Characterization of Dissolved Organic Matter Using Size Exclusion Chromatography
Date Issued
2007
Date
2007
Author(s)
Chang, Cheng-Hsuan
DOI
zh-TW
Abstract
This thesis reported the characteristics of dissolved organic matters using size exclusion chromatography (SEC). First work adopted IHSS humic acid (HA) and bovine serum albumin (BSA) as the model NOM. For HA and BSA alone tests, major fraction was consist of hydrophobic acid (HPOA) and hydrophobic netural (HPON), and the hydrophobic compounds contributed 85% of total DOC on average, while the two BSA-HA mixture tests were only 71.7% and 60.9% in hydrophobic part respectively. The leakage part was collected as hydrophilic base by a cation exchange resin. Hence, the interplay of HA and BSA exhibits reduced hydrophobicity and reduced acidity.
Second, the DOM in raw water from Chang-Hsing treatment plant was characterized by SEC and resin fractionation and measurements as the previous description. Five peaks between 1200-10,000 Da were related to the same humic-like and protein-like fluorescent compound, and most DOM were absorbed as hydrophobic fraction by DAX-8 resin. The DOM removal by treatment train showed no significant difference in DOC and reduced only part of high molecules. For coagulation-flocculation tests, high MW DOM can be gradually removed with increasing PAC dosing probably because of forming electrostatic patch and sweep, but no effects for small molecules. For activated carbon treatment, most of fluorescent compound can be adsorbed.
Third, the leachate samples from different landfill age and bio-treatment were fractionated in molecular weight (MW) using size exclusion chromatography coupling with DOC, UV254, RI and EEM measurement. The leachate from fresh waste had DOC of 19900 mgL-1, with 85.2% of which being carbohydrates and alike with some aromatic proteins of MW 300-1800 Da. Over 99% of this fraction of DOM was degraded following 3-7 years of landfill, leaving those with fluorescent activity. The DOM in leachate from fresh waste of MW<300 Da, accounting for 11% of DOC in S1 and having strong EEM intensities, certain RI but no UV254 absorbance, could be degraded by 91% in landfill up to seven years. The DOM in leachate from fresh waste of MW>1800 Da, having low DOC content, strong UV254 absorbance and strong EEM peaks, could be degraded by near 44% in landfill in the first 1-2 years. Further landfilling could not effectively remove this fraction of DOM. Anaerobic or aerobic treatment of landfill leachate could degrade DOM of MW<300 Da, and transformed those with fluorescent activities of MW>105 Da to those of 2000-105 Da. The aromatic proteins and humic substances were enriched in landfill leachate along with landfill age and with anaerobic/aerobic treatments.
Fourth, the elution of polyethylene glycols (PEG) of molecular weight 200-20000 from aerobic granules were experimentally evaluated, from which the pore size distribution characterized with PEG molecular weights and the corresponding internal permeability of phenol-fed, aerobic granules were estimated with the help of one-dimensional convection-dispersion model and double porosity model. The exclusion limits in terms of molecular weight are 139,000 Da, 123,000 Da, and 54,500 Da, for 0.46 mm, 1.08 mm, and 1.28 mm granules, respectively. The available porosity and Peclet number decreased with increase in molecular weight of the molecules and granule size. The granule with high permeability ratio can’t guarantee high bio-activity while with long transit time. Therefore, the porosity only reflect part of bio-activity.
Subjects
分子大小排斥層析法
溶解態有機物
size exclusion chromatography
dissolved organic matter
SDGs
Type
thesis
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