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Yoo H, Seo D, Shin D, Ro CU. Direct Observation of Particle-To-Particle Variability in Ambient Aerosol pH Using a Novel Analytical Approach Based on Surface-Enhanced Raman Spectroscopy. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:7977-7985. [PMID: 38664901 DOI: 10.1021/acs.est.4c00220] [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: 05/08/2024]
Abstract
The pH of atmospheric aerosols is a key characteristic that profoundly influences their impacts on climate change, human health, and ecosystems. Despite widely performed aerosol pH research, determining the pH levels of individual atmospheric aerosol particles has been a challenge. This study presents a novel analytical technique that utilizes surface-enhanced Raman spectroscopy to assess the pH of individual ambient PM2.5-10 aerosol particles in conjunction with examining their hygroscopic behavior, morphology, and elemental compositions. The results revealed a substantial pH variation among simultaneously collected aerosol particles, ranging from 3.3 to 5.7. This variability is likely related to each particle's unique reaction and aging states. The extensive particle-to-particle pH variability suggests that atmospheric aerosols present at the same time and location can exhibit diverse reactivities, reaction pathways, phase equilibria, and phase separation properties. This pioneering study paves the way for in-depth investigations into particle-to-particle variability, size dependency, and detailed spatial and temporal variations of aerosol pH, thus deepening our understanding of atmospheric chemistry and its environmental implications.
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Affiliation(s)
- Hanjin Yoo
- Department of Chemistry, Inha University, Incheon 22212, Republic of Korea
- Particle Pollution Management Center, Inha University, Incheon 21999, Republic of Korea
| | - Dongkwon Seo
- Department of Chemistry, Inha University, Incheon 22212, Republic of Korea
| | - Dongha Shin
- Department of Chemistry, Inha University, Incheon 22212, Republic of Korea
| | - Chul-Un Ro
- Department of Chemistry, Inha University, Incheon 22212, Republic of Korea
- Particle Pollution Management Center, Inha University, Incheon 21999, Republic of Korea
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2
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Sun J, Hu Y, Cao X, Pang SF, Liu P, Huang Q, Zhang YH. Role of WSOCs and pH on Ammonium Nitrate Aerosol Efflorescence: Insights into Secondary Aerosol Formation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:20074-20084. [PMID: 37974434 DOI: 10.1021/acs.est.3c07603] [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: 11/19/2023]
Abstract
Efflorescence of ammonium nitrate (AN) aerosols significantly impacts atmospheric secondary aerosol formation, climate, and human health. We investigated the effect of representative water-soluble organic compounds (WSOCs) (sucralose (SUC), glycerol (GLY), and citric acid (CA) on AN:WSOC aerosol efflorescence using vacuum Fourier transform infrared spectroscopy. Combining efflorescence relative humidity (ERH) measurements, heterogeneous nucleation rates, and model predictions, we found that aerosol viscosity, correlating with molecular diffusion, effectively predicted ERH variations among the AN:WSOC aerosols. WSOCs with higher viscosity (SUC and CA) hindered efflorescence, while GLY with a lower viscosity showed a minor effect. At a low AN:CA molar ratio (10:1), CA promoted ERH, likely due to CA crystallization. Increasing the droplet pH inhibited AN:CA aerosol efflorescence. In contrast, for AN:SUC and AN:GLY aerosols, efflorescence is pH-insensitive. With the addition of trivial sulfate, AN:SUC droplets exhibited two-stage efflorescence, coinciding with ammonium sulfate and AN efflorescence. Given the atmospheric abundance, the morphology, phase, and mixing state of nitrate aerosols are significant for atmospheric chemistry and physics. Our results suggest that AN:WSOCs aerosols can exist in the amorphous phase in the atmosphere, with efflorescence behavior depending on the aerosol composition, viscosity, pH, and the cation and anion interactions in a complex manner.
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Affiliation(s)
- Jian Sun
- Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Yangyun Hu
- Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Xue Cao
- Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Shu-Feng Pang
- Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Pai Liu
- Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Qishen Huang
- Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Yun-Hong Zhang
- Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
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Jones LR, Wright SJ, Gant TW. A critical review of microplastics toxicity and potential adverse outcome pathway in human gastrointestinal tract following oral exposure. Toxicol Lett 2023; 385:51-60. [PMID: 37659479 DOI: 10.1016/j.toxlet.2023.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 08/21/2023] [Accepted: 08/29/2023] [Indexed: 09/04/2023]
Abstract
Microplastics (MPs) are typically produced via environmental degradation of larger plastics, where they enter the human food chain. MPs are complex materials containing chemical and physical characteristics that can potentially affect their hazard and exposure. These physical properties can be altered by environmental exposure potentially altering any risk assessment conducted on the primary material. We conducted a literature review using an Adverse Outcome Pathway (AOP)-based approach from Molecular Initiating Event (MIE) to cell effect event to identify multiple knowledge gaps that affect MPs hazard assessment. There is some convergence of key biological events but could relate to most lying along well-established biological effector pathways such as apoptosis which can respond to many MIEs. In contrast, MIEs of chemicals will be via protein interaction. As MPs may occur in the lumen of the alimentary canal for example to the mucus, therefore, not requiring translocation of MPs across the epithelial membrane. At the other end of the AOP, currently it is not possible to identify a single adverse outcome at the organ level. This work did establish a clear need to understand both external and internal exposure (resulting from translocation) and develop hazard data at both levels to inform on risk assessments.
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Affiliation(s)
- Lorna R Jones
- UK Health Security Agency. Toxicology Department, Harwell Campus, Oxfordshire, United Kingdom; Environmental Research Group, Imperial College London, United Kingdom; Health Protection Research Unit in Environmental Exposures and Health, United Kingdom.
| | - Stephanie J Wright
- Environmental Research Group, Imperial College London, United Kingdom; Health Protection Research Unit in Environmental Exposures and Health, United Kingdom
| | - Timothy W Gant
- UK Health Security Agency. Toxicology Department, Harwell Campus, Oxfordshire, United Kingdom; Environmental Research Group, Imperial College London, United Kingdom; Health Protection Research Unit in Environmental Exposures and Health, United Kingdom
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Brown EK, Rovelli G, Wilson KR. pH jump kinetics in colliding microdroplets: accelerated synthesis of azamonardine from dopamine and resorcinol. Chem Sci 2023; 14:6430-6442. [PMID: 37325131 PMCID: PMC10266468 DOI: 10.1039/d3sc01576a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 05/21/2023] [Indexed: 06/17/2023] Open
Abstract
Recent studies report the dramatic acceleration of chemical reactions in micron-sized compartments. In the majority of these studies the exact acceleration mechanism is unknown but the droplet interface is thought to play a significant role. Dopamine reacts with resorcinol to form a fluorescent product azamonardine and is used as a model system to examine how droplet interfaces accelerate reaction kinetics. The reaction is initiated by colliding two droplets levitated in a branched quadrupole trap, which allows the reaction to be observed in individual droplets where the size, concentration, and charge are carefully controlled. The collision of two droplets produces a pH jump and the reaction kinetics are quantified optically and in situ by measuring the formation of azamonardine. The reaction was observed to occur 1.5 to 7.4 times faster in 9-35 micron droplets compared to the same reaction conducted in a macroscale container. A kinetic model of the experimental results suggests that the acceleration mechanism arises from both the more rapid diffusion of oxygen into the droplet, as well as increased reagent concentrations at the air-water interface.
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Affiliation(s)
- Emily K Brown
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley CA 94720 USA +1 510-495-2474
- Department of Chemistry, University of California Berkeley CA 94720 USA
| | - Grazia Rovelli
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley CA 94720 USA +1 510-495-2474
| | - Kevin R Wilson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley CA 94720 USA +1 510-495-2474
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Li M, Kan Y, Su H, Pöschl U, Parekh SH, Bonn M, Cheng Y. Spatial homogeneity of pH in aerosol microdroplets. Chem 2023. [DOI: 10.1016/j.chempr.2023.02.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
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Estefany C, Sun Z, Hong Z, Du J. Raman spectroscopy for profiling physical and chemical properties of atmospheric aerosol particles: A review. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 249:114405. [PMID: 36508807 DOI: 10.1016/j.ecoenv.2022.114405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 12/05/2022] [Accepted: 12/06/2022] [Indexed: 06/17/2023]
Abstract
Atmosphere aerosols have significant impact on human health and the environment. Aerosol particles have a number of characteristics that influence their health and environmental effects, including their size, shape, and chemical composition. A great deal of difficulty is associated with quantifying and identifying atmospheric aerosols because these parameters are highly variable on a spatial and temporal scale. An important component of understanding aerosol fate is Raman Spectroscopy (RS), which is capable of resolving chemical compositions of individual particles. This review presented strategic techniques, especially RS methods for characterizing atmospheric aerosols. The nature and properties of atmospheric aerosols and their influence on environment and human health were briefly described. Analytical methodologies that offer insight into the chemistry and multidimensional properties of aerosols were discussed. In addition, perspectives for practical applications of atmospheric aerosols using RS are featured.
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Affiliation(s)
- Cedeño Estefany
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Key Laboratory of Resources and Environmental System Optimization of Ministry of Education, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China
| | - Zhenli Sun
- Key Laboratory of Resources and Environmental System Optimization of Ministry of Education, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China
| | - Zijin Hong
- Key Laboratory of Resources and Environmental System Optimization of Ministry of Education, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China
| | - Jingjing Du
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
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Jing X, Chen Z, Huang Q, Liu P, Zhang YH. Spatiotemporally Resolved pH Measurement in Aerosol Microdroplets Undergoing Chloride Depletion: An Application of In Situ Raman Microspectrometry. Anal Chem 2022; 94:15132-15138. [PMID: 36251492 DOI: 10.1021/acs.analchem.2c03381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Acidity is a defining property of atmospheric aerosols that profoundly affects environmental systems, human health, and climate. However, directly measuring the pH of aerosol microdroplets remains a challenge, especially when the microdroplets' composition is nonhomogeneous or dynamically evolving or both. As a result, a pH measurement technique with high spatiotemporal resolution is needed. Here, we report a spatiotemporally resolved pH measurement technique in microdroplets using spontaneous Raman spectroscopy. Our target sample was the microdroplets comprising sodium chloride and oxalic acid─laboratory surrogates of sea spray aerosols and water-soluble organic compounds, respectively. Our measurements show that the chloride depletion from the microdroplets caused a continuous increase in pH by ∼0.5 units in 2 hours. Meanwhile, the surface propensity of chloride anions triggers a stable pH gradient inside a single droplet, with the pH at the droplet surface lower than that at the core by ∼ 0.4 units. The uncertainties arising from the Raman detection limit (±0.08 pH units) and from the nonideal solution conditions (-0.06 pH units) are constrained. Our findings indicate that spontaneous Raman spectroscopy is a simple yet robust technique for precise pH measurement in aerosols with high spatiotemporal resolution.
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Affiliation(s)
- Xinbo Jing
- Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing100081, China
| | - Zhe Chen
- Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing100081, China
| | - Qishen Huang
- Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing100081, China.,Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania16801, United States
| | - Pai Liu
- Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing100081, China
| | - Yun-Hong Zhang
- Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing100081, China
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Li M, Su H, Zheng G, Kuhn U, Kim N, Li G, Ma N, Pöschl U, Cheng Y. Aerosol pH and Ion Activities of HSO 4- and SO 42- in Supersaturated Single Droplets. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:12863-12872. [PMID: 36047919 PMCID: PMC9494740 DOI: 10.1021/acs.est.2c01378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 08/23/2022] [Accepted: 08/25/2022] [Indexed: 06/15/2023]
Abstract
Accurate determination of acidity (pH) and ion activities in aqueous droplets is a major experimental and theoretical challenge for understanding and simulating atmospheric multiphase chemistry. Here, we develop a ratiometric Raman spectroscopy method to measure the equilibrium concentration of sulfate (SO42-) and bisulfate (HSO4-) in single microdroplets levitated by aerosol optical tweezers. This approach enables determination of ion activities and pH in aqueous sodium bisulfate droplets under highly supersaturated conditions. The experimental results were compared against aerosol thermodynamic model calculations in terms of simulating aerosol ion concentrations, ion activity coefficients, and pH. We found that the Extended Aerosol Inorganics Model (E-AIM) can well reproduce the experimental results. The alternative model ISORROPIA, however, exhibits substantial deviations in SO42- and HSO4- concentrations and up to a full unit of aerosol pH under acidic conditions, mainly due to discrepancies in simulating ion activity coefficients of SO42--HSO4- equilibrium. Globally, this may cause an average deviation of ISORROPIA from E-AIM by 25 and 65% in predicting SO42- and HSO4- concentrations, respectively. Our results show that it is important to determine aerosol pH and ion activities in the investigation of sulfate formation and related aqueous phase chemistry.
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Affiliation(s)
- Meng Li
- Minerva
Research Group, Max Planck Institute for
Chemistry, 55128 Mainz, Germany
| | - Hang Su
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, 55128 Mainz, Germany
| | - Guangjie Zheng
- Minerva
Research Group, Max Planck Institute for
Chemistry, 55128 Mainz, Germany
| | - Uwe Kuhn
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, 55128 Mainz, Germany
| | - Najin Kim
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, 55128 Mainz, Germany
| | - Guo Li
- Minerva
Research Group, Max Planck Institute for
Chemistry, 55128 Mainz, Germany
| | - Nan Ma
- Minerva
Research Group, Max Planck Institute for
Chemistry, 55128 Mainz, Germany
- Institute
for Environmental and Climate Research, Jinan University, Guangzhou 511443, China
| | - Ulrich Pöschl
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, 55128 Mainz, Germany
| | - Yafang Cheng
- Minerva
Research Group, Max Planck Institute for
Chemistry, 55128 Mainz, Germany
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Liu B, Huang Y, Zheng W, Wang D, Fan M. A SERS pH sensor for highly alkaline conditions and its application for pH sensing in aerosol droplets. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2022; 14:1856-1861. [PMID: 35510989 DOI: 10.1039/d2ay00387b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Surface-Enhanced Raman Scattering (SERS) has been widely used in pH sensing. However, SERS sensors capable of stably analysing pH under highly alkaline conditions are still scarce. In this work, a SERS pH sensor employing Alizarin Yellow R as the molecular probe was carefully developed for strong alkaline solutions. The results showed that the probe presented excellent sensing performance in the pH range of 10.04-14.04, including desirable stability and reversibility. Raman band assignments of the probe molecules with the protonated and deprotonated forms were calculated using Gaussian 09. To demonstrate the application, we measured the centroid pH of the phosphate buffer (PB) droplet and compared it to the value obtained with 4-mercaptobenzoic acid (4-MBA) as a probe.
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Affiliation(s)
- Boyu Liu
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, 610031, China.
| | - Yuting Huang
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, 610031, China.
| | - Wenxu Zheng
- College of Material and Energy, South China Agricultural University, Guangzhou, 510642, China
| | - Dongmei Wang
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, 610031, China.
- State-province Joint Engineering Laboratory of Spatial Information Technology of High-Speed Rail Safety, Chengdu, 610031, China
| | - Meikun Fan
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, 610031, China.
- State-province Joint Engineering Laboratory of Spatial Information Technology of High-Speed Rail Safety, Chengdu, 610031, China
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Huang Q, Wang W, Vikesland PJ. Implications of the Coffee-Ring Effect on Virus Infectivity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:11260-11268. [PMID: 34525305 DOI: 10.1021/acs.langmuir.1c01610] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The factors contributing to the survival of enveloped viruses (e.g., influenza and SARS-CoV-2) on fomite surfaces are of societal interest. The bacteriophage Phi6 is an enveloped viral surrogate commonly used to study viability. To investigate how viability changes during the evaporation of droplets on polypropylene, we conducted experiments using a fixed initial Phi6 concentration while systematically varying the culture concentration and composition (by amendment with 2% fetal bovine serum (FBS), 0.08 wt % BSA, or 0.5 wt % SDS). The results were consistent with the well-founded relative humidity (RH) effect on virus viability; however, the measured viability change was greater than that previously reported for droplets containing either inorganic salts or proteins alone, and the protein effects diverged in 1× Dulbecco's modified Eagle's medium (DMEM). We attribute this discrepancy to changes in virus distribution during droplet evaporation that arise due to the variable solute drying patterns (i.e., the "coffee-ring" effect) that are a function of the droplet biochemical composition. To test this hypothesis, we used surface-enhanced Raman spectroscopy (SERS) imaging and three types of gold nanoparticles (pH nanoprobe, positively charged (AuNPs(+)), and negatively charged (AuNPs(-))) as physical surrogates for Phi6 and determined that lower DMEM concentrations, as well as lower protein concentrations, suppressed the coffee-ring effect. This result was observed irrespective of particle surface charge. The trends in the coffee-ring effect correlate well with the measured changes in virus infectivity. The correlation suggests that conditions resulting in more concentrated coffee rings provide protective effects against inactivation when viruses and proteins aggregate.
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Affiliation(s)
- Qishen Huang
- Civil and Environmental Engineering and Institute of Critical Technology and Applied Science (ICTAS) Sustainable Nanotechnology, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Wei Wang
- Civil and Environmental Engineering and Institute of Critical Technology and Applied Science (ICTAS) Sustainable Nanotechnology, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Peter J Vikesland
- Civil and Environmental Engineering and Institute of Critical Technology and Applied Science (ICTAS) Sustainable Nanotechnology, Virginia Tech, Blacksburg, Virginia 24061, United States
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