Characterizing Ohio River NOM Variability and Reconstituted-Lyophilized NOM as a Source Surrogate

Natural organic matter (NOM) was collected, concentrated, and lyophilized on a monthly basis for 15 months to create a temporal NOM library and assess seasonal variability of untreated Ohio River water. Using fluorescence spectroscopy with parallel factor analysis, similar spectral components for both the ultrafiltered source water (UF1X) and reconstituted lyophilized NOM were observed in a two-component model throughout the study, with overall average emission and excitation wavelengths of 418 nm and 270 nm, respectively, for component 1 and 482 nm and 370 nm, respectively, for component 2. Fluorescence spectroscopy, high-pressure liquid chromatography-size exclusion chromatography, and elemental analysis indicated that the NOM was humic-like during the study with only small seasonal changes. Data from these analyses also demonstrated similarity between results for UF1X, reverse osmosis-concentrated NOM, and reconstituted- lyophilized NOM, validating the use of the reconstituted- lyophilized NOM as a surrogate for its source.