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Showing 1 to 20 of 62 for “"humic substances"”.
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Humic Substances Removal by Activated Carbon
A commercial humic acid and a fulvic acid extracted from peat were used to evaluate the removal of humic substances by various activated carbons. Different analytical methods were investigated to determine humic substances as possible indicators of chloroform formation potential. Total organic …
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The characterization of humic substances in seawater
Humic substances were isolated in gram quantities from seawater by a newly developed procedure of adsorption on a crosslinked polystyrene-divinylbenzene resin. The chemical and physical characteristics of both humic acid and fulvic acid fractions were studied. The elemental composition, the …
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The characterization of humic substances in seawater
Thesis. 1975. Ph.D.--Massachusetts Institute of Technology. Dept. of Earth and Planetary Sciences.
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Some aspects of the interaction of humic substances with metal ions
Humic substances are the major organic constituents of soils and sediments. They are heterogeneous, polyfunctional, polydisperse, macromolecular and have no accurately known chemical structure. Their interactions with radionuclides are particularly important since they provide leaching mechanisms …
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An electrostatic model for the metal binding properties of humic substances
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1990.
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The effect of iron on the photo-oxidation of humic substances
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1998.
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NMR STRUCTURAL INVESTIGATIONS OF AQUATIC HUMIC SUBSTANCES (PYRAZOLINE, 1,3-DIPOLAR ADDITION, NITROGEN-15).
… group functionality of a series of aquatic humic and fulvic acids was examined by methylating the samples with ¹³C-enriched reagents and looking at the ¹³C NMR of the resulting methyl esters and ethers. The methylation procedure entailed methylation with ¹³C-diazomethane followed by …
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The catalytic role of birnessite in the Maillard reaction and the abiotic formation of humic substances
Humic substances are ubiquitous in soils and sediments and because of their agricultural and environmental importance have been the subject of much research. The Maillard (browning) reaction involving the polycondensation of carbohydrates and amino acids has been postulated as being an important …
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Electron Transfer Processes between Hydrogen Sulfide and Humic Substances - Implications for Anaerobic Sulfur Cycling in Freshwater Ecosystems
… emphasis on the impact of redox active humic substances. The interactions between sulfide, sulfate (SO42-) reduction, methanogenesis, and organic matter (OM) redox processes were investigated in controlled abiotic and biotic incubation experiments. In the first study, we investigated the …
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Enhanced degradation of fats, oils and greases in domestic wastewater sewer networks and grease interception systems using peat humic substances
The efficacy of peat humic substances in enhancing the degradation of fats, oils and greases (FOG) was investigated under controlled laboratory conditions using bench scale well-mixed bioreactors. An experimental design was used to evaluate the effects of temperature and peat humic substance (PHS) …
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Copper speciation in estuaries and coastal waters
… Cu speciation (filtration), I show that riverine humic substances, filtrable, recalcitrant and light absorbing molecules from degraded plant material, can account for all of the Cu binding in the Saco River estuary. This finding directly supports the hypothesis that terrestrial humic substances …
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Characterization and treatment of UV quenching substances and organic nitrogen in landfill leachates and thermal hydrolysis/anaerobic digestion centrate
… fractionated on basis of hydrophobic nature. Humic substances were the major UV light quenching fractions. Majority of the humic substances were > 1 kDa molecular weight cut off (MWCO) indicating that membrane treatment might be effective for UV quenching substances removal. UV absorbing …
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Two - Stage AnMBR for Removal of UV Quenching Organic Carbon from Landfill Leachates: Feasibility and Microbial Community Analyses
… carbon in landfill leachates, specifically humic and fulvic acids (together referred to as "humic substances") contain aromatic groups that can absorb large amounts of ultraviolet (UV) light, greatly reducing the UV transmissivity in wastewater plants using UV disinfection as the final …
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The role of soil clays and clay-humic complexes in processes controlling colloidal stability and the sorption and degradation of tetracyclines
… flocculation and dispersion of natural soil clay-humic complexes. The results indicate that high Ca 2+, levels enhance the formation of large QCs, which readily flocculate and settle out of suspension. Increasing the concentration of Na+, K+, or NH4+ results in the breakup of large Ca-QCs, which …
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Characterization and treatment of organic matter, UV quenching substances, and organic nitrogen in landfill leachates
… fraction of the landfill leachates studied. Humic substances are refractory components present in landfill leachates that are resistant to biological treatment and responsible for a portion of the UV quenching ability of leachates. Humic substances were also fractionated to humic acid (HA), …
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Soil carbon dynamics in the upper Mersey estuarine floodplain, northwest England : implications for soil carbon sequestration
… on soil carbon content, characterisation of humic substances, adsorption capacity, and microbial activities. The historically contaminated Upper Mersey Estuarine floodplain was selected as the study site. The results indicated that the study area has elevated concentration of heavy metals …
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Assessing the role of soil chemoautotrophs in carbon cycling: An investigation into isotopically labelled soil microorganisms
… of this major component of the carbon cycle. Humic substances are a large, operationally defined fraction of soil organic matter. It was thought that humic substances consist of cross-linked macromolecular structures forming a distinct class of compounds. However, it was recently concluded by …
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Factors Affecting Mobility of Copper in Soil-Water Matrices
… and column processes. The effects of pH, TOC and humic substances were investigated. The mobility of copper was found to be higher through A-horizon soil. The pH was found to have a considerable effect on the mobility of copper and TOC. The highest mobility of copper was achieved at pH 6.24 and …
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