Dynamic light scattering measurements of particle size development in aqueous humic materials

Palmer, Noel E.; Wandruszka, Ray von

doi:10.1007/s002160101037

Cited by 83 publications

(66 citation statements)

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“…Numerous studies have shown that the extent and type of HA aggregation depends on HA components, pH, ionic strength, type of electrolyte, and temperature (Palmer and von Wandruszka 2001;Terashima et al 2004;Chilom et al 2009;Wang et al 2013). The obtained values of the CQ internal oxidation acc.…”

Section: Resultsmentioning

confidence: 89%

“…Humic acids have an amphiphilic nature, that is why they spontaneously form micelle-like structures in aquatic solutions, which are rather a variety of species of different molecular size (Palmer and von Wandruszka 2001;Chilom et al 2009). Numerous studies have shown that the extent and type of HA aggregation depends on HA components, pH, ionic strength, type of electrolyte, and temperature (Palmer and von Wandruszka 2001;Terashima et al 2004;Chilom et al 2009;Wang et al 2013).…”

Section: Resultsmentioning

confidence: 99%

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Studying of the interaction between peat humic acids and metazachlor using spectroscopy methods

et al. 2018

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Purpose The analysis covered the interaction of humic acids (HA) isolated from peats with the metazachlor using spectroscopic methods. Materials and methods Five peatlands have been selected for the study in the southern and northern parts of Poland. Extraction of humic acids (HA1, HA2, HA3, HA4, and HA5) was performed using a procedure recommended by the International Humic Substances Society. Metazachlor 500 SC with metazachlor as a biologically active substance [2-chloro-N-(pyrazol-1-ylmethyl)acet-2′,6′-xylidide] has been used. HA have been assessed on the basis of their elemental composition. Spectroscopic techniques have been used to study the HA structure and their interaction with metazachlor including: UVvisible spectroscopy, dynamic light scattering, and delayed luminescence (DL) Results and discussion Based on their morphological and chemical properties, the studied peat soils can be classified as follows: (1) Eutric Murshic Sapric Histosols, (2) Eutric Sapric Histosols, (3) Eutric Hemic Histosols, (4) Eutric Fibric Histosols, and (5) Dystric Dranic Hemic Histosols according to the WRB guidelines (2015). Results showed that the largest particle size, measured by E 4/6 coefficient, was found in HA2 sample, while the smallest in HA3 sample. The addition of metazachlor to HA solutions reduced the values of E 4/6 coefficient by 33 to 72%, while the values of hydrodynamic diameter by 4 to 32%. No significant changes were found between E 4/6 after adding of metazachlor to HA solutions. The largest changes in DL intensity, excited both by blue and red light after herbicide addition, were observed in HA2 sample, which is characterized by the largest particle size, the highest oxygen content and CQ value as well as the lowest Baromatization rate^value. Conclusions The particle sizes of HA molecules measured by E 4/6 coefficient do not impact on the particle sizes of HA-herbicide systems measured by the same ratio. The delayed luminescence may become valuable, because it is simple, fast, and sensitive. Additionally, the results show minor errors comparing with chemical methods. This method may provide information about structure and nature of humic acids, as well as their photoreactivity. The using of delayed luminescence in studies of HApesticides interaction may enable us to better understand the luminescence properties of HA.

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Section: Resultsmentioning

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Studying of the interaction between peat humic acids and metazachlor using spectroscopy methods

et al. 2018

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“…SRFA consists of 0.5-1.5 kDa organic macroligands, which are amphiphilic and contain carbonyl, phenol, and ketone moieties. While these masses are well below the expected sizes of most known ice nucleation entities (INE), both dynamic light scattering and small angle neutron scattering indicate that aggregates ∼ 100-500 nm in diameter can form even in dilute solutions of SRFA (Diallo et al, 2005;Palmer and Von Wandruszka, 2001). These aggregates contain macrostructures that could induce ice nucleation.…”

Section: Effect Of Sp2 Laser On Mixtures Of Inp Proxies With Rbcmentioning

confidence: 87%

Use of the Single Particle Soot Photometer (SP2) as a pre-filter for ice nucleation measurements: effect of particle mixing state and determination of SP2 conditions to fully vaporize refractory black carbon

Schill¹,

DeMott²,

Levin³

et al. 2018

Atmos. Meas. Tech.

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Abstract. Ice nucleation is a fundamental atmospheric process that impacts precipitation, cloud lifetimes, and climate. Challenges remain to identify and quantify the compositions and sources of ice-nucleating particles (INPs). Assessment of the role of black carbon (BC) as an INP is particularly important due to its anthropogenic sources and abundance at upper-tropospheric cloud levels. The role of BC as an INP, however, is unclear. This is, in part, driven by a lack of techniques that directly determine the contribution of refractory BC (rBC) to INP concentrations. One previously developed technique to measure this contribution uses the Single Particle Soot Photometer (SP2) as a pre-filter to an online icenucleating particle counter. In this technique, rBC particles are selectively heated to their vaporization temperature in the SP2 cavity by a 1064 nm laser. From previous work, however, it is unclear under what SP2 conditions, if any, the original rBC particles were fully vaporized. Furthermore, previous work also left questions about the effect of the SP2 laser on the ice-nucleating properties of several INP proxies and their mixtures with rBC.To answer these questions, we sampled the exhaust of an SP2 with a Scanning Mobility Particle Sizer and a Continuous Flow Diffusion Chamber. Using Aquadag ® as an rBC proxy, the effect of several SP2 instrument parameters on the size distribution and physical properties of particles in rBC SP2 exhaust were explored. We found that a high SP2 laser power (930 nW/(220 nm PSL)) is required to fully vaporize a ∼ 0.76 fg rBC particle. We also found that the exhaust particle size distribution is minimally affected by the SP2 sheath-to-sample ratio; the size of the original rBC particle, however, greatly influences the size distribution of the SP2 exhaust. The effect of the SP2 laser on the ice nucleation efficiency of Snomax ® , NX-illite, and Suwannee River Fulvic Acid was studied; these particles acted as proxies for biological, illite-rich mineral dust, and brown carbon INPs, respectively. The original size distribution and ice nucleation efficiency of all non-rBC proxies were unaffected by the SP2 laser. Furthermore, the ice nucleation efficiencies of all proxies were not affected when externally mixed with rBC. These proxies, however, always show a reduction in ice-nucleating ability when internally mixed with rBC. We end this work with recommendations for users who wish to use the SP2 as a pre-filter to remove large rBC particles from an aerosol stream.

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“…SRFA consists of 0.5-1.5 kDa organic macroligands, which are 15 amphiphilic and contain carbonyl, phenol, and ketone moieties. While these masses are well below the expected sizes of most known ice nucleation entities (INE), both dynamic light scattering and small angle neutron scattering indicate that aggregates ~100-500 nm in diameter can form even in dilute solutions of SRFA (Diallo et al, 2005;Palmer and Von Wandruszka, 2001). These aggregates contain macrostructures that could induce ice nucleation.…”

Section: Effect Of Sp2 Laser On Mixtures Of Inp Proxies With Rbcmentioning

confidence: 99%

Use of the Single Particle Soot Photometer (SP2) as a pre-filter for ice nucleation measurements: Effect of particle mixing state and determination of SP2 conditions to fully vaporize refractory black carbon

Schill¹,

DeMott²,

Levin³

et al. 2017

Preprint

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Abstract. Ice nucleation is a fundamental atmospheric process that impacts precipitation, cloud lifetimes, and climate. Challenges remain to identify and quantify the compositions and sources of ice nucleating particles (INPs). Assessment of the role of black 10 carbon (BC) as an INP is particularly important due to its anthropogenic sources and abundance at upper tropospheric cloud levels.The role of BC as an INP, however, is unclear. This is, in part, driven by a lack of techniques that directly determine the contribution of refractory BC (rBC) to INP concentrations. One previously developed technique to measure this contribution uses the Single Particle Soot Photometer (SP2) as a pre-filter to an online ice nucleating particle counter. In this technique, rBC particles are selectively heated to their vaporization temperature in the SP2 cavity by a 1064-nm laser. From previous work, however, it is 15 unclear under what SP2 conditions, if any, that the original rBC particles were fully vaporized. Furthermore, previous work also left questions about the effect of the SP2 laser on the ice nucleating properties of several INP proxies and their mixtures with rBC.To answer these questions, we sampled the exhaust of an SP2 with a Scanning Mobility Particle Sizer and a Continuous Flow Diffusion Chamber. Using Aquadag® as an rBC proxy, the effect of several SP2 instrument parameters on the size distribution and physical properties of particles in rBC SP2 exhaust were explored. We found that a high SP2 laser fluence [930 20 nW/(220-nm PSL)] is required to fully vaporize a ~0.76 fg rBC particle. We also found that the exhaust particle size distribution is minimally affected by the SP2 sheath-to-sample ratio; the size of the original rBC particle, however, greatly influences the size distribution of the SP2 exhaust. The effect of the SP2 laser on the ice nucleation efficiency of Snomax®, NX-illite, and Suwannee River Fulvic Acid was studied; these particles acted as proxies for biological, illite-rich mineral dust, and brown carbon INPs, respectively. The original size distribution and ice nucleation efficiency of all non-rBC proxies were unaffected by the SP2 laser. 25 Furthermore, the ice nucleation efficiencies of all proxies were not affected when externally mixed with rBC. These proxies, however, always show a reduction in ice nucleating ability when internally mixed with rBC. We end this work with recommendations for users who wish to use the SP2 as a prefilter to remove large rBC particles from an aerosol stream.

show abstract

Dynamic light scattering measurements of particle size development in aqueous humic materials

Cited by 83 publications

References 1 publication

Studying of the interaction between peat humic acids and metazachlor using spectroscopy methods

Studying of the interaction between peat humic acids and metazachlor using spectroscopy methods

Use of the Single Particle Soot Photometer (SP2) as a pre-filter for ice nucleation measurements: effect of particle mixing state and determination of SP2 conditions to fully vaporize refractory black carbon

Use of the Single Particle Soot Photometer (SP2) as a pre-filter for ice nucleation measurements: Effect of particle mixing state and determination of SP2 conditions to fully vaporize refractory black carbon

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