17 results match your criteria Acs Earth And Space Chemistry[Journal]

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Resolving ambient organic aerosol formation and aging pathways with simultaneous molecular composition and volatility observations.

ACS Earth Space Chem 2020 Mar;4(3):391-402

Department of Atmospheric Sciences, University of Washington, Seattle, WA, U.S.A.

Organic aerosol (OA) constitutes a significant fraction of atmospheric fine particle mass. However, the precursors and chemical processes responsible for a majority of OA are rarely conclusively identified. We use online observations of hundreds of simultaneously measured molecular components obtained from 15 laboratory OA formation experiments with constraints on their effective saturation vapor concentrations to attribute the VOC precursors and subsequent chemical pathways giving rise to the vast majority of OA mass measured in two forested regions. Read More

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http://dx.doi.org/10.1021/acsearthspacechem.9b00302DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7180062PMC

Plutonium(IV) Sorption during Ferrihydrite Nanoparticle Formation.

ACS Earth Space Chem 2019 Nov 16;3(11):2437-2442. Epub 2019 Sep 16.

Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, School of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, United Kingdom.

Understanding interactions between iron (oxyhydr)oxide nanoparticles and plutonium is essential to underpin technology to treat radioactive effluents, in cleanup of land contaminated with radionuclides, and to ensure the safe disposal of radioactive wastes. These interactions include a range of adsorption, precipitation, and incorporation processes. Here, we explore the mechanisms of plutonium sequestration during ferrihydrite precipitation from an acidic solution. Read More

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http://dx.doi.org/10.1021/acsearthspacechem.9b00105DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7011701PMC
November 2019

Structure and Properties of Nanosilicates with Olivine (MgSiO) and Pyroxene (MgSiO) Compositions.

ACS Earth Space Chem 2019 Nov 19;3(11):2390-2403. Epub 2019 Jul 19.

Departament de Ciència de Materials i Química Física & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, E-08028 Barcelona, Spain.

Magnesium-rich silicates are ubiquitous both terrestrially and astronomically, where they are often present as small particles. Nanosized Mg-rich silicate particles are likely to be particularly important for understanding the formation, processing, and properties of cosmic dust grains. Although astronomical observations and laboratory studies have revealed much about such silicate dust, our knowledge of this hugely important class of nanosolids largely rests on top-down comparisons with the properties of bulk silicates. Read More

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http://dx.doi.org/10.1021/acsearthspacechem.9b00139DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7009040PMC
November 2019

Solid-State Isomerization and Infrared Band Strengths of Two Conformational Isomers of Cyclopropanecarboxaldehyde, A Candidate Interstellar Molecule.

ACS Earth Space Chem 2019 17;3(7):1182-1188. Epub 2019 May 17.

Astrochemistry Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.

At least a dozen of the known interstellar molecules possess a formyl group (HCO), suggesting that other such species exist and await discovery in the interstellar medium. Here we examine the mid-infrared (mid-IR) spectrum and selected physical properties of one such candidate, cyclopropanecarboxaldehyde, in amorphous ices. Mid-IR transmission spectra of solid cyclopropanecarboxaldehyde are presented for the first time and used to determine the -to- ratio of conformational isomers present in amorphous samples. Read More

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http://dx.doi.org/10.1021/acsearthspacechem.9b00058DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6894396PMC

Experimental and theoretical investigation on the OH + CHC(O)CH reaction at interstellar temperatures (T=11.7-64.4 K).

ACS Earth Space Chem 2019 Sep 12;3(9):1873-1883. Epub 2019 Aug 12.

Departamento de Química Física. Facultad de Ciencias y Tecnologías Químicas. Universidad de Castilla-La Mancha, Avda. Camilo José Cela, 1B. 13071 Ciudad Real, Spain.

The rate coefficient, (), for the gas-phase reaction between OH radicals and acetone CHC(O)CH, has been measured using the pulsed CRESU (French acronym for Reaction Kinetics in a Uniform Supersonic Flow) technique ( = 11.7-64.4 K). Read More

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http://dx.doi.org/10.1021/acsearthspacechem.9b00144DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6887536PMC
September 2019

Calcium in Carbonate Water Facilitates the Transport of U(VI) in Roots and Enables Root-to-Shoot Translocation.

ACS Earth Space Chem 2019 Oct 26;3(10):2190-2196. Epub 2019 Sep 26.

Department of Civil Engineering, University of New Mexico, MSC01 1070, Albuquerque, New Mexico 87131, United States.

The role of calcium (Ca) on the cellular distribution of U(VI) in roots and root-to-shoot translocation was investigated using hydroponic experiments, microscopy, and spectroscopy. Uranium accumulated mainly in the roots (727-9376 mg kg) after 30 days of exposure to 80 M dissolved U in water containing 1 mM HCO at different Ca concentrations (0-6 mM) at pH 7.5. Read More

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http://dx.doi.org/10.1021/acsearthspacechem.9b00171DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6859903PMC
October 2019

Vapor-pressure pathways initiate but hydrolysis products dominate the aerosol estimated from organic nitrates.

ACS Earth Space Chem 2019 Aug;3(8):1426-1437

National Exposure Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States.

Organic nitrates contribute significantly to the total organic aerosol burden. However, the formation and loss mechanisms of particulate organic nitrates (PONs) remain poorly understood. In this study, with the CMAQ modeling system, we implement a detailed biogenic volatile organic carbon gas phase oxidation mechanism and an explicit representation of multiphase organic nitrate formation and loss, including both aqueous-phase uptake and vapor-pressure driven partitioning into organic aerosol as well as condensed-phase reactions. Read More

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http://dx.doi.org/10.1021/acsearthspacechem.9b00067DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6820051PMC
August 2019
1 Read

Secondary Organic Aerosol Formation from Healthy and Aphid-Stressed Scots Pine Emissions.

ACS Earth Space Chem 2019 Sep 14;3(9):1756-1772. Epub 2019 Aug 14.

Department of Applied Physics, University of Eastern Finland, P.O. Box 1626, 70211 Kuopio, Finland.

One barrier to predicting biogenic secondary organic aerosol (SOA) formation in a changing climate can be attributed to the complex nature of plant volatile emissions. Plant volatile emissions are dynamic over space and time, and change in response to environmental stressors. This study investigated SOA production from emissions of healthy and aphid-stressed Scots pine saplings via dark ozonolysis and photooxidation chemistry. Read More

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http://dx.doi.org/10.1021/acsearthspacechem.9b00118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6757509PMC
September 2019

Zero- and high-pressure mechanisms in the complex forming reactions of OH with methanol and formaldehyde at low temperatures.

ACS Earth Space Chem 2019 Jul 14;3(7):1158-1169. Epub 2019 May 14.

Instituto de Física Fundamental (IFF-CSIC), C.S.I.C., Serrano 123, 28006 Madrid, Spain.

A recent Ring Polymer Molecular Dynamics study of the reactions of OH with methanol and formaldehyde, at zero pressure and below 100 K, has shown the formation of long lived complexes, with long lifetimes, longer than 100 ns for the lower temperatures studied, 20-100 K (del Mazo-Sevillano , 2019). These long lifetimes support the existence of multi collision events with the He buffer-gas atoms under experimental conditions, as suggested by several transition state theory studies of these reactions. In this work we study these secondary collisions, as a dynamical approach to study pressure effects on these reactions. Read More

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http://dx.doi.org/10.1021/acsearthspacechem.9b00051DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6739233PMC

A Polyextreme Hydrothermal System Controlled by Iron: The Case of Dallol at the Afar Triangle.

ACS Earth Space Chem 2019 Jan 6;3(1):90-99. Epub 2018 Dec 6.

Unidad Asociada UVa-CSIC al Centro de Astrobiología, University of Valladolid, 47002 Valladolid, Spain.

One of the latest volcanic features of the Erta Ale range at the Afar Triangle (NE Ethiopia) has created a polyextreme hydrothermal system located at the Danakil depression on top of a protovolcano known as the dome of Dallol. The interaction of the underlying basaltic magma with the evaporitic salts of the Danakil depression has generated a unique, high-temperature (108 °C), hypersaline (NaCl supersaturated), hyperacidic (pH values from 0.1 to -1. Read More

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http://dx.doi.org/10.1021/acsearthspacechem.8b00141DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6380227PMC
January 2019
4 Reads

Carbonate Adsorption to Ferrihydrite: Competitive Interaction with Phosphate for Use in Soil Systems.

ACS Earth Space Chem 2019 Jan 3;3(1):129-141. Epub 2018 Dec 3.

Soil Chemistry and Chemical Soil Quality Group, Wageningen University, 6708 PB, Wageningen, The Netherlands.

Carbonate (CO) interacts with Fe-(hydr)oxide nanoparticles, affecting the availability and geochemical cycle of other important oxyanions in nature. Here, we studied the carbonate-phosphate interaction in closed systems with freshly prepared ferrihydrite (Fh), using batch experiments that cover a wide range of pH values, ionic strength, and CO and PO concentrations. The surface speciation of CO has been assessed by interpreting the ion competition with the Charge Distribution (CD) model, using CD coefficients derived from MO/DTF optimized geometries. Read More

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http://dx.doi.org/10.1021/acsearthspacechem.8b00160DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6369681PMC
January 2019
6 Reads

In Situ Nanoscale Investigation of Step Retreat on Fluoranthene Crystal Surfaces.

ACS Earth Space Chem 2018 Dec 2;2(12):1301-1311. Epub 2018 Nov 2.

Leiden Observatory, Faculty of Science, Leiden University, 2300 RA Leiden, The Netherlands.

Fluoranthene, a polycyclic aromatic hydrocarbon, has been detected on Earth as well as in asteroids and meteorites and may have played a role in the formation of life. Increasing the ionic strength of aqueous solutions has been observed to lower the fluoranthene solubility, but it is unclear how solution composition controls the release rate of fluoranthene to an aqueous solution. To elucidate this, we performed in situ atomic force microscopy experiments in which we characterized the sublimation and dissolution behavior of fluoranthene crystal surfaces. Read More

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http://pubs.acs.org/doi/10.1021/acsearthspacechem.8b00120
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http://dx.doi.org/10.1021/acsearthspacechem.8b00120DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6326534PMC
December 2018
10 Reads

NO Suppression of Autoxidation-Inhibition of Gas-Phase Highly Oxidized Dimer Product Formation.

Authors:
Matti P Rissanen

ACS Earth Space Chem 2018 Nov 12;2(11):1211-1219. Epub 2018 Oct 12.

Institute for Atmospheric and Earth System Research (INAR), University of Helsinki, Helsinki, Finland.

Atmospheric autoxidation of volatile organic compounds (VOC) leads to prompt formation of highly oxidized multifunctional compounds (HOM) that have been found crucial in forming ambient secondary organic aerosol (SOA). As a radical chain reaction mediated by oxidized peroxy (RO) and alkoxy (RO) radical intermediates, the formation pathways can be intercepted by suitable reaction partners, preventing the production of the highest oxidized reaction products, and thus the formation of the most condensable material. Commonly, NO is expected to have a detrimental effect on RO chemistry, and thus on autoxidation, whereas the influence of NO is mostly neglected. Read More

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http://pubs.acs.org/doi/10.1021/acsearthspacechem.8b00123
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http://dx.doi.org/10.1021/acsearthspacechem.8b00123DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6251564PMC
November 2018
21 Reads

Impact of Intrinsic Structural Properties on the Hydration of 2:1 Layer Silicates.

ACS Earth Space Chem 2017 Dec 3;1(10):608-620. Epub 2017 Oct 3.

Competence Center for Material Moisture, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.

Several 2:1 layer silicates comprising di- and trioctahedral smectites of different layer charge between 0.2 and 0.4 per formula unit and a trioctahedral vermiculite were studied by an method that allowed Fourier transform infrared spectroscopy (FTIR) spectra and water vapor sorption isotherms to be obtained simultaneously. Read More

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http://dx.doi.org/10.1021/acsearthspacechem.7b00091DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5896019PMC
December 2017
14 Reads

Reaction Kinetics of CaOH with H and O and OCaOH with O: Implications for the Atmospheric Chemistry of Meteoric Calcium.

ACS Earth Space Chem 2017 Sep 14;1(7):431-441. Epub 2017 Jul 14.

School of Chemistry, University of Leeds, Leeds LS2 9JT, United Kingdom.

The ablation of cosmic dust particles entering the Earth's upper atmosphere produces a layer of Ca atoms around 90 km. Here, we present a set of kinetic experiments designed to understand the nature of the Ca molecular reservoirs on the underside of the layer. CaOH was produced by laser ablation of a Ca target in the fast flow tube and detected by non-resonant laser-induced fluorescence, probing the D(Σ) ← X(Σ) transition at 346. Read More

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http://dx.doi.org/10.1021/acsearthspacechem.7b00072DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5611678PMC
September 2017
6 Reads

Cation Exchange in the Presence of Oil in Porous Media.

ACS Earth Space Chem 2017 Apr 16;1(2):101-112. Epub 2017 Mar 16.

Delft University of Technology, 2628 CD Delft, The Netherlands.

Cation exchange is an interfacial process during which cations on a clay surface are replaced by other cations. This study investigates the effect of oil type and composition on cation exchange on rock surfaces, relevant for a variety of oil-recovery processes. We perform experiments in which brine with a different composition than that of the in situ brine is injected into cores with and without remaining oil saturation. Read More

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http://dx.doi.org/10.1021/acsearthspacechem.6b00015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5448445PMC
April 2017
37 Reads

Mineral Surface Rearrangement at High Temperatures: Implications for Extraterrestrial Mineral Grain Reactivity.

ACS Earth Space Chem 2017 Apr 31;1(2):113-121. Epub 2017 Mar 31.

Institut für Mineralogie, University of Münster, Corrensstrasse 24, 48149 Münster, Germany.

Mineral surfaces play a critical role in the solar nebula as a catalytic surface for chemical reactions and potentially acted as a source of water during Earth's accretion by the adsorption of water molecules to the surface of interplanetary dust particles. However, nothing is known about how mineral surfaces respond to short-lived thermal fluctuations that are below the melting temperature of the mineral. Here we show that mineral surfaces react and rearrange within minutes to changes in their local environment despite being far below their melting temperature. Read More

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http://dx.doi.org/10.1021/acsearthspacechem.6b00016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5407656PMC
April 2017
6 Reads
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