1
|
Kim K, Kim B, Ahn YY, Tran KD, My Truong HT, Kim J. Production of Molecular Iodine via a Redox Reaction between Iodate and Organic Compounds in Ice. J Phys Chem A 2023; 127:2830-2838. [PMID: 36919929 DOI: 10.1021/acs.jpca.3c00482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
The abiotic mechanism of molecular iodine (I2) production from iodate (IO3-) remains largely unknown. Here, we demonstrate the production of I2 in the presence of IO3- and organic compounds in ice. When the solution containing IO3- (100 μM) and furfuryl alcohol (100 μM) at pH 3.0 was frozen at -20 °C, 13.1 μM of I2 was produced with complete degradation of furfuryl alcohol after 20 min. However, there was little change in the IO3- and furfuryl alcohol concentrations in water at 25 °C. The production of I2 in ice is due to the freeze concentration effect, which induces the accumulation of IO3-, furfuryl alcohol, and protons in the ice grain boundaries. This behavior facilitated the production of I2 via a redox reaction between IO3- and organic compounds. The production of I2 increased with increasing furfuryl alcohol concentration and decreasing pH. However, freezing temperature had a minor effect on the maximum production of I2. The production of I2 is highly dependent on the type of organic compounds. It was higher for organic compounds with higher electron-donating properties. This study suggests a new mechanism for I2 production, which is helpful for predicting precisely the atmospheric I2 budget in cold regions.
Collapse
Affiliation(s)
- Kitae Kim
- Korea Polar Research Institute (KOPRI), Incheon 21990, Republic of Korea.,Department of Polar Sciences, University of Science and Technology (UST), Incheon 21990, Republic of Korea
| | - Bomi Kim
- Korea Polar Research Institute (KOPRI), Incheon 21990, Republic of Korea.,Department of Polar Sciences, University of Science and Technology (UST), Incheon 21990, Republic of Korea
| | - Yong-Yoon Ahn
- Korea Polar Research Institute (KOPRI), Incheon 21990, Republic of Korea
| | - Khen Duy Tran
- Department of Environmental Sciences and Biotechnology, Hallym University, Chuncheon, Gangwon-do 24252, Republic of Korea
| | - Hanh Thi My Truong
- Department of Environmental Sciences and Biotechnology, Hallym University, Chuncheon, Gangwon-do 24252, Republic of Korea
| | - Jungwon Kim
- Department of Environmental Sciences and Biotechnology, Hallym University, Chuncheon, Gangwon-do 24252, Republic of Korea
| |
Collapse
|
2
|
Kim K, Ju J, Kim B, Chung HY, Vetráková L, Heger D, Saiz-Lopez A, Choi W, Kim J. Nitrite-Induced Activation of Iodate into Molecular Iodine in Frozen Solution. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:4892-4900. [PMID: 30916540 DOI: 10.1021/acs.est.8b06638] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A new mechanism for the abiotic production of molecular iodine (I2) from iodate (IO3-), which is the most abundant iodine species, in dark conditions was identified and investigated. The production of I2 in aqueous solution containing IO3- and nitrite (NO2-) at 25 °C was negligible. However, the redox chemical reaction between IO3- and NO2- rapidly proceeded in frozen solution at -20 °C, which resulted in the production of I2, I-, and NO3-. The rapid redox chemical reaction between IO3- and NO2- in frozen solution is ascribed to the accumulation of IO3-, NO2-, and protons in the liquid regions between ice crystals during freezing (freeze concentration effect). This freeze concentration effect was verified by confocal Raman microscopy for the solute concentration and UV-visible absorption spectroscopy with cresol red (acid-base indicator) for the proton concentration. The freezing-induced production of I2 in the presence of IO3- and NO2- was observed under various conditions, which suggests this abiotic process for I2 production is not restricted to a specific region and occurs in many cold regions. NO2--induced activation of IO3- to I2 in frozen solution may help explain why the measured values of iodine are larger than the modeled values in some polar areas.
Collapse
Affiliation(s)
- Kitae Kim
- Korea Polar Research Institute (KOPRI) , Incheon 21990 , Republic of Korea
- Department of Polar Sciences , University of Science and Technology (UST) , Incheon 21990 , Republic of Korea
| | - Jinjung Ju
- Department of Environmental Sciences and Biotechnology , Hallym University , Chuncheon , Gangwon-do 24252 , Republic of Korea
| | - Bomi Kim
- Korea Polar Research Institute (KOPRI) , Incheon 21990 , Republic of Korea
- Department of Polar Sciences , University of Science and Technology (UST) , Incheon 21990 , Republic of Korea
| | - Hyun Young Chung
- Korea Polar Research Institute (KOPRI) , Incheon 21990 , Republic of Korea
- Department of Polar Sciences , University of Science and Technology (UST) , Incheon 21990 , Republic of Korea
| | - L'ubica Vetráková
- Department of Chemistry and Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science , Masaryk University , Kamenice 5 , 625 00 Brno , Czech Republic
| | - Dominik Heger
- Department of Chemistry and Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science , Masaryk University , Kamenice 5 , 625 00 Brno , Czech Republic
| | - Alfonso Saiz-Lopez
- Department of Atmospheric Chemistry and Climate , Institute of Physical Chemistry Rocasolano, CSIC , Madrid 28006 , Spain
| | - Wonyong Choi
- Division of Environmental Science and Engineering , Pohang University of Science and Technology (POSTECH) , Pohang 37673 , Republic of Korea
| | - Jungwon Kim
- Department of Environmental Sciences and Biotechnology , Hallym University , Chuncheon , Gangwon-do 24252 , Republic of Korea
| |
Collapse
|
3
|
Iskra J, Murphree SS. Rapid aerobic iodination of arenes mediated by hypervalent iodine in fluorinated solvents. Tetrahedron Lett 2017. [DOI: 10.1016/j.tetlet.2017.01.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
4
|
Hojo M, Yamamoto M, Okamura K. Dilute nitric or nitrous acid solution containing halide ions as effective media for pure gold dissolution. Phys Chem Chem Phys 2015; 17:19948-56. [DOI: 10.1039/c5cp02288f] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Bromide salts are more effective than chloride salts in gaining the ability of dissolving gold in dilute aqueous nitric acid solution. At 60 °C, a piece of gold-wire (ca. 20 mg) is dissolved in 20 mL of as low as 0.10 mol L−1 HNO3 solution containing 1.0–5.0 mol L−1 NaBr and the dissolution rate constant, log(k/s−1), increases linearly with increasing NaBr concentration.
Collapse
Affiliation(s)
- Masashi Hojo
- Department of Chemistry
- Faculty of Science
- Kochi University
- Akebono-cho
- Japan
| | - Masahiko Yamamoto
- Department of Chemistry
- Faculty of Science
- Kochi University
- Akebono-cho
- Japan
| | - Kei Okamura
- Center for Advanced Marine Core Research
- Kochi University
- Nankoku
- Japan
| |
Collapse
|
5
|
O’Concubhair R, Sodeau JR. The effect of freezing on reactions with environmental impact. Acc Chem Res 2013; 46:2716-24. [PMID: 23829881 DOI: 10.1021/ar400114e] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The knowledge that the freezing process can accelerate certain chemical reactions has been available since the 1960s, particularly in relation to the food industry. However, investigations into such effects on environmentally relevant reactions have only been carried out since the late 1980s. Some 20 years later, the field has matured and scientists have conducted research into various important processes such as the oxidation of nitrite ions to nitrates, sulfites to sulfates, and elemental mercury to inorganic mercury. Field observations mainly carried out in the polar regions have driven this work. For example, researchers have found that both ozone and mercury are removed from the troposphere completely (and almost instantaneously) at the time of Arctic polar sunrise. The monitoring activities suggested that both the phenomena were caused by involvement of bromine (and possibly iodine) chemistry. Scientists investigating the production of interhalide products (bromine and iodine producing interhalides) in frozen aqueous solutions have found that these reactions result in both rate accelerations and unexpected products. Furthermore, these scientists did this research with environmentally relevant concentrations of reagents, thereby suggesting that these reactions could occur in the polar regions. The conversion of elemental mercury to more oxidized forms has also shown that the acceleration of reactions can occur when environmentally relevant concentrations of Hg(0) and oxidants are frozen together in aqueous solutions. These observations, coupled with previous investigations into the effect of freezing on environmental reactions, lead us to conclude that this type of chemistry could potentially play a significant role in the chemical processing of a wide variety of inorganic components in polar regions. More recently, researchers have recognized the implications of these complementary field and laboratory findings toward human health and climate change. In this Account, we focus on the chemical and physical mechanisms that may promote novel chemistry and rate accelerations when water-ice is present. Future prospects will likely concentrate, once again, on the low-temperature chemistry of organic compounds, such as the humic acids, which are known cryospheric contaminants. Furthermore, data on the kinetics and thermodynamics of all types of reaction promoted by the freezing process would provide much assistance in determining their implications to environmental computer models.
Collapse
Affiliation(s)
- Ruairí O’Concubhair
- Department of Chemistry and Environmental Research Institute, University College Cork, Cork, Ireland
| | - John R. Sodeau
- Department of Chemistry and Environmental Research Institute, University College Cork, Cork, Ireland
| |
Collapse
|
6
|
Bedrač L, Iskra J. Iodine(I) Reagents in Hydrochloric Acid-Catalyzed Oxidative Iodination of Aromatic Compounds by Hydrogen Peroxide and Iodine. Adv Synth Catal 2013. [DOI: 10.1002/adsc.201300127] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
7
|
|
8
|
O'Concubhair R, Sodeau JR. Freeze-induced formation of bromine/chlorine interhalogen species from aqueous halide ion solutions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:10589-10596. [PMID: 22938711 DOI: 10.1021/es301988s] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Both gaseous bromine and bromine chloride have been monitored in polar environments and implicated in the destruction of tropospheric ozone. The formation mechanisms operating for these halogen compounds have been suggested previously. However, few laboratory studies have been performed using environmentally relevant concentrations of bromide and chloride ions in polar ice mimics. In aqueous solutions held at room temperature, previous studies have shown that the major product is the Cl(2)Br¯ trihalide ion when solutions of bromate, hydrochloric acid, and bromide ions are left to equilibrate. In contrast, the results of the cryochemical experiments presented here suggest that the dibromochloride ion (BrBrCl¯) is the major product when solutions of bromate, sulfuric acid, bromide, and chloride ions are frozen. Such a species would preferentially release bromine to the gas phase. Hence, similar halide starting materials form structurally different trihalide ions when frozen, which are capable of releasing differing active halogens, BrCl and Br(2), to the gas-phase. This is a potentially important finding because Br(2) is photolyzed more readily and to longer wavelengths than BrCl and therefore the efficiency in forming products that can lead to ozone destruction in the atmosphere would be increased. Evidence is provided for the mechanism to occur by means of both the freeze-concentration effect and the incorporation of ions into the growing ice phase.
Collapse
|
9
|
Rhyman L, Armata N, Ramasami P, Dyke JM. A Study of the Atmospherically Important Reactions between Dimethyl Selenide (DMSe) and Molecular Halogens (X2 = Cl2, Br2, and I2) with ab initio Calculations. J Phys Chem A 2012; 116:5595-603. [DOI: 10.1021/jp302750a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lydia Rhyman
- Computational Chemistry Group,
Department of Chemistry, University of Mauritius, Réduit, Mauritius
| | - Nerina Armata
- School of Chemistry, University of Southampton, Southampton, UK SO17 1BJ
| | - Ponnadurai Ramasami
- Computational Chemistry Group,
Department of Chemistry, University of Mauritius, Réduit, Mauritius
| | - John M. Dyke
- School of Chemistry, University of Southampton, Southampton, UK SO17 1BJ
| |
Collapse
|
10
|
O'Concubhair R, O'Sullivan D, Sodeau JR. Dark oxidation of dissolved gaseous mercury in polar ice mimics. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:4829-4836. [PMID: 22482942 DOI: 10.1021/es300309n] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The low-temperature chemistry associated with environmentally available mercury has recently attracted considerable scientific interest due to the discovery of systemic gas-phase mercury depletion events (MDEs) which occur periodically at the poles. However, the fate of the mercury once it enters the snowpack is not fully understood, even its chemical speciation has yet to be well characterized. An issue that is of particular concern in frozen environments is the transformation of elemental mercury (Hg(0)) to more bioavailable oxidized forms, which can then be methylated by biotic and abiotic processes. The resulting methyl mercury species produced can bioaccumulate through the food chain and the health effects of this on humans and mammals have been well-documented. During the current study, a novel set of "freeze-induced" pathways, which can potentially affect the reactivity of dissolved gaseous mercury (DGM) were followed. The experiments were performed using environmentally relevant cosolutes at appropriate concentration levels and temperatures. Evidence is thereby presented that due to rate accelerations associated with the operation of the freeze-concentration effect, DGM is oxidized to Hg(2+) ions when frozen in the presence of a variety of materials including hydrogen peroxide, nitrous acid and the sulfuric acid/O(2) couple.
Collapse
Affiliation(s)
- Ruairí O'Concubhair
- Department of Chemistry and Environmental Research Institute, University College Cork, Cork, Ireland
| | | | | |
Collapse
|
11
|
He S, Wang B, Chen H, Tang C, Feng Y. Preparation and antimicrobial properties of gemini surfactant-supported triiodide complex system. ACS APPLIED MATERIALS & INTERFACES 2012; 4:2116-2123. [PMID: 22404136 DOI: 10.1021/am300094f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Iodine is an effective, simple, and inexpensive bactericide in disinfection. However, the poor solubility and stability of iodine in water limit its applications. In addition, the active iodine content in the commercial iodophors is quite low, and the reported triiodide complex is unstable. In this work, a long-term stable triiodide complex antimicrobial system was prepared by mixing iodine and a cationic gemini surfactant into lauryldimethylamine oxide (LDAO) aqueous solution, and its stability was examined by means of UV-vis spectrophotometry. It was found that the content of LDAO, cationic gemini surfactant and H(2)SO(4) played crucial roles in stabilizing antimicrobial system, and the active iodine (i.e., triiodide complex) content of the optimum formulation can remain stable for 150 days, as iodine is encapsulated by the mixed vesicles assembled by the protonated LDAO and the added gemini surfactant. However, the active iodine reduced rapidly when NaCl was added or the pH was increased in the environment. Furthermore, the antimicrobial efficacy of the optimized formulation was studied against Candida albicans, and more than 4 log reduction in viable cell after 5 min of contact was obtained.
Collapse
Affiliation(s)
- Shuai He
- Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, People's Republic of China
| | | | | | | | | |
Collapse
|
12
|
Beccaceci S, Armata N, Ogden JS, Dyke JM, Rhyman L, Ramasami P. A study of the atmospherically important reactions of dimethylsulfide (DMS) with I2 and ICl using infrared matrix isolation spectroscopy and electronic structure calculations. Phys Chem Chem Phys 2012; 14:2399-407. [DOI: 10.1039/c2cp23392d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
13
|
Saiz-Lopez A, Plane JMC, Baker AR, Carpenter LJ, von Glasow R, Gómez Martín JC, McFiggans G, Saunders RW. Atmospheric Chemistry of Iodine. Chem Rev 2011; 112:1773-804. [DOI: 10.1021/cr200029u] [Citation(s) in RCA: 383] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Alfonso Saiz-Lopez
- Laboratory for Atmospheric and Climate Science (CIAC), CSIC, Toledo, Spain
| | - John M. C. Plane
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Alex R. Baker
- School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Lucy J. Carpenter
- Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Roland von Glasow
- School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | | | - Gordon McFiggans
- School of Earth, Atmospheric & Environmental Sciences, University of Manchester, Manchester, M13 9PL, United Kingdom
| | | |
Collapse
|
14
|
Crider PE, Harrison AW, Neumark DM. Two- and three-body photodissociation dynamics of diiodobromide (I2Br−) anion. J Chem Phys 2011; 134:134306. [DOI: 10.1063/1.3571474] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
15
|
O'Sullivan D, Sodeau JR. Freeze-induced reactions: formation of iodine-bromine interhalogen species from aqueous halide ion solutions. J Phys Chem A 2010; 114:12208-15. [PMID: 21043531 DOI: 10.1021/jp104910p] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Interhalide ion formation resulting from the freezing of dilute solutions containing components found in natural sea salt are investigated as a potential mechanism for the release of interhalogens to the polar atmosphere. Acidified solutions containing iodide, bromide, and nitrite ions have been frozen and then thawed, with changes in speciation analyzed using UV-visible spectrophotometry. The freezing process is shown to induce the formation of the important interhalide ion, IBr(2)(-). This species has previously been predicted to be a precursor of iodine monobromide, IBr, and represents a potentially important source of halogen atoms in the polar marine boundary layer. The reaction mechanisms that lead to the formation of IBr(2)(-) under freezing conditions are explored using both experimental and computational methodologies. The chemistry involved was subsequently modified in order to mimic naturally occurring conditions more closely and also incorporated the use of hydrogen peroxide as an oxidant. In contrast to previous studies, the freeze-induced production of IBr(2)(-) was thereby observed to occur up to pH <5.1, where the acidity levels are comparable to those found in the polar snowpack.
Collapse
Affiliation(s)
- Daniel O'Sullivan
- Department of Chemistry and Environmental Research Institute, University College Cork, Cork, Ireland
| | | |
Collapse
|
16
|
Beccaceci S, Ogden JS, Dyke JM. Spectroscopic study of the reaction between Br2 and dimethyl sulfide (DMS), and comparison with a parallel study made on Cl2 + DMS: possible atmospheric implications. Phys Chem Chem Phys 2010; 12:2075-82. [DOI: 10.1039/b917173h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
|
17
|
Anastasio C, Chu L. Photochemistry of nitrous acid (HONO) and nitrous acidium ion (H2ONO) in aqueous solution and ice. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:1108-1114. [PMID: 19320166 DOI: 10.1021/es802579a] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We have examined the photochemistries of two N(III) species, nitrous acid (HONO) and nitrous acidium ion (H2ONO+), in solution and ice. Although the light absorption spectra for these two species are very similar, their photochemical efficiencies are quite different: the *OH (and NO) quantum yield for HONO is approximately 8 times greater than that of H2ONO+ at 274 K. The temperature dependent expressions for the *OH (and NO) quantum yields are In(phi(HONO --> *OH) = (7.14 +/- 0.57) - (2430 +/- 160)/T and In(phi(H2ONO+ --> *OH) = (3.16 +/- 0.67) - (1890 +/- 180)/T. The temperature dependence for H2ONO+ includes both solution and ice data (255-283 K), suggesting that its ice photochemistry is occurring in a quasi-liquid environment. The quantum yields for HONO and H2ONO+ are independent of wavelength, in contrast to NO2-. On the basis of the pH dependence of N(III) photolysis, our results are consistent with recently reported pKa values of 1.7 for H2ONO+ and 2.8 for HONO. Using our results in a kinetic model of nitrogen chemistry illustrates that the fluxes of HONO and NO(x) from sunlit snow can be explained by nitrate photolysis and are pH dependent because of a competition between HONO evaporation and N(III) reactions on ice grains.
Collapse
Affiliation(s)
- Cort Anastasio
- Atmosphere Science Program, Department of Land, Air, and Water Resources, University of California, One Shields Avenue, Davis, California 95616-8627, USA.
| | | |
Collapse
|
18
|
Huang RJ, Hoffmann T. Development of a Coupled Diffusion Denuder System Combined with Gas Chromatography/Mass Spectrometry for the Separation and Quantification of Molecular Iodine and the Activated Iodine Compounds Iodine Monochloride and Hypoiodous Acid in the Marine Atmosphere. Anal Chem 2009; 81:1777-83. [DOI: 10.1021/ac801839v] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ru-Jin Huang
- Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg-University of Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany
| | - Thorsten Hoffmann
- Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg-University of Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany
| |
Collapse
|
19
|
O'Driscoll P, Minogue N, Takenaka N, Sodeau J. Release of nitric oxide and iodine to the atmosphere from the freezing of sea-salt aerosol components. J Phys Chem A 2008; 112:1677-82. [PMID: 18251528 DOI: 10.1021/jp710464c] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The known room-temperature, solution-phase reaction between nitrite ions and iodide ions, which occurs in acidic conditions (pH < 5.5), is shown to be accelerated when neutral aqueous solutions are frozen. The reaction is proposed to occur in liquid "micropockets" within the ice structure at temperatures between the freezing point and the eutectic temperature. The products, nitric oxide and molecular iodine, are known to play significant roles in atmospheric compositional change, and therefore, the results obtained here, which are not dependent on acidification, may impact on observed snowpack chemistry. Investigation of the effect of oxygen on the chemical processing indicates that a chain reaction mechanism is operative.
Collapse
|
20
|
Takenaka N, Bandow H. Chemical Kinetics of Reactions in the Unfrozen Solution of Ice. J Phys Chem A 2007; 111:8780-6. [PMID: 17705357 DOI: 10.1021/jp0738356] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Some reactions are accelerated in ice compared to aqueous solution at higher temperatures. Accelerated reactions in ice take place mainly due to the freeze-concentration effect of solutes in an unfrozen solution at temperatures higher than the eutectic point of the solution. Pincock was the first to report an acceleration model for reactions in ice,1 which successfully simulated experimental results. We propose here a modified version of the model for reactions in ice. The new model includes the total molar change involved in reactions in ice. Furthermore, we explain why many reactions are not accelerated in ice. The acceleration of reactions can be observed in the cases of (i) second- or higher-order reactions, (ii) low concentrations, and (iii) reactions with a small activation energy. Reactions with a buffer solution or additives in order to adjust ion strength, zero- or first-order reactions, or reactions containing high reactant concentrations are not accelerated by freezing. We conclude that the acceleration of reactions in the unfrozen solution of ice is not an abnormal phenomenon.
Collapse
Affiliation(s)
- Norimichi Takenaka
- Laboratory of Environmental Chemistry, Graduate School of Engineering, Osaka Prefecture University, Gakuen-cho 1-1, Sakai-shi, Osaka 599-8531, Japan.
| | | |
Collapse
|
21
|
Hellebust S, Roddis T, Sodeau JR. Potential Role of the Nitroacidium Ion on HONO Emissions from the Snowpack. J Phys Chem A 2007; 111:1167-71. [PMID: 17263519 DOI: 10.1021/jp068264g] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The effects of photolysis on frozen, thin films of water-ice containing nitrogen dioxide (as its dimer dinitrogen tetroxide) have been investigated using a combination of Fourier transform reflection-absorption infrared (FT-RAIR) spectroscopy and mass spectrometry. The release of HONO is ascribed to a mechanism in which nitrosonium nitrate (NO+NO3-) is formed. Subsequent solvation of the cation leads to the nitroacidium ion, H2ONO+, i.e., protonated nitrous acid. The pathway proposed explains why the field measurement of HONO at different polar sites is often contradictory.
Collapse
|