Mass, charge, and radius of droplets in a linear quadrupole electrodynamic balance

A method has been developed to determine the temperature of single microparticles levitated in an electrodynamic balance. Particle temperatures were ascertained from the measured intensities of the Stokes and anti-Stokes Raman spectra. Temperatures near ambient were obtained for titanium dioxide and calcium nitrate microparticles with the use of a Raman-based calibration of the optical system to correct for wavelength-dependent effects. Higher temperatures were also measured with the use of a carbon dioxide infrared laser to electromagnetically heat the particle. In an effort to minimize particle instabilities caused by the heating beam, the Gaussian intensity profile of the beam was modified with an axicon beam expander to produce a doughnut-like intensity distribution. The temperature measurement technique and quantitative Raman composition analysis were applied to study dehydration of a calcium nitrate tetrahydrate particle.

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Electrodynamic balance measurements of thermodynamic, kinetic, and optical aerosol properties inaccessible to bulk methods

Atmospheric Measurement Techniques ◽

10.5194/amt-8-2397-2015 ◽

2015 ◽

Vol 8 (6) ◽

pp. 2397-2408 ◽

Cited By ~ 26

Author(s):

S. S. Steimer ◽

U. K. Krieger ◽

Y.-F. Te ◽

D. M. Lienhard ◽

A. J. Huisman ◽

...

Keyword(s):

Refractive Index ◽

Light Scattering ◽

Room Temperature ◽

Shikimic Acid ◽

Resonance Spectroscopy ◽

Equilibrium Conditions ◽

Electrodynamic Balance ◽

Mie Resonance ◽

Water Diffusivity ◽

Activity Density

Abstract. Measurements of a single, levitated particle in an electrodynamic balance are an established tool for deriving thermodynamic and material data such as density, refractive index and activities of components of an aqueous solution under supersaturated conditions, where bulk measurements are not possible. The retrieval relies on combining mass-to-charge data and size data from light scattering. Here, we use a combination of low- and high-resolution Mie resonance spectroscopy to obtain radius data, enabling an accurate size determination not only when the particle is in equilibrium, but also when it is out of equilibrium due to kinetic limitation of mass transport. With the data measured under non-equilibrium conditions, it is possible to retrieve the water diffusivity. A challenge is that the radius retrieval by comparing measured light scattering with Mie theory requires the knowledge of refractive index as a function of concentration. Here, we show an iterative retrieval of refractive index and size for compounds for which data cannot be obtained in the bulk either due to lack of sufficient amounts of sample or limited solubility. We demonstrate the measurement strategy and the retrieval of water activity, density, refractive index and water diffusivity for aqueous shikimic acid. Water diffusivity in concentrated shikimic acid decreases by 6 orders of magnitude at 250 K compared to that at room temperature.

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Incineration of Contaminated Soils in an Electrodynamic Balance

Emerging Technologies in Hazardous Waste Management II - ACS Symposium Series ◽

10.1021/bk-1991-0468.ch003 ◽

1991 ◽

pp. 29-49 ◽

Cited By ~ 2

Author(s):

M. Flytzani-Stephanopoulos ◽

A. F. Sarofim ◽

L. Tognotti ◽

H. Kopsinis ◽

M. Stoukides

Keyword(s):

Contaminated Soils ◽

Electrodynamic Balance

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An octopole electrodynamic balance for three-dimensional microparticle control

Review of Scientific Instruments ◽

10.1063/1.1384453 ◽

2001 ◽

Vol 72 (8) ◽

pp. 3380-3385 ◽

Cited By ~ 8

Author(s):

F. Zheng ◽

X. Qu ◽

E. J. Davis

Keyword(s):

Three Dimensional ◽

Electrodynamic Balance

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Why not modernize the textbooks also? II. Hydrolysis and its relation to ionic charge and radius

Journal of Chemical Education ◽

10.1021/ed017p509 ◽

1940 ◽

Vol 17 (11) ◽

pp. 509 ◽

Cited By ~ 1

Author(s):

Laurence S. Foster

Keyword(s):

Ionic Charge ◽

Charge And Radius

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Chemical Reactions with Single Microparticles

MRS Bulletin ◽

10.1557/s088376940006070x ◽

1990 ◽

Vol 15 (1) ◽

pp. 26-33 ◽

Cited By ~ 13

Author(s):

E. James Davis ◽

Mark F. Buehler

Keyword(s):

Ultrafine Particles ◽

Fine Particles ◽

Reaction Rates ◽

Pure Metal ◽

Metal Alkoxide ◽

Electrodynamic Balance ◽

Hydrolysis Rates ◽

Photochemical Polymerization ◽

Titanium Silicon ◽

Hydrolysis Of

Fine particles can be produced via aerosol processes either by means of vapor phase reactions that produce solid or liquid particles or by reactions between a preexisting solid or liquid particle and a reactive gas. This article examines the latter processes because a strong interest has developed in the production of materials via aerosol processing. Although fine particles are frequently produced using flow systems, such as in the laminar flow aerosol reactor of McRae and his co-workers, fundamental studies of the chemical kinetics are more readily done using single microparticles or microdroplets. Design of an aerosol reactor requires knowledge of the reaction rates, for there must be a sufficient residence time of the reacting species in the reactor to complete the desired reaction.Matijević reviewed early work on preparing well-defined and very pure metal oxides by hydrolysis of alkoxide aerosol particles, and Ingebrethsen and co-workers studied the hydrolysis rates of aerosol droplets of aluminum and titanium alkoxides and mixtures of the two alkoxides. Following Matijevic and his colleagues, Okuyama et al. used the thermal decomposition of metal alkoxide vapors to produce ultrafine particles of the oxides of titanium, silicon, and aluminum. The preparation of polymeric aerosols has been studied by Partch et al. and by Ward et al. The latter investigators used single-particle techniques (the electrodynamic balance) to obtain polymerization rate data for the photochemical polymerization of acrylamide monomer microparticles.

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Effect of ammonium salts on the photochemical degradation of iron containing organic aerosol

10.5194/egusphere-egu2020-15572 ◽

2020 ◽

Author(s):

Ulrich Krieger ◽

Nir Bluvshtein ◽

Jing Dou

Keyword(s):

Citric Acid ◽

Gas Phase ◽

Degradation Rate ◽

Uv Light ◽

Lower Troposphere ◽

Organic Aerosol ◽

Photochemical Degradation ◽

Single Particles ◽

Electrodynamic Balance ◽

Humidity Dependence

Formation of organic aerosol by oxidation of gas phase compounds has been intensely studied, and is much better understood than the aerosol ageing transformations during the lifetime of organic aerosol. Aerosol ageing influences how those aerosol particles affect climate and human health and is still not well constrained in current models.Photochemistry in the condensed phase is an important mechanism responsible for ageing of organic aerosol. In the lower troposphere, where UV light intensity with sufficiently low wavelength to directly photolyze aerosol components is low, indirect photochemistry (catalyzing redox processes of non-absorbing molecules) is especially relevant. Recently we studied transition metal complex photochemistry in single particles levitated in an electrodynamic balance. In particular, we investigated the aqueous iron(III)-citrate/citric acid system and found that irradiation at 473 nm led to rapid and significant degradation of the citric acid. Up to 80% of the initial particle mass was partitioned to the gas phase with the degradation rate depending on kinetic transport limitations of oxygen. These kinetic limitations arise are influenced strongly by the relative humidity dependence of particle viscosity where water acts as a plasticizer.Here we will report on photochemical degradation experiments adding various salts in different (ammonium sulfate, ammonium bisulfate, etc.) to the reference system iron(III)-citrate/citric acid. Preliminary experiments suggest that pH of the aerosol particle influences the degradation rate in this system significantly.

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