1
|
Wallace BJ, Mongeau ML, Zuend A, Preston TC. Impact of pH on Gas-Particle Partitioning of Semi-Volatile Organics in Multicomponent Aerosol. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:16974-16988. [PMID: 37885068 DOI: 10.1021/acs.est.3c02894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
The partitioning of semivolatile organic compounds (SVOCs) between the condensed and gas phases can have significant implications for the properties of aerosol particles. In addition to affecting size and composition, this partitioning can alter radiative properties and impact cloud activation processes. We present measurements and model predictions on how activity and pH influence the evaporation of SVOCs from particles to the gas phase, specifically investigating aqueous inorganic particles containing dicarboxylic acids (DCAs). The aerosols are studied at the single-particle level by using optical trapping and cavity-enhanced Raman spectroscopy. Optical resonances in the spectra enable precise size tracking, while vibrational bands allow real-time monitoring of pH. Results are compared to a Maxwell-type model that accounts for volatile and nonvolatile solutes in aqueous droplets that are held at a constant relative humidity. The aerosol inorganic-organic mixture functional group activity coefficients thermodynamic model and Debye-Hückel theory are both used to calculate the activities of the species present in the droplet. For DCAs, we find that the evaporation rate is highly sensitive to the particle pH. For acidity changes of approximately 1.5 pH units, we observe a shift from a volatile system to one that is completely nonvolatile. We also observe that the pH itself is not constant during evaporation; it increases as DCAs evaporate, slowing the rate of evaporation until it eventually ceases. Whether a DCA evaporates or remains a stable component of the droplet is determined by the difference between the lowest pKa of the DCA and the pH of the droplet.
Collapse
Affiliation(s)
- Brandon J Wallace
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
| | - Michel Laforest Mongeau
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
| | - Andreas Zuend
- Department of Atmospheric and Oceanic Sciences, McGill University, 805 Sherbrooke Street West, Montreal, Quebec, Canada H3A 0B9
| | - Thomas C Preston
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
- Department of Atmospheric and Oceanic Sciences, McGill University, 805 Sherbrooke Street West, Montreal, Quebec, Canada H3A 0B9
| |
Collapse
|
2
|
Pei WX, Ma SS, Chen Z, Zhu Y, Pang SF, Zhang YH. Heterogeneous uptake of NO 2 by sodium acetate droplets and secondary nitrite aerosol formation. J Environ Sci (China) 2023; 127:320-327. [PMID: 36522064 DOI: 10.1016/j.jes.2022.05.048] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 05/25/2022] [Accepted: 05/25/2022] [Indexed: 06/17/2023]
Abstract
The high NO3- concentration in fine particulate matters (PM2.5) during heavy haze events has attracted much attention, but the formation mechanism of nitrates remains largely uncertain, especially concerning heterogeneous uptake of NOX by aqueous phase. In this work, the heterogeneous uptake of NO2 by sodium acetate (NaAc) droplets with different NO2 concentrations and relative humidity (RH) conditions is investigated by microscopic Fourier transform infrared spectrometer (micro-FTIR). The IR feature changes of aqueous droplets indicate the acetate depletion and nitrite formation in humid environment. This implies that acetate droplets can provide the alkaline aqueous circumstances caused by acetate hydrolysis and acetic acid (HAc) volatilization for nitrite formation during the NO2 heterogeneous uptake. Meanwhile, the nitrite formation will exhibit a pH neutralizing effect on acetate hydrolysis, further facilitating HAc volatilization and acetate depletion. The heterogeneous uptake coefficient increases from 5.2 × 10-6 to 1.27 × 10-5 as RH decreases from 90% to 60% due to the enhanced HAc volatilization. Furthermore, no obvious change in uptake coefficient with different NO2 concentrations is observed. This work may provide a new pathway for atmospheric nitrogen cycling and secondary nitrite aerosol formation.
Collapse
Affiliation(s)
- Wen-Xiu Pei
- School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Shuai-Shuai Ma
- College of Chemistry and Material Engineering, Quzhou University, Quzhou 324000, China
| | - Zhe Chen
- School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Yue Zhu
- School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Shu-Feng Pang
- School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.
| | - Yun-Hong Zhang
- School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.
| |
Collapse
|
3
|
Chang YP, Devi Y, Chen CH. Micro-droplet Trapping and Manipulation: Understanding Aerosol Better for a Healthier Environment. Chem Asian J 2021; 16:1644-1660. [PMID: 33999498 DOI: 10.1002/asia.202100516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Indexed: 11/09/2022]
Abstract
Understanding the physicochemical properties and heterogeneous processes of aerosols is key not only to elucidate the impacts of aerosols on the atmosphere and humans but also to exploit their further applications, especially for a healthier environment. Experiments that allow for spatially control of single aerosol particles and investigations on the fundamental properties and heterogeneous chemistry at the single-particle level have flourished during the last few decades, and significant breakthroughs in recent years promise better control and novel applications aimed at resolving key issues in aerosol science. Here we propose graphene oxide (GO) aerosols as prototype aerosols containing polycyclic aromatic hydrocarbons, and GO can behave as two-dimensional surfactants which could modify the interfacial properties of aerosols. We describe the techniques of trapping single particles and furthermore the current status of the optical spectroscopy and chemistry of GO. The current applications of these single-particle trapping techniques are summarized and interesting future applications of GO aerosols are discussed.
Collapse
Affiliation(s)
- Yuan-Pin Chang
- Department of Chemistry, National Sun Yat-sen University, No. 70 Lien-hai Rd., Kaohsiung, 80424, Taiwan.,Aerosol Science Research Center, National Sun Yat-sen University, No. 70 Lien-hai Rd., Kaohsiung, 80424, Taiwan
| | - Yanita Devi
- Department of Chemistry, National Sun Yat-sen University, No. 70 Lien-hai Rd., Kaohsiung, 80424, Taiwan
| | - Chun-Hu Chen
- Department of Chemistry, National Sun Yat-sen University, No. 70 Lien-hai Rd., Kaohsiung, 80424, Taiwan
| |
Collapse
|
4
|
Ingram S, Rovelli G, Song YC, Topping D, Dutcher CS, Liu S, Nandy L, Shiraiwa M, Reid JP. Accurate Prediction of Organic Aerosol Evaporation Using Kinetic Multilayer Modeling and the Stokes-Einstein Equation. J Phys Chem A 2021; 125:3444-3456. [PMID: 33861595 DOI: 10.1021/acs.jpca.1c00986] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Organic aerosol can adopt a wide range of viscosities, from liquid to glass, depending on the local humidity. In highly viscous droplets, the evaporation rates of organic components are suppressed to varying degrees, yet water evaporation remains fast. Here, we examine the coevaporation of semivolatile organic compounds (SVOCs), along with their solvating water, from aerosol particles levitated in a humidity-controlled environment. To better replicate the composition of secondary aerosol, nonvolatile organics were also present, creating a three-component diffusion problem. Kinetic modeling reproduced the evaporation accurately when the SVOCs were assumed to obey the Stokes-Einstein relation, and water was not. Crucially, our methodology uses previously collected data to constrain the time-dependent viscosity, as well as water diffusion coefficients, allowing it to be predictive rather than postdictive. Throughout the study, evaporation rates were found to decrease as SVOCs deplete from the particle, suggesting path function type behavior.
Collapse
Affiliation(s)
- Stephen Ingram
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Grazia Rovelli
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Young-Chul Song
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - David Topping
- Department of Earth and Environmental Sciences, University of Manchester, Oxford Rd, Manchester M13 9PL, U.K
| | - Cari S Dutcher
- Department of Mechanical Engineering, University of Minnesota, 111 Church Street SE, Minneapolis, Minnesota 55455, United States.,Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
| | - Shihao Liu
- Department of Mechanical Engineering, University of Minnesota, 111 Church Street SE, Minneapolis, Minnesota 55455, United States
| | - Lucy Nandy
- Department of Mechanical Engineering, University of Minnesota, 111 Church Street SE, Minneapolis, Minnesota 55455, United States
| | - Manabu Shiraiwa
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Jonathan P Reid
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| |
Collapse
|
5
|
Wu FM, Wang XW, Pang SF, Zhang YH. Measuring hygroscopicity of internally mixed NaNO 3 and glutaric acid particles by vacuum FTIR. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 219:104-109. [PMID: 31030037 DOI: 10.1016/j.saa.2019.04.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 03/31/2019] [Accepted: 04/17/2019] [Indexed: 06/09/2023]
Abstract
Sodium nitrate as an important inorganic component can be chemically formed from the reactions of nitrogen oxides and nitric acid (HNO3) with sea salt in atmosphere. Organic acids contribute a significant fraction of photochemical formed secondary organics that can condense on the preexisting nitrate-containing particles. Atmospheric particles often include a complex mixture of nitrate and secondary organic materials accumulated within the same individual particles. Here we studied the hygroscopicity of aerosol particles composed of sodium nitrate and glutaric acid (GA) by using a pulsed RH controlling system and a rapid scan vacuum FTIR spectrometer (PRHCS-RSVFTIR). The water content in the particles and efflorescence ratios of both NaNO3 and GA at ambient relative humidity (RH) as a function of time were obtained from the rapid-scan infrared spectra with a sub-second time resolution. Our study showed that both NaNO3 and GA crystallized at 44.1% RH during two different RH control processes (stepwise and pulsed processes). It was found that the addition of GA could suppress the efflorescence of NaNO3 during the dehumidifying process. In addition, the mixed NaNO3/GA particles release HNO3 during the dehumidifying and humidifying cycles. These findings are important in further understanding the role of interactions between water-soluble dicarboxylic acids and nitrates on hygroscopicity and environmental effects of atmospheric particles.
Collapse
Affiliation(s)
- Feng-Min Wu
- School of Chemical Engineering and Pharmaceutics, Henan University of Science and Technology, Luoyang 471023, China; School of Chemistry and Chemical Physics Engineering, Beijing Institute of Technology, Beijing 100081, China.
| | - Xiao-Wei Wang
- School of Chemical Engineering and Pharmaceutics, Henan University of Science and Technology, Luoyang 471023, China; School of Chemistry and Chemical Physics Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Shu-Feng Pang
- School of Chemistry and Chemical Physics Engineering, Beijing Institute of Technology, Beijing 100081, China.
| | - Yun-Hong Zhang
- School of Chemistry and Chemical Physics Engineering, Beijing Institute of Technology, Beijing 100081, China.
| |
Collapse
|
6
|
Yang H, Wang N, Pang SF, Zheng CM, Zhang YH. Chemical reaction between sodium pyruvate and ammonium sulfate in aerosol particles and resultant sodium sulfate efflorescence. CHEMOSPHERE 2019; 215:554-562. [PMID: 30342400 DOI: 10.1016/j.chemosphere.2018.10.062] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 09/29/2018] [Accepted: 10/10/2018] [Indexed: 06/08/2023]
Abstract
The hygroscopicity of aerosols is dependent upon their chemical composition. When their chemical compositions are altered, the water content in aerosols often changes, which may further modify phase behaviour. However, the study of phase behaviour dependence on chemical reactions is still limited. In this work, internally mixed sodium pyruvate (SP)/ammonium sulfate (AS) droplets were studied using an in-situ ATR-FTIR spectrometer. FTIR spectral analysis showed that solid sodium sulfate (SS) formed during the dehydration process, indicating a chemical reaction between SP and AS. In addition, the water content decreased after a dehydration-hydration process despite organic salt (SS) to inorganic salt (AS) mole ratios (OIRs) During the second relative humidity (RH) cycle, the water content remained constant, however, the efflorescence relative humidity (ERH) was lower than that in the first dehydration. The crystal relative humidities (CRHs) of SS are 66.7-53.1%, 66.0-58.2%, 62.2-57.1% and 49.6-43.6% for OIRs of 3:1, 2:1, 1:1 and 1:3, respectively, suggesting the crystallization of SS was favoured by higher SP content. For 2:1 OIRs, the solid SS was the greatest and an excess of either SP or AS blocked the solid SS formation. At a constant 80% RH, depletion of reagents was ∼0.97, and water loss was ∼0.6 in ∼40 min. After 90 min, solid SS formed. The chemical reaction was faster than water loss; furthermore, water loss from the chemical reaction led to solid SS above the ERH of pure SS particles (∼75% RH). When the RH changed rapidly, the reaction was slow and solid SS decreased.
Collapse
Affiliation(s)
- Hui Yang
- School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Na Wang
- School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Shu-Feng Pang
- School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China.
| | - Chuan-Ming Zheng
- School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Yun-Hong Zhang
- School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China.
| |
Collapse
|
7
|
Gorkowski K, Donahue NM, Sullivan RC. Emerging investigator series: determination of biphasic core-shell droplet properties using aerosol optical tweezers. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2018; 20:1512-1523. [PMID: 29897369 DOI: 10.1039/c8em00166a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We present a new algorithm for the analysis of whispering gallery modes (WGMs) found in the cavity enhanced Raman spectra retrieved from optically tweezed droplets. Our algorithm improves the computational scaling when analyzing core-shell droplets (i.e. phase-separated or biphasic droplets) in the aerosol optical tweezers (AOT), making it computationally practical to analyze spectra collected at a few Hz over hours-long experiments. This enables the determination of the size and refractive index of both the core and shell phases with high accuracy, at 0.5 Hz time resolution. Phase-separated core-shell droplets are common morphologies in a wide variety of biophysical, colloidal, and aerosolized chemical systems, and have recently become a major focus in understanding the atmospheric chemistry of particulate matter. Our new approach reduces the number of parameters directly searched for, decreasing computational demands. We assess the accuracy of the diameters and refractive indices retrieved from a homogeneous or core-shell droplet. We demonstrate the performance of the new algorithm using experimental data from a droplet of aqueous glycerol coated by squalane. We demonstrate that a shell formation causes adjacent WGMs to split from each other in their wavenumber position through the addition of a secondary organic aerosol shell around a NaCl(aq) droplet. Our new algorithm paves the way for more in-depth physiochemical experiments into liquid-liquid phase separation and their consequences for interfacial chemistry-a topic with growing experimental needs for understanding the dynamics and chemistry of atmospheric aerosol particles, and in biochemical systems.
Collapse
Affiliation(s)
- Kyle Gorkowski
- Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA, USA.
| | | | | |
Collapse
|
8
|
Gao X, Cai C, Ma J, Zhang Y. Repartitioning of glycerol between levitated and surrounding deposited glycerol/NaNO 3/H 2O droplets. ROYAL SOCIETY OPEN SCIENCE 2018; 5:170819. [PMID: 29410802 PMCID: PMC5792879 DOI: 10.1098/rsos.170819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Accepted: 11/24/2017] [Indexed: 06/07/2023]
Abstract
Repartitioning of semi-volatile organic compounds (SVOCs) between particles is an important process to understand the particle growth and shrinkage in the atmosphere environment. Here, by using optical tweezers coupled with cavity-enhanced Raman spectroscopy, we report the repartitioning of glycerol between a levitated glycerol/NaNO3/H2O droplet and surrounding glycerol/NaNO3/H2O droplets deposited on the inner wall of a chamber with different organic to inorganic molar ratios (OIRs). For the high OIR with 3 : 1, no NaNO3 crystallization occurs both for levitated and deposited droplets in the whole relative humidity (RH) range, the radius of the levitated droplet decreases slowly due to the evaporation of glycerol from the levitated droplet at constant RHs. The levitated droplets radii with OIR of 1 : 1 and 1 : 3 increase with constant RHs that are lower than 45.3% and 55.7%, respectively, indicating that the repartitioning of glycerol occurs. The reason is that NaNO3 in the deposited droplets is crystallized when RH is lower than 45.3% for 1 : 1 or 55.7% for 1 : 3. So the vapour pressure of glycerol at the surface of deposited droplets is higher than that of the levitated droplet which always remains as liquid droplet without NaNO3 crystallization, resulting in the transfer of glycerol from the deposited ones to the levitated one. The process of the glycerol repartitioning we discussed herein is a useful model to interpret the repartitioning of SVOCs between the externally mixed particles with different phase states.
Collapse
Affiliation(s)
| | | | - Jiabi Ma
- Authors for correspondence: Jiabi Ma e-mail:
| | | |
Collapse
|
9
|
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
|
10
|
Gorkowski K, Donahue NM, Sullivan RC. Emulsified and Liquid-Liquid Phase-Separated States of α-Pinene Secondary Organic Aerosol Determined Using Aerosol Optical Tweezers. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:12154-12163. [PMID: 28985066 DOI: 10.1021/acs.est.7b03250] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We demonstrate the first capture and analysis of secondary organic aerosol (SOA) on a droplet suspended in an aerosol optical tweezers (AOT). We examine three initial chemical systems of aqueous NaCl, aqueous glycerol, and squalane at ∼75% relative humidity. For each system we added α-pinene SOA-generated directly in the AOT chamber-to the trapped droplet. The resulting morphology was always observed to be a core of the original droplet phase surrounded by a shell of the added SOA. We also observed a stable emulsion of SOA particles when added to an aqueous NaCl core phase, in addition to the shell of SOA. The persistence of the emulsified SOA particles suspended in the aqueous core suggests that this metastable state may persist for a significant fraction of the aerosol lifecycle for mixed SOA/aqueous particle systems. We conclude that the α-pinene SOA shell creates no major diffusion limitations for water, glycerol, and squalane core phases under humid conditions. These experimental results support the current prompt-partitioning framework used to describe organic aerosol in most atmospheric chemical transport models and highlight the prominence of core-shell morphologies for SOA on a range of core chemical phases.
Collapse
Affiliation(s)
- Kyle Gorkowski
- Center for Atmospheric Particle Studies, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - Neil M Donahue
- Center for Atmospheric Particle Studies, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - Ryan C Sullivan
- Center for Atmospheric Particle Studies, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| |
Collapse
|
11
|
Haddrell AE, Miles REH, Bzdek BR, Reid JP, Hopkins RJ, Walker JS. Coalescence Sampling and Analysis of Aerosols using Aerosol Optical Tweezers. Anal Chem 2017; 89:2345-2352. [DOI: 10.1021/acs.analchem.6b03979] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Allen E. Haddrell
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | | | - 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
| | - Rebecca J. Hopkins
- Defence Science and Technology Laboratory (DSTL), Porton Down, Salisbury SP4 0JQ, United Kingdom
| | - Jim S. Walker
- Bristol Industrial and Research Associates Ltd (BIRAL), Unit 8 Harbour Road Trading Estate, Portishead, Bristol BS20 7BL, United Kingdom
| |
Collapse
|
12
|
Preston TC, Davies JF, Wilson KR. The frequency-dependent response of single aerosol particles to vapour phase oscillations and its application in measuring diffusion coefficients. Phys Chem Chem Phys 2017; 19:3922-3931. [PMID: 28106191 DOI: 10.1039/c6cp07711k] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new method for measuring diffusion in the condensed phase of single aerosol particles is proposed and demonstrated. The technique is based on the frequency-dependent response of a binary particle to oscillations in the vapour phase of one of its chemical components. We discuss how this physical situation allows for what would typically be a non-linear boundary value problem to be approximately reduced to a linear boundary value problem. For the case of aqueous aerosol particles, we investigate the accuracy of the closed-form analytical solution to this linear problem through a comparison with the numerical solution of the full problem. Then, using experimentally measured whispering gallery modes to track the frequency-dependent response of aqueous particles to relative humidity oscillations, we determine diffusion coefficients as a function of water activity. The measured diffusion coefficients are compared to previously reported values found using the two common experiments: (i) the analysis of the sorption/desorption of water from a particle after a step-wise change to the surrounding relative humidity and (ii) the isotopic exchange of water between a particle and the vapour phase. The technique presented here has two main strengths: first, when compared to the sorption/desorption experiment, it does not require the numerical evaluation of a boundary value problem during the fitting process as a closed-form expression is available. Second, when compared to the isotope exchange experiment, it does not require the use of labeled molecules. Therefore, the frequency-dependent experiment retains the advantages of these two commonly used methods but does not suffer from their drawbacks.
Collapse
Affiliation(s)
- Thomas C Preston
- Department of Atmospheric and Oceanic Sciences and Department of Chemistry, McGill University, 805 Sherbrooke Street West, Montreal, QC, Canada H3A 0B9.
| | - James F Davies
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94611, USA
| | - Kevin R Wilson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94611, USA
| |
Collapse
|
13
|
Moridnejad A, Preston TC. Models of Isotopic Water Diffusion in Spherical Aerosol Particles. J Phys Chem A 2016; 120:9759-9766. [PMID: 27973801 DOI: 10.1021/acs.jpca.6b11241] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Isotopic exchange experiments that utilize D2O and H2O have received attention as a method for studying water diffusion in high viscosity aerosol particles. However, the mathematical models used to retrieve diffusion coefficients from these measurements have yet to be critically examined. Here, two models for the isotopic exchange of D2O and H2O in spherical particles are analyzed and compared. The primary difference between the two models is the choice of boundary condition at the surface of the spherical particle. In one model, it is assumed that the concentration of D2O at the surface is fixed, while in the other model, it is assumed that, at the particle surface, the concentration of D2O in the condensed phase is in equilibrium with D2O vapor. Closed-form expressions for the two boundary value problems that describe these physical models are found and discussed. Then, specific examples of aqueous droplets containing either sucrose, citric acid, and shikimic acid are examined with both models. It is found that at low relative humidities the choice of boundary condition has a negligible effect on the predicted lifetime of isotopic exchange, while at high relative humidities predicted lifetimes can differ by orders of magnitude. The implication of this result is that the choice of model can greatly affect diffusion coefficients retrieved from experimental measurements under certain conditions. Finally, discrepancies between diffusion coefficients measured using isotopic exchange and water sorption and desorption experiments are discussed.
Collapse
Affiliation(s)
- Ali Moridnejad
- Department of Atmospheric and Oceanic Sciences and Department of Chemistry, McGill University , 805 Sherbrooke Street West, Montreal, QC Canada H3A 0B9
| | - Thomas C Preston
- Department of Atmospheric and Oceanic Sciences and Department of Chemistry, McGill University , 805 Sherbrooke Street West, Montreal, QC Canada H3A 0B9
| |
Collapse
|
14
|
Cai C, Miles REH, Cotterell MI, Marsh A, Rovelli G, Rickards AMJ, Zhang YH, Reid JP. Comparison of Methods for Predicting the Compositional Dependence of the Density and Refractive Index of Organic-Aqueous Aerosols. J Phys Chem A 2016; 120:6604-17. [PMID: 27500411 DOI: 10.1021/acs.jpca.6b05986] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Representing the physicochemical properties of aerosol particles of complex composition is of crucial importance for understanding and predicting aerosol thermodynamic, kinetic, and optical properties and processes and for interpreting and comparing analysis methods. Here, we consider the representations of the density and refractive index of aqueous-organic aerosol with a particular focus on the dependence of these properties on relative humidity and water content, including an examination of the properties of solution aerosol droplets existing at supersaturated solute concentrations. Using bulk phase measurements of density and refractive index for typical organic aerosol components, we provide robust approaches for the estimation of these properties for aerosol at any intermediate composition between pure water and pure solute. Approximately 70 compounds are considered, including mono-, di- and tricarboxylic acids, alcohols, diols, nitriles, sulfoxides, amides, ethers, sugars, amino acids, aminium sulfates, and polyols. We conclude that the molar refraction mixing rule should be used to predict the refractive index of the solution using a density treatment that assumes ideal mixing or, preferably, a polynomial dependence on the square root of the mass fraction of solute, depending on the solubility limit of the organic component. Although the uncertainties in the density and refractive index predictions depend on the range of subsaturated compositional data available for each compound, typical errors for estimating the solution density and refractive index are less than ±0.1% and ±0.05%, respectively. Owing to the direct connection between molar refraction and the molecular polarizability, along with the availability of group contribution models for predicting molecular polarizability for organic species, our rigorous testing of the molar refraction mixing rule provides a route to predicting refractive indices for aqueous solutions containing organic molecules of arbitrary structure.
Collapse
Affiliation(s)
- Chen Cai
- The Institute of Chemical Physics, Key Laboratory of Cluster Science, Beijing Institute of Technology , Beijing 100081, People's Republic of China.,School of Chemistry, University of Bristol , Bristol, BS8 1TS, U.K
| | | | | | - Aleksandra Marsh
- School of Chemistry, University of Bristol , Bristol, BS8 1TS, U.K
| | - Grazia Rovelli
- School of Chemistry, University of Bristol , Bristol, BS8 1TS, U.K.,Department of Earth and Environmental Sciences, University of Milano-Bicocca , 20124 Milan, Italy
| | | | - Yun-Hong Zhang
- The Institute of Chemical Physics, Key Laboratory of Cluster Science, Beijing Institute of Technology , Beijing 100081, People's Republic of China
| | - Jonathan P Reid
- School of Chemistry, University of Bristol , Bristol, BS8 1TS, U.K
| |
Collapse
|
15
|
Preston TC, Reid JP. Determining the size and refractive index of microspheres using the mode assignments from Mie resonances. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2015; 32:2210-2217. [PMID: 26560936 DOI: 10.1364/josaa.32.002210] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A new method for determining the radius and refractive index of microspheres using Mie resonances is presented. Previous methods have relied on searching multidimensional space to find the radius and refractive index that minimize the difference between observed and calculated Mie resonances. For anything but simple refractive index functions, this process can be very time consuming. Here, we demonstrate that once the mode assignment for the observed Mie resonances is known, no search is necessary, and the radius and refractive index of best-fit can be found immediately. This superior and faster way to characterize microspheres using Mie resonances should supplant previous fitting algorithms. The derivation and implementation of the equations that give the parameters of best-fit are shown and discussed. Testing is performed on systems of physical interest, and the effect of noise on measured peak positions is investigated.
Collapse
|
16
|
Bilde M, Barsanti K, Booth M, Cappa CD, Donahue NM, Emanuelsson EU, McFiggans G, Krieger UK, Marcolli C, Topping D, Ziemann P, Barley M, Clegg S, Dennis-Smither B, Hallquist M, Hallquist ÅM, Khlystov A, Kulmala M, Mogensen D, Percival CJ, Pope F, Reid JP, Ribeiro da Silva MAV, Rosenoern T, Salo K, Soonsin VP, Yli-Juuti T, Prisle NL, Pagels J, Rarey J, Zardini AA, Riipinen I. Saturation Vapor Pressures and Transition Enthalpies of Low-Volatility Organic Molecules of Atmospheric Relevance: From Dicarboxylic Acids to Complex Mixtures. Chem Rev 2015; 115:4115-56. [DOI: 10.1021/cr5005502] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Merete Bilde
- Department
of Chemistry, Aarhus University, DK-8000 Aarhus, Denmark
| | - Kelley Barsanti
- Department
of Civil and Environmental Engineering, Portland State University, Portland, Oregon 97207, United States
| | | | | | - Neil M. Donahue
- Centre
for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | | | | | - Ulrich K. Krieger
- Institute
for Atmospheric and Climate Science, ETH Zurich, 8092 Zurich, Switzerland
| | - Claudia Marcolli
- Institute
for Atmospheric and Climate Science, ETH Zurich, 8092 Zurich, Switzerland
- Marcolli Chemistry and Physics Consulting GmbH, 8047 Zurich, Switzerland
| | | | - Paul Ziemann
- Department
of Chemistry and Biochemistry and Cooperative Institute for Research
in Environmental Sciences (CIRES), University of Colorado, Boulder, Colorado 80309, United States
| | | | - Simon Clegg
- School
of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | | | - Mattias Hallquist
- Atmospheric
Science, Department of Chemistry and Molecular Biology, University of Gothenburg, SE-405 30 Gothenburg, Sweden
| | - Åsa M. Hallquist
- IVL Swedish Environmental Research Institute, SE-411 33 Gothenburg, Sweden
| | - Andrey Khlystov
- Division
of Atmospheric Sciences, Desert Research Institute, Reno, Nevada 89512, United States
| | - Markku Kulmala
- Department
of Physics, University of Helsinki, FI-00014 Helsinki, Finland
| | - Ditte Mogensen
- Department
of Physics, University of Helsinki, FI-00014 Helsinki, Finland
| | | | - Francis Pope
- School of Geography, Earth and Environmental
Sciences, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Jonathan P. Reid
- School
of Chemistry, University of Bristol, Bristol BS8 1TH, United Kingdom
| | - M. A. V. Ribeiro da Silva
- Centro
de Investigação em Química, Department of Chemistry
and Biochemistry, Faculty of Science, University of Porto, 4099-002 Porto, Portugal
| | - Thomas Rosenoern
- Department
of Chemistry, University of Copenhagen, DK-1165 Copenhagen, Denmark
| | - Kent Salo
- Maritime
Environment, Shipping and Marine Technology, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Vacharaporn Pia Soonsin
- Institute
for Atmospheric and Climate Science, ETH Zurich, 8092 Zurich, Switzerland
- Center
of Excellence on Hazardous Substance Management, Chulalongkorn University, Bangkok 10330, Thailand
| | - Taina Yli-Juuti
- Department
of Physics, University of Helsinki, FI-00014 Helsinki, Finland
- Department
of Applied Physics, University of Eastern Finland, FI-70211 Kuopio, Finland
| | - Nønne L. Prisle
- Department
of Physics, University of Helsinki, FI-00014 Helsinki, Finland
| | - Joakim Pagels
- Ergonomics & Aerosol Technology, Lund University, SE-221 00 Lund, Sweden
| | - Juergen Rarey
- School
of Chemical Engineering, University of KwaZulu-Natal, Durban 4041, South Africa
- DDBST GmbH, D-26129 Oldenburg, Germany
- Industrial
Chemistry, Carl von Ossietzky University Oldenburg, D-26129 Oldenburg, Germany
| | - Alessandro A. Zardini
- European
Commission Joint Research Centre (JRC), Institute for Energy and Transport, Sustainable Transport Unit, I-21027 Ispra, Italy
| | - Ilona Riipinen
- Department
of Environmental Science and Analytical Chemistry (ACES) and Bolin
Centre for Climate Research, Stockholm University, SE-106 91 Stockholm, Sweden
| |
Collapse
|
17
|
Cai C, Stewart DJ, Reid JP, Zhang YH, Ohm P, Dutcher CS, Clegg SL. Organic Component Vapor Pressures and Hygroscopicities of Aqueous Aerosol Measured by Optical Tweezers. J Phys Chem A 2015; 119:704-18. [DOI: 10.1021/jp510525r] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Chen Cai
- The
Institute of Chemical Physics, Key Laboratory of Cluster Science, Beijing Institute of Technology, Beijing 100081, People’s Republic of China
- School
of Chemistry, University of Bristol, Bristol, BS8 1TS, U.K
| | - David J. Stewart
- School
of Chemistry, University of Bristol, Bristol, BS8 1TS, U.K
| | - Jonathan P. Reid
- School
of Chemistry, University of Bristol, Bristol, BS8 1TS, U.K
| | - Yun-hong Zhang
- The
Institute of Chemical Physics, Key Laboratory of Cluster Science, Beijing Institute of Technology, Beijing 100081, People’s Republic of China
| | - Peter Ohm
- Department
of Mechanical Engineering, University of Minnesota, 111 Church
Street SE, Minneapolis, Minnesota 55455, United States
| | - Cari S. Dutcher
- Department
of Mechanical Engineering, University of Minnesota, 111 Church
Street SE, Minneapolis, Minnesota 55455, United States
| | - Simon L. Clegg
- School
of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, U.K
| |
Collapse
|
18
|
Power RM, Reid JP. Probing the micro-rheological properties of aerosol particles using optical tweezers. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2014; 77:074601. [PMID: 24994710 DOI: 10.1088/0034-4885/77/7/074601] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The use of optical trapping techniques to manipulate probe particles for performing micro-rheological measurements on a surrounding fluid is well-established. Here, we review recent advances made in the use of optical trapping to probe the rheological properties of trapped particles themselves. In particular, we review observations of the continuous transition from liquid to solid-like viscosity of sub-picolitre supersaturated solution aerosol droplets using optical trapping techniques. Direct measurements of the viscosity of the particle bulk are derived from the damped oscillations in shape following coalescence of two particles, a consequence of the interplay between viscous and surface forces and the capillary driven relaxation of the approximately spheroidal composite particle. Holographic optical tweezers provide a facile method for the manipulation of arrays of particles allowing coalescence to be controllably induced between two micron-sized aerosol particles. The optical forces, while sufficiently strong to confine the composite particle, are several orders of magnitude weaker than the capillary forces driving relaxation. Light, elastically back-scattered by the particle, is recorded with sub-100 ns resolution allowing measurements of fast relaxation (low viscosity) dynamics, while the brightfield image can be used to monitor the shape relaxation extending to times in excess of 1000 s. For the slowest relaxation dynamics studied (particles with the highest viscosity) the presence and line shape of whispering gallery modes in the cavity enhanced Raman spectrum can be used to infer the relaxation time while serving the dual purpose of allowing the droplet size and refractive index to be measured with accuracies of ±0.025% and ±0.1%, respectively. The time constant for the damped relaxation can be used to infer the bulk viscosity, spanning from the dilute solution limit to a value approaching that of a glass, typically considered to be >10(12) Pa s, whilst the frequencies of the normal modes of the oscillations of the particle can be used to infer surface properties. We will review the use of optical tweezers for studying the viscosity of aerosol particles and discuss the potential use of this micro-rheological tool for probing the fundamental concepts of phase, thermodynamic equilibrium and metastability.
Collapse
Affiliation(s)
- Rory M Power
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK
| | | |
Collapse
|