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Amine-functionalized metal-organic framework ZIF-8 toward colorimetric CO 2 sensing in indoor air environment
Carbon dioxide (CO 2 ) has been shown to contribute to human health consequences indoors, such as shortness of breath, nasal and optic irritation, dizziness, and nausea. Here in this work, we explore the potential of metal–organic frameworks (MOFs) as highly-porous, crystalline sorbents for sensitive colorimetric CO 2 detection. In particular, the zeolitic imidazolate framework (ZIF-8) is chosen as the sorptive material due to its chemical stability and tunable CO 2 affinity. The colorimetric gas sensor is developed in methanol with three components: (i) MOF ZIF-8 as a high surface area adsorbent; (ii) ethylenediamine (ED) as the CO 2 -affinitive basic function; and (iii) phenolsulfonpthalein (PSP) as the pH indicator. Colorimetric assays and ratiometric analysis confirm a colorimetric response to variable CO 2 concentrations of relevance to indoor air quality. The color response is attributed to a zwitterion mechanism whereby ED reacts with CO 2 to form a zwitterionic intermediate. This intermediate is then deprotonated by the pH indicator, shifting the pH and inducing a color change. Given its simple fabrication, rapid and obvious response, and stability in ambient environment, the ZIF-8-based colorimetric sensor provides a promising route for an improved indoor air quality monitoring.
Environmental life cycle assessment methods applied to amine-ionic liquid hybrid CO 2 absorbents
A hybrid solvent mixture of triethyl(octyl)phosphonium cyanopyrrolide [P2228][2-CNPyr] and aqueous monoethanolamine (MEA) has the potential for absorbing CO 2 from post combustion flue gas. However, previous studies have found that the production of phosphonium based ionic liquids (IL) had significantly higher potential environmental impacts compared to MEA. Literature attributes these higher environmental impacts to the phosphine and phosgene-based intermediates required to produce the phosphonium ion of the ionic liquid. This study proposes a novel synthesis pathway that eliminates the need for phosphine and phosgene intermediates in the production of [P2228][2-CNPyr]. The environmental impacts of producing 1kg of the ionic liquid through this novel synthesis route was evaluated using the TRACI 2.1 methodology within the life cycle assessment (LCA) framework. Additionally, the environmental impacts for the production of 1kg of a hybrid solvent was also evaluated and compared against MEA. The life cycle inventory for the production of the IL and its hybrid solvent were calculated based on the stoichiometry and then scaled up. This study found that the IL and its hybrid solvents had higher environmental impacts among 9 of the 10 environmental impact categories calculated by the TRACI 2.1 methodology, except for the ecotoxicity potential. A sensitivity analysis indicated that these solvents were more sensitive to the assumptions of the material requirements of the phosphonium cation than the overall energy or transportation requirements. Despite this sensitivity, both the solvents demonstrated a lower Ecotoxicity Potential compared to MEA, the rest of the environmental impacts were still found to be higher than that of MEA, thereby underscoring the need to investigate novel synthesis routes for the production of phosphonium cation. The uncertainty analysis performed confirmed the findings that the IL has a higher environmental impact potentials across all categories except ecotoxicity potential. The uncertainty analysis also confirms that the phosphonium cation is a major hotspot in production route of these solvents and a source of uncertainty in the model compared to the anion. Altogether, this study underscores the need for investigating novel green chemistry pathway for the synthesis of phosphonium based ionic liquids, such as [P2228][2-CNPyr], to ensure that the these ILs can be a truly green alternative to MEA by not only offering superior CO₂ capture capacity compared to MEA but also being sustainably produced.
Amine–Oxide Hybrid Materials for CO 2 Capture from Ambient Air
Not Available
Uncatalyzed N-Alkylation of Amines in Ionic Wind from Ambient Corona Discharge
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α-Amine Desaturation of d -Arginine by the Iron(II)- and 2-(Oxo)glutarate-Dependent l -Arginine 3-Hydroxylase, VioC
When challenged with substrate analogues, iron(II)- and 2-(oxo)glutarate-dependent (Fe/2OG) oxygenases can promote transformations different from those they enact upon their native substrates. We show here that the Fe/2OG enzyme, VioC, which is natively an l-arginine 3-hydroxylase, catalyzes an efficient oxidative deamination of its substrate enantiomer, d-Arg. The reactant complex with d-Arg retains all interactions between enzyme and substrate functional groups, but the required structural adjustments and opposite configuration of C2 position this carbon more optimally than C3 to donate hydrogen (H•) to the ferryl intermediate. The simplest possible mechanism, C2 hydroxylation followed by elimination of ammonia, is inconsistent with the demonstrated solvent origin of the ketone oxygen in the product. Rather, the reaction proceeds via a hydrolytically labile C2-iminium intermediate, demonstrated by its reductive trapping in solution with NaB 2 H 4 to produce racemic [ 2 H]Arg. Of two alternative pathways to the iminium species, C2 hydroxylation followed by dehydration versus direct desaturation, the latter possibility appears to be more likely, because the former mechanism would be expected to result in detectable incorporation of 18 O from 18 O 2 . Here, the direct desaturation of a C–N bond implied by this analysis is analogous to that recently posited for the reaction of the l-Arg 4,5-desaturase, NapI, thus lending credence to the prior mechanistic proposal. Such a pathway could also potentially be operant in a subset of reactions catalyzed by Fe/2OG N-demethylases, which have instead been purported to enact C–N bond cleavage by methyl hydroxylation and elimination of formaldehyde.
Polar Ferromagnetic Metal by Intercalation of Metal?Amine Complexes
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Polymorphic Control of Solution-Processed Cu 2 SnS 3 Films with Thiol–Amine Ink Formulation
Not Available
Effect of Amines on MIL-101(Cr) for Simultaneous H 2 S/CO 2 Removal from Biogas
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Integrated CO 2 Capture, Conversion, and Storage To Produce Calcium Carbonate Using an Amine Looping Strategy
Abstract not provided
Computational Assessment of an Amine-Based Solvent Library for High-Salinity Brine Desalination
Not provided.
Amine Functionalization of Microsized and Nanosized Mesoporous Carbons for Carbon Dioxide Capture
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Molecular Modeling of the Physical Properties for Aqueous Amine Solution Containing a CO 2 Hydration Catalyst
The effects of an amphiphilic CO 2 hydration catalyst (C3P) on the physical properties of aqueous monoethanolamine (MEA) solutions were studied using molecular simulations and verified experimentally. Adding 2.7–27.7 g/L of C3P in 30 wt % MEA aqueous solution did not significantly affect the solution viscosity, surface tension, or CO 2 diffusivity. These results confirm that the previously reported increase in CO 2 mass transfer by C3P is due to CO 2 hydration catalysis and not due to changes in the physical properties of the MEA solution. Additional simulations indicate that the catalyst molecules tend to aggregate in MEA solution and are preferentially adsorbed at the gas–liquid interface region. Finally, for the catalyst molecules remaining in the bulk solution, the local concentrations of CO 2 and MEA in the area immediately around the catalyst are increased while the local water concentration is decreased, relative to their concentrations in the rest of the bulk MEA solution.