• Journal of Korean Society of Water Science and Technology
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• v.26 no.6
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• pp.117-124
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• 2018

For the effective removal of phosphorus in water, a novel type of composite was prepared by combining Poly Alumiun Chloride, widely used in sewage/wastewater treatment plants, and Humic Acid particles, which are known to have phosphorus removal ability, with CI. The surface of the ferromagnetic CI particles was oxidized and activated, and then PAC and HA were synthesized to finally produce CIPAC and CIHA. CIPAC and CIHA prepared by this study showed similar results to the phosphorus removal efficiencies of PAC and HA coagulants. The novel composite has a larger weight than the conventional coagulant, and the coagulated sludge precipitates rapidly. The sludge could be easily separated in a short time if the external magnetic field was given by the ferromagnetic force of CIPAC and CIHA prepared with CI as support. Therefore, it can be concluded that if phosphorus removal is carried out using CIPAC and CIHA prepared through this study with external magnetic field, the sedimentation rate will be much faster than that of conventional coagulant. Thus it is possible to obtain a high economic benefit in the sludge recovery part.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.340-340
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• 2017

Rice straw is very important to maintain fertility in agricultural soil with several aspects such as carbon and nitrogen cycles in Korea. Recently, concerning about climate change, carbon sequestration in agricultural land has become one of the most interesting and debating issues. Rice straw is most representative source of organic material produced in agricultural sectors. In order to evaluate changes of soil carbon treated by rice straw during cultivating rice in paddy field, we carried out to treat rice straw with 0, 0.5, 1, 1.5, and $2.0ton\;ha^{-1}$ at $50{\times}50{\times}20cm$ blocks made of wood board, and analyze contents of fulvic acid and humic acid form, and total carbon periodically. The experiment was conducted in 2013-2016, and sampled with interval in a month. The organic material was applied to treatment blocks in 2 weeks ago in rice transplanting of each year. Total carbon in beginning time is low as $7.9g\;kg^{-1}$. The contents of total carbon with treatments of rice straw after experiment are recorded as 8.7, 11.2, 9.5, 10.5, and $10.9g\;kg^{-1}$ applied by 0, 0.5, 1, 1.5, and $2.0ton\;ha^{-1}$, respectively. When trend lines were calculated on changes of soil carbon in periods of experiments, The trend equations of soil carbon changes with treatments of 0, 0.5, 1, 1.5, and $2.0ton\;ha^{-1}$ were Y=0.0015X+8.479, Y=0.073X+8.2577, Y=0.0503X+8.4477, Y=0.0822X+8.2103, and Y=0.082X+8.5736. These trends suggested several results. When rice straw was applied in cultivating paddy fields, most carbon in rice straw would be decomposed regardless the amount of rice straw in soil. We calculated sequestration rate of applied rice straw as about 0.1% per year during rice cultivation in paddy fields. It means that if farmer want to increase 1% soil organic matter by using application of rice straw returned after cultivation, famer should apply rice straw continuously for ten years. The change of soil carbon as fulvic acid, humic acid, and humane is showed that only content of carbon as mumine is increased significantly while fulvic acid and humic acid were changed in range of 10 to 30% among total carbon in soil. In conclusion, to sequestrate soil carbon with rice straw, it is important for rice straw to apply continuously every year. The amount of rice straw applied is not much effected to increase soil organic matter.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.12
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• pp.1321-1326
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• 2005

As a results of this research, the Nakdong River consisted of 43% of hydrophobic fraction, 39% of hydrophilic fraction, and 18% of transphilic fraction. The hydrophobic fraction in this raw water was mostly fulvic acid. Fulvic acid comprised of 62% and the rest was humic acid(38%). There was more carboxylic acid functional roup(64%) than phenolic group(36%). HPI-N and HPI-C comprised of 17% and 22% in the hydrophilic portion, respectively. The results of the membrane fouling test using UF membrane according to NOM fractions. HPI-N caused more fouling than HPI-C. Humic acid caused more fouling than fulvic acid probably due to higher adsorption capacity. Since humic acid has higher adsorption capacity than fulvic acid, it would be more adsorbed onto the membrane pores. The carboxylic acid functional group caused more fouling than the phenolic group.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.11
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• pp.1067-1074
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• 2008

In this study, the organic carbon normalized-sorption coefficients (Koc) for the binding affinity of phenanthrene (PHE) to 16 different soil humic and fulvic acids of various origins were determined by fluorescence quenching. The humic and fulvic acids used in this study were isolated from 6 different domestic soils including Mt. Hanla soil, IHSS standard soil and peat as well as Aldrich humic acid and characterized by elemental composition, ultraviolet absorption at 254 nm, composition of main structural fragments determined by CPMAS $^{13}$C NMR. The Koc values($\times$10$^4$, L/kg C) for each of HA and FA samples were in the range of 1.48$\sim$8.65 and higher in HA compared to that of FA(3.13$\sim$8.65 vs 1.48$\sim$2.48) in the experimental condition([PHE]/[HS] = 0.02$\sim$0.2(mg/L)/(mg-OC/L), pH 6). The correlation study between the structural descriptors of humic and fulvic acids and log Koc values of phenanthrene, show that the magnitude of Koc values positively correlated with the UV$_{254}$ absorptivity([ABS]$_{254}$) and two $^{13}$C NMR descriptors (C$_{Ar-H,C}$, $\sum$C$_{Ar}$/$\sum$C$_{Alk}$), while negatively correlated with the independent descriptors of the(N+O)/C atomic ratios and $^{13}$C NMR descriptors (I$_{C-O}$/I$_{C-H,C}$). These results confirmed that the binding affinity for the hydrophobic organic compound, phenanthrene are significantly influenced by the polarity and aromaticity of soil humc and fulvic acids.

• Journal of Environmental Impact Assessment
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• v.16 no.1
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• pp.69-77
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• 2007

This study has been conducted to assess blackish-water phenomena in Dam reservoir. To searching for the reason, we survey physical changes in reservoir and analyze metal and organic content in particulate materials and water. The blackish-water phenomena in lake A are occurred with turbidity increases in turnover season irregularly. It was reported on 6 Jan. 2005 weakly and the water column mixed with 35~40m depth and water temperature shows $7^{\circ}C$. The turbidity of AD and AM site increased up to 20NTU. Especially, AN site shows 27NTU, such a result makes that Dam manager conclude it to blackish-water phenomena. The results of sequential extraction analysis show that over 80% of Al, Cr and Fe is existed in residual form in sediment. On the other hand, the most part of Mn shows exchangeable and carbonates form, which have a good possibility of release to water column. Mn contents in pore waters of the sediment samples are also found to be ~4 times higher than Fe contents. The metal contents in pore water of different dam sites are in order of AN (Fe: 9.98, Mn: 40.6) > AD(8.33, 37.5) > DD(1.91, 2.55). According to the results of extracted organic materials from sediment, humic substances is occupied with over 85% in total organic carbon including 23~45% of humic acid (HA) and 0.9~8.5% of fulvic acid (FA). However, HA content in pore water is not detectable while FA contents, acid-soluble humic fractions is higher than that of sediment(10~15%). which indicating that FA is a main humic components affecting water color. The color unit per DOC of FA in pore waters of different dam sites are found to be higher in lake A than lake D. From the results, it could be suggested that blackish-water phenomena of lake A are mainly arise from higher concentration of Mn and water soluble organic fractions (e.g., FA) released from sediments as well as the strength of turnover in Dam reservoir.

• Journal of Environmental Science International
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• v.21 no.9
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• pp.1031-1041
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• 2012

This study was carried out to investigate the characteristics of disinfection by-products (DBPs-trihalomethanes (THMs), haloacetic acids (HAAs) and haloacetonitriles (HANs) formation in chlorination of principal raw waters used for drinking water on Jeju Island, Korea. The domestic water supply of other area and humic acid solution (HA) were used as a reference point. The effects of chlorine contact time, solution temperature and pH on DBPs formation potential (DBPFP) were investigated for raw waters. In addition, the effect of $Br^-$ was studied for HA. The DBPFP (THMFP, HAAFP and HANFP) were increased with increasing chlorine contact time. Comparing the individual DBPFPs for raw waters, they decreased in the order of HAAFP > THMFP ${\geq}$ HANFP. As the solution temperature was increased, the THMFP, HAAFP and HANFP increased. With increasing the solution pH, the THMFP was increased, but HAAFP and HANFP were decreased. With the addition of 0.3 mg/L $Br^-$ for HA, the DBPFP was increased and the major chemical species changed: from trichloromethane to dibromochloromethane and tribromomethane for THMs; from dichloroacetic acid and trichloroacetic acid to tribromoacetic acid for HAAs; and from dichloroacetonitrile to dibromoacetonitrile for HANs.

• Analytical Science and Technology
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• v.14 no.2
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• pp.159-166
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• 2001

A humic acid(HA, Aldrich Co) sample was subjected to ultrafiltration for molecular size fractionation and three fractions of different nominal size($F_1$: 1,000-10,000 daltons; $F_2$: 10,000-50,000 daltons; $F_3$: 100,000-300,000 daltons) were obtained. The structural characteristics of the size-fractionated HA were analyzed using their IR and solid state C-13 NMR spectral data, and the carboxylate group contents of the humic acids were determined using their pH titration data. The $^7F_0-{^5}D_0$ excitation spectra of Eu(III) complexes of the size-fractionated mgHA in aqueous solution were acquired($[Eu(III)]=1.0{\times}10^{-4}mol\;L^{-1}$, $(HA)=470-970mg\;L^{-1}$) at pH 5.0 using a pulsed tunable laser system, in which metal binding properties of the size-fractionated HA were elucidated and compared on another. Characterization of the IR and C-13 NMR spectral data indicated that the fraction($F_3$) with molecules of larger size were primarily aliphatic, while the fractions($F_1$, $F_2$) with smaller molecules of less than 50,000 daltons were predominantly aromatic. Titration data were consistent with an increase in the number of carboxylate groups per unit mass as molecular size became smaller. The $^7F_0-{^5}D_0$ excitation spectral data of Eu(III)-humate complexes showed that the peak maxima on these spectra were shifted toward lower energies with increasing molecular size of HA, indicating the higher degree of bindings of the Eu in the molecules of larger size. We also discussed the relationship of the lower energy shifts of the maximum peaks with increasing the molecular size of HA with the structural differences of the size-fractionated HA.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.7
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• pp.445-453
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• 2012

An investigation for removal of 1-indanone (1-ID), which were commonly produced from the biological and/or chemical treatment and natural weathering of the PAHs-contaminated soils, via oxidative transformation mediated by birnessite in the presence of various phenolic mediators is described. This study also examines the potential effect of the natural occurring substance humic acid (HA) on the oxidative transformation. The experiment was carried out in aqueous phase as a batch test (10 mg/L 1-ID, 0.3 mM phenolic mediators, $1.0g/L\;{\delta}-MnO_2$, at pH 5). All of the 11 tested phenoilic mediators belong to the group of natural occurring phenols and are widely used as model constituents of humic substances. From the results of HPLC analysis, it is demonstrated that 1-ID was not reactive to birnessite itself, but it can be effectively removed in birnessite-mediated cross coupling reactions in the presence of the phenolic mediators. The percent removals of 1-ID after 2 day incubation were ranged from 9.2 to 71.2% depending on the phenolic mediators applied. The initial rate constant ($K_{int}$, $hr^{-1}$) values for the 1-ID removals obtained from the pseudo-first-order kinetic plots also widely ranged from 0.18 to 15.0. Results of the correlative analysis between the removal efficiencies and structural characteristics of phenolic mediators indicate that the transformation of the 1-ID was considerably enhanced by the addition of electron-donating substituents (e.g., -OH, $-OCH_3$) at the benzne ring, and much less enhanced by the addition of electron-withdrawing substituents (e.g., -COOH, -CHO). The presence of HA showed that removal efficiencies of 1-ID in the birnessite-phenolic mediator systems decreased with increasing HA concentrations. However at low concentration of HA (< 2 mg/L), it caused some enhancement in the removals of 1-ID as compared to the control.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.9
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• pp.989-994
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• 2005

The treatment efficiency and the degradation characteristics of humic acid were investigated in three processes-GAC adsorption, Ozone alone and Ozone/GAC hybrid process, in which $UV_{254}$, DOC, molecular size distribution and surface change of GAC were evaluated. DOC removal rate in Ozone/GAC hybrid profess(ca. 80%) was higher than the arithmetic sum of Ozone alone(38%) and GAC adsorption(19%). This result approves that the combined Ozone/GAC hybrid process brings synergistic effects on DOC removal from the HA containing water. $UV_{254}$ decrease rate was also at the highest in Ozone/GAC hybrid process from the three processes. It may be interpreted that the granular activated carbon in Ozone/GAC hybrid process acts as not only an adsorbent but also a catalyst for ozonation, and futhermore offers an additional reaction site between adsorbed organic matter and ozone. In the study of molecular sire distribution, there was no significant change of molecular size distribution in the GAC adsorption process during the reaction time of 120 min. In Ozone alone process, the fraction of molecular size over 30 kDa was decreased a little at the beginning and left constant after 10 min. But in Ozone/GAC hybrid process, the molecules size over 30 kDa of HA was significantly decreased from 36.3% to 3.9%. And also the fraction of smaller molecular size below 0.5 kDa was increased from 4.8%(untreated HA) to 12.3%(in Ozone alone) and 40.1%(in Ozone/GAC) respectively at the reaction time of 120 min.

• Membrane Journal
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• v.23 no.1
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• pp.61-69
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• 2013

The effect of humic acid (HA), and the roles of microfiltration (MF), PES (polyethersulfone) beads adsorption, and photo-oxidation were investigated in hybrid process of ceramic MF and PES beads loaded with titanium dioxide ($TiO_2$) photocatalyst for advanced drinking water treatment. Those were compared and studied in viewpoints of membrane fouling resistance ($R_f$), permeate flux (J), and total permeate volume ($V_T$). Because membrane fouling increased dramatically as decreasing HA, $R_f$ increased and J decreased, and finally $V_T$ was the highest at 2 mg/L HA. In the experiment to investigate the roles of photo-oxidation and adsorption at humic acid 4 mg/L and 6 mg/L. In both conditions, $R_f$ was the lowest and $V_T$ was the highest in MF + $TiO_2$ + UV process. The average treatment efficiencies of turbidity and dissolved organic matters were the highest in MF + $TiO_2$ + UV process, too.