Fulvic acids Fourier transform-infrared spectroscopy

Critical Coagulation Concentration Chromatographable Organic Carbon Chloral Hydrate Forming Potential Disinfection By-Product Diethylaminoethyl Diffusion Limited Aggregation Dissolved O anic Carbon Dissolved Organic Matter Direct Observation through the Membrane Technique Diffusive Reflectance Fourier Transform Infrared Spectroscopy Electronic Conductive Carbon Black Electron Dispersive Spectra Ethylene Diamine Tetra Acetic Acid Fulvic Acid... 

Figure 4.6. Fourier transform infrared spectra of humic acids (HAs) and fulvic acids (FAs) isolated from pig slurry (PS), unamended soil (PSO, and soils amended with 90 and 150m3ha 1yr 1 of PS for 7 years (PS90 and PS150, respectively). Reprinted from Hernandez, D., Plaza, C., Senesi, N., and Polo, A. (2006). Detection of copper(II) and zinc(II) binding to humic acids from pig slurry and amended soils by fluorescence spectroscopy. Environ. Pollut. 143, 212-220, with permission from Elsevier, and from Hernandez, D., Plaza, C., Senesi, N., and Polo, A. (2007). Fluorescence analysis of copper(II) and zinc(II) binding behavior of fulvic acids from pig slurry and amended soils. Eur. J. Soil Sci. 58, 900-908, with permission from Blackwell Publishing.

For this study, humic and fulvic materials obtained from a small glaciated bog were separated into five size fractions by using hollow-fiber ultrafiltration techniques. The major cations associated with these organics are reported as a measure of the natural binding capacity of each size range. The structural characteristics and carboxylate content of each group were studied by CIR spectroscopy the results are compared with those obtained by traditional Fourier transform infrared techniques. To aid in spectral interpretation, results were compared to those for selected model polyelectrolytes and simple acids. 

Detailed experimental procedures for obtaining infrared spectra on humic and fulvic acids have been reported previously 9,22,25-26) and will be briefly described here. Infrared spectra were taken on the size-fractionated samples by using a Fourier transform infrared spectrometer (Mattson, Polaris) with a cooled Hg/Cd/Te detector. Dried humic and fulvic materials were studied by diffuse reflectance infrared spectroscopy (Spectra Tech DRIFT accessory) and reported in K-M units, as well as by transmission absorbance in a KBr pellet. Infrared absorption spectra were obtained directly on the aqueous size-fractioned concentrates with CIR (Spectra Tech CIRCLE accessory). Raman spectra were taken by using an argon ion laser (Spectra-Physics Model 2025-05), a triple-grating monochromator (Spex Triplemate Model 1877), and a photodiode array detector system (Princeton Applied Research Model 1420). All Raman and infrared spectra were taken at 2 cm resolution. 

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