Carbon dioxide adsorption based on porous materials

Behavior, mechanisms, and applications of low-concentration CO2 in energy media

This review explores the behavior of low-concentration CO2 (LCC) in various energy media, such as solid adsorbents, liquid absorbents, and catalytic surfaces. It delves into the mechanisms of diffusion, adsorption, and catalytic reactions, while analyzing the potential applications and challenges of these properties in technologies like air separation, compressed gas energy storage, and CO2 catalytic conversion. Given the current lack of comprehensive analyses, especially those encompassing multiscale studies of LCC behavior, this review aims to provide a theoretical foundation and data support for optimizing CO2 capture, storage, and conversion technologies, as well as guidance for the development and application of new materials. By summarizing recent advancements in LCC separation techniques (e.g., cryogenic air separation and direct air carbon capture) and catalytic conversion technologies (including thermal catalysis, electrochemical catalysis, photocatalysis, plasma catalysis, and biocatalysis), this review highlights their importance in achieving carbon neutrality. It also discusses the challenges and future directions of these technologies. The findings emphasize that advancing the efficient utilization of LCC not only enhances CO2 reduction and resource utilization efficiency, promoting the development of clean energy technologies, but also provides an economically and environmentally viable solution for addressing global climate change.

Adsorption Structure and Selectivity of Phenols in Water-Immersed Organomontmorillonite Investigated by Molecular Simulation

The two-dimensional interlayer space of layered materials has been highlighted due to their adsorption property, whose nanostructure in the water-immersed state is scarcely understood by experiment. Recent developments in molecular simulation have enabled researchers to investigate the interlayer structure, but water content is necessary for accurate modeling. In the present study, we proposed a theoretical method to estimate the saturated water content and adsorption selectivity of trichlorophenol and phenol in montmorillonite modified with hexadecyltrimethylammonium ions. By analyzing non-bond energy in interlayer water and following comparison with the bulk water model, the saturated water content was estimated to be between 12.7 and 14.2 wt %, which is consistent with the corresponding thermogravimetry data. In the water-immersed state, trichlorophenol was distributed in the center of the interlayer due to the van der Waals interaction with the organocation. Solvation free energy analysis revealed that trichlorophenol was more stable in the interlayer than in the aqueous solution, while the opposite result was obtained for phenol, reproducing the adsorption selectivity reported experimentally. Thus, it was found that both the saturated water content and adsorption selectivity are predicted by molecular simulation. The adsorption site of trichlorophenol changed from the center of the interlayer to the clay surface in the dry state, indicating that accurate modeling in the water-immersed state is significant for revealing the adsorption structure.

Supported Cu3 cluster on N-doped graphene: An efficient triatom catalyst for CO electroreduction to propanol at low potential

Electroreduction of carbon monoxide into high-energy fuel is an excellent energy strategy for sustainable development, but the high yield of multi-carbon products remains a difficult challenge. Inspired by the successful synthesis of various trimer metal clusters and studies on electrocatalysis of CO to C3 products by Cu-based catalysts, Cu3 supported on N-doped graphene structures (Cu3@NG) are investigated as electrocatalysts for CORR toward propanol in this paper. Due to the appropriate Cu-Cu bond length, the moderate charge of the Cu site, mild CO adsorption energy, and 100 % CO coverage, the absorbed 3*CO substance can form the critical *CO-CO-CO intermediate with a rather low kinetic barrier of 0.25 eV. The limiting potential of the whole process for the formation of propanol is just -0.15 V. Our work not only showed that Cu3@NG is an excellent catalyst for the formation of propanol with high selectivity at low potential but also indicated that the *CO coverage can greatly reduce the CO hydrogenation potential and bonding of some intermediates such as *CH2O. This research will provide a new idea for the material design of products tending to multi-carbon.

Process-based screening of porous materials for vacuum swing adsorption based on 1D classical density functional theory and PC-SAFT

Adsorption-based processes are showing substantial potential for carbon capture. Due to the vast space of potential solid adsorbents and their influence on the process performance, the choice of the material is not trivial but requires systematic approaches. In particular, the material choice should be based on the performance of the resulting process. In this work, we present a method for the process-based screening of porous materials for pressure and vacuum swing adsorption. The method is based on an equilibrium process model that incorporates one-dimensional classical density functional theory (1D-DFT) and the PC-SAFT equation of state. Thereby, the presented method can efficiently screen databases of potential adsorbents and identify the best-performing materials as well as the corresponding optimized process conditions for a specific carbon capture application. We apply our method to a point-source carbon capture application at a cement plant. The results show that the process model is crucial to evaluating the performance of adsorbents instead of relying solely on material heuristics. Furthermore, we enhance our approach through multi-objective optimization and demonstrate for materials with high performance that our method is able to capture the trade-offs between two process objectives, such as specific work and purity. The presented method thus provides an efficient screening tool for adsorbents to maximize process performance.

Tailorable Ionic Frameworks for Selective Gas Adsorption and Separation: Bridging Experimental Insights with Mechanistic Understanding

The selective adsorption and separation of gases using solid adsorbents represent a crucial method for the treatment of toxic gases and the preparation of high-purity gases. The interaction forces between gas molecules and solid adsorbents are influenced by various factors, making precise design of adsorbents to achieve specific gas adsorption a pressing issue that requires urgent attention. In this study, a series of ionic frameworks constructed from Na+ and polyoxometalates (POMs) have been constructed through ionic interactions, and possess multiple adjustable parameters. These frameworks exhibit 3D open channels and demonstrate excellent thermal, humidity, and solvent stability. The synthesized ionic frameworks show strong adsorption capabilities for polar gas molecules such as SO2 and NH3, while exhibiting negligible adsorption for nonpolar or weakly polar gases like CO, O2, CH4, N2, and H2, thereby highlighting their significant gas selectivity. Theoretical calculations reveal that the interaction strength between the ionic frameworks and the polar gases is substantially stronger than that for other gaseous species, corroborating the experimental findings. This research not only provides a series of effective absorbents for polar gases but also elucidates key influencing factors on gas adsorption process, thereby inspiring new directions in the development of innovative gas adsorbents.

CO2 selectivity and adsorption performance of K2CO3-modified zeolite: a temperature-dependent study

High-performing zeolite materials for carbon dioxide capture are promising for applications such as flue gas CO2 capture. Potassium carbonate-loaded zeolites can offer a plethora of benefits. In this work, for the first time, zeolite-Y impregnated with K2CO3 was studied as a gas adsorbent (CO2, CH4, and N2) and characterized using TGA (thermogravimetric analyzer), XRD, BET, FTIR, FETEM (Field-Emission Transmission Electron Microscope), and XPS. The effect of carbonate loading, temperature, and pressure was particularly targeted and assessed. Accordingly, for a variation in K2CO3 loading from 5 to 15 wt.%, the CO2 adsorption capacity reduced from 3.61 to 1.73 mmol g-1 in the synthesized adsorbents. Among all the cases, KYZC10 exhibited very good cyclic adsorption-desorption performance and thermal stability. Further equilibrium modeling studies indicate that the stable and optimally K2CO3-loaded adsorbent (KYZC10) demonstrates effective adsorption isotherm behavior, making it suitable for different temperature variation processes in commercial carbon dioxide capture applications. The KYZC10 adsorbent's stable performance at varying temperatures contributes to its enhanced economic feasibility. This study also used the ideal adsorbed solution theory (IAST) to predict CO2 selectivity over other gases (CH4 and N2).

Two Sustainable Pathways of MOF-Catalyzed Room Temperature Chemical Fixation of CO2 inside Alkynes under Atmospheric Pressure

The rising atmospheric CO2 levels necessitate the development of effective materials for its mitigation. Utilization of adsorbent materials for the reversible physisorption of CO2 has a significantly less impact. Recognizing this need, herein, we present a nitrogen-rich, aqua-stable, Ag(0)-nanoparticle-doped metal-organic framework (MOF) designed for the irreversible chemical conversion of CO2 into valuable fine chemicals. We demonstrate two sustainable pathways for CO2 fixation, utilizing the catalyst, 1'@Ag NPs. The designed catalyst facilitates the cyclization of propargylic amines and alcohols under ambient temperature and pressure conditions. Remarkably, this is the first MOF-based catalyst that allows for quantitative conversion of propargylic amines into 2-oxazolidinones at room temperature with atmospheric CO2 pressure. The process successfully transforms various propargylic amines and alcohols into 2-oxazolidinones and α-alkylidene cyclic carbonates under the CO2 atmosphere. Additionally, the catalyst shows excellent recyclability, maintaining its activity and structural integrity across multiple reuse cycles. Control experiments revealed that the catalytic efficiency of 1'@Ag NPs is attributed to the highly exposed alkynophilic Ag(0) sites on its pore walls. Computational studies further elucidate the mechanistic pathway for CO2 fixation. This work highlights the potential of 1'@Ag NPs to enhance environmental sustainability by converting CO2 into valuable bioactive chemicals under mild conditions.

Porous liquids: a novel porous medium for efficient carbon dioxide capture

Porous liquids (PLs) are the combination of porous solid material and flowing liquid, which provides alternative options to solve difficulties in the development of porous solids. With the booming development of PLs since 2015, plenty of syntheses and applications have been reported with a specific focus on gas adsorption. Given the lack of a comprehensive review, this paper reviews the application of PLs in CO2 capture. To start with, ground-breaking case studies are reviewed to help understand the progress of PLs research. Then, as a major part of this paper, studies of PLs for CO2 capture are reviewed separately. Moreover, five basic properties of porous liquids, including stability, viscosity, selectivity, porosity, capacity, and the influencing factors are systemically reviewed respectively. Furthermore, gas storage and release mechanisms in PLs are briefly outlined, and potential processing methods of PLs used for CO2 capture are discussed.

Leveraging experimental and computational tools for advancing carbon capture adsorbents research

CO2 emissions have been steadily increasing and have been a major contributor for climate change compelling nations to take decisive action fast. The average global temperature could reach 1.5 °C by 2035 which could cause a significant impact on the environment, if the emissions are left unchecked. Several strategies have been explored of which carbon capture is considered the most suitable for faster deployment. Among different carbon capture solutions, adsorption is considered both practical and sustainable for scale-up. But the development of adsorbents that can exhibit satisfactory performance is typically done through the experimental approach. This hit and trial method is costly and time consuming and often success is not guaranteed. Machine learning (ML) and other computational tools offer an alternate to this approach and is accessible to everyone. Often, the research towards materials focuses on maximizing its performance under simulated conditions. The aim of this study is to present a holistic view on progress in material research for carbon capture and the various tools available in this regard. Thus, in this review, we first present a context on the workflow for carbon capture material development before providing various machine learning and computational tools available to support researchers at each stage of the process. The most popular application of ML models is for predicting material performance and recommends that ML approaches can be utilized wherever possible so that experimentations can be focused on the later stages of the research and development.

Supramolecular Complexation-Enhanced CO2 Chemisorption in Amine-Derived Sorbents

A supramolecular complexation approach is developed to improve the CO2 chemisorption performance of solvent-lean amine sorbents. Operando spectroscopy techniques reveal the formation of carbamic acid in the presence of a crown ether. The reaction pathway is confirmed by theoretical simulation, in which the crown ether acts as a proton acceptor and shuttle to drive the formation and stabilization of carbamic acid. Improved CO2 capacity and diminished energy consumption in sorbent regeneration are achieved.

Adsorption Modeling Based on Classical Density Functional Theory and PC-SAFT: Temperature Extrapolation and Fluid Transfer

Adsorption is at the heart of many processes from gas separation to cooling. The design of adsorption-based processes requires equilibrium adsorption properties. However, data for adsorption equilibria are limited, and therefore, a model is desirable that uses as little data as possible for its parametrization, while allowing for data interpolation or even extrapolation. This work presents a physics-based model for adsorption isotherms and other equilibrium adsorption properties. The model is based on one-dimensional classical density functional theory (1D-DFT) and the perturbed-chain statistical associating fluid theory (PC-SAFT). The physical processes inside the pores are considered in a thermodynamically consistent approach that is computationally efficient. Once parametrized with a single isotherm, the model is able to extrapolate to other temperatures and outperforms the extrapolation capabilities of state-of-the-art models, such as the empirical isotherm models from Langmuir or Toth. Furthermore, standard combining rules can be used to transfer parameters adjusted to an adsorbent/fluid pair to other fluids. These features are demonstrated for the adsorption of N2, CH4, and CO2 in metal-organic frameworks. Thereby, the presented model can calculate temperature-dependent isotherms for various fluids by using data limited to a single isotherm as input.

Engineered lignocellulosic based biochar to remove endocrine-disrupting chemicals: Assessment of binding mechanism

The safety and health of aquatic organisms and humans are threatened by the increasing presence of pollutants in the environment. Endocrine disrupting chemicals are common pollutants which affect the function of endocrine and causes adverse effects on human health. These chemicals can disrupt metabolic processes by interacting with hormone receptors upon consumptions by humans or aquatic species. Several studies have reported the presence of endocrine disrupting chemicals in waterbodies, food, air and soil. These chemicals are associated with increasing occurrence of obesity, metabolic disorders, reproductive abnormalities, autism, cancer, epigenetic variation and cardiovascular risk. Conventional treatment processes are expensive, not environment friendly and unable to achieve complete removal of these harmful chemicals. In recent years, biochar from different sources has gained a considerable interest due to their adsorption efficiency with porous structure and large surface areas. biochar derived from lignocellulosic biomass are widely used as sustainable catalysts in soil remediation, carbon sequestration, removal of organic and inorganic pollutants and wastewater treatment. This review conceptualizes the production techniques of biochar from lignocellulosic biomass and explores the functionalization and interaction of biochar with endocrine-disrupting chemicals. This review also identifies the further needs of research. Overall, the environmental and health risks of endocrine-disrupting chemicals can be dealt with by biochar produced from lignocellulosic biomass as a sustainable and prominent approach.

Mesoporous Fe3O4/SiO2/poly(2-carboxyethyl acrylate) composite polymer particles for pH-responsive loading and targeted release of bioactive molecules

pH-responsive polymer microspheres undergoing reversible changes in their surface properties have been proved useful for drug delivery to targeted sites. This paper is aimed at preparing pH-responsive polymer-modified magnetic mesoporous SiO2 particles. First, mesoporous magnetic (Fe3O4) core-particles are prepared using a one-pot solvothermal method. Then, magnetic Fe3O4 particles are covered with a C[double bond, length as m-dash]C functional mesoporous SiO2 layer before seeded emulsion polymerization of 2-carboxyethyl acrylate (2-CEA). The composite polymer particles are named Fe3O4/SiO2/P(2-CEA). The average diameters of the Fe3O4 core and Fe3O4/SiO2/P(2-CEA) composite polymer particles are 414 and 595 nm, respectively. The mesoporous (pore diameter = 3.41 nm) structure of Fe3O4/SiO2/P(2-CEA) composite polymer particles is confirmed from Brunauer-Emmett-Teller (BET) surface analysis. The synthesized Fe3O4/SiO2/P(2-CEA) composite polymer exhibited pH-dependent changes in volume and surface charge density due to deprotonation of the carboxyl group under alkaline pH conditions. The change in the surface properties of Fe3O4/SiO2/P(2-CEA) composite polymer particles following pH change is confirmed from the pH-dependent sorption of cationic methylene blue (MB) and anionic methyl orange (MO) dye molecules. The opening of the pH-responsive P(2-CEA) gate valve at pH 10.0 allowed the release of loaded vancomycin up to 99% after 165 min and p-acetamido phenol (p-AP) up to 46% after 225 min. Comparatively, the amount of release is lower at pH 8.0 but still suitable for drug delivery applications. These results suggested that the mesoporous Fe3O4/SiO2 composite seed acted as a microcapsule, while P(2-CEA) functioned as a gate valve across the porous channel. The prepared composite polymer can therefore be useful for treating intestine/colon cancer, where the pH is comparatively alkaline.

Mechanochemical Synthesis of MOF-303 and Its CO2 Adsorption at Ambient Conditions

Metal-organic structures have great potential for practical applications in many areas. However, their widespread use is often hindered by time-consuming and expensive synthesis procedures that often involve hazardous solvents and, therefore, generate wastes that need to be remediated and/or recycled. The development of cleaner, safer, and more sustainable synthesis methods is extremely important and is needed in the context of green chemistry. In this work, a facile mechanochemical method involving water-assisted ball milling was used for the synthesis of MOF-303. The obtained MOF-303 exhibited a high specific surface area of 1180 m2/g and showed an excellent CO2 adsorption capacity of 9.5 mmol/g at 0 °C and under 1 bar.

Research on carbon dioxide capture materials used for carbon dioxide capture, utilization, and storage technology: a review

In recent years, climate change has increasingly become one of the major challenges facing mankind today, seriously threatening the survival and sustainable development of mankind. Dramatically increasing carbon dioxide concentrations are thought to cause a severe greenhouse effect, leading to severe and sustained global warming, associated climate instability and unwelcome natural disasters, melting glaciers and extreme weather patterns. The treatment of flue gas from thermal power plants uses carbon capture, utilization, and storage (CCUS) technology, one of the most promising current methods to accomplish significant CO2 emission reduction. In order to implement the technological and financial system of CO2 capture, which is the key technology of CCUS technology and accounts for 70-80% of the overall cost of CCUS technology, it is crucial to create more effective adsorbents. Nowadays, with the development and application of various carbon dioxide capture materials, it is necessary to review and summarize carbon dioxide capture materials in time. In this paper, the main technologies of CO2 capture are reviewed, with emphasis on the latest research status of CO2 capture materials, such as amines, zeolites, alkali metals, as well as emerging MOFs and carbon nanomaterials. More and more research on CO2 capture materials has used a variety of improved methods, which have achieved high CO2 capture performance. For example, doping of layered double hydroxides (LDH) with metal atoms significantly increases the active site on the surface of the material, which has a significant impact on improving the CO2 capture capacity and performance stability of LDH. Although many carbon capture materials have been developed, high cost and low technology scale remain major obstacles to CO2 capture. Future research should focus on designing low-cost, high-availability carbon capture materials.

Utilizing Gelatin Waste for Efficient Bimodal Porous Silica Adsorbents for Carbon Dioxide Capture

This study explores the modification of pore structures in porous silica materials synthesized using sodium silicate and waste gelatin, under varying silica-to-gelatin ratios. At ratios of 1.0-1.5, bimodal porous silica with mesopores and macropores emerged due to spaces between silica nanoparticles and clusters, following gelatin elimination. The study further evaluated the obtained bimodal porous silica as polyethyleneimine (PEI) supports for CO2 capture, alongside PEI-loaded unimodal porous silica and hollow silica sphere for comparison. Notably, the PEI-loaded bimodal silica showcased superior CO2 uptake, achieving 145.6 mg g-1 at 90 °C. Transmission electron microscopy (TEM) revealed PEI's uniform distribution within the pores of bimodal silica, unlike the excessive surface layering seen in unimodal silica. Conversely, PEI completely filled the hollow porous silica's interior, extending gas molecule diffusion distance. All sorbents displayed nearly constant CO2 adsorption across 20 cycles, demonstrating outstanding stability. Notably, the bimodal porous silica displayed a negligible capacity loss, underscoring its robust performance.

Breakthrough applications of porous organic materials for membrane-based CO2 separation: a review

Over the last decades, porous organic materials (POMs) have been extensively employed in various industrial approaches including gas separation, catalysis and energy production due to possessing indisputable advantages like great surface area, high permeability, controllable pore size, appropriate functionalization and excellent processability compared to traditional substances like zeolites, Alumina and polymers. This review presents the recent breakthroughs in the multifunctional POMs for potential use in the membrane-based CO2 separation. Some examples of highly-selective membranes using multifunctional POMs are described. Moreover, various classifications of POMs following with their advantages and disadvantages in CO2 separation processes are explained. Apart from reviewing the state-of-the-art POMs in CO2 separation, the challenges/limitations of POMs with tailored structures for reasonable application are discussed.

The emergence of nanocellulose aerogels in CO2 adsorption

Mitigating the effect of climate change toward a sustainable development is one of the main challenges of our century. The emission of greenhouse gases, especially carbon dioxide (CO2), is a leading cause of the global warming crisis. To address this issue, various sustainable strategies have been formulated for CO2 capture. Renewable nanocellulose aerogels have risen as a highly attractive candidate for CO2 capture thanks to their porous and surface-tunable nature. Nanocellulose offer distinctive characteristics, including significant aspect ratios, exceptional biodegradability, lightweight nature, and the ability for chemical modification due to the abundant presence of hydroxyl groups. In this review, recent research studies on nanocellulose-based aerogels designed for CO2 absorption have been highlighted. The state-of-the-art of nanocellulose-based aerogel has been thoroughly assessed, including their synthesis, drying methods, and characterization techniques. Additionally, discussions were held about the mechanisms of CO2 adsorption, the effects of the porous structure, surface functionalization, and experimental parameters. Ultimately, this synthesis review provides an overview of the achieved adsorption rates using nanocellulose-based aerogels and outlines potential improvements that could lead to optimal adsorption rates. Overall, this research holds significant promise for tackling the challenges of climate change and contributing to a more sustainable future.

Green Synthesis and Efficient Adsorption: Na-X Zeolite vs. C/Mn/SiO2 Composite for Heavy Metals Removal

The studies aimed to test the adsorption capacity of two silica-enriched porous materials, synthetic Na-X zeolite and Mn-containing carbon composite, towards Pb(II) and Zn(II) ions in single and mixed systems and in the presence of diclofenac (DCF) and (or) poly(acrylic acid) (PAA). The synthetic zeolite was characterized by a well-developed surface area of 728 m2/g and a pore diameter of 1.73 nm, while the carbon composite exhibited 268 m2/g and 7.37 nm, respectively. Na-X was found to be more efficient than the carbon composite (75-212 mg/g) in adsorbing heavy metal ions in both single and bimetallic systems (322-333 mg/g). In turn, the C/Mn/SiO2 composite was more effective in removing Pb(II) ions from the systems that simultaneously contained DCF or PAA (480 and 476 mg/g, respectively). The Na-X zeolite demonstrated the greatest stability in all the systems studied. The highest stability was observed in the DCF + Pb(II) mixture, in contrast to the carbon composites where the stability was much lower. To evaluate the possibility of regeneration of the solids, HCl proved to be the best desorbent for heavy metal ions (efficiency of 99%). In general, both adsorbents offer promising potential for solving environmental problems.

Accelerated Discovery of Metal-Organic Frameworks for CO2 Capture by Artificial Intelligence

The existence of a very large number of porous materials is a great opportunity to develop innovative technologies for carbon dioxide (CO2) capture to address the climate change problem. On the other hand, identifying the most promising adsorbent and membrane candidates using iterative experimental testing and brute-force computer simulations is very challenging due to the enormous number and variety of porous materials. Artificial intelligence (AI) has recently been integrated into molecular modeling of porous materials, specifically metal-organic frameworks (MOFs), to accelerate the design and discovery of high-performing adsorbents and membranes for CO2 adsorption and separation. In this perspective, we highlight the pioneering works in which AI, molecular simulations, and experiments have been combined to produce exceptional MOFs and MOF-based composites that outperform traditional porous materials in CO2 capture. We outline the future directions by discussing the current opportunities and challenges in the field of harnessing experiments, theory, and AI for accelerated discovery of porous materials for CO2 capture.

A novel approach to environmental pollution management/remediation techniques using derived advanced materials

The carbon dioxide (CO2) crisis is one of the world's most urgent issues. Meeting the worldwide targets set for CO2 capture and storage (CCS) is crucial. Because it may significantly reduce energy consumption compared to traditional amine-based adsorption capture, adsorption dependant CO2 capture is regarded as one of the most hopeful techniques in this paradigm. The expansion of unique, critical edge adsorbent materials has received most of the research attention to date, with the main objective of improving adsorption capacity and lifespan while lowering the temperature of adsorption, thereby lowering the energy demand of sorbent revival. There are specific materials needed for each step of the carbon cycle, including capture, regeneration, and conversion. The potential and efficiency of metal-organic frameworks (MOFs) in overcoming this obstacle have recently been proven through research. In this study, we pinpoint MOFs' precise structural and chemical characteristics that have contributed to their high capture capacity, effective regeneration and separation processes, and efficient catalytic conversions. As prospective materials for the next generation of energy storage and conversion applications, carbon-based compounds like graphene, carbon nanotubes, and fullerenes are receiving a lot of interest. Their distinctive physicochemical characteristics make them suitable for these popular study topics, including structural stability and flexibility, high porosity, and customizable physicochemical traits. It is possible to precisely design the interior of MOFs to include coordinatively unsaturated metal sites, certain heteroatoms, covalent functionalization, various building unit interactions, and integrated nanoscale metal catalysts. This is essential for the creation of MOFs with improved performance. Utilizing the accuracy of MOF chemistry, more complicated materials must be built to handle selectivity, capacity, and conversion all at once to achieve a comprehensive solution. This review summarizes, the most recent developments in adsorption-based CO2 combustion capture, the CO2 adsorption capacities of various classes of solid sorbents, and the significance of advanced carbon nanomaterials for environmental remediation and energy conversion. This review also addresses the difficulties and potential of developing carbon-based electrodes for energy conversion and storage applications.

From grape bagasse to graphene-like porous carbon nanosheets for CO2 capture

Graphene-based materials have increasingly attracted attention in recent years. It is a material is recognized worldwide due to its numerous applications in several sectors. However, graphene production involves several challenges: scalability, high costs, and high-quality production. This study synthesized graphene-like porous carbon nanosheets (GPCNs) through a thermochemical process under a nitrogen atmosphere using grape bagasse as a precursor. Three temperatures (700, 800, and 900 ºC) of the pyrolysis process were studied. Chemical graphitization and activation were used to form high-specific surface area materials: FeCl3.6H2O(aq) and ZnCl2(s) in a simultaneous activation-graphitization (SAG) method. The materials obtained (GPCN700, GPCN800, and GPCN900) were compared to previously produced chars (C700, C800, and C900). A high specific surface area and total pore volume were obtained for GPCN materials, and GPCN900 presented the highest values: 1062.7 m2g-1 and 0.635 cm3 g-1, respectively. The GPCN and char materials were classified as mesoporous and applied as adsorbents for CO2(g). The GPCN800 presented the best CO2(g) adsorbent, with a CO2(g) adsorption capacity of 168.71 mg g-1.

Ionic Liquids Hybridization for Carbon Dioxide Capture: A Review

CO2 absorption has been driven by the need for efficient and environmentally sustainable CO2 capture technologies. The development in the synthesis of ionic liquids (ILs) has attracted immense attention due to the possibility of obtaining compounds with designated properties. This allows ILs to be used in various applications including, but not limited to, biomass pretreatment, catalysis, additive in lubricants and dye-sensitive solar cell (DSSC). The utilization of ILs to capture carbon dioxide (CO2) is one of the most well-known processes in an effort to improve the quality of natural gas and to reduce the green gases emission. One of the key advantages of ILs relies on their low vapor pressure and high thermal stability properties. Unlike any other traditional solvents, ILs exhibit high solubility and selectivity towards CO2. Frequently studied ILs for CO2 absorption include imidazolium-based ILs such as [HMIM][Tf2N] and [BMIM][OAc], as well as ILs containing amine groups such as [Cho][Gly] and [C1ImPA][Gly]. Though ILs are being considered as alternative solvents for CO2 capture, their full potential is limited by their main drawback, namely, high viscosity. Therefore, the hybridization of ILs has been introduced as a means of optimizing the performance of ILs, given their promising potential in capturing CO2. The resulting hybrid materials are expected to exhibit various ranges of chemical and physical characteristics. This review presents the works on the hybridization of ILs with numerous materials including activated carbon (AC), cellulose, metal-organic framework (MOF) and commercial amines. The primary focus of this review is to present the latest innovative solutions aimed at tackling the challenges associated with IL viscosity and to explore the influences of ILs hybridization toward CO2 capture. In addition, the development and performance of ILs for CO2 capture were explored and discussed. Lastly, the challenges in ILs hybridization were also being addressed.

Dolomite industrial by-products as active material for CO2 adsorption and catalyst for the acetone condensation

The feasibility of using dolomite powders, by-product from the refractory industry, as a CO2 adsorbent and as a catalyst for the acetone liquid-phase self-condensation is demonstrated in this article. The performance of this material can be largely improved by combining physical pretreatments (hydrothermal ageing, sonication) and thermal activation at different temperatures (500-800 °C). The highest CO2 adsorption capacity was observed for the sample after sonication and activated at 500 °C (46 mg·g-1). As to the acetone condensation, the best results were obtained also with the sonicated dolomites, mainly after activation at 800 °C (17.4% of conversion after 5 h at 120 °C). The kinetic model reveals that this material optimizes the equilibrium between catalytic activity (proportional to the total basicity) and deactivation by water (specific adsorption process). These results demonstrate that the valorisation of dolomite fines is feasible, proposing attractive pretreatments for obtaining activated materials with promising results as adsorbents and basic catalysts.

Carbon Capture Using Porous Silica Materials

As the primary greenhouse gas, CO₂ emission has noticeably increased over the past decades resulting in global warming and climate change. Surprisingly, anthropogenic activities have increased atmospheric CO₂ by 50% in less than 200 years, causing more frequent and severe rainfall, snowstorms, flash floods, droughts, heat waves, and rising sea levels in recent times. Hence, reducing the excess CO₂ in the atmosphere is imperative to keep the global average temperature rise below 2 °C. Among many CO₂ mitigation approaches, CO₂ capture using porous materials is considered one of the most promising technologies. Porous solid materials such as carbons, silica, zeolites, hollow fibers, and alumina have been widely investigated in CO₂ capture technologies. Interestingly, porous silica-based materials have recently emerged as excellent candidates for CO₂ capture technologies due to their unique properties, including high surface area, pore volume, easy surface functionalization, excellent thermal, and mechanical stability, and low cost. Therefore, this review comprehensively covers major CO₂ capture processes and their pros and cons, selecting a suitable sorbent, use of liquid amines, and highlights the recent progress of various porous silica materials, including amine-functionalized silica, their reaction mechanisms and synthesis processes. Moreover, CO₂ adsorption capacities, gas selectivity, reusability, current challenges, and future directions of porous silica materials have also been discussed.

Optimized Pore Nanospace through the Construction of a Cagelike Metal-Organic Framework for CO2/N2 Separation

The development of metal-organic framework (MOF) adsorbents with a potential molecule sieving effect for CO₂ capture and separation from flue gas is of critical importance for reducing the CO₂ emissions to the atmosphere yet challenging. Herein, a cagelike MOF with a suitable cage window size falling between CO₂ and N₂ and the cavity has been constructed to evaluate its CO₂/N₂ separation performance. It is noteworthy that the introduction of coordinated dimethylamine (DMA) and N,N'-dimethylformamide (DMF) molecules not only significantly reduces the cage window size but also enhances the framework-CO₂ interaction via C-H···O hydrogen bonds, as proven by molecular modeling, thus leading to an improved CO₂ separation performance. Moreover, transient breakthrough experiments corroborate the efficient CO₂/N₂ separation, revealing that the introduction of DMA and DMF molecules plays a vital role in the separation of a CO₂/N₂ gas mixture.

CO2 Adsorption on Natural Zeolites from Puebla, México, by Inverse Gas Chromatography

The applicability of clinoptilolite zeolites in controlling the emission of greenhouse gases (GHGs) such as CO2, the most significant GHG, is investigated herein. In this research, Mexican natural zeolites (ATN) originating from an Atzinco deposit in the state of Puebla were used. Samples of modified clinoptilolite (ATH4, ATH3, ATH2 and ATH1) were obtained from the starting material by acid treatment of various intensities. Inverse gas chromatography was used to evaluate CO2 adsorption in clinoptilolite, natural and chemically modified. Adsorption of CO2 was investigated in the temperature range of 433–573 K, using a TCD detector, and He as a carrier gas. The experimental CO2 adsorption data were processed by Freundlich and Langmuir equations. The degree of interaction between CO2 and the dealuminated clinoptilolite samples was examined through the evaluation of the isosteric enthalpy of adsorption. This calculation was made by using the Clausius–Clapeyron equation, which established the following sequence: ATH1 > ATH2 > ATH4 > ATN > ATH3. The nanoporosity of these clinoptolite zeolites from new deposit in sedimentary rocks was studied through HRADS adsorption of N2. Simultaneously, these zeolites were, respectively, characterized by XRD, EDS, and SEM. Micropores are described by the Dubinin–Asthakov distribution. Various adsorption mechanisms that occur in these nanoporous materials at different relative pressures can be visualized. The quantitative determination of starting mineral is described as: Ca-Clinoptilolite (88.76%) >> Montmorillonite (11.11%) >> quartz (0.13%). The Si/Al molar ratio after acid treatment is: ATH4 > ATH2 > ATN > ATH3 > ATH1. The Langmuir specific surface area (ASL) varies as follows: ATN > ATH2 > ATH4 > ATH3 > ATH1. At the same time, the VΣ values are as follows: ATN > ATH4 > ATH3 > ATH1 > ATH2.

An Upper Bound Visualization of Design Trade-Offs in Adsorbent Materials for Gas Separations: CO2 , N2 , CH4 , H2 , O2 , Xe, Kr, and Ar Adsorbents

The last 20 years have seen many publications investigating porous solids for gas adsorption and separation. The abundance of adsorbent materials (this work identifies 1608 materials for CO2 /N2 separation alone) provides a challenge to obtaining a comprehensive view of the field, identifying leading design strategies, and selecting materials for process modeling. In 2021, the empirical bound visualization technique was applied, analogous to the Robeson upper bound from membrane science, to alkane/alkene adsorbents. These bound visualizations reveal that adsorbent materials are limited by design trade-offs between capacity, selectivity, and heat of adsorption. The current work applies the bound visualization to adsorbents for a wider range of gas pairs, including CO2 , N2 , CH4 , H2 , Xe, O2 , and Kr. How this visual tool can identify leading materials and place new material discoveries in the context of the wider field is presented. The most promising current strategies for breaking design trade-offs are discussed, along with reproducibility of published adsorption literature, and the limitations of bound visualizations. It is hoped that this work inspires new materials that push the bounds of traditional trade-offs while also considering practical aspects critical to the use of materials on an industrial scale such as cost, stability, and sustainability.

Thermally Induced Phase Transition of Cubic Structure II Hydrate: Crystal Structures of Tetrahydropyran-CO2 Binary Hydrate

We report a thermally induced phase transition of cubic structure II hydrates of tetrahydropyran (THP) and CO₂ below about 140 K. The phase transition was characterized by powder X-ray diffraction measurements at variable temperatures. A dynamical ordering of the CO₂ guests in small pentagonal dodecahedral 5¹² host water cages, not previously observed in the simple CO₂ hydrate, occurs simultaneously with the symmetry lowering transition from a cubic structure II (space group Fd-3m with cell dimensions a = 17.3202(7) Å at 153 K) to a tetragonal (space group I4₁/amd with cell dimensions a = 17.484(4) Å and c = 12.145(1) Å at 138 K) unit cell. The effect of guest molecules on the phase transition at low temperatures is discussed, which demonstrates that the clathrate hydrate structures and thermodynamic properties can be modified by adjusting the size and chemical structure of larger and smaller guest molecules.

Regulation of the Si/Al ratios and Al distributions of zeolites and their impact on properties

Zeolites are typically a class of crystalline microporous aluminosilicates that are constructed by SiO4 and AlO4 tetrahedra. Because of their unique porous structures, strong Brönsted acidity, molecular-level shape selectivity, exchangeable cations, and high thermal/hydrothermal stability, zeolites are widely used as catalysts, adsorbents, and ion-exchangers in industry. The activity, selectivity, and stability/durability of zeolites in applications are closely related to their Si/Al ratios and Al distributions in the framework. In this review, we discussed the basic principles and the state-of-the-art methodologies for regulating the Si/Al ratios and Al distributions of zeolites, including seed-assisted recipe modification, interzeolite transformation, fluoride media, and usage of organic structure-directing agents (OSDAs), etc. The conventional and newly developed characterization methods for determining the Si/Al ratios and Al distributions were summarized, which include X-ray fluorescence spectroscopy (XRF), solid state 29Si/27Al magic-angle-spinning nuclear magnetic resonance spectroscopy (29Si/27Al MAS NMR), Fourier-transform infrared spectroscopy (FT-IR), etc. The impact of Si/Al ratios and Al distributions on the catalysis, adsorption/separation, and ion-exchange performance of zeolites were subsequently demonstrated. Finally, we presented a perspective on the precise control of the Si/Al ratios and Al distributions of zeolites and the corresponding challenges.

Epoxy-functionalized polyethyleneimine modified epichlorohydrin-cross-linked cellulose aerogel as adsorbents for carbon dioxide capture

Developing affordable and effective carbon dioxide (CO₂) capture technology has attracted substantial intense attention due to the continued growth of global CO₂ emissions. The low-cost and biodegradable cellulosic materials are developed into CO₂ adsorbent recently. Epoxy-functionalized polyethyleneimine modified epichlorohydrin-cross-linked cellulose aerogel (EBPCa) was synthesized from alkaline cellulose solution, epoxy-functionalized polyethyleneimine (EB-PEI), and epichlorohydrin (ECH) through the freezing-thawing processes and freeze-drying. The Fourier transform infrared spectroscopy confirmed that the cellulose aerogel was successfully modified by EB-PEI. The X-ray photoelectron spectroscopy analyses confirmed the presence of N 1s and Cl 2p in EBPCa, meaning that the chlorine of ECH and the amino groups of EB-PEI exist in the cellulose surface. The obtained sample has a rich porous structure with a specific surface area in the range of 97.5-149.5 m²/g. Owing to its uniformly three-dimensional porous structure, the sample present preferable rigidity and carrying capacity, which 1 g of sample could easily carry the weight of a 3000 ml Erlenmeyer flask filled with water (total 4 kg). The sample showed good adsorption performance, with a maximum adsorption capacity of 6.45 mmol/g. This adsorbent has broad prospects in the CO₂ capture process.

Zinc(II) Carboxylate Coordination Polymers with Versatile Applications

This review considers the applications of Zn(II) carboxylate-based coordination polymers (Zn-CBCPs), such as sensors, catalysts, species with potential in infections and cancers treatment, as well as storage and drug-carrier materials. The nature of organic luminophores, especially both the rigid carboxylate and the ancillary N-donor bridging ligand, together with the alignment in Zn-CBCPs and their intermolecular interaction modulate the luminescence properties and allow the sensing of a variety of inorganic and organic pollutants. The ability of Zn(II) to act as a good Lewis acid allowed the involvement of Zn-CBCPs either in dye elimination from wastewater through photocatalysis or in pathogenic microorganism or tumor inhibition. In addition, the pores developed inside of the network provided the possibility for some species to store gaseous or liquid molecules, as well as to deliver some drugs for improved treatment.

Microporous Polymelamine Framework Functionalized with Re(I) Tricarbonyl Complexes for CO2 Absorption and Reduction

A mixture of polymeric complexes based on the reaction between Re(CO)₅Cl and the porous polymeric network coming from the coupling of melamine and benzene-1,3,5-tricarboxaldehyde was obtained and characterized by FTIR, NMR, SEM, XPS, ICP, XRD, and cyclic voltammetry (CV). The formed rhenium-based porous hybrid material reveals a noticeable capability of CO₂ absorption. The gas absorption amount measured at 295 K was close to 44 cm³/g at 1 atm. An interesting catalytic activity for CO₂ reduction reaction (CO₂RR) is observed, resulting in a turn over-number (TON) close to 6.3 under 80 min of test at -1.8 V vs. Ag/AgCl in a TBAPF₆ 0.1 M ACN solution. A possible use as filler in membranes or columns can be envisaged.

Photocurable 3D-Printable Systems with Controlled Porosity towards CO2 Air Filtering Applications

Porous organic polymers are versatile platforms, easily adaptable to a wide range of applications, from air filtering to energy devices. Their fabrication via vat photopolymerization enables them to control the geometry on a multiscale level, obtaining hierarchical porosity with enhanced surface-to-volume ratio. In this work, a photocurable ink based on 1,6 Hexanediol diacrylate and containing a high internal phase emulsion (HIPE) is presented, employing PLURONIC F-127 as a surfactant to generate stable micelles. Different parameters were studied to assess the effects on the morphology of the pores, the printability and the mechanical properties. The tests performed demonstrates that only water-in-oil emulsions were suitable for 3D printing. Afterwards, 3D complex porous objects were printed with a Digital Light Processing (DLP) system. Structures with large, interconnected, homogeneous porosity were fabricated with high printing precision (300 µm) and shape fidelity, due to the addition of a Radical Scavenger and a UV Absorber that improved the 3D printing process. The formulations were then used to build scaffolds with complex architecture to test its application as a filter for CO₂ absorption and trapping from environmental air. This was obtained by surface decoration with NaOH nanoparticles. Depending on the surface coverage, tested specimens demonstrated long-lasting absorption efficiency.

Understanding the effect of the divalent cations (Ni, Cu, and Zn) exchanged FAU zeolite on the kinetic of CO2 cycloaddition with ethylene oxide: A DFT study

Epoxide ring opening and cycloaddition with CO₂ is one of the promising routes to convert CO₂ to more valuable industrial chemicals. In this work, density functional theory calculations with the M06-L/6-31G(d,p) level of theory have been employed to study the cycloaddition of ethylene oxide (EO) with CO₂ over M(II)-faujasite zeolite (M = Ni, Cu, and Zn) in the absence of a co-catalyst. The influence of the exchanged metals strongly dominates the adsorption of EO. The binding energies of EO on the active site are -39.9 (Ni-FAU), -24.2 (Cu-FAU), and -35.0 (Zn-FAU) kcal/mol, respectively. The reaction mechanism is proposed to occur via the concerted mechanism, in which the metals initiate the EO ring opening and the formation of two new C-O bonds between the adsorbed EO and CO₂ proceed in a single step. The activation energy of the reaction catalyzed by Cu-FAU is 24.2 kcal/mol whereas that of Ni and Zn-FAU is found to be 31.1 and 31.4 kcal/mol, respectively. Moderate adsorption of EO and a larger electron transfer at the transition state are the important keys that reduce the activation energy for the Cu-FAU lower than in the other systems.

One-Step Synthesis of 3D Pore-Structured Adsorbent by Cross-Linked PEI and Graphene Oxide Sheets and Its Application in CO2 Adsorption

In this study, a one-step method of polyethylenimine (PEI) cross-linking graphene oxide (GO) was used to prepare a 3D pore-structured adsorbent with abundant amine groups for chemisorption of CO₂. The cross-linking of PEI with GO sheets and the vacuum freeze-drying step are the keys to the formation of the 3D pore structure. The results of characterization analysis revealed that the as-prepared adsorbent had a 3D porous structure rich in amine groups. Besides, the adsorption/desorption test showed that the prepared adsorbent has excellent and stable adsorption performance, and the maximum CO₂ adsorption capacity is 2.18 mmol/g at 343 K and 10 vol % CO₂. Moreover, the adsorption kinetics analysis indicated that the adsorption process was dominated by homogeneous adsorption, and the adsorbent had a strong affinity with CO₂. Finally, the correlation analysis shows that the kinetic constants obtained by the Avrami model simulation can be effectively used for the actual CO₂ adsorption process design.

Using carbon dioxide-added microalgal-bacterial granular sludge for carbon-neutral municipal wastewater treatment under outdoor conditions: Performance, granule characteristics and environmental sustainability

Microalgal-bacterial granular sludge (MBGS) process has a gorgeous prospect for municipal wastewater treatment, but the research on the treatment of complex organic wastewater by MBGS process with CO₂ addition under outdoor conditions is not enough. Therefore, this paper evaluated the feasibility of CO₂-added MBGS process for complex organic wastewater disposal under natural day-night cycles. The results showed that the addition of CO₂ overall improved the removal efficiency of pollutants. Typically, the removal efficiency of total phosphorus increased averagely from 88.5 % to 95.0 % in 12-h day cycle and from 26.2 % to 45.3 % in 12-h night cycle. The addition of CO₂ increased the size of MBGS from 1.0 mm to 16.5 mm within 30 days due to extracellular polymeric substances secretion and the dominant filamentous microalgae on granules. The decrease of catalase activity and malondialdehyde content indicated that CO₂ reduced oxidative damage and maintained the normal growth of MBGS. Further estimates of the collected gas showed that CO₂-added MBGS process could reduce global CO₂ emissions by one hundred million tons per year. This study is expected to contribute to the goal of carbon neutrality in the area of wastewater treatment by MBGS process.

Comparison of three different structures of zeolites prepared by template-free hydrothermal method and its CO2 adsorption properties

In this study, zeolite sodalite SOD (50NaO₂:Al₂O₃:5SiO₂), zeolite LTA (2NaO₂:Al₂O₃:1.926SiO₂) and zeolite FAU (16NaO₂:Al₂O₃:4SiO₂) of different structures were synthesized successfully through simple conventional hydrothermal crystallization technique without using any template agent. Morphological analysis of three different types of zeolites revealed that the samples exhibit three different shapes such as the "Raspberry-like", "Dice" cube like and "Octahedral" shaped morphology respectively. The thermal stability was found to be about 4.8%, 14.6% and 20.5% for the synthesized zeolites SOD, LTA and FAU respectively. From the N₂ adsorption-desorption studies, it was observed that adsorption types IV and I correspond to the synthesized samples. CO₂ adsorption by the synthesized zeolite SOD, LTA and FAU were examined in the pressure range from 0 to 101.325 kPa at a constant temperature of 297.15 K. The highest adsorption capacity of 3.7 mmol/g was obtained for zeolite FAU. The synthesized zeolite was studied using a nonlinear regression curve fit to determine the adsorption isotherm model using Langmuir and Freundlich isotherm model. It has been found that the synthesized zeolites have a large electric field gradient due to which they can strongly adsorb quadrupole of CO₂ molecules.

Porous Structure of β-Cyclodextrin for CO2 Capture: Structural Remodeling by Thermal Activation

With a purpose of extending the application of β-cyclodextrin (β-CD) for gas adsorption, this paper aims to reveal the pore formation mechanism of a promising adsorbent for CO2 capture which was derived from the structural remodeling of β-CD by thermal activation. The pore structure and performance of the adsorbent were characterized by means of SEM, BET and CO2 adsorption. Then, the thermochemical characteristics during pore formation were systematically investigated by means of TG-DSC, in situ TG-FTIR/FTIR, in situ TG-MS/MS, EDS, XPS and DFT. The results show that the derived adsorbent exhibits an excellent porous structure for CO2 capture accompanied by an adsorption capacity of 4.2 mmol/g at 0 °C and 100 kPa. The porous structure is obtained by the structural remodeling such as dehydration polymerization with the prior locations such as hydroxyl bonded to C6 and ring-opening polymerization with the main locations (C4, C1, C5), accompanied by the release of those small molecules such as H2O, CO2 and C3H4. A large amount of new fine pores is formed at the third and fourth stage of the four-stage activation process. Particularly, more micropores are created at the fourth stage. This revealed that pore formation mechanism is beneficial to structural design of further thermal-treated graft/functionalization polymer derived from β-CD, potentially applicable for gas adsorption such as CO2 capture.

One-Pot Synthesis of N-Rich Porous Carbon for Efficient CO2 Adsorption Performance

N-enriched porous carbons have played an important part in CO2 adsorption application thanks to their abundant porosity, high stability and tailorable surface properties while still suffering from a non-efficient and high-cost synthesis method. Herein, a series of N-doped porous carbons were prepared by a facile one-pot KOH activating strategy from commercial urea formaldehyde resin (UF). The textural properties and nitrogen content of the N-doped carbons were carefully controlled by the activating temperature and KOH/UF mass ratios. As-prepared N-doped carbons show 3D block-shaped morphology, the BET surface area of up to 980 m2/g together with a pore volume of 0.52 cm3/g and N content of 23.51 wt%. The optimal adsorbent (UFK-600-0.2) presents a high CO2 uptake capacity of 4.03 mmol/g at 0 °C and 1 bar. Moreover, as-prepared N-doped carbon adsorbents show moderate isosteric heat of adsorption (43-53 kJ/mol), acceptable ideal adsorption solution theory (IAST) selectivity of 35 and outstanding recycling performance. It has been pointed out that while the CO2 uptake was mostly dependent on the textural feature, the N content of carbon also plays a critical role to define the CO2 adsorption performance. The present study delivers favorable N-doped carbon for CO2 uptake and provides a promising strategy for the design and synthesis of the carbon adsorbents.

Facile Synthesis of Mesoporous Silica at Room Temperature for CO2 Adsorption

Although mesoporous silica materials have been widely investigated for many applications, most silica materials are made by calcination processes. We successfully developed a convenient method to synthesize mesoporous materials at room temperature. Although the silica materials made by the two different methods, which are the calcination process and the room-temperature process, have similar specific surface areas, the silica materials produced with the room-temperature process have a significantly larger pore volume. This larger pore volume has the potential to attach to functional groups that can be applied to various industrial fields such as CO₂ adsorption. This mesoporous silica with a larger pore volume was analyzed by TEM, FT-IR, low angle X-ray diffraction, N₂-adsorption analysis, and CO₂ adsorption experiments in comparison with the mesoporous silica synthesized with the traditional calcination method.

A Systematic Review of Amino Acid-Based Adsorbents for CO2 Capture

The rise of carbon dioxide (CO2) levels in the atmosphere emphasises the need for improving the current carbon capture and storage (CCS) technology. A conventional absorption method that utilises amine-based solvent is known to cause corrosion to process equipment. The solvent is easily degraded and has high energy requirement for regeneration. Amino acids are suitable candidates to replace traditional alkanolamines attributed to their identical amino functional group. In addition, amino acid salt is a green material due to its extremely low toxicity, low volatility, less corrosive, and high efficiency to capture CO2. Previous studies have shown promising results in CO2 capture using amino acids salts solutions and amino acid ionic liquids. Currently, amino acid solvents are also utilised to enhance the adsorption capacity of solid sorbents. This systematic review is the first to summarise the currently available amino acid-based adsorbents for CO2 capture using PRISMA method. Physical and chemical properties of the adsorbents that contribute to effective CO2 capture are thoroughly discussed. A total of four categories of amino acid-based adsorbents are evaluated for their CO2 adsorption capacities. The regeneration studies are briefly discussed and several limitations associated with amino acid-based adsorbents for CO2 capture are presented before the conclusion.