Characterization of NOM and its adsorption by iron oxide coated sand (IOCS) using UV and fluorescence spectroscopy

The removal of natural organic matter (NOM) by adsorption onto iron oxide coated sand (IOCS) can be interpreted based on analysis of the absorbance and fluorescence spectra of the water before and after treatment. The useful spectral parameters include SUVA₂₅₄, the widths of the benzenoid and electron transfer absorbance bands (W_Bz, and W_ET, respectively), the ratio of the absorbance intensities of these two bands (A_ET/A_Bz), and the wavelength of the emission maximum (λ_max^em). These parameters appear to reflect both the activated aromatic content in the sample and its average molecular weight, and are good indicators of the adsorbability of NOM onto IOCS. A multi-parametric spectroscopic approach for online monitoring of NOM and its reactions can be valuable for both practical treatment studies and for fundamental explorations of NOM reactivity. Key words: natural organic matter, UV absorbance, adsorption, activated aromatics.