• Journal of the Korean Chemical Society
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• v.12 no.4
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• pp.155-159
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• 1968

On the extraction of humic acid from peat, the optimum conditions were studied and the effects of them on the characteristics of humic acid were also examined by means of infrared spectroscopy. 1. Pretreatment of peat with diluted 6-8% HCl solution for 5 hrs. prior to extraction with alcohol-benzol azeotropic mixture have resulted the better yield of humic acid. The water soluble Na-humates were obtained by the subsequent extraction with one hundred times quantity of caustic soda solutieon for 1hr. at 90 $^{\circ}C$. Thus the pure humic acids have been yielded approximately 40% (by wt.) from the raw peat. 2. In characteristics of humic acid, the chemical structure, mainly the contents of such functional groups as -COOH, -OH (phenol type), $-CH_2CO-$, $-CH_2{\cdot}O{\cdot}CH_2-$ and aromatic rings were varied according to the concentration of alkaline solution, temperature and time when the humic acids were extracted with alkali.

• Journal of Environmental Science International
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• v.8 no.3
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• pp.337-347
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• 1999

This study was carried out to evaluate the characteristics of dissolved organics based on their origins, which were divided into two categories. The first group consisted of river, lake and secondary sewage treatment effluent, which were chosen as representative of their origins. The second group were artificial samples which were made of AHA(Aldrich humic acids) and WHA(Wako humic acids). Physicochemical characteristics, biological degradability and THMEP(trihalomethane formation potential) of the samples were analysed based on the AMWD(apparent molecular weight distribution). Large portion of dissolved organic carbon(DOC) in the river and lake samples was comprised of LMW(low molecular weight), which that of AHA and WHA was HMW(high molecular weight). The DOC of the lake was evenly distributed in the all range of molecular weight. The river, lake and secondary treated effluent have lower ultraviolet(UV) absorbance at 254nm, and have a higher amount of humic acids. Higher absorbance of humic acids means that aliphatic bond and benzenoid type components that absorb UV light were contained in these kind of humic acids. It was expected that lake sample was the most biodegradable in the different samples investigated, and in order of secondary sewage treatment effluent, river, WHA and AHA based on the result of determination of specific ultraviolet absorbance(SUVA). Biodegradability showed similar result except for AHA, while dissolved organics in the range of LMW decreased during the biodegradability test, and on the contrary those of HMW increased. Production of the SMPs(soluble micobial products) was observed during humicfication of dissolved organics and the SMPs were higher production of the SMPs. THM formation was high in the samples containing HMW and similar tendency was shown in the THMEP(trihalomethane formation potential), except for WHA.

• Journal of Korea Soil Environment Society
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• v.5 no.3
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• pp.55-64
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• 2001

Many organochlorine pesticides are persistent in the environment and have a tendency to bioaccumulate significantly through food chains. Aquatic environments are particularly more affected because the pesticides applied to agriculture systems are eventually carried into water bodies, through surface runoff, rivers, and groundwater flow. The objective of this paper is to study the effect of the coexistence of a heavy metal on the solubility enhancement of the two representative organochlorine pesticides, lindane and dieldrin, by humic acids. The solubility enhancement of pesticides by humic acid in a single system was compared with that in a binary system. The extent of solubility enhancement of lindane by humic acids was constant. while that of dieldrin by humic acids increased. Also, the solubility enhancement of dieldrin by humic acid with Pb decreased than that by humic acid without Pb.

• Journal of the Korean Chemical Society
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• v.16 no.5
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• pp.320-327
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• 1972

The coupling of aromatic diazonium salts with humic or nitrohumic acid, as a supplemental method of determining the structure and utilization of humic acid, were studied. The following results were obtained. 1) Humic acids have many vacan to-and p-positions in their phenol kernels. 2) Humic acids have not so many benzene kernels in their structure units. 3) When coupled with aromatic diazonium salts (such as aniline, aminonaphthalene and aminoanthraquinone derivatives), various azo-dye were obtained.

• Bulletin of the Korean Chemical Society
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• v.15 no.9
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• pp.777-781
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• 1994

Three humic acids (HA) and one fulvic acid (FA) are extracted from soils of the Okch'on Basin (Koyesan, Yongkwang and Taejon), and are purified and characterized using $^1H,\;^{13}C$ NMR, and IR spectroscopic methods. The results are compared with one another and with commerical humic acid (Aldrich Co) and aquatic humic acid from Gorleben underground aquifer in Germany. The IR and $^1H\;and\;^{13}C$ NMR spectral features are found to be nearly identical, suggesting that humic substances formed in the Okch'on Basin have quite similar chemical properties. These humic substances from Okch'on Basin soils have undergone low degree of aromatic condensation and have high contents of aliphatic functionalities including carbohydrates.

• Ocean and Polar Research
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• v.45 no.3
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• pp.113-123
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• 2023

Humic substances are refractory organic compounds that are relatively low in biological activity but known to stimulate phytoplankton growth in estuarine and marine environments. The effect of humic substances on phytoplankton growth was investigated in the seawater zone of the Yeongsan River estuary where an episodic anthropogenic freshwater is discharged, affecting its water properties directly. Water samples and data of water properties were collected at three stations (Sts. A-C) along the channel of the seawater zone in February, May, August and November, 2009. The collected water samples were incubated after humic acids (HA) were added in mesocosm experiments. Phytoplankton (chlorophyll-a) were fractionated into net- (> 20 ㎛) and nano-size (< 20 ㎛) to examine the response of phytoplankton according to size. Their response to HA treatment was assessed by repeated measures analysis of variance (RM-ANOVA). The experiments showed that phytoplankton biomass (chlorophyll-a) significantly increased after HA were added at the stations near the sea dike. Especially, nano-sized chlorophyll-a concentrations increased significantly throughout the seasons. This indicates that understanding the behavior of refractory organic matters such as humic substances is required to better manage altered estuarine ecosystems including the Yeongsan River estuary which are affected by episodic discharge of freshwater from sea dikes.

• Environmental Engineering Research
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• v.11 no.6
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• pp.311-317
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• 2006

Feasibility of destroying synthetic and actual leachate containing humic acids and ammonia compounds by supercritical water oxidation (SCWO) was evaluated. In this study, destruction efficiencies of humic acids and ammonia respectively were investigated at various reaction temperatures and residence times under pressure a supercritical pressure (280 atm). To lower reaction temperature, chemical oxidants were used. The experiment was carried out in a cylindrical batch reactor made of Hastelloy C-276 that can withstand high temperature and pressure. Concentrations of humic acids and ammonia were measured using a $COD_{Cr}$ method and an ammonia selective electrode, respectively. The optimal destructive condition of humic acids in the presence of stoichiometric oxygen(air) was 3 min at $380^{\circ}C$, but the temperature could be lowered to subcritical region ($360^{\circ}C$) along with $H_2O_2$ as an oxidant. For ammonia, the optimal destructive condition with air was 5 min at $660^{\circ}C$, but it was possible to operate the process for 3 minutes at $550^{\circ}C$ or 2 min at $600^{\circ}C$ along with $H_2O_2$ as an oxidant. At 2 min and $550^{\circ}C$ along with $H_2O_2$ as an oxidant, humic and ammonia compounds in the actual leachate were easily destructed and the effluent quality met the Korea Standard Leachate Quality.

• Korean Journal of Environmental Agriculture
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• v.26 no.4
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• pp.313-318
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• 2007

In greenhouse farming, a variety of humic acids have been applied to improve soil conditions and plant growth. However, it is still unclear that how humic acids combined with chemical fertilizers affect growth and quality of fruit vegetable crops. This study was conducted to determine the combination effect of humic acids and chemical fertilizers on the growth and fruit quality of tomato (Lycopersicon esculentum MILL.) grown under greenhouse conditions. Three different formulation types of humic acid were used: liquid type A, liquid type B and solid type C. The tomato plants were grown in three treatment combination plots and in conventional fertilizer (CF) plot with recommended levels of nitrogen, phosphorus and potassium: HA combined with CF (HA+CF), HB combined with CF (HB+CF) and HC combined with CF (HC+CF). For most of growth characteristics (i.e. leaf number, internode length, maximum leaf length, leaf width and chlorophyll contents) determined in this experiment, no significant differences were observed between all combination treatments and CF. However, integrated fruit qualities (i.e. averaged weight, sugar contents and acidity) were slightly improved in the humic acid combined with CF treatments when compared with CF alone treatment. No phytotoxicity was observed with humic acid treatments. However, further studies will probably be needed to use widely and safely these humic acids, in order to ensure a maximizing growth, fruit yield and quality of tomato.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.1
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• pp.44-52
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• 1996

Humic substances of 17 organic fertilizers available on the market were the objects of study. The list of ingredients for formulation of them comprised fish meal. bone meal, oil-cakes, brewer's grains, peat, sawdust, wood bark, zeolite, soil conditioner, live-stock droppings, amino acid fermentation byproduct, chaff, limestone and others. Humic and fulvic acids were isolated from those substances and given chemical and spectroscopic analyses. Nutritional values of the organic fertilizers showed big diversity. Humification of organic matter was incomplete for some of the fertilizers as indicated by a high C/N ratio. Extractable humic acid percentage was higher, in general, than that of fulvic acid. Also the relative content of humin increased with advanced humification. Total acidity was closely related to phenolic hydroxyl groups. Relationships between carboxyl and hydroxyl groups. and carboxyl and alcoholic hydroxyl groups were very significant. Ultraviolet and visible light absorption spectra of humic and fulvic acids were substantially similar. The types of humic acids were B. P, and Rp. Two humic acids of the 17 samples belonged to B type. 3 to P type and all the rest to Rp type.

• Near Infrared Analysis
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• v.1 no.1
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• pp.31-35
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• 2000

Near-infrared reflectance spectroscopy(NIRS) was used to determine the humic acids in soil samples from the fields of different crops and land-use over Youngnam and Honam regions in Korea. An InfraAlyzer 500 scanning spectrophotometer was obtained near infrared relectance spectra of soil at 2-nm intervals from 1100 to 2500nm. Multiple linear regression(MLR) or partial least square regression (PLSR) was used to evaluate a NIRS method for the rapid and nondestructive determination of humic acid, fulvic acid and its total contents in soils. The raw spectral data(log 1/R) can be used for estimating humic acid, fulvic acid and its total contents in soil by MLR procedure between the content of a given constituent and the spectral response of several bands. In which the predicted results for fulvic acid is the best in the constituents. The new spectral data are converted from the raw spectra by PLSR method such as the first derivative of each spectrum can also be used to predict humic acid and fulvic acid of the soil samples. A low SEC, SEP and a high coefficient of correlation in the calibration and validation stages enable selection of the best manipulation. But a simple calibration and prediction method for determining humic acid and fulvic acid should be selected under similar accuracy and precision of prediction. NIRS technique may be an effective method for rapid and nondestructive determination for humic acid, fulvic acid and its total contents in soils.