Three-Dimensional Excitation Emission Matrix Fluorescence Spectroscopic Characterization of Complexation Between Mercury(II) and Dissolved Organic Matter Extracted from Landfill Leachate
To investigate the change of complexation between heavy metals and dissolved organic matter (DOM) extracted from landfill leachate over time,three-dimensional excitation emission matrix fluorescence spectroscopy (3DEEM) ,Rayleigh scattering,fluorescence quenching titration and nonlinear regression analysis were applied to study complexation process between Hg(Ⅱ) and DOM extracted from landfill leachate with different ages.The experimental results showed that there was no precipitation production during the titrating process,and the complexation ratios between Hg(Ⅱ) and the fluorescence group in DOMs were nearly 1∶1; the conditional stability constants and the percentage of fluorophores participating in the complexation between Hg(Ⅱ) and protein-like matter with different ages were 4.3-5.7 and 54.1%-92.3% ,respectively,while those between Hg(Ⅱ) and fulvic-like matter with different ages were 4.35-4.98 and 35.8%-60.1% , respectively.The complexation ability between Hg(Ⅱ) and fulvic-like matter decreases with the increase of landfill time,though the percentage of fluorophores participating in the complexation increased.Besides,the complexation process was easily affected by the pH value,especially under the acidity or alkality circumstance.