In recent years, carbon capture and utilization (CCU) has been proposed as a potential technological solution to the problems of greenhouse‐gas emissions and the ever‐growing energy demand. To combat climate change and ocean acidification as a result of anthropogenic CO2 emissions, efforts have already been put forth to capture and sequester CO2 from large point sources, especially power plants; however, the utilization of CO2 as a feedstock to make valuable chemicals, materials, and transportation fuels is potentially more desirable and provides a better and long‐term solution than sequestration. The products of CO2 utilization can supplement or replace chemical feedstocks in the fine chemicals, pharmaceutical, and polymer industries. In this review, we first provide an overview of the current status of CO2‐capture technologies and their associated challenges and opportunities with respect to efficiency and economy followed by an overview of various carbon‐utilization approaches. The current status of combined CO2 capture and utilization, as a novel efficient and cost‐effective approach, is also briefly discussed. We summarize the main challenges associated with the design, development, and large‐scale deployment of CO2 capture and utilization processes to provide a perspective and roadmap for the development of new technologies and opportunities to accelerate their scale‐up in the near future.

Honeycomb monoliths loaded with metal-organic frameworks (MOFs) are highly desirable adsorption contactors because of their low-pressure drop, rapid mass-transfer kinetics, and high-adsorption capacity. Moreover, three-dimensional (3D)-printing technology renders direct material modification a realistic and economic prospect. In this study, 3D printing was utilized to impregnate kaolin-based monolith with UTSA-16 metal formation precursor (Co), whereupon an internal growth was facilitated via a solvothermal synthesis approach. The cobalt weight loading in the kaolin support was varied systematically to optimize the MOF growth while retaining monolith mechanical integrity. The obtained UTSA-16 monolith with 90 wt % loading exhibited similar textural features and adsorption characteristics to its powder analogue while improving upon structural integrity. In comparison to previously developed 3D-printed UTSA-16 monoliths, the UTSA-16-kaolin monolith not only showed higher MOF loading but also higher compression stress, indicative of its robust structure. Furthermore, the 3D-printed UTSA-16-kaolin monolith displayed a comparable CO adsorption capacity to the UTSA-16 powder (3.1 vs 3.5 mmol/g at 25 °C and 1 bar), which was proportional to its loading. Selectivity values of 49, 238, and 3725 were obtained for CO/CH, CO/N, and CO/H, respectively, demonstrating good separation potential of the 3D-printed MOF monolith for various gas mixtures, as determined by both equilibrium and dynamic adsorption measurements. Overall, this study provides a novel route for the fabrication of UTSA-16-loaded monoliths, which demonstrate both high MOF loading and mechanical integrity that could be readily applied to various CO capture applications.

The use of paraffin-selective adsorbents in separation of paraffin/olefin pairs has been recently demonstrated as a sustainable platform for recovering a highly pure olefin product directly from the adsorption step. These materials allow for development of a less expensive and economically attractive technology for olefin/paraffin separation. Herein, we report formulation of paraffin-selective adsorbents into monolithic contactors and evaluation of their adsorptive performance in ethane/ethylene separation. More specifically, Ni(bdc)(ted) 0.5 and ZIF-7 were used as ethane-selective adsorbents for development of monoliths via 3D printing. Their formulation was optimized according to printability of the extruded paste and mechanical stability of the final monolith piece. Through equilibrium and dynamic adsorption experiments, it was demonstrated that formulation of the adsorbents into monoliths does not adversely affect their separation efficiency, and the monoliths exhibit uptakes proportional to the adsorbent loading and comparable to those of their powder analogues. Application of the ideal adsorption solution theory method predicted C 2 H 6 /C 2 H 4 selectivities in the ranges 1.9−11.8 and 1.2−2.0 for ZIF-7 and Ni(bdc)(ted) 0.5 monoliths, respectively. The findings of this study highlight the feasibility of 3D printing as a facile and cost-effective approach in shaping paraffin-selective adsorbents into practical contactors.

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High levels of indoor air CO2 in commercial buildings can lead to various health effects, commonly known as sick building syndrome. Passive control of indoor air CO2 through solid adsorbents incorporated into the paint offers a high potential to handle CO2 without utilizing much energy. This study focuses on incorporating silica-supported aminopolymers into a polyacrylic-based latex that could be used as a buffer material for the passive control of CO2 in enclosed environments. To maximize the effect of the pigment (adsorbent), paints were all prepared at critical pigment volume concentration (CPVC) levels. CO2 at 800 and 3000 ppm were used to asses both low and high level contaminations. The removal efficiency of the surface coatings was evaluated within typical time frames (10 h for adsorption and desorption). Our laboratory-scale chamber results indicated that the silica-tetraethylenepentamine-based paint with 70 wt % loading exhibits the best adsorption performance, comparable to that of the powder-based sorbent, with only a ∼20% decrease in the adsorption efficiency. Our results also revealed that the optimization of paint formulation is critical in passively controlling indoor air CO2. The findings of this study highlight the potential of amine-based adsorbents as pigments in high PVC paints for indoor CO2 control in commercial buildings.

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Volatile organic air pollutants such as aldehyde compounds have been identified as progressively damaging chemicals impacting human health at small albeit dangerous quantities. This study focuses on evaluating the dynamic adsorption of formaldehyde over binary mixed-metal oxides (MMOs) such as ZrO 2 /SiO 2 and TiO 2 /SiO 2 with different metal ratios. In addition, a metal−organic framework (MOF), namely, MIL-101(Cr), was synthesized and used as a base adsorbent to which the performance of MMOs was compared. The formaldehyde dynamic adsorption capacity of the materials was determined through breakthrough experiments. Our results indicated that zirconiabased materials exhibit a comparatively higher affinity toward formaldehyde than their titania-based counterparts at very dilute concentrations. In particular, ZrO 2 /SiO 2 with weight ratio of 25/75 exhibited a dynamic adsorption capacity of 2.9 mmol/g at room temperature using a formaldehyde concentration of 170 ppm v , which was comparable to that of . Characterization of the materials before and after formaldehyde exposure indicated that formaldehyde was chemically adsorbed on the MMOs. This study highlights the potential of MMOs for efficient abatement of airborne formaldehyde.

In this study, we evaluated solid sorbents for their ability to passively control indoor CO concentration in buildings or rooms with cyclic occupancy (eg, offices, bedrooms). Silica supported amines were identified as suitable candidates and systematically evaluated in the removal of CO from indoor air by equilibrium and dynamic techniques. In particular, sorbents with various amine loadings were synthesized using tetraethylenepentamine (TEPA), poly(ethyleneimine) (PEI) and a silane coupling agent 3-aminopropyltriethoxysilane (APS). TGA analysis indicates that TEPA impregnated silica not only displays a relatively high adsorption capacity when exposed to ppm level CO concentrations, but also is capable of desorbing the majority of CO by air flow (eg, by concentration gradient). In 10 L flow-through chamber experiments, TEPA-based sorbents reduced outlet CO by up to 5% at 50% RH and up to 93% of CO adsorbed over 8 hours was desorbed within 16 hours. In 8 m flow-through chamber experiments, 18 g of the sorbent powder spread over a 2 m area removed approximately 8% of CO injected. By extrapolating these results to real buildings, we estimate that meaningful reductions in the CO can be achieved, which may help reduce energy requirements for ventilation and/or improve air quality.