Chemical imaging of individual salt particles advances aerosol research

Aug 02, 2011

Scientists recently combined experimental approaches and molecular dynamics modeling to gain new insights into the internal structure of sea salt particles and relate it to their fundamental chemical reactivity in the atmosphere. They used laboratory-proxy sea salt composed of mixed sodium methanesulfonate and sodium chloride salts (CH3SO3Na/NaCl). Sea salt particles are emitted into the atmosphere by the action of ocean waves and bubble bursting at the ocean surface.

They are ubiquitous in the . impact and drive atmospheric that are known to influence Earth’s radiative balance and thereby physico-chemical processes that impact air quality and climate change. Using molecular dynamics simulations and surface tension measurements, the research team assessed the surfactant properties of CH3SO3- ions and their surface accumulation in wet, deliquesced particles. They investigated the internal structure of dry CH3SO3Na/NaCl particles using a combination of experimental chemical imaging techniques: scanning electron microscopy X-ray microanalysis and time-of-flight secondary ion mass spectrometry at EMSL and synchrotron-based X-ray microspectroscopy at Lawrence Berkeley National Laboratory.

The results indicate that the surfaces of aqueous (deliquesced) sea salt particles contain a substantial number of CH3SO3 ions, while in the dry (effloresced) particles, methanesulfonate salts form a coating layer that modifies the particles’ ability to absorb atmospheric moisture and contribute to chemical reactions. This research shows that surface enhancement or depletion of chemical components in marine particles can occur because of the difference in the chemical nature of the species. Because the atmospheric chemistry of the salt particles takes place at the gas-particle interface, understanding their complex surfaces provides new insights about their effect on the environment and climate change.

Explore further: Incorporation of DOPA into engineered mussel glue proteins

More information: Liu Y, B Minofar, Y Desyaterik, E Dames, Z Zhu, JP Cain, RJ Hopkins, MK Gilles, H Wang, P Jungwirth, and A Laskin. 2011. “Internal Structure, Hygroscopic and Reactive Properties of Mixed Sodium Methanesulfonate-Sodium Chloride Particles.” Phys. Chem. Chem. Phys. DOI: 10.1039/c1cp20444k

add to favorites email to friend print save as pdf

Related Stories

Watching particles' jekyll-to-hyde transformation

Jun 21, 2011

(PhysOrg.com) -- Whether a common atmospheric particle stays in a stable form or twists into something else depends on the amount of water it encounters in the atmosphere, according to scientists at the University ...

Tropical cloud 'dust' could hold the key to climate change

Oct 26, 2005

Scientists at the University of Manchester will set off for Australia this week to undertake an in-depth study of tropical clouds and the particles sucked up into them to gain further insight into climate change and the depletion ...

Airborne Mites

Nov 24, 2005

Aerosol particles influence atmospheric chemistry, climate, and human health They are tiny and very finely dispersed and play important roles for our climate and health. We are talking about aerosol particles, airborne droplets ...

Recommended for you

Separation of para and ortho water

Sep 18, 2014

(Phys.org) —Not all water is equal—at least not at the molecular level. There are two versions of the water molecule, para and ortho water, in which the spin states of the hydrogen nuclei are different. ...

User comments : 0