• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.372-378
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• 2003

This study investigates the fractional composition and the leaching characteristics of heavy metals in polluted soils due to mining activities. The fractionated composition of heavy metals is classified into five fractions, adsorbed, carbonate, reducible, organic and residual fraction. The status of humic substances in mine wastes of most sites are polyhumic except tailing from Sangdong mine. According to the sequential extraction procedures (SEPs), leaching probabilities of Cd in coal wastes and tailing are relatively low due to high percentage of residual fraction. 46.4% of Ni in tailings from Sangdong mine is probably leached under oxidized environment, and 39.4% of Cu in these tailings is readily extracted under strongly oxidized environment by organic fraction. According to leaching condition of pH 3.0 and pH 5.6, the amount of heavy metals leached out of coal wastes and tailing increases to 1/2 hours. At pH 3.0 and pH 5.6, concentration of Ni in tailing increases up three times of the initial value. Heavy metals released from coal wastes and tailing were not influenced significantly by leaching time.

• Journal of the Korean Applied Science and Technology
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• v.21 no.4
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• pp.364-369
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• 2004

It has been confirmed that some Trihalomethanes (THMs) suspected as carcinogens, can be formed during chlorination for water supply through the reaction of chlorine and humic substances in water. The electrochemical characteristics on activated carbon fiber filter (ACF) electrode were investigated to remove the THMs in the chlorination process of drinking water. The electrochemical removal efficiency depended on the applied voltage and flow rate. In this study, the best result showed that the removal efficiency of THMs was higher than 99%.

• Bulletin of the Korean Chemical Society
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• v.25 no.12
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• pp.1907-1910
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• 2004

Generation of hydroxyl radical, one of their major active species in ozonation of water was directly observed with spin-trapping/electron spin resonance (ESR) technique using 5,5-dimethyl-pyrrolidine-1-oxyl (DMPO) as a spin-trapping reagent. Hydroxyl radical was trapped with DMPO as a stable radical, DMPO-OH. 80 mM of ozone produced $1.08{\times}10^{-6}$M of DMPO-OH, indicating that 1.4% of ${\cdot}$OH is trapped with DMPO if ${\cdot}$OH is produced stoichiometrically from ozone. Humic acid suppressed DMPO-OH generation in a dose-dependent manner. Generation rate of DMPO-OH was determined with ESR/stopped-flow measurement. Phenol derivatives increased the amount and generation rate of DMPO-OH, indicating that phenol derivatives enhance·OH generation during ozonation of water.

• Journal of Environmental Health Sciences
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• v.27 no.1
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• pp.27-35
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• 2001

This aim of the work presented in this paper is to investigate the factors that affcet chlorine decay and to develop functional relationships that can be used to enhance the durability of network models. predictive relationships were established that correlated the rate of chlorine decay to the various water conditions such as DOC, N $H_3$-N, initial chlorine, contact time, temperature and pH values. Free chlorine residual decreased with increasing temperature, DOC, N $H_3$-N, reaction time and chlorine dose. At 2$0^{\circ}C$, pH 7, The initial chlorine demand per mg as DOC/L and mg as N $H_3$-N/L was about 0.43, 2.69 mg/$\ell$ respectively at 180 minutes contact time. The Reaction between chlorine and humic acids was lasted intil 48hr, but the reaction between chlorine and N $H_3$-N was almost completed in 180 min. When the temperature is raised by 1$0^{\circ}C$, chlorine is more consumed about 0.25 mg/$\ell$ in the absence of organic substances and it is more consumed about 3.4 mg/$\ell$ in the presence of humic acid (5 mg/$\ell$) in water at pH 7 for 180 min. Regression Analysis created the resulting prediction equation for the chlorine decay in a SPSS package of the computer system. The model is as follows; $C_{t}$=1.239+0.707(Co)-0.000529(Time)-0.0112(Temp)+0.02227(pH)-0.42(DOC)-2.132(N $H_3$-N).).

• Journal of Korean Society on Water Environment
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• v.36 no.3
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• pp.194-205
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• 2020

The characteristics and behavior of dissolved organic matter (DOM) were determined by analyzing the molecular weight fractions and fluorescence properties of water samples in the downstream Nakdong River. Biogeochemical water quality parameters and fluorescent dissolved organic matter (FDOM) were analyzed at five sampling points in the downstream area of the Nakdong River January-August 2019. The molecular weight fractions of the DOM were separated by the Liquid Chromatography-Organic Carbon Detection (LC-OCD). The DOM predominantly comprised humic substances, followed by the building blocks, low molecular weight neutrals and biopolymers. The hydrophobic (aromatic) and hydrophilic properties were shown as coexisting, as most of the SUVA_254nm values were under four. The FDOM was characterized as humic-like (FDOM_H) with allochthonous origin and protein-like (FDOM_P) with autochthonous origin; the FDOM_H with autochthonous origin was also identified. The FDOM_H relies on the aromaticity of the allochthonous organic matter and increases during summer. The FDOM_H and FDOM_P, which depend on the biodegradable dissolved organic matter from phytoplankton, were highly fluorescent in winter. The allochthonous organic matter was the dominant factor contributing to the behavior of the DOM, externally introduced to the river by rainfall. The FDOM only minimally contributed to the behavior of the DOM. It can be explained as the seasonal characteristics of the DOM, varied by the source of the organic matter.

• Journal of Korean Society of Water and Wastewater
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• v.8 no.2
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• pp.12-24
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• 1994

The occurrence of objectionable tastes and odors in drinking water is a common and widespread problem. The most troublesome odors are usually those described as muddy or earthy-musty. Two organic compounds which have been implicated as the cause of earthy-musty odor problems in water are geosmin and 2-Methylisoborneol. These earthy-musty organics have been shown to be metabolites of actinomycetes and blue green algae. The purpose of this paper is to describe adsorbability in removing these two oder causing compounds(geosmin and 2-MIB) upon various conditions like pH variation, adding humic acid and different activated carbon. The conclusion of this study are as followings. In batch test, carbon dosage is 10mg/100ml for geosmin and 15mg/100ml for 2-MIB. Both were in equilibrium state after 60 hours. In model simulation, F-P model described experiment data and modelling data appropriately in geosmin but F-S model not. In case of 2-MIB, models didn't describe relation between experiment and modelling data well. Two causative agents of earthy-musty odor compounds, geosmin and 2-MIB, are strongly adsorbed by activated carbon either coconut or brown. There appears to be no effect of pH (3,7,9) on adsorption of these two organics. Activated carbon proved to be more effective for removing geosmin than for removing 2-MIB. When activated carbon is. used in removing these two organics, the removal of these appeared to be adversely affected by back ground organic compounds, such as humic substances, due to competitive adsorption.

• Journal of Korean Society on Water Environment
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• v.34 no.4
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• pp.399-408
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• 2018

This research investigated the effects of weir (Ipobo) construction on the dynamics and the related spatial distributions of pollutants inflowing from tributaries (Yanghwacheon and Bokhacheon). Conductivity measurements and water sampling were conducted longitudinally, horizontally, and vertically in the waterbody upstream of the area located in Ipobo. Additionally, collected water samples were used for the dissolved organic carbon (DOC) analysis and fluorescence analysis which results in the SUVA, HIX, BIX, and FI calculation and parallel factor analysis (PARAFAC). Consequently, the results of the Conductivity, DOC, SUVA, and HIX showed that high concentration of pollutants that were flowing from the area of Bokhacheon which was mixed along the flow of the main river. The results of the BIX and FI did not show significant difference along the river flow which represented that allochthonous and terrestrial DOM, and for this reason was dominated in the whole waterbody rather than just the autochthonous DOM. The PARAFAC results showed that the two fluorescence components, humic-like and protein-like, constituted the fluorescence matrices of the water samples. The prevailing discipline notes that the two components were inflowing from the tributaries, however, a refractory component, humic-like substances, was relatively accumulated near the weir. From the results, the dynamics and spatial distributions of the DOM are dependent on the DOM characteristics, which induces the application of a specialized DOM analysis method to investigate the effects of a subsequent weir construction on the dynamics and spatial distributions of pollutants inflowing from the tributaries.

• Journal of Korean Society on Water Environment
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• v.39 no.6
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• pp.465-474
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• 2023

The chemical composition and molecular weight characteristics of dissolved organic matter (DOM) exert a profound influence on the efficiency of organic matter removal in water treatment systems, acting as efficiency predictive indicators. This research evaluated the primary chemical and molecular weight properties of DOM derived from diverse sources, including rivers, lakes, and biomasses, and assessed their relationship with the efficiency of coagulation/flocculation treatments. Dissolved organic carbon (DOC) removal efficiency through coagulation/flocculation exhibited significant correlations with DOM's hydrophobic distribution, the ratio of humic-like to protein-like fluorescence, and the molecular weight associated with humic substances (HS). These findings suggest that the DOC removal rate in coagulation/flocculation processes is enhanced by a higher presence of HS in DOM, an increased influence of externally sourced DOM, and more presence of high molecular weight compounds. The results of this study further posit that the efficacy of water treatment processes can be more accurately predicted when considering multiple DOM characteristics rather than relying on a singular trait. Based on major results from this study, a predictive model for DOC removal efficiency by coagulation/flocculation was formulated as: 24.3 - 7.83 × (fluorescence index) + 0.089 × (hydrophilic distribution) + 0.102 × (HS molecular weight). This proposed model, coupled with supplementary monitoring of influent organic matter, has the potential to enhance the design and predictive accuracy for coagulation/flocculation treatments targeting DOC removal in future applications.

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.3
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• pp.127-144
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• 1979

Recent trend in the studies on the forming processes, chemical characteristics and chemical structure of humic substances with some discussions are reviewed and some arguments for the elucidation of the chemical structure of humic substances are summarized.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.3
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• pp.239-254
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• 2015

Little information on HUmic-Like Substances (HULIS) in ambient particulate matter has been reported yet in Korea. HULIS makes up a significant fraction of the water-soluble organic mass in the atmospheric aerosols and influence their water uptake properties. In this study 24-hr $PM_{2.5}$ samples were collected between December 2013 and October 2014 at an urban site in Gwangju and analyzed for organic carbon (OC), elemental carbon (EC), water-soluble OC (WSOC), HULIS, and ionic species, to investigate possible sources and formation processes of HULIS. HULIS was separated using solid phase extraction method and quantified by total organic carbon analyzer. During the study period, HULIS concentration ranged from 0.19 to $5.65{\mu}gC/m^3$ with an average of $1.83{\pm}1.22{\mu}gC/m^3$, accounting for on average 45% of the WSOC (12~ 73%), with higher in cold season than in warm season. Strong correlation of WSOC with HULIS ($R^2=0.91$) indicates their similar chemical characteristics. On the basis of the relationships between HULIS and a variety of chemical species (EC, $K^+$, $NO_3{^-}$, $SO_4{^{2-}}$, and oxalate), it was postulated that HULIS observed during summer and winter were likely attributed to secondary formation and primary emissions from biomass burning (BB) and traffics. Stronger correlation of HULIS with $K^+$, which is a BB tracer, in winter ($R^2=0.81$) than in summer ($R^2=0.66$), suggests more significant contribution of BB emissions in winter to the observed HULIS. It is interesting to note that BB emissions may also have an influence on the HULIS in summer, but further study using levoglucosan that is a unique organic marker of BB emissions is required during summer. Higher correlation between HULIS and oxalate, which is mainly formed through cloud processing and/or photochemical oxidation processes, was found in the summer ($R^2=0.76$) than in the winter ($R^2=0.63$), reflecting a high fraction of secondary organic aerosol in the summer.