Indoor CO2 direct air capture and utilization: Key strategies towards carbon neutrality

Chen Y., Zhang J., Liu H., Wang X., Chen S.

Solid-amine adsorbents are promising CO2 post-combustion adsorption materials to mitigate global warming. As one of the most important evaluation criteria, the CO2 adsorption capacity of the adsorbent was determined by both kinetic and thermodynamic factors, while high temperature is good for mass transfer and low temperature is advantageous for equilibrium to move towards adsorption. In this study, surfactants were added into polyethylenimine (PEI) cryogel to enhance mass transfer and reduce the adsorption temperature, thereby promoting its adsorption capacity. With the addition of polyethylene glycol (PEG200), the CO2 adsorption capacity reached a maximum value of 6.48 mmol/g at 65 °C, and the amine efficiency reached a maximum value of 0.52 mol C/mol N at 45 °C. Further characterization revealed that the addition of PEG not only enhanced the mass transfer, but also changed the chemisorption mechanisms, which were very similar to the effects of water. Besides, PEG would form hydrogen bonds with the PEI polymer network and showed stable regeneration capacity, thereby exhibiting a greater application potential.

Baus L., Nehr S., Maeda N.

Direct air capturing (DAC) is an energy demanding process for CO2-removal from air. Ongoing research focuses on the potential of indoor air as DAC-feed to profit from currently unused energetic synergies between DAC and the built environment. In this work, we investigated the performance of three different readily available, solid DAC-adsorbers under typical indoor environmental conditions of 16-25°C, 25-60% relative humidity (RH), and CO2-concentrations of less than 800 ppm above atmospheric concentrations. The measured mass-specific CO2-adsorption capacities of K2CO3-impregnated activated carbon, polyethylenimine-snow (PEI-snow), and polyethylenimine (PEI) on silica amount to 6.5 ± 0.3   mg   g − 1 , 52.9 ± 4.9   mg   g − 1 , and 56.9 ± 4.2   mg   g − 1 , respectively. Among the three investigated adsorber materials, PEI on silica is the most promising candidate for DAC-applications as its synthesis is rather simple, the CO2-desorption is feasible at moderate conditions of about 80°C at 100 mbar, and the competing co-adsorption of water does not strongly affect the CO2-adsorption under the investigated experimental conditions.

Oloruntobi O., Mokhtar K., Mohd Rozar N., Gohari A., Asif S., Chuah L.F.

This article examines the challenges of implementing the United Nation Sustainable Development Goals 2050 green initiative for warehouse management and operation and highlights a gap in the literature on specific strategies for reducing greenhouse gas emissions and pollution in warehousing and logistics operations. A four-step review process was used to analyze 75 recent research articles on environmental sustainability, smart energy consumption and warehouse green practices. Warehouse building configuration and operation were reviewed to identify critical environmental issues, along with green industrial building legislation in the European Union, the United States and Asia. This study found that increasing warehouse construction and renovations are worsening pollution and industrial waste production, while space demand in the United States will reach 560 × 106 by 2025. Findings showed that packaging waste from warehouses accounted for 12% of the 146.1 × 106 t of municipal solid waste in the United States landfills in 2018 and the industry's growth is increasing indoor and outdoor air pollution. Warehouses' energy consumption is also worsening due to their energy needs. This article proposes green warehouse practices and technologies as potential solutions to mitigate the environmental effects of the industry's growth. Legislation is needed to solve many warehousing issues as global e-commerce grows for better consumer accountability demands and efficiency gains.

Sodiq A., Abdullatif Y., Aissa B., Ostovar A., Nassar N., El-Naas M., Amhamed A.

As the concentration of carbon dioxide (CO2) in the atmosphere continues to rise, and the reality of global warming challenges hits the world, global research societies are developing innovative technologies to address climate change challenges brought about by high atmospheric concentration of CO2. One of such challenges is the direct removal of CO2 from the atmosphere. Among all the currently available CO2 removal technologies, direct air capture (DAC) is positioned to deliver the needed CO2 removal from the atmosphere because it is independent of CO2 emission origin, and the capture machine can be stationed anywhere. Research efforts in the last two decades, however, have identified the system overall energy requirements as the bottleneck to the realization of DAC’s commercialization. As a result, global research community continues to seek better ways to minimize the required energy per ton of CO2 removed via DAC. In this work, the literature was comprehensively reviewed to assess the progress made in DAC, its associated technologies, and the advances made in the state-of-the-art. Thus, it is proposed to use traditional heating, ventilation, and air conditioning (HVAC) system (mainly the air conditioning system), as a preexisting technology, to capture CO2 directly from the atmosphere, such that the energy needed to capture is provided by the HVAC system of choice.

López L.R., Dessì P., Cabrera-Codony A., Rocha-Melogno L., Kraakman B., Naddeo V., Balaguer M.D., Puig S.

In the developed world, individuals spend most of their time indoors. Poor Indoor Air Quality (IAQ) has a wide range of effects on human health. The burden of disease associated with indoor air accounts for millions of premature deaths related to exposure to Indoor Air Pollutants (IAPs). Among them, CO2 is the most common one, and is commonly used as a metric of IAQ. Indoor CO2 concentrations can be significantly higher than outdoors due to human metabolism and activities. Even in presence of ventilation, controlling the CO2 concentration below the Indoor Air Guideline Values (IAGVs) is a challenge, and many indoor environments including schools, offices and transportation exceed the recommended value of 1000 ppmv. This is often accompanied by high concentration of other pollutants, including bio-effluents such as viruses, and the importance of mitigating the transmission of airborne diseases has been highlighted by the COVID-19 pandemic. On the other hand, the relatively high CO2 concentration of indoor environments presents a thermodynamic advantage for direct air capture (DAC) in comparison to atmospheric CO2 concentration. This review aims to describe the issues associated with poor IAQ, and to demonstrate the potential of indoor CO2 DAC to purify indoor air while generating a renewable carbon stream that can replace conventional carbon sources as a building block for chemical production, contributing to the circular economy.

Du X., Li X., Qian P., Wu H.

Few studies have focused on the influence of indoor air pollution on depression and cognitive impairment; besides, the underlying mechanism is not well-established.This study aimed to fill the above gaps by exploring the underlying influence mechanism of solid fuel use, the major cause of indoor air pollution, with the risk of depression and cognitive impairment.This data came from China Health and Retirement Longitudinal Study (CHARLS) 2015 dataset. Self-reported household cooking fuels were collected and categorized as clean fuels and solid fuels. High-sensitivity C-reactive protein (CRP) and white blood cells (WBC) were used to measure inflammation. Depression and cognitive function were assessed by using standardized questionnaires.Respondents had an average Center for Epidemiologic Studies Depression Scale (CESD-10) scores of 7.68 (SD = 6.14) and cognitive function scores of 15.97 (SD = 4.84). In the whole sample, 36.4 % of respondents used solid fuels use, but this proportion was much greater among those living in rural areas (78.38 %). Compared with clean fuel users, solid fuel users had more depression and worse cognitive function. After adjusting for confounders, indoor air pollution was significantly associated with depression and cognitive function respectively (β = -0.444, p < 0.001; β = 0.656, p < 0.001). Indoor air pollution was significantly related to the WBC (β = 0.170, p < 0.01), but not for the CRP. The WBC mediated the association between indoor air pollution and depression (β = 0.026, p < 0.01).In conclusion, solid fuel use was significantly associated with a higher risk of depression and cognitive impairment. Furthermore, we found that solid fuel use influences depression partly via the inflammatory profile.

Hu X., Nie Z., Ou Y., Qian Z., McMillin S.E., Aaron H.E., Zhou Y., Dong G., Dong H.

Epidemiological evidence suggests associations between long-term exposure to air pollution and accelerated cognitive decline. China implemented a strict clean air action plan in 2013; however, it is unclear whether the improvement of air quality has alleviated cognitive impairment in the population. From the China Health and Retirement Longitudinal Study, 8536 Chinese adults were enrolled in 2011 and followed up in 2015. Satellite-based spatiotemporal models were used to estimate exposure to air pollutants (including particles with diameters ≤1.0 μm [PM1], ≤2.5 μm [PM2.5], ≤10 μm [PM10], nitrogen dioxide [NO2], and ozone [O3]). Cognitive function was evaluated using a structured questionnaire in three dimensions: episodic memory, orientation and attention, and visuoconstruction. The associations between changes in the levels of air pollutants and cognitive function were elucidated by a logistic model. The Bayesian Kernel Machine Regression (BKMR) model was applied to evaluate the cumulative effect of air pollutants. The mean (standard deviation) age of all participants was 58.6 (8.7) years. The odds ratio (95% confidence interval) between the highest and the lowest quartile of PM1 exposure reduction for cognitive impairment was 0.46 (0.41, 0.53) after adjusting for confounders. Similar protective effects of cognitive function were observed with the decrease in the level of PM2.5 (0.34 [0.30, 0.39]), PM10 (0.54 [0.48, 0.62]), and NO2 (0.59 [0.51, 0.67]), while the reduction in O3 appeared to be less related to changes in cognitive function (OR: 0.97 [0.85, 1.10]). The protective association of PM1 reduction was stronger in males than in females. Decreased in PM2.5 dominate the cognitive function benefit relative to PM1, PM10, NO2. The implementation of the clean air action plan led to a significant reduction in PM1, PM2.5, PM10, and NO2, which could slow the decline of cognitive function, while a reduction in O3 may not.

Al-Absi A.A., Mohamedali M., Domin A., Benneker A.M., Mahinpey N.

• CO2 adsorption was studied on in-situ polymerized amine into mesoporous silica. • Kinetics of adsorption of CO2 at different relative humidity values was analyzed. • The material showed a high CO2 uptake at ultralow concentration of 400 ppm. • The maximum CO2 uptake was obtained at 25 °C and 65% relative humidity. • The sorbent showed good stability and complete regenerability after ten cycles. Direct air CO 2 capture (DAC) is inevitable to achieve negative emissions and lower CO 2 concentration in the atmosphere. The use of class III supported amine materials has shown great potential as effective materials for CO 2 capture from both flue gas and low concentrations of CO 2 . In this work, a linear polyethylene amine tethered to mesoporous silica foam was synthesized by controlled in situ cationic ring opening polymerization of 2-methyl-2-oxazoline. The sorbent was characterized based on porosity, FTIR, elemental analysis, and surface morphology. The CO 2 capture performance at different temperatures was measured using a volumetric method, whereas the dynamic breakthrough analysis (DBA) technique was evaluated using simulated air of 400 ppm CO 2 at different temperatures and relative humidities. The CO 2 adsorption isotherms were studied in the temperature range from 5 to 80 °C and were fitted using different isotherm models. To evaluate the effects of moisture on the CO 2 capture performance, breakthrough experiments were performed using 400 ppm CO 2 at various relative humidities (0–65%). It was found that the CO 2 uptake calculated from the breakthrough experiment is enhanced at higher moisture contents and decreases at higher temperatures. The maximum CO 2 uptake was 1.50 mmol/g at 25 °C and 65% RH. The CO 2 adsorption kinetics of the sorbent was found to follow the Avrami model, whereas the dual site Langmuir model was found to be the best fit for the adsorption isotherms. The developed sorbent exhibited a stable cyclic performance and retained its initial CO 2 uptake during 10 consecutive cycles. This study demonstrates that in situ polymerization of amines into porous supports is a viable route for designing sorbents with high CO 2 adsorption performance for DAC applications.

Sadrizadeh S., Yao R., Yuan F., Awbi H., Bahnfleth W., Bi Y., Cao G., Croitoru C., de Dear R., Haghighat F., Kumar P., Malayeri M., Nasiri F., Ruud M., Sadeghian P., et. al.

Several research studies have ranked indoor pollution among the top environmental risks to public health in recent years. Good indoor air quality is an essential component of a healthy indoor environment and significantly affects human health and well-being. Poor air quality in such environments may cause respiratory disease for millions of pupils around the globe and, in the current pandemic-dominated era, require ever more urgent actions to tackle the burden of its impacts. The poor indoor quality in such environments could result from poor management, operation, maintenance, and cleaning. Pupils are a different segment of the population from adults in many ways, and they are more exposed to the poor indoor environment: They breathe in more air per unit weight and are more sensitive to heat/cold and moisture. Thus, their vulnerability is higher than adults, and poor conditions may affect proper development. However, a healthy learning environment can reduce the absence rate, improves test scores, and enhances pupil/teacher learning/teaching productivity. In this article, we analyzed recent literature on indoor air quality and health in schools, with the primary focus on ventilation, thermal comfort, productivity, and exposure risk. This study conducts a comprehensive review to summarizes the existing knowledge to highlight the latest research and solutions and proposes a roadmap for the future school environment. In conclusion, we summarize the critical limitations of the existing studies, reveal insights for future research directions, and propose a roadmap for further improvements in school air quality. More parameters and specific data should be obtained from in-site measurements to get a more in-depth understanding at contaminant characteristics. Meanwhile, site-specific strategies for different school locations, such as proximity to transportation routes and industrial areas, should be developed to suit the characteristics of schools in different regions. The socio-economic consequences of health and performance effects on children in classrooms should be considered. There is a great need for more comprehensive studies with larger sample sizes to study on environmental health exposure, student performance, and indoor satisfaction. More complex mitigation measures should be evaluated by considering energy efficiency, IAQ and health effects. • Most schools worldwide have basic natural ventilation systems; typically, inadequate for meeting the needs of pupils. • Exposure to various air pollutants in school buildings risks severe damage to pupils' health. • Pupils tend to feel comfortable in indoor climates that are cooler than environments where adults feel thermally neutral. • Studies show that reduced classroom air quality will cause a reduction in cognitive performance of pupils. • There is limited insight demonstrating detailed energy use profiles in school buildings.

Beaumont M.L.

Direct Air Capture (DAC) is an important solution to curb global warming and enable a circular economy. As fossil fuels dwindle, carbon for commodities such as plastic, cement, steel and liquid fuel, will need to come from somewhere. With the low cost of industrial CO2 (roughly $80 a ton) as well as the low value of most carbon credits, making DAC-produced CO2 competitive at scale is almost impossible. But what if we could scale DAC processes in markets that make sense now, building on learnings as we go while making industries less carbon intensive? The first such application is air quality and energy efficiency in indoor spaces. DAC technology can stabilize CO2 and water levels inside indoor environments to enhance the recirculation rate of internal air, thereby saving significant energy for the HVAC. Another application is the use of small-scale DAC units—providing CO2 at the scale of kilos a day rather than tons, taking advantage of the high CO2 price at that scale as well as B2C markets that otherwise rely on bottled CO2. The approach is called Decentralised DAC or DDAC (analogous to decentralised solar). DAC processes need to be developed but to scale our learnings and drive down costs, we must fund R&amp;D and introduce a significant carbon tax. Finally, interesting new developments such as electro-swing and humidity-swing carbon capture, have the potential to drastically decrease the energy footprint of DAC (its main cost driver), paving the way to making DAC affordable.

Daniel T., Masini A., Milne C., Nourshagh N., Iranpour C., Xuan J.

Carbon capture technologies are crucial for mitigating climate change and play an important role in the net zero roadmap. Recently the greenhouse gas removal (GGR) technology has come under scrutiny as a negative emission solution which will remove CO2 from the atmosphere, either capturing it directly from the air or indirectly via biomass. This study proposed and designed a novel direct air carbon capture process integrated with a solid oxide electrolysis unit for the chemical utilisation of the captured CO2. A detailed techno-economic analysis is performed to determine if the addition of CO2 utilisation is able to offset the high cost of carbon capture. An initial net present value (NPV) and levelised cost of -$4.6B and $382 tCO2−1 were calculated, indicating the unfavourable techo-economics. However, a scenario analysis suggested that in the near future (i.e., in 4-5 years) the NPV could be positive and the levelised cost could be neutral with the advances of technology maturity and the net zero economy. A carbon emissions assessment calculated that during plant operation over 24.2B kg of carbon dioxide would be removed, and hence the real term carbon removal would be approximately 97% of the theoretical maximum.

Baus L., Nehr S.

This concept study presents an approach for resolving the trade-off between energy-efficient building operation and the provision of hygienically harmless indoor air quality. A novel coupling of HVAC-systems (heating, ventilation and air conditioning systems) with DAC-technology (direct air capturing technology) is proposed to separate CO 2 in the exhaust air of buildings and recirculate the CO 2 -depleted air back into the building. In a mainly theoretical approach, the corresponding potentials and limitations of the novel HVAC/DAC-coupling in recirculation mode are evaluated. For that purpose, CO 2 -loads in the feed and exhaust air of four buildings located in Germany were measured using calibrated non-dispersive infrared (NDIR) sensors with pyroelectric detection principle. Subsequent numerical model simulations resort to typical meteorological data as well as building operation parameters grouped in different scenarios. The measurement and simulation results were assessed with regard to: (i) the unique possibilities of a HVAC/DAC-coupling in recirculation mode for the improvement of indoor air quality, (ii) the energy saving potentials through reduced air conditioning requirements enabled by a HVAC/DAC-coupling in recirculation mode, and (iii) the potential allocation of CO 2 separated from building exhaust air for energetic and/or material reutilization in decentralized systems. In conclusion, a HVAC/DAC-coupling in recirculation mode can not only reduce the energy demand of buildings but also facilitates access to unutilized CO 2 -resources transported in the built environment and additionally offers the potential to improve indoor air quality. However, a suitable DAC module for operation in indoor air is not yet commercially available. • HVAC/DAC-coupling in recirculation mode is proposed as new ventilation concept. • DAC-technology is expected to efficiently lower the CO 2 concentration indoors. • HVAC/DAC-coupling allows to lower the energy demand of buildings for certain scenarios. • DAC in the built environment facilitates access to unutilized carbon sources. • Urban infrastructure enables DAC as keystone for sector coupling.

Yang L., Xu M., Fan J., Liang X., Zhang X., Lv H., Wang D.

Traditional policy incentives for carbon capture and storage (CCS) mainly rely on fiscal subsidies, which tend to put an inordinate strain on public finances. This study attempts to explore a non-fiscal incentive policy, granting a time extension (extra electricity quota), to finance early CCS demonstration projects in China. We find that coal-fired power plant (CFPP) operate at a loss even without CCS retrofitting under the current electricity quota (4000 h per year), while it can make profits with CCS retrofitting if extra electricity quotas are provided. Specifically, the electricity quota needs to be roughly 4709–7260 h per year with the CO 2 capture level ranging from 0.1 to 1 Mt per year in the demonstration stage. In particular, the levelized cost of electricity (LCOE) of CFPP with a capture level of 1 Mt per year is estimated at 298.8 CNY/MWh if the electricity quota reaches 7000 h per year, which is approximately equal to that of CFPP without CCS retrofitting and extra electricity quota (292.2 CNY/MWh). Thus, the extra electricity quota can be considered as an economically feasible policy incentive, and related results are able to provide useful information for electric power enterprises and government decision-makers. • Extra electricity quota is proposed as an incentives mechanism for CCS project. • The NPV and LCOE are estimated under different electricity quotas. • Carbon trading can reduce the power generation cost to some extent. • The critical conditions are discussed in various scenarios. • The effects of changes in parameters are estimated through sensitivity analysis.

Cannone S.F., Lanzini A., Stendardo S.

Coupling solar thermal energy with the hybrid TC/CG-ES (thermochemical/compressed gas energy storage) is a breakthrough option used to overcome the main challenge of solar energy, i.e., intermittent resource and low density. This paper proposes an innovative storage system that improves the competitiveness of solar thermal energy technologies compared to conventional fossil-based power plants, potentially leading to deep decarbonization of the energy and industrial sectors. This study uses thermochemical energy storage based on the calcium looping (CaL) process and takes advantage of a number of factors: high energy density (2 GJ/m3), absence of heat loss (seasonal storage), high operation temperature (high efficiency of the power plant), and use of cheap and environmentally friendly reactant feedstock (CaO/CaCO3). This work deals with the integration of the solar CaL storage system with an unconventional supercritical CO2 (s-CO2) Brayton cycle. We analyze different s-CO2 Brayton cycle layouts suitable for direct integration with the storage system. Energy integration via pinch analysis methodology is applied to the whole system to optimize the internal heat recovery and increase the efficiency of the system. A parametric study highlights how the integration of solar CaL with an intercooling Brayton cycle shows better results than the combination with the Rankine cycle that we investigated previously, resulting in net and global system efficiencies equal to 39.5 and 51.5%. Instead, the new calculated net and global system efficiencies are 44.4 and 57.0%, respectively, for TC-CG-ES coupled with the Brayton power cycle.

Schellevis H.M., van Schagen T.N., Brilman D.W.

• Parallel fixed bed reactor system designed for direct air capture by adsorption. • Solid basis for process optimization is achieved through dynamic modelling. • High desorption temperature always desired according to sensitivity analyses. • Weather conditions highly affect direct air capture process performance. The extraction of CO 2 directly from the atmosphere (Direct Air Capture) is commonly employed using supported-amine sorbents. This adsorption technology is under rapid development with novel sorbent materials emerging and with processes being demonstrated on increasingly larger scale. Optimization of such processes requires accurate knowledge on sorbent characteristics and knowledge on how operational variables affect process performance. This study primarily focuses on the latter, where we aim to quantify the influence of operational parameters on the energy duty and CO 2 productivity. In addition, we examine the influence of weather conditions on the adsorption rate. For this, we develop a dynamic model of the complete temperature-vacuum swing adsorption cycle (TVSA). This model was validated by experimental results on a kg-scale direct air capture system. The impact of selected operational variables was assessed by two-dimensional sensitivity analyses. We show that desorption temperature is preferably high, limited by the chemical stability of the sorbent material in this particular case. In addition, the sorbent working capacity should be high when opting for an optimization towards energy duty, whereas it reaches a clear optimum in terms of CO 2 productivity. Finally, we conclude that weather conditions and diurnal variations can significantly affect the performance of a direct air capture process and should certainly be considered during design and operation. With these insights and the developed model, this study provides a sound basis for further process development and optimization of direct air capture using fixed bed technology combined with solid amine sorbents.

Yang K., Zhang Y., Zhang Z., Wang Q., Ye G., Xue Z., Luo J., Yang H.

Bagheri M., Fakhroleslam M., Fatemi S.

Klemenčič K., Krajnc A., Puškarić A., Huš M., Marinič D., Likozar B., Zabukovec Logar N., Mazaj M.

AbstractEfficient CO2 capture at concentrations between 400–2000 ppm is essential for maintaining air quality in a habitable environment and advancing carbon capture technologies. This study introduces NICS‐24 (National Institute of Chemistry Structures No. 24), a Zn‐oxalate 3,5‐diamino‐1,2,4‐triazolate framework with two distinct square‐shaped channels, designed to enhance CO2 capture at indoor‐relevant concentrations. NICS‐24 exhibits a CO2 uptake of 0.7 mmol/g at 2 mbar and 25 °C, significantly outperforming the compositionally related Zn‐oxalate 1,2,4‐triazolate – CALF‐20 (0.17 mmol/g). Improved performance is attributed to amino‐functions that enhance CO2 binding and enable superior selectivity over N2 and O2, achieving 8‐fold and 30‐fold improvements, respectively, in simulated CO2/N2 and CO2/O2 atmospheric ratios. In humid environments, NICS‐24 retained structural integrity but exhibited an 85 % reduction in CO2 capacity due to competitive water adsorption. Breakthrough sorption experiments, atomistic NMR analysis, and DFT calculations revealed that water preferentially adsorbs over CO2 due to strong hydrogen‐bonding interactions within the framework. Gained understanding of the interaction between CO2 and H2O within the MOF framework could guide the modification via rational design with improved performance under real‐world conditions.

Klemenčič K., Krajnc A., Puškarić A., Huš M., Marinič D., Likozar B., Zabukovec Logar N., Mazaj M.

AbstractEfficient CO2 capture at concentrations between 400–2000 ppm is essential for maintaining air quality in a habitable environment and advancing carbon capture technologies. This study introduces NICS‐24 (National Institute of Chemistry Structures No. 24), a Zn‐oxalate 3,5‐diamino‐1,2,4‐triazolate framework with two distinct square‐shaped channels, designed to enhance CO2 capture at indoor‐relevant concentrations. NICS‐24 exhibits a CO2 uptake of 0.7 mmol/g at 2 mbar and 25 °C, significantly outperforming the compositionally related Zn‐oxalate 1,2,4‐triazolate – CALF‐20 (0.17 mmol/g). Improved performance is attributed to amino‐functions that enhance CO2 binding and enable superior selectivity over N2 and O2, achieving 8‐fold and 30‐fold improvements, respectively, in simulated CO2/N2 and CO2/O2 atmospheric ratios. In humid environments, NICS‐24 retained structural integrity but exhibited an 85 % reduction in CO2 capacity due to competitive water adsorption. Breakthrough sorption experiments, atomistic NMR analysis, and DFT calculations revealed that water preferentially adsorbs over CO2 due to strong hydrogen‐bonding interactions within the framework. Gained understanding of the interaction between CO2 and H2O within the MOF framework could guide the modification via rational design with improved performance under real‐world conditions.

Wells J.D., Belancik G.A.

Rahmah W., Khoiruddin K., Wenten I.G., Kawi S.

Xu H., Yu L., Chong C., Wang F.

Caruso M.R., Calvino M.M., Šiler P., Cába L., Milioto S., Lisuzzo L., Lazzara G., Cavallaro G.

AbstractIn this work, it is reported a scalable and systematic protocol for the preparation of xerogels based on the use of green, highly available, and low‐cost materials, i.e. halloysite nanoclay and chitosan, without the need for any expensive equipment or operational/energetic demands. Starting from colloidal dispersions, rheological studies demonstrate the formation of hydrogels with zero‐shear viscosities enhanced by ≈9 orders of magnitude and higher storage moduli. Hence, the corresponding self‐standing xerogels are prepared by a simple solvent casting method and their properties depend on the concentration of halloysite, possessing enhanced thermal stability and outstanding mechanical performances (elastic modulus and ultimate elongation of 165 MPa and 43%, respectively). The resulting biohybrid materials can be exploited for environmental remediation. High removal efficiencies are reached for the capture of organic molecules from aqueous media and the CO2 capture from the atmosphere is also investigated. Most importantly, the presence of an inorganic skeleton within the xerogels prevents the structure from collapsing upon drying and it allows for the control over their morphology and shape. Therefore, taking advantage of the overall features, the designed xerogels offer an attractive strategy for sustainably tackling pollution and for environmental remediation in a plethora of different domains.

Alli Y.A., Bamisaye A., Bamidele M.O., Etafo N.O., CHKIRIDA S., Lawal A., Hammed V.O., Akinfenwa A.S., Hanson E., Nwakile C., Kazeem K.O., Ayanwunmi R.J., Ige A.S., Parga Torres J.R., Al Nageim H.