Methanesulfonic Acid-driven New Particle Formation Enhanced by Monoethanolamine: A Computational Study

Area of Science:

• Atmospheric Chemistry
• Environmental Science
• Chemical Physics

Background:

• Amines are known to enhance new particle formation (NPF) driven by methanesulfonic acid (MSA).
• Monoethanolamine (MEA) is present in the atmosphere, with potential concentration increases due to CO2 capture technologies.
• Understanding MEA's role in MSA-driven NPF is critical for atmospheric modeling.

Purpose of the Study:

• To evaluate the enhancing potential of monoethanolamine (MEA) on methanesulfonic acid (MSA)-driven new particle formation (NPF).
• To investigate the formation mechanisms of MEA-MSA clusters.
• To compare MEA's enhancing capacity with known agents like methylamine (MA).

Main Methods:

• Utilized quantum chemical calculations to study MEA-MSA cluster formation.
• Employed kinetics modeling to analyze NPF pathways.
• Examined hydrogen bonding interactions within MEA-containing clusters.

Main Results:

• MEA exhibits a higher enhancing potential for MSA-driven NPF than methylamine (MA).
• The hydroxyl (-OH) group of MEA forms hydrogen bonds, increasing binding free energy.
• The primary growth pathway involves sequential addition of MEA and MSA molecules to form clusters.

Conclusions:

• MEA is a potent enhancer of MSA-driven NPF, attributed to its strong hydrogen bonding and gas-phase basicity.
• The hydrogen-bonding capacity of non-amino groups in amines is vital for enhancing MSA-driven NPF.
• The formation pathway of MEA-MSA clusters differs from MA-MSA clusters, highlighting the influence of amine structure.