes in the state of adsorbed molecules caused by contributions from adsorbate–adsorbent and adsorbate–adsorbate interactions. A simple model of nanoporous carbon adsorbents as randomly oriented nanocrystallites interconnected by a disordered carbon phase is proposed to represent the adsorption- and temperature-induced deformation of nanocrystallites with the macroscopic deformation of the adsorbent granules.

Trace SO2 Gas Capture in Stable 3D Viologen Ionic Porous Organic Framework Microsphere.

Eliminating trace sulfur dioxide (SO2) using nanoporous adsorbents is industrially preferred yet of great challenge due to the competitive adsorption of CO2. Herein, we reported a highly stable 3D viologen porous organic framework (Viologen-POF) microsphere via one pot polymerization reaction of 4,4'-bipyridine and tetrakis(4-(bromomethyl)phenyl)methane. Compared to the previously reported irregular POF particles, viologen-POF microsphere shows better mass transfer uniformity. Owing to the intrinsic separated positive and negative electric charges center in viologen-POF microspheres, it exhibits excellent SO2 selective capture performance, which can be collaboratively confirmed by static single-component gas adsorption, time-dependent adsorption rate, and multicomponent dynamic breakthrough experiments. Viologen-POF exhibits high SO2 absorption capacity (1.45 mmol g-1) at ultralow pressure of 0.002 bar and high SO2/CO2 selectivity of 467 at 298 K and 100 kPa (SO2/CO2, 10/90, v/v). The theoretical calculations based on density functional theory (DFT) and DMol3 modules in Material Studio (MS) were also performed to elucidate the adsorption mechanism of viologen-POF toward SO2 at the molecular level. This study represents a new type of viologen porous framework microsphere for trace SO2 capture, which will pave the way on the applications of ionic POF for toxic gas adsorption and separation.

Competitive and Cooperative CO2-H2O Adsorption through Humidity Control in a Polyimide Covalent Organic Framework.

In order to capture and separate CO2 from the air or flue gas streams through nanoporous adsorbents, the influence of the humidity in these streams has to be taken into account as it hampers the capture process in two main ways: (1) water preferentially binds to CO2 adsorption sites and lowers the overall capacity, and (2) water causes hydrolytic degradation and pore collapse of the porous framework. Here, we have used a water-stable polyimide covalent organic framework (COF) in N2/CO2/H2O breakthrough studies and assessed its performance under varying levels of relative humidity (RH). We discovered that at limited relative humidity, the competitive binding of H2O over CO2 is replaced by cooperative adsorption. For some conditions, the CO2 capacity was significantly higher under humid versus dry conditions (e.g., a 25% capacity increase at 343 K and 10% RH). These results in combination with FT-IR studies on equilibrated COFs at controlled RH values allowed us to assign the effect of cooperative adsorption to CO2 being adsorbed on single-site adsorbed water. Additionally, once water cluster formation sets in, loss of CO2 capacity is inevitable. Finally, the polyimide COF used in this research retained performance after a total exposure time of >75 h and temperatures up to 403 K. This research provides insight in how cooperative CO2-H2O can be achieved and as such provides directions for the development of CO2 physisorbents that can function in humid streams.