Method for investigating the hygroscopic and optical character of organic carbon in atmospheric aerosols

Kanu, Amadu

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https://hdl.handle.net/2142/89101 Copy

Description

Title

Method for investigating the hygroscopic and optical character of organic carbon in atmospheric aerosols

Author(s)

Kanu, Amadu

Issue Date

2015-12-11

Director of Research (if dissertation) or Advisor (if thesis)

Bond, Tami C

Department of Study

Civil & Environmental Engineering

Discipline

Environmental Engineering in Civil Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

Ion-Exchange High Performance Liquid Chromatography

Abstract

The hygroscopic and optical characteristics of organic carbon aerosols impact the radiative energy balance of the atmosphere, and therefore Earth’s climate. This thesis discusses the development of a method to fractionate organic carbon according to climate-relevant properties. Ion-exchange High Performance Liquid Chromatography (IE-HPLC) is developed as a single analytical method to provide information on both water affinity (via column affinity) and wavelength-dependent optical absorption of the water-soluble organic carbon (WSOC) component of the aerosol. This method is applied to organic aerosol generated by burning and pyrolyzing biomass. The IE-HPLC method can fractionate WSOC, generated from a range of combustion conditions, into several distinct groups using gradients of two solvents in the liquid phase. The retention times of these compounds lies within the range of organic standards. Furthermore, the immersion of WSOC into salty or acidic aqueous environments increased the absorbance of the fractionated peaks by an order of magnitude. This increase did not scale with the amount of WSOC extracted from the samples. A correlation between chromatographic retention time and spectral absorption was found: WSOC fractions that exhibit stronger column affinity and hence water affinity were also found to absorb more intensely at longer wavelengths, up to about 400 nm.

Graduation Semester

2015-12

Type of Resource

text

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Copyright and License Information

Copyright 2015 Amadu Kanu

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