Fluorescence Characterization of Fractionated Colloids in Wastewaters Received by Huangpu River

Abstract

The spectral characteristics of fractionated colloids in wastewaters from Huangpu River were isolated and investigated via cross flow ultrafiltration systems with different molecular mass of membranes and three-dimensional excitation-emission matrix fluorescence spectroscopy. The results showed that the colloidal concentration (CC) and colloidal organic carbon content (COC) of all size fractions in all samples were in the ranges 9.60-32.50 mg·L-1 and 0.03-6.25 mg·L-1, respectively. Moreover, both CC and COC values increased as the colloidal size increased. The protein- (i.e., peaks D and T) and humic-like (peaks C and A) materials were present in all the size fractions (except for the Mr 300×103-1 μm size fraction of the influent sample), of which protein- and humic-like materials were mainly in the Mr 1×103-5×103 and Mr 10×103-300×103 size fractions, respectively. In addition, fluorescence indices (including the fluorescence index (FI), humification index (HIX), and the index of recent autochthonous contribution (BIX)) were introduced to determine the source and spectral characteristic of the selected colloids. These indices indicated that the relatively small colloids with high aromaticity and hydrophobicity mainly originated from terrestrial sources, whereas the relatively large colloids were predominantly from the recent autochthonous organic matter and the protein-like components.