1
|
Wei W, Liu S, Li G, Mao K, Wang K, Xu X, Li S, Wu X. Magnetoelectricity-Mediated Tunable Absorption and Release of Peroxide Dianions. NANO LETTERS 2023; 23:3694-3700. [PMID: 37074399 DOI: 10.1021/acs.nanolett.2c04803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Peroxide dianion (O22-) has strong oxidizing activity and ease of proton abstraction and is extremely unstable. Direct and controllable adsorption and release of O22- has large application implication and is a large challenge so far. Here, we use a unique metal (Ni)-organic (diphenylalanine, DPA) framework (MOF), Ni(DPA)2, as adsorbents for absorption and release of O22-. This MOF structure has room-temperature magnetoelectricity via distortion of the Ni-centered octahedron {NiN2O4} and thus possesses a tunable ferroelectric polarization under applied electric/magnetic fields. Controllable adsorption and release of O22- are realized in such a MOF system via electrochemical redox measurements. Structural/spectroscopic characterization and calculations reveal that a number of NH active sites in the nanopores of MOF can effectively adsorb O22- by hydrogen bonds and then tunable ferroelectric polarization induces controllable release of O22- under applied magnetic fields. This work presents a constructive way for controllable adsorption and release of reactive oxygen species.
Collapse
Affiliation(s)
- Wenqing Wei
- National Laboratory of Solid States Microstructures, School of Physics, Nanjing University, Nanjing 210093, P. R. China
| | - Shuo Liu
- National Laboratory of Solid States Microstructures, School of Physics, Nanjing University, Nanjing 210093, P. R. China
| | - Guoao Li
- Key Laboratory of Mesoscopic Chemistry of Ministry of Education, Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. China
| | - Kaihui Mao
- National Laboratory of Solid States Microstructures, School of Physics, Nanjing University, Nanjing 210093, P. R. China
| | - Ka Wang
- National Laboratory of Solid States Microstructures, School of Physics, Nanjing University, Nanjing 210093, P. R. China
| | - Xiaobing Xu
- College of Electronic Engineering, Nanjing Xiaozhuang University, Nanjing 211171, P. R. China
| | - Shuhua Li
- Key Laboratory of Mesoscopic Chemistry of Ministry of Education, Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. China
| | - Xinglong Wu
- National Laboratory of Solid States Microstructures, School of Physics, Nanjing University, Nanjing 210093, P. R. China
| |
Collapse
|
2
|
Dementyev P, Khayya N, Kreie J, Gölzhäuser A. Vapor Adsorption Measurements with Two-Dimensional Membranes. Chemphyschem 2021; 23:e202100732. [PMID: 34817107 PMCID: PMC9300110 DOI: 10.1002/cphc.202100732] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/22/2021] [Indexed: 11/08/2022]
Abstract
Two-dimensional (2D) membranes display extraordinary mass transfer properties, in particular for the permeation of gaseous substances. Their ultimate thickness not only ensures the shortest diffusion pathways, but also makes the membrane surface play a significant role in accommodating and guiding the permeating molecules. As saturated vapors of water and organic solvents are often observed to pass 2D membranes faster than inert gases, condensation is believed to be responsible for surface-mediated transport. Here, we present a spectroscopic experiment to probe adsorption of condensable species on 2D membranes under realistic conditions. Polarization-modulation infrared reflection absorption spectroscopy (PM IRAS) is coupled with a reaction chamber and a vacuum system to control the vaporous environments. The measurements are demonstrated to yield quantitative information on the amount of adsorbates onto supported 2D layers. As a case study, the azeotropic mixture of water and propanol is revealed to maintain its molar composition upon interaction with carbon nanomembranes.
Collapse
Affiliation(s)
- Petr Dementyev
- Faculty of Physics, Bielefeld University, Universitätsstr. 25, 33615, Bielefeld, Germany
| | - Neita Khayya
- Faculty of Physics, Bielefeld University, Universitätsstr. 25, 33615, Bielefeld, Germany
| | - Jakob Kreie
- Faculty of Physics, Bielefeld University, Universitätsstr. 25, 33615, Bielefeld, Germany
| | - Armin Gölzhäuser
- Faculty of Physics, Bielefeld University, Universitätsstr. 25, 33615, Bielefeld, Germany
| |
Collapse
|
3
|
Martinez MN, Smith AG, Nowack LM, Lin B, Rice SA. Interaction between dilute water vapor and dodecane thiol ligated Au nanoparticles: Hydrated structure and pair potential of mean force. J Chem Phys 2021; 155:144902. [PMID: 34654291 DOI: 10.1063/5.0065718] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The interaction between two ligated nanoparticles depends on whether they are isolated or immersed in a liquid solvent. However, very little is known about the influence of solvent vapor on the interaction between two ligated nanoparticles. Recent experiments yield the surprising result that the cyclic exposure of solvent free suspended monolayers of dodecane thiol ligated gold nanoparticles (AuNPs) to water vapor and dry nitrogen generates reversible cyclic decreases and increases in Young's modulus of the monolayer, implying corresponding cyclic changes in the AuNP-AuNP interaction. We examine how water vapor interacts with an isolated dodecane thiol dressed AuNP and how water vapor affects the interaction between a pair of nanoparticles, using all-atom molecular-dynamics simulations. We find that there is condensation of water molecules onto the ligand shell of an AuNP in the form of clusters of 100-2000 molecules that partially cover the shell, with most of the water in a few large clusters. A water cluster bridges the AuNPs, with a sensibly constant number of water molecules for AuNP-AuNP separations from the edge-to-edge contact up to center-to-center separations of 100 Å. The wet AuNP-AuNP interaction has a slightly deeper and wider asymmetric well than does the dry interaction, a change that is qualitatively consistent with that implied by the observed water vapor induced change in Young's modulus of a monolayer of these AuNPs. We find that macroscopic analyses of water drop-deformable surface interactions and dynamics provide both guidance to understanding and qualitatively correct predictions of the phenomena observed in our simulations.
Collapse
Affiliation(s)
- Michael N Martinez
- James Franck Institute, University of Chicago, 929 E. 57th Street, Chicago, Illinois 60637, USA
| | - Alex G Smith
- James Franck Institute, University of Chicago, 929 E. 57th Street, Chicago, Illinois 60637, USA
| | - Linsey M Nowack
- James Franck Institute, University of Chicago, 929 E. 57th Street, Chicago, Illinois 60637, USA
| | - Binhua Lin
- James Franck Institute, University of Chicago, 929 E. 57th Street, Chicago, Illinois 60637, USA
| | - Stuart A Rice
- James Franck Institute, University of Chicago, 929 E. 57th Street, Chicago, Illinois 60637, USA
| |
Collapse
|
4
|
Shiraiwa M, Carslaw N, Tobias DJ, Waring MS, Rim D, Morrison G, Lakey PSJ, Kruza M, von Domaros M, Cummings BE, Won Y. Modelling consortium for chemistry of indoor environments (MOCCIE): integrating chemical processes from molecular to room scales. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2019; 21:1240-1254. [PMID: 31070639 DOI: 10.1039/c9em00123a] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We report on the development of a modelling consortium for chemistry in indoor environments that connects models over a range of spatial and temporal scales, from molecular to room scales and from sub-nanosecond to days, respectively. Our modeling approaches include molecular dynamics (MD) simulations, kinetic process modeling, gas-phase chemistry modeling, organic aerosol modeling, and computational fluid dynamics (CFD) simulations. These models are applied to investigate ozone reactions with skin and clothing, oxidation of volatile organic compounds and formation of secondary organic aerosols, and mass transport and partitioning of indoor species to surfaces. MD simulations provide molecular pictures of limonene adsorption on SiO2 and ozone interactions with the skin lipid squalene, providing kinetic parameters such as surface accommodation coefficient, desorption lifetime, and bulk diffusivity. These parameters then constrain kinetic process models, which resolve mass transport and chemical reactions in gas and condensed phases for analysis of experimental data. A detailed indoor chemical box model is applied to simulate α-pinene ozonolysis with improved representation of gas-particle partitioning. Application of 2D-volatility basis set reveals that OH-induced aging sometimes drives increases in indoor organic aerosol concentrations, due to organic mass functionalization and enhanced partitioning. CFD simulations show that concentrations of ozone and primary product change near the human surface rapidly, indicating non-uniform spatial distributions from the occupant surface to ambient air, while secondary ozone product is relatively well-mixed throughout the room. This development establishes a framework to integrate different modeling tools and experimental measurements, opening up an avenue for development of comprehensive and integrated models with representations of various chemistry in indoor environments.
Collapse
Affiliation(s)
- Manabu Shiraiwa
- Department of Chemistry, University of California, Irvine, CA, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Rahman M, Al-Abadleh HA. Surface Water Structure and Hygroscopic Properties of Light Absorbing Secondary Organic Polymers of Atmospheric Relevance. ACS OMEGA 2018; 3:15519-15529. [PMID: 31458208 PMCID: PMC6644084 DOI: 10.1021/acsomega.8b02066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 11/01/2018] [Indexed: 06/09/2023]
Abstract
Hygroscopic properties and chemical reactivity of secondary organic aerosols (SOA) influence their overall contribution to the indirect effect on the climate. In this study, we investigate the hygroscopic properties of organic and organometallic polymeric particles, namely polycatechol, polyguaiacol, Fe-polyfumarte, and Fe-polymuconate. These particles efficiently form in iron-catalyzed reactions with aromatic and aliphatic dicarboxylic acid compounds detected in field-collected SOA. The structure of surface water was studied using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and the uptake of gas water was quantified using quartz crystal microbalance (QCM) as a function of relative humidity. Spectroscopic data show that water bonding with organic functional groups acting as hydrogen bond acceptors causes shifts in their vibrational modes. Analysis of the hydroxyl group stretching region revealed weak and strong hydrogen bonding networks that suggest cluster formation reflecting water-water and water-organics interactions, respectively. A modified Type II multilayer Brunauer-Emmett-Teller adsorption model described the adsorption isotherm on the nonporous materials, polycatechol, polyguaiacol, and Fe-polymuconate. However, water adsorption on porous Fe-polyfumarate was best described using a Type V adsorption model, namely the Langmuir-Sips model that accounts for condensation in pores. The data revealed that organometallic polymers are more hygroscopic than organic polymers. The implications of these investigations are discussed in the context of the chemical reactivity of these particles relative to known SOA.
Collapse
|
6
|
Guo Y, Wan R. Evaporation of nanoscale water on a uniformly complete wetting surface at different temperatures. Phys Chem Chem Phys 2018; 20:12272-12277. [PMID: 29687804 DOI: 10.1039/c8cp00037a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The evaporation of nanoscale water films on surfaces affects many processes in nature and industry. Using molecular dynamics (MD) simulations, we show the evaporation of a nanoscale water film on a uniformly complete wetting surface at different temperatures. With the increase in temperature, the growth of the water evaporation rate becomes slow. Analyses show that the hydrogen bond (H-bond) lifetimes and orientational autocorrelation times of the outermost water film decrease slowly with the increase in temperature. Compared to a thicker water film, the H-bond lifetimes and orientational autocorrelation times of a monolayer water film are much slower. This suggests that the lower evaporation rate of the monolayer water film on a uniformly complete wetting surface may be caused by the constriction of the water rotation due to the substrate. This finding may be helpful for controlling nanoscale water evaporation within a certain range of temperatures.
Collapse
Affiliation(s)
- Yuwei Guo
- Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P.O. Box 800-204, Shanghai 201800, China.
| | | |
Collapse
|
7
|
Bzdek BR, Reid JP. Perspective: Aerosol microphysics: From molecules to the chemical physics of aerosols. J Chem Phys 2017; 147:220901. [DOI: 10.1063/1.5002641] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Affiliation(s)
- Bryan R. Bzdek
- School of Chemistry, University of Bristol, Bristol BS8 1TS,
United Kingdom
| | - Jonathan P. Reid
- School of Chemistry, University of Bristol, Bristol BS8 1TS,
United Kingdom
| |
Collapse
|
8
|
|
9
|
Ramírez-Gutiérrez D, Nieto-Draghi C, Pannacci N, Castro LV, Álvarez-Ramírez F, Creton B. Surface photografting of acrylic acid on poly(dimethylsiloxane). Experimental and dissipative particle dynamics studies. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:1400-1409. [PMID: 25558765 DOI: 10.1021/la503694h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This work includes both experimental and theoretical studies of the wetting property changes of water on a surface of poly(dimethylsiloxane) (PDMS) modified with different amounts of acrylic acid (AA). The default surface properties of PDMS were changed from hydrophobic to hydrophilic behavior which was characterized with contact angle measurements by two approaches: (i) experimental tests of samples subjected to a photografting polymerization procedure to obtain a functionalized surface and (ii) DPD (dissipative particle dynamics) simulations which also involve the calculation of sets of repulsive parameters determined following two methods: the use of the "Blends" module in the Materials Studio software and the calculation of cohesive energy density with molecular simulations. Changes of contact angle values observed from both experimental and numerical simulation results provide qualitative and quantitative information on the wetting behavior of photografted surfaces.
Collapse
|
10
|
Shrestha M, Zhang Y, Upshur MA, Liu P, Blair SL, Wang HF, Nizkorodov SA, Thomson RJ, Martin ST, Geiger FM. On Surface Order and Disorder of α-Pinene-Derived Secondary Organic Material. J Phys Chem A 2015; 119:4609-17. [DOI: 10.1021/jp510780e] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Mona Shrestha
- Department
of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Yue Zhang
- School of Engineering and Applied Sciences & Department of Earth and Planetary Sciences, Harvard University, 29 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Mary Alice Upshur
- Department
of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Pengfei Liu
- School of Engineering and Applied Sciences & Department of Earth and Planetary Sciences, Harvard University, 29 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Sandra L. Blair
- Department
of Chemistry, University of California, 1102 Natural Sciences 2, Irvine, California 92697, United States
| | - Hong-fei Wang
- Environmental
Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 3335 Innovative Boulevard, Richland, Washington 99354, United States
| | - Sergey A. Nizkorodov
- Department
of Chemistry, University of California, 1102 Natural Sciences 2, Irvine, California 92697, United States
| | - Regan J. Thomson
- Department
of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Scot T. Martin
- School of Engineering and Applied Sciences & Department of Earth and Planetary Sciences, Harvard University, 29 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Franz M. Geiger
- Department
of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| |
Collapse
|
11
|
Al-Abadleh HA. Review of the bulk and surface chemistry of iron in atmospherically relevant systems containing humic-like substances. RSC Adv 2015. [DOI: 10.1039/c5ra03132j] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The current state of knowledge and future research directions of the bulk and surface chemistry of iron relevant to atmospheric surfaces are reviewed.
Collapse
Affiliation(s)
- Hind A. Al-Abadleh
- Department of Chemistry and Biochemistry
- Wilfrid Laurier University
- Waterloo
- Canada
| |
Collapse
|
12
|
Nishino N, Hollingsworth SA, Stern AC, Roeselová M, Tobias DJ, Finlayson-Pitts BJ. Interactions of gaseous HNO3 and water with individual and mixed alkyl self-assembled monolayers at room temperature. Phys Chem Chem Phys 2014; 16:2358-67. [PMID: 24352159 PMCID: PMC4000124 DOI: 10.1039/c3cp54118e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The major removal processes for gaseous nitric acid (HNO3) in the atmosphere are dry and wet deposition onto various surfaces. The surface in the boundary layer is often covered with organic films, but the interaction of gaseous HNO3 with them is not well understood. To better understand the factors controlling the uptake of gaseous nitric acid and its dissociation in organic films, studies were carried out using single component and mixtures of C8 and C18 alkyl self-assembled monolayers (SAMs) attached to a germanium (Ge) attenuated total reflectance (ATR) crystal upon which a thin layer of SiOx had been deposited. For comparison, diffuse reflectance infrared Fourier transform spectrometry (DRIFTS) studies were also carried out using a C18 SAM attached to the native oxide layer on the surface of silicon powder. These studies show that the alkyl chain length and order/disorder of the SAMs does not significantly affect the uptake or dissociation/recombination of molecular HNO3. Thus, independent of the nature of the SAM, molecular HNO3 is observed up to 70-90% relative humidity. After dissociation, molecular HNO3 is regenerated on all SAM surfaces when water is removed. Results of molecular dynamics simulations are consistent with experiments and show that defects and pores on the surfaces control the uptake, dissociation and recombination of molecular HNO3. Organic films on surfaces in the boundary layer will certainly be more irregular and less ordered than SAMs studied here, therefore undissociated HNO3 may be present on surfaces in the boundary layer to a greater extent than previously thought. The combination of this observation with the results of recent studies showing enhanced photolysis of nitric acid on surfaces suggests that renoxification of deposited nitric acid may need to be taken into account in atmospheric models.
Collapse
Affiliation(s)
- Noriko Nishino
- Department of Chemistry, University of California, Irvine, California, 92697-2025, USA
| | - Scott A. Hollingsworth
- Department of Molecular Biology and Biochemistry, University of California Irvine, CA, 92697-2025, USA
| | - Abraham C. Stern
- Department of Chemistry, University of California, Irvine, California, 92697-2025, USA
| | - Martina Roeselová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nam. 2, 16610 Prague 6, Czech Republic
| | - Douglas J. Tobias
- Department of Chemistry, University of California, Irvine, California, 92697-2025, USA
| | | |
Collapse
|
13
|
Nishino N, Arquero KD, Dawson ML, Finlayson-Pitts BJ. Infrared studies of the reaction of methanesulfonic acid with trimethylamine on surfaces. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 48:323-330. [PMID: 24304088 DOI: 10.1021/es403845b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Organosulfur compounds generated from a variety of biological as well as anthropogenic sources are oxidized in air to form sulfuric acid and methanesulfonic acid (MSA). Both of these acids formed initially in the gas phase react with ammonia and amines in air to form and grow new particles, which is important for visibility, human health and climate. A competing sink is deposition on surfaces in the boundary layer. However, relatively little is known about reactions after they deposit on surfaces. We report here diffuse reflectance infrared Fourier transform spectrometry (DRIFTS) studies of the reaction of MSA with trimethylamine (TMA) on a silicon powder at atmospheric pressure in synthetic air and at room temperature, either in the absence or in the presence of water vapor. In both cases, DRIFTS spectra of the product surface species are essentially the same as the transmission spectrum obtained for trimethylaminium methanesulfonate, indicating the formation of the salt on the surface with a lower limit to the reaction probability of γ > 10(-6). To the best of our knowledge, this is the first infrared study to demonstrate this chemistry from the heterogeneous reaction of MSA with an amine on a surface. This heterogeneous chemistry appears to be sufficiently fast that it could impact measurements of gas-phase amines through reactions with surface-adsorbed acids on sampling lines and inlets. It could also represent an additional sink for amines in the boundary layer, especially at night when the gas-phase reactions of amines with OH radical and ozone are minimized.
Collapse
Affiliation(s)
- Noriko Nishino
- Department of Chemistry, University of California , Irvine, California, 92697-2025, United States
| | | | | | | |
Collapse
|
14
|
Ebben CJ, Ault AP, Ruppel MJ, Ryder OS, Bertram TH, Grassian VH, Prather KA, Geiger FM. Size-Resolved Sea Spray Aerosol Particles Studied by Vibrational Sum Frequency Generation. J Phys Chem A 2013; 117:6589-601. [DOI: 10.1021/jp401957k] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Carlena J. Ebben
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208,
United States
| | - Andrew P. Ault
- Department
of Chemistry, University of Iowa, Iowa
City, Iowa 52242, United States
| | - Matthew J. Ruppel
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California
92093, United States
| | - Olivia S. Ryder
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California
92093, United States
| | - Timothy H. Bertram
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California
92093, United States
| | - Vicki H. Grassian
- Department
of Chemistry, University of Iowa, Iowa
City, Iowa 52242, United States
| | - Kimberly A. Prather
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California
92093, United States
- Scripps Institution of Oceanography, La Jolla, California 92093, United
States
| | - Franz M. Geiger
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208,
United States
| |
Collapse
|
15
|
Woodill LA, O’Neill EM, Hinrichs RZ. Impacts of Surface Adsorbed Catechol on Tropospheric Aerosol Surrogates: Heterogeneous Ozonolysis and Its Effects on Water Uptake. J Phys Chem A 2013; 117:5620-31. [DOI: 10.1021/jp400748r] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Laurie A. Woodill
- Department of Chemistry, Drew University, Madison, New Jersey 07940, United
States
| | - Erinn M. O’Neill
- Department of Chemistry, Drew University, Madison, New Jersey 07940, United
States
| | - Ryan Z. Hinrichs
- Department of Chemistry, Drew University, Madison, New Jersey 07940, United
States
| |
Collapse
|
16
|
Darvas M, Picaud S, Jedlovszky P. Molecular dynamics simulations of the water adsorption around malonic acid aerosol models. Phys Chem Chem Phys 2013; 15:10942-51. [DOI: 10.1039/c3cp50608h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
17
|
Moussa SG, Stern AC, Raff JD, Dilbeck CW, Tobias DJ, Finlayson-Pitts BJ. Experimental and theoretical studies of the interaction of gas phase nitric acid and water with a self-assembled monolayer. Phys Chem Chem Phys 2013; 15:448-58. [DOI: 10.1039/c2cp42405c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
18
|
Wang S, Tu Y, Wan R, Fang H. Evaporation of Tiny Water Aggregation on Solid Surfaces with Different Wetting Properties. J Phys Chem B 2012; 116:13863-7. [DOI: 10.1021/jp302142s] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Shen Wang
- Shanghai Institute of Applied
Physics, Chinese Academy of Sciences, P.O.
Box 800-204, Shanghai, 201800, China
- Graduate School of the Chinese Academy of Sciences, Beijing 100080,
China
| | - Yusong Tu
- Institute of Systems
Biology, Shanghai University, Shanghai,
200444, China
| | - Rongzheng Wan
- Shanghai Institute of Applied
Physics, Chinese Academy of Sciences, P.O.
Box 800-204, Shanghai, 201800, China
| | - Haiping Fang
- Shanghai Institute of Applied
Physics, Chinese Academy of Sciences, P.O.
Box 800-204, Shanghai, 201800, China
| |
Collapse
|
19
|
Tu A, Kwag HR, Barnette AL, Kim SH. Water adsorption isotherms on CH3-, OH-, and COOH-terminated organic surfaces at ambient conditions measured with PM-RAIRS. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:15263-9. [PMID: 23075312 DOI: 10.1021/la302848k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The water adsorption isotherms on methyl (CH(3))-, hydroxyl (OH)-, and carboxylic acid (COOH)-terminated alkylthiol self-assembled monolayers (SAMs) on Au were studied at room temperature and ambient pressure with polarization modulation reflection-absorption infrared spectroscopy (PM-RAIRS). PM-RAIRS analysis showed that water does not adsorb at all on the CH(3)-SAM/Au at subsaturation humidity conditions. In a dry Ar environment, the OH-SAM/Au holds at least 2 layer thick strongly bound water molecules which exhibit a broad O-H stretch vibration peak centered at ∼3360 cm(-1). The peak position implies that the strongly bound water layer on the OH SAM is more like a liquid than an ice. The additional uptake of water in humid environments is relatively weak, and the peak position changes very little. Unlike the OH-SAM/Au, the COOH-SAM/Au does not have strongly bound water layer. This seems to be due to the strong hydrogen bonding between terminal COOH groups in dry conditions. The weak interactions between water and carboxyl groups at low relative humidity (RH) and the solvation of dissociated carboxylic groups in high RH lead to a type III isotherm behavior, based on the BET categories, for water adsorption on the COOH-SAM/Au. The water spectra on the COOH-SAM at RH > 45% are centered at ∼3430 cm(-1) and very broad, indicating that the hydrogen-bonding network of water on the COOH-SAM is much different from that on the OH-SAM.
Collapse
Affiliation(s)
- Aimee Tu
- Department of Chemical Engineering and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | | | | | | |
Collapse
|
20
|
Cao P, Xu K, Varghese JO, Heath JR. The microscopic structure of adsorbed water on hydrophobic surfaces under ambient conditions. NANO LETTERS 2011; 11:5581-6. [PMID: 22050080 DOI: 10.1021/nl2036639] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The interaction of water vapor with hydrophobic surfaces is poorly understood. We utilize graphene templating to preserve and visualize the microscopic structures of adsorbed water on hydrophobic surfaces. Three well-defined surfaces [H-Si(111), graphite, and functionalized mica] were investigated, and water was found to adsorb as nanodroplets (∼10-100 nm in size) on all three surfaces under ambient conditions. The adsorbed nanodroplets were closely associated with atomic-scale surface defects and step-edges and wetted all the hydrophobic substrates with contact angles<∼10°, resulting in total water adsorption that was similar to what is found for hydrophilic surfaces. These results point to the significant differences between surface processes at the atomic/nanometer scales and in the macroscopic world.
Collapse
Affiliation(s)
- Peigen Cao
- Kavli Nanoscience Institute and Division of Chemistry and Chemical Engineering, California Institute of Technology, MC 127-72, Pasadena, California 91125, United States
| | | | | | | |
Collapse
|
21
|
James M, Ciampi S, Darwish TA, Hanley TL, Sylvester SO, Gooding JJ. Nanoscale water condensation on click-functionalized self-assembled monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:10753-10762. [PMID: 21780835 DOI: 10.1021/la202359c] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We have examined the nanoscale adsorption of molecular water under ambient conditions onto a series of well-characterized functionalized surfaces produced by Cu(I)-catalyzed alkyne-azide cycloaddition (CuAAC or "click") reactions on alkyne-terminated self-assembled monolayers on silicon. Water contact angle (CA) measurements reveal a range of macroscopic hydrophilicity that does not correlate with the tendency of these surfaces to adsorb water at the molecular level. X-ray reflectometry has been used to follow the kinetics of water adsorption on these "click"-functionalized surfaces, and also shows that dense continuous molecular water layers are formed over 30 h. For example, a highly hydrophilic surface, functionalized by an oligo(ethylene glycol) moiety (with a CA = 34°) showed 2.9 Å of adsorbed water after 30 h, while the almost hydrophobic underlying alkyne-terminated monolayer (CA = 84°) showed 5.6 Å of adsorbed water over the same period. While this study highlights the capacity of X-ray reflectometry to study the structure of adsorbed water on these surfaces, it should also serve as a warning for those intending to characterize self-assembled monolayers and functionalized surfaces to avoid contamination by even trace amounts of water vapor. Moreover, contact angle measurements alone cannot be relied upon to predict the likely degree of moisture uptake on such surfaces.
Collapse
Affiliation(s)
- Michael James
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC NSW 2232, Australia.
| | | | | | | | | | | |
Collapse
|
22
|
Xu Z, Song K, Yuan SL, Liu CB. Microscopic wetting of self-assembled monolayers with different surfaces: a combined molecular dynamics and quantum mechanics study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:8611-8620. [PMID: 21639099 DOI: 10.1021/la201328y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Molecular dynamics simulations are used to study the micronature of the organization of water molecules on the flat surface of well-ordered self-assembled monolayers (SAMs) of 18-carbon alkanethiolate chains bound to a silicon (111) substrate. Six different headgroups (-CH(3), -C═C, -OCH(3), -CN, -NH(2), -COOH) are used to tune the character of the surface from hydrophobic to hydrophilic, while the level of hydration is consistent on all six SAM surfaces. Quantum mechanics calculations are employed to optimize each alkyl chain of the different SAMs with one water molecule and to investigate changes in the configuration of each headgroup under hydration. We report the changes of the structure of the six SAMs with different surfaces in the presence of water, and the area of the wetted surface of each SAM, depending on the terminal group. Our results suggest that a corrugated and hydrophobic surface will be formed if the headgroups of SAM surface are not able to form H-bonds either with water molecules or between adjacent groups. In contrast, the formation of hydrogen bonds not only among polar heads but also between polar heads and water may enhance the SAM surface hydrophilicity and corrugation. We explicitly discuss the micromechanisms for the hydration of three hydrophilic SAM (CN-, NH(2)- and COOH-terminated) surfaces, which is helpful to superhydrophilic surface design of SAM in biomimetic materials.
Collapse
Affiliation(s)
- Zhen Xu
- Key Laboratory of Colloid and Interface Chemistry, Shandong University, Jinan, China
| | | | | | | |
Collapse
|
23
|
Casey G, Wentworth GR, Hamilton I, Al-Abadleh HA. Quantum chemical calculations on solvation effects for selected photoreactive aromatic organic molecules of atmospheric relevance. COMPUT THEOR CHEM 2011. [DOI: 10.1016/j.comptc.2010.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
24
|
Knopf DA, Forrester SM, Slade JH. Heterogeneous oxidation kinetics of organic biomass burning aerosol surrogates by O3, NO2, N2O5, and NO3. Phys Chem Chem Phys 2011; 13:21050-62. [DOI: 10.1039/c1cp22478f] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
25
|
Raff JD, Szanyi J, Finlayson-Pitts BJ. Thermal and photochemical oxidation of self-assembled monolayers on alumina particles exposed to nitrogen dioxide. Phys Chem Chem Phys 2011; 13:604-11. [DOI: 10.1039/c0cp01041c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
26
|
Moussa SG, Finlayson-Pitts BJ. Reaction of gas phase OH with unsaturated self-assembled monolayers and relevance to atmospheric organic oxidations. Phys Chem Chem Phys 2010; 12:9419-28. [PMID: 20532334 DOI: 10.1039/c000447b] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The kinetics and mechanisms of the reaction of gas phase OH radicals with organics on surfaces are of fundamental chemical interest, as well as relevant to understanding the degradation of organics on tropospheric surfaces or when they are components of airborne particles. We report here studies of the oxidation of a terminal alkene self-assembled monolayer (7-octenyltrichlorosilane, C8= SAM) on a germanium attenuated total reflectance crystal by OH radicals at a concentration of 2.1 x 10(5) cm(-3) at 1 atm total pressure and 298 K in air. Loss of the reactant SAM and the formation of surface products were followed in real time using infrared spectroscopy. From the rate of loss of the C=C bond, a reaction probability within experimental error of unity was derived. The products formed on the surface include organic nitrates and carbonyl compounds, with yields of 10 +/- 4% and < or = 7 +/- 4%, respectively, and there is evidence for the formation of organic products with C-O bonds such as alcohols, ethers and/or alkyl peroxides and possibly peroxynitrates. The yield of organic nitrates relative to carbonyl compounds is higher than expected based on analogous gas phase mechanisms, suggesting that the branching ratio for the RO(2) + NO reaction is shifted to favor the formation of organic nitrates when the reaction occurs on a surface. Water uptake onto the surface was only slightly enhanced upon oxidation, suggesting that oxidation per se cannot be taken as a predictor of increased hydrophilicity of atmospheric organics. These experiments indicate that the mechanisms for the surface reactions are different from gas phase reactions, but the OH oxidation of surface species will still be a significant contributor to determining their lifetimes in air.
Collapse
Affiliation(s)
- Samar G Moussa
- Department of Chemistry, University of California, Irvine, California 92697-2025, USA
| | | |
Collapse
|
27
|
Njegic B, Raff JD, Finlayson-Pitts BJ, Gordon MS, Gerber RB. Catalytic Role for Water in the Atmospheric Production of ClNO. J Phys Chem A 2010; 114:4609-18. [DOI: 10.1021/jp912155a] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Bosiljka Njegic
- Department of Chemistry, University of California, Irvine, California 92697-2025, Department of Chemistry, Iowa State University, Ames, Iowa 50011, and The Institute of Chemistry, The Hebrew University, Jerusalem, 91904, Israel
| | - Jonathan D. Raff
- Department of Chemistry, University of California, Irvine, California 92697-2025, Department of Chemistry, Iowa State University, Ames, Iowa 50011, and The Institute of Chemistry, The Hebrew University, Jerusalem, 91904, Israel
| | - Barbara J. Finlayson-Pitts
- Department of Chemistry, University of California, Irvine, California 92697-2025, Department of Chemistry, Iowa State University, Ames, Iowa 50011, and The Institute of Chemistry, The Hebrew University, Jerusalem, 91904, Israel
| | - Mark S. Gordon
- Department of Chemistry, University of California, Irvine, California 92697-2025, Department of Chemistry, Iowa State University, Ames, Iowa 50011, and The Institute of Chemistry, The Hebrew University, Jerusalem, 91904, Israel
| | - R. Benny Gerber
- Department of Chemistry, University of California, Irvine, California 92697-2025, Department of Chemistry, Iowa State University, Ames, Iowa 50011, and The Institute of Chemistry, The Hebrew University, Jerusalem, 91904, Israel
| |
Collapse
|
28
|
Takahama S, Liu S, Russell LM. Coatings and clusters of carboxylic acids in carbon-containing atmospheric particles from spectromicroscopy and their implications for cloud-nucleating and optical properties. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009jd012622] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
|
29
|
Szőri M, Jedlovszky P, Roeselová M. Water adsorption on hydrophilic and hydrophobic self-assembled monolayers as proxies for atmospheric surfaces. A grand canonical Monte Carlo simulation study. Phys Chem Chem Phys 2010; 12:4604-16. [DOI: 10.1039/b923382b] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
30
|
Miller Y, Thomas JL, Kemp DD, Finlayson-Pitts BJ, Gordon MS, Tobias DJ, Gerber RB. Structure of Large Nitrate−Water Clusters at Ambient Temperatures: Simulations with Effective Fragment Potentials and Force Fields with Implications for Atmospheric Chemistry. J Phys Chem A 2009; 113:12805-14. [DOI: 10.1021/jp9070339] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Yifat Miller
- Department of Physical Chemistry and the Fritz Haber Research Center for Molecular Dynamics, Hebrew University, Jerusalem 91904, Israel, Department of Chemistry and AirUCI, University of California, Irvine, California 92697-2025, and Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | - Jennie L. Thomas
- Department of Physical Chemistry and the Fritz Haber Research Center for Molecular Dynamics, Hebrew University, Jerusalem 91904, Israel, Department of Chemistry and AirUCI, University of California, Irvine, California 92697-2025, and Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | - Daniel D. Kemp
- Department of Physical Chemistry and the Fritz Haber Research Center for Molecular Dynamics, Hebrew University, Jerusalem 91904, Israel, Department of Chemistry and AirUCI, University of California, Irvine, California 92697-2025, and Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | - Barbara J. Finlayson-Pitts
- Department of Physical Chemistry and the Fritz Haber Research Center for Molecular Dynamics, Hebrew University, Jerusalem 91904, Israel, Department of Chemistry and AirUCI, University of California, Irvine, California 92697-2025, and Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | - Mark S. Gordon
- Department of Physical Chemistry and the Fritz Haber Research Center for Molecular Dynamics, Hebrew University, Jerusalem 91904, Israel, Department of Chemistry and AirUCI, University of California, Irvine, California 92697-2025, and Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | - Douglas J. Tobias
- Department of Physical Chemistry and the Fritz Haber Research Center for Molecular Dynamics, Hebrew University, Jerusalem 91904, Israel, Department of Chemistry and AirUCI, University of California, Irvine, California 92697-2025, and Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | - R. Benny Gerber
- Department of Physical Chemistry and the Fritz Haber Research Center for Molecular Dynamics, Hebrew University, Jerusalem 91904, Israel, Department of Chemistry and AirUCI, University of California, Irvine, California 92697-2025, and Department of Chemistry, Iowa State University, Ames, Iowa 50011
| |
Collapse
|
31
|
Giovambattista N, Debenedetti PG, Rossky PJ. Enhanced surface hydrophobicity by coupling of surface polarity and topography. Proc Natl Acad Sci U S A 2009; 106:15181-5. [PMID: 19706474 PMCID: PMC2741225 DOI: 10.1073/pnas.0905468106] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2009] [Indexed: 11/18/2022] Open
Abstract
We use atomistic computer simulation to explore the relationship between mesoscopic (liquid drop contact angle) and microscopic (surface atomic polarity) characteristics for water in contact with a model solid surface based on the structure of silica. We vary both the magnitude and direction of the solid surface polarity at the atomic scale and characterize the response of an aqueous interface in terms of the solvent molecular organization and contact angle. We show that when the topography and polarity of the surface act in concert with the asymmetric charge distribution of water, the hydrophobicity varies substantially and, further, can be maximal for a surface with significant polarity. The results suggest that patterning of a surface on several length scales, from atomic to mum lengths, can make important independent contributions to macroscopic hydrophobicity.
Collapse
Affiliation(s)
- Nicolas Giovambattista
- Department of Physics, Brooklyn College of the City University of New York, Brooklyn, NY 11210-2889
- Department of Chemical Engineering, Princeton University, Princeton, NJ 08544-5263; and
| | - Pablo G. Debenedetti
- Department of Chemical Engineering, Princeton University, Princeton, NJ 08544-5263; and
| | - Peter J. Rossky
- Department of Chemistry and Biochemistry and Institute for Computational Engineering and Sciences, University of Texas, Austin, TX 78712
| |
Collapse
|
32
|
Chlorine activation indoors and outdoors via surface-mediated reactions of nitrogen oxides with hydrogen chloride. Proc Natl Acad Sci U S A 2009; 106:13647-54. [PMID: 19620710 DOI: 10.1073/pnas.0904195106] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Gaseous HCl generated from a variety of sources is ubiquitous in both outdoor and indoor air. Oxides of nitrogen (NO(y)) are also globally distributed, because NO formed in combustion processes is oxidized to NO(2), HNO(3), N(2)O(5) and a variety of other nitrogen oxides during transport. Deposition of HCl and NO(y) onto surfaces is commonly regarded as providing permanent removal mechanisms. However, we show here a new surface-mediated coupling of nitrogen oxide and halogen activation cycles in which uptake of gaseous NO(2) or N(2)O(5) on solid substrates generates adsorbed intermediates that react with HCl to generate gaseous nitrosyl chloride (ClNO) and nitryl chloride (ClNO(2)), respectively. These are potentially harmful gases that photolyze to form highly reactive chlorine atoms. The reactions are shown both experimentally and theoretically to be enhanced by water, a surprising result given the availability of competing hydrolysis reaction pathways. Airshed modeling incorporating HCl generated from sea salt shows that in coastal urban regions, this heterogeneous chemistry increases surface-level ozone, a criteria air pollutant, greenhouse gas and source of atmospheric oxidants. In addition, it may contribute to recently measured high levels of ClNO(2) in the polluted coastal marine boundary layer. This work also suggests the potential for chlorine atom chemistry to occur indoors where significant concentrations of oxides of nitrogen and HCl coexist.
Collapse
|
33
|
Stokes GY, Chen EH, Walter SR, Geiger FM. Two Reactivity Modes in the Heterogeneous Cyclohexene Ozonolysis under Tropospherically Relevant Ozone-Rich and Ozone-Limited Conditions. J Phys Chem A 2009; 113:8985-93. [DOI: 10.1021/jp904104s] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Grace Y. Stokes
- Department of Chemistry, Northwestern University, 2145 Sheridan Rd. Evanston, Illinois 60208
| | - Ehow H. Chen
- Department of Chemistry, Northwestern University, 2145 Sheridan Rd. Evanston, Illinois 60208
| | - Stephanie R. Walter
- Department of Chemistry, Northwestern University, 2145 Sheridan Rd. Evanston, Illinois 60208
| | - Franz M. Geiger
- Department of Chemistry, Northwestern University, 2145 Sheridan Rd. Evanston, Illinois 60208
| |
Collapse
|
34
|
Cowen S, Al-Abadleh HA. DRIFTS studies on the photodegradation of tannic acid as a model for HULIS in atmospheric aerosols. Phys Chem Chem Phys 2009; 11:7838-47. [PMID: 19727490 DOI: 10.1039/b905236d] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Humic like substances (HULIS) are important components of atmospheric aerosols, yet little is known about their photochemical transformation and the role of adsorbed water in this photochemistry. We report herein in situ and surface-sensitive spectroscopic studies on (1) the photodegradation of solid tannic acid, (2) structure of adsorbed water before and after photodegradation, and (3) the change in the hydrophilicity of tannic acid as a result of this photochemistry. Tannic acid (TA) was chosen as a synthetic proxy for HULIS because it has a defined molecular structure. Photochemical studies were conducted using diffuse reflectance infrared spectroscopy (DRIFTS) as a function of time (3 h), relative humidity (5-30%) and total irradiance (7, 20, 290 W m(-2) at 555 nm). Water adsorption isotherm measurements were recorded before and after photodegradation, which provided information on the structure of interfacial water and the thermodynamics of adsorption. The structure of water adsorbed on TA resembles that of water at the interface with polar organic solvents. Difference spectral data collected during irradiation shows loss features in the 1700-1000 cm(-1) range and growth in carbonyl features that are blue shifted relative to the starting material, suggesting oxidative photodegradation of TA and formation of aryl aldehydes. Under our experimental conditions, we observed no enhancement in water uptake after photodegradation relative to that on unirradiated samples. The implications of our results to the understanding of heterogeneous photochemistry of HULIS and the role of adsorbed water in these reactions are discussed.
Collapse
Affiliation(s)
- Scott Cowen
- Department of Chemistry, University of Guelph, Guelph, Ontario, Canada
| | | |
Collapse
|
35
|
Finlayson-Pitts BJ. Reactions at surfaces in the atmosphere: integration of experiments and theory as necessary (but not necessarily sufficient) for predicting the physical chemistry of aerosols. Phys Chem Chem Phys 2009; 11:7760-79. [DOI: 10.1039/b906540g] [Citation(s) in RCA: 203] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
|