Figure 8.
Trends in relative organic functional group concentrations with time for the soluble organics of FAW (with and without minerals) as determined by FTIR for the peak intensity ratios of (a) C=O (ester)/C=C, (b) C=O (carboxyl, aldehyde, amide)/C=C, (c) C=O (carboxyl, aldehyde, amide)/C=O (ester), (d) CH2/CH3, and (e) (CH2 + CH3)/C=C. The C=O (ester), C=O (carboxyl, aldehyde, amide), and C=C peak intensities are obtained by the peak top height of the band around 1765, 1700, and 1600 cm−1, respectively, with the linear baseline between 1840 and 1520 cm−1. The CH2 and CH3 peak intensities are obtained by the peak top height of the band at 2935 cm−1 (CH2) and the band at 2960 cm−1 (CH3), respectively, with the linear baseline between 3010 and 2790 cm−1.