Vibrational spectral studies of solutions at elevated temperatures and pressures. 8. A Raman spectral study of ammonium hydrogen sulfate solutions and the hydrogen sulfate-sulfate equilibrium

Dawson, Bernard S. W.; Irish, D. E.; Toogood, G. E.

doi:10.1021/j100274a027

Cited by 89 publications

(101 citation statements)

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“…10b. A new band centered at 874 cm −1 corresponds to combination bands of the vibrational mode (δ(S-OH)) of the HSO − 4 ion from NH 4 HSO 4 (Dawson et al, 1986) (Villepin and Novak, 1971). Therefore, the evolution of Raman spectra of the mixed OA / AS droplets (OIR = 1 : 3) during the dehydration process confirms that OA could react with AS to form NH 4 HSO 4 and NH 4 HC 2 O 4 , which supports previous speculation for the reaction between OA and AS (Miñam-bres et al, 2013).…”

Section: Raman Spectra Of Oa / As Mixturesmentioning

confidence: 99%

Hygroscopic behavior and chemical composition evolution of internally mixed aerosols composed of oxalic acid and ammonium sulfate

et al. 2017

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Abstract. Although water uptake of aerosol particles plays an important role in the atmospheric environment, the effects of interactions between components on chemical composition and hygroscopicity of particles are still not well constrained. The hygroscopic properties and phase transformation of oxalic acid (OA) and mixed particles composed of ammonium sulfate (AS) and OA with different organic to inorganic molar ratios (OIRs) have been investigated by using confocal Raman spectroscopy. It is found that OA droplets first crystallize to form OA dihydrate at 71 % relative humidity (RH), and further lose crystalline water to convert into anhydrous OA around 5 % RH during the dehydration process. The deliquescence and efflorescence point for AS is determined to be 80.1 ± 1.5 % RH and 44.3 ± 2.5 % RH, respectively. The observed efflorescence relative humidity (ERH) for mixed OA / AS droplets with OIRs of 1 : 3, 1 : 1 and 3 : 1 is 34.4 ± 2.0, 44.3 ± 2.5 and 64.4 ± 3.0 % RH, respectively, indicating the elevated OA content appears to favor the crystallization of mixed systems at higher RH. However, the deliquescence relative humidity (DRH) of AS in mixed OA / AS particles with OIRs of 1 : 3 and 1 : 1 is observed to occur at 81.1 ± 1.5 and 77 ± 1.0 % RH, respectively. The Raman spectra of mixed OA / AS droplets indicate the formation of ammonium hydrogen oxalate (NH 4 HC 2 O 4 ) and ammonium hydrogen sulfate (NH 4 HSO 4 ) from interactions between OA and AS in aerosols during the dehydration process on the time scale of hours, which considerably influence the subsequent deliquescence behavior of internally mixed particles with different OIRs. The mixed OA / AS particles with an OIR of 3 : 1 exhibit no deliquescence transition over the RH range studied due to the considerable transformation of (NH 4 ) 2 SO 4 into NH 4 HC 2 O 4 with a high DRH. Although the hygroscopic growth of mixed OA / AS droplets is comparable to that of AS or OA at high RH during the dehydration process, Raman growth factors of mixed particles after deliquescence are substantially lower than those of mixed OA / AS droplets during the efflorescence process and further decrease with elevated OA content. The discrepancies for Raman growth factors of mixed OA / AS particles between the dehydration and hydration process at high RH can be attributed to the significant formation of NH 4 HC 2 O 4 and residual OA, which remain solid at high RH and thus result in less water uptake of mixed particles. These findings improve the understanding of the role of reactions between dicarboxylic acid and inorganic salt in the chemical and physical properties of aerosol particles, and might have important implications for atmospheric chemistry.

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Section: Raman Spectra Of Oa / As Mixturesmentioning

confidence: 99%

Hygroscopic behavior and chemical composition evolution of internally mixed aerosols composed of oxalic acid and ammonium sulfate

et al. 2017

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“…The resolution of the spectra obtained was about 6 cm −1 . The assignments of Raman peaks were based on those used by Dawson et al (1986), Lin-Vien et al (1991), andDong et al (2007).…”

Section: Raman Spectroscopy Of Single Levitated Particlesmentioning

confidence: 99%

Displacement of Ammonium from Aerosol Particles by Uptake of Triethylamine

Chan

2012

Aerosol Science and Technology

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The displacement of ammonium by triethylammonium (TEAH) in aerosol particles of about 15-35 µm in diameter was investigated using an electrodynamic balance (EDB) coupled with in situ Raman spectroscopy. ] led to increases in particle mass of over 90%. A complete displacement of ammonium by TEAH was confirmed by direct EDB mass measurements and the Raman spectra obtained. TEAH sulfate was formed during the exposure of aqueous droplets of (NH 4 ) 2 SO 4 and NH 4 HSO 4 to TEA vapor at 50% RH; but a fraction of it decomposed to TEAH bisulfate when the TEA supply was removed. Crystalline solid particles of (NH 4 ) 2 SO 4 and (NH 4 ) 2 C 2 O 4 experienced small mass increases of <5%, both of which were attributed to the hindered mass transfer of TEA in crystalline solids. However, TEA reacted with the amorphous solid NH 4 NO 3 particle at <3% RH as effectively as if it was in the aqueous NH 4 NO 3 droplet (50% RH) and formed TEAH nitrate. On the other hand, the amorphous NH 4 HSO 4 solid particle reacted with TEA at <3% RH to form crystalline (NH 4 ) 2 SO 4 and liquid TEAH bisulfate and sulfate. The formation of rather inert crystalline (NH 4 ) 2 SO 4 suppressed the ammonium exchange.

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“…The X function for bisulfate is aerosol at 298.15K plotted against square root of molality (m, mol/kg of solvent) of salt in the aerosol. The literature data (Young et al 1959;Dawson et al 1986) were measured using a Raman spectrometer for aqueous NH 4 HSO 4 solution. available only for KHSO 4 over the narrow range of RHs between 90% and 99% (Rochester 1970).…”

Section: Extrapolation Of C-ruv To Weakly Acidic Aerosolmentioning

confidence: 99%

“…The degrees of dissociation of HSO 4 − (αHSO 4 − ) for NH 4 HSO 4 aerosol were calculated using the C-RUV data and compared to both E-AIM predictions and 2 different literature data sets (Young et al 1959;Dawson et al 1986) measured for aqueous NH 4 HSO 4 solution using a Raman spectrometer (Figure 8a). Both literature data are applicable only for high humidity conditions.…”

Section: Extrapolation Of C-ruv To Weakly Acidic Aerosolmentioning

confidence: 99%

Aerosol Acidity Measurement Using Colorimetry Coupled With a Reflectance UV-Visible Spectrometer

Jang

2012

Aerosol Science and Technology

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In this study, aerosol acidity was measured using colorimetry integrated with a Reflectance UV-Visible spectrometer (C-RUV). An inorganic aerosol comprising NH 4 + −H + −SO 4 2− −H 2 O was generated using an atomizer and introduced into a 2-m 3 indoor Teflon film chamber. The produced aerosol was collected on the Tefloncoated glass fiber filter dyed with metanil yellow (MY) as an indicator for measuring proton concentrations in aerosol. A calibration curve for measuring aerosol acidity using the C-RUV technique was obtained through the relationship between the absorbance of the UV-Visible spectrum of the filter sample vs. theoretically calculated proton concentrations using the E-AIM Model II. To develop the C-RUV method under various humidities, the aerosol filter sample was mounted inside a small optical flow chamber controlled for humidity in situ. The humidity effect on the equilibrium thermodynamics of the indicator was theoretically described by inclusion of excess acidity (X) into the calibration curve. The calibration curve obtained from relatively highly acidic aerosols (e.g., H 2 SO 4 , NH 4 H 3 (SO 4 ) 2 , and (NH 4 ) 7 H 13 (SO 4 ) 10 ) was extrapolated to estimate proton concentrations for weakly acidic aerosols (e.g., NH 4 HSO 4 and (NH 4 ) 3 H(SO 4 ) 2 ), which is more relevant to the ambient aerosol acidity but has been poorly predicted with typical inorganic thermodynamic models due to the limited experimental data. The C-RUV technique of this study permits one to estimate aerosol acidity for a variety of compositions of the NH 4 + −H + −SO 4 2− −H 2 O system including both ammonia-poor and ammonia-rich sulfate aerosols.

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Vibrational spectral studies of solutions at elevated temperatures and pressures. 8. A Raman spectral study of ammonium hydrogen sulfate solutions and the hydrogen sulfate-sulfate equilibrium

Cited by 89 publications

References 1 publication

Hygroscopic behavior and chemical composition evolution of internally mixed aerosols composed of oxalic acid and ammonium sulfate

Hygroscopic behavior and chemical composition evolution of internally mixed aerosols composed of oxalic acid and ammonium sulfate

Displacement of Ammonium from Aerosol Particles by Uptake of Triethylamine

Aerosol Acidity Measurement Using Colorimetry Coupled With a Reflectance UV-Visible Spectrometer

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