• Applied Biological Chemistry
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• 제12권
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• pp.115-118
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• 1969

답토양부식물(畓土壤腐植物)에 대(對)한 일련(一連)의 토양화학적연구(土壞化學的硏究)에서 본실험(本實驗)은 수개(數個) 고위(高位)및 저위답토양(低位畓土壞)에서 부식물(腐植物)을 추출(抽出)하고 hymatomelan 산(酸)과 humin 산(酸)으로 분획(分劃)하여 가시(可視), 자외(紫外) 및 적외부(赤外部)에시 흡광(吸光) spectrum을 측정(測定)하여 비교검토(比較檢討)하였다. 토양비옥도(土壞肥沃度)의 차이(差異)에 따라 부식분획물(腐植分劃物)의 흡광(吸光)은 어느 광파역(光波域)에서도 별(別)다른 상이성(相異性)이 존재(存在)하지 않으며 자외광흡수(紫外光吸收) spectrum이 퇴비(堆肥)와 다른 유형(類型)의 토양(土壞)에서 분리(分離)한 부식산(腐植酸)의 spectrum과는 다르게 hymatomelan 산(酸)이 나 humin 산(酸) 모두 $235\;m{\mu}$에서 최고(最高), $395\;m{\mu}$에서 최저(最低)의 만곡접(灣曲點)을 나타내었다. 적외광흡수(赤外光吸收) spectrum은 양(兩) fraction간(間)에 상이점(相異點)을 보여 파수(波數) $1720\;cm^{-1}$에 특징적(特徵的)인 Peak가 존재하(存在)하며 이보다 장파역(長波域)($7.5{\sim}9.5{\mu}$)에서도 상이(相異)한 양상(樣狀)이었다. 또한 이 spectrum 들을 다른 연구자(硏究者)들에 의(依)한것과 대조(對照)하여 상이성(相異成)을 고찰(考察)하였다.

• 한국토양비료학회지
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• 제32권4호
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• pp.429-439
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• 1999

토양으로 투입되는 유기물의 종류나 투입된 후의 부식화과정(humification)을 고려하여 선정된 논 밭 토양으로부터 부식간(humic acid)을 추출 정제하였다. 부식간의 유효흡착 부위에 대한 수소이온과 다른 이온간의 흡착 경쟁을 이해하기 위한 첫단계로 수소이온에 대한 친화력(proton affinity)를 전위차적정에 의하여 측정하였다. 또한, 이의 전개양상을 Discrete ligand electrostatic model인 Model A와 Model V로 해석하고자 하였다. 추출 정제된 부식산들은 pH 변화(pH 3~11)에 따라 수소이온 친화력의 분포양상이 서로 차이를 보였으며, 서로 다른 농도의 배경전해질(0.01, 0.10, 0.50 and 1.00 M NaNO3)하에서 이온강도의 증가에 따라 부식산의 표면 음전하량이 증가하였다. 특히 남원통의 경우 증가폭이 pH 6.39 이하에서 상대적으로 컸다. 또한, continuous titration보다 batch titration에서 표면전하에 대한 이온강도에 따른 차이가 확인하였다. 이는 continuous titration시 반응시간의 부족으로 평형상태를 이루지 못해 전해질의 영향을 완전히 반영하지 못하여 이런 결과가 도출된 것으로 생각되어진다. 그러므로, 부식산을 다른 이온종과 반응시키고자 할 때 충분한 반응시간(7일)을 가능케 하는 batch titration이 적절할 것으로 생각된다. 이번 실험에 적용된 Model A와 V는 모두 좋은 예측값 (RSD<$5.46{\times}10-2cmolc\;kg-1$)을 보였다. Model A는 Model V에 비하여 단순하나, 상대적으로 많은 매개변수(fitted parameters)을 필요로 하며, 결합부위인 부식산 관능기들의 겉보기 해리상수(Kapp) 변화는 관능기의 불균일성이라기 보다는 정전기적 인력의 영향이 더 크다고 생각된다. Model V는 관능기들의 해리상수를 중간값과 전개인자로 나타냄으로써 부식산 표면의 불균일성(heterogeneity)을 좀 더 실질적으로 표현해 주고 있다.

• Environmental Engineering Research
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• 제23권2호
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• pp.181-188
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• 2018

Photocatalytic oxidation in the presence of Fe-doped, Zn-doped or Fe-Zn co-doped $TiO_2$ was used to effectively decompose humic acids (HAs) in water. The highest HAs removal efficiency (65.7%) was achieved in the presence of $500^{\circ}C$ calcined 0.0010% Fe-Zn co-doped $TiO_2$ with the Fe:Zn ratio of 3:2. The initial solution pH value, inorganic cations and anions also affected the catalyst photocatalytic ability. The HAs removal for the initial pH of 2 was the highest, and for the pH of 6 was the lowest. The photocatalytic oxidation of HAs was enhanced with the increase of the $Ca^{2+}$ or $Mg^{2+}$ concentration, and reduced when concentrations of some anions increased. The inhibition order of the anions on $TiO_2$ photocatalytic activities was $CO{_3}^{2-}$ > $HCO_3{^-}$ > $Cl^-$, but a slightly promotion was achieved when $SO{_4}^{2-}$ was added. Total organic carbon (TOC) removal was used to evaluate the actual HAs mineralization degree caused by the $500^{\circ}C$ calcined 0.0010% Fe-Zn (3:2) co-doped $TiO_2$. For tap water added with HAs, the $UV_{254}$ and TOC removal rates were 57.2% and 49.9%, respectively. The $UV_{254}$ removal efficiency was higher than that of TOC because of the generation of intermediates that could significantly reduce the $UV_{254}$, but not the TOC.

• 한국토양비료학회지
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• 제16권4호
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• pp.347-352
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• 1983

한국산(韓國産) 이탄(泥炭), 화산회토(火山灰土) 및 무기질(無機質) 답토양(畓土壤)에 유기물(有機物)에 대(對)한 일련의 토양화학적성상(土壤化學的性狀)의 비교연구(比較硏究)로부터 본(本) 실험(實驗)은 김포(金浦), 평택(平澤), 김제(金堤) 및 영동(永同)의 이탄(泥炭)과 제주도(濟州島) 화산회토(火山灰土) 그리고 수원(水原)의 답토양(畓土壤)으로부터 각각(各各) 부식물(腐植物)을 유출(油出)하고 Hymatomelanic acid와 Humic acid로 분획(分劃)하여 가시(可視), UV 및 IR 광역(光域)에서 흡수(吸收) Spectra를 측정(測定)하여 비교(比較)하여 보았다. Humic acid와 Hymatomelanic acid는 UV 및 가시광역(可視光域)에서 극대(極大)나 극소(極小)의 Peak를 가지지 않으며 파장(波長)의 감소에 따라 단조로운 Optical density의 증가를 보이는 Spectra를 나타내었다. 또한 이탄(泥炭) 및 화산회토(火山灰土)와 답토양(畓土壤) 부식물간(腐植物間)의 흡수(吸收) Spectra는 이 범위의 광파장역(光波長域)에서 별다른 상이성(相異性)이 없었으나 화산회토(火山灰土), 이탄(泥炭), 무기질(無機質) 답토양(畓土壤)의 순(順)으로 완만(緩慢)한 경사(傾斜)를 이루었다. Humic acid와 Hymatomelanic acid의 IR spectrum의 주요한 흡수대(吸收帶)는 $3400cm^{-1}$, $2900cm^{-1}$, $1720cm^{-1}$, $1625cm^{-1}$, $1400-1450cm^{-1}$, $1200-1250cm^{-1}$, $1050cm^{-1}$ 등이며 토양형간(土壤型間)의 상이점(相異點)은 미미(微微)하나 Hymatomelanic acid는 파수(波數) $2900cm^{-1}$에서 흡수(吸收) peak를 가지며 파수(波數) $1720cm^{-1}$ 부근에서의 흡수(吸收)가 $1625cm^{-1}$ 부근보다 큰 반면에 Humic acid는 $1625cm^{-1}$ 부근이 $1720cm^{-1}$ 부근보다 큰 흡수(吸收) band를 이루었다. Humic acid의 관능기(官能基)의 함량(含量)은 공시(供試)된 토양형(土壤型) 사이에 큰 차이(差異)가 없었으나 화산회토(火山灰土), 이탄(泥炭), 무기질(無機質) 답토양(畓土壤)의 순(順)으로 전산도(全酸度)가 낮았고 Carboxyl기(基)의 함량(含量)이 적었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권7호
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• pp.70-79
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• 2015

A sample of soil humic acid (HA) was divided by ultrafiltration (UF) into five fractions of different molecular size (UF₁: > 300, UF₂: 100~300, UF₃: 30~100, UF₄: 10~30, UF₅: 1~10 kilodaltons). Apparent average molecular weight (M_w) of the HA fractions were measured using high performance size exclusion chromatography (HPSEC), and the chemical and structural properties of the five HA fractions were characterized by elemental compositions (H/C, O/C and w ((2O + 3NH)/ C)) and ultraviolet-visible absorption ratios (SUVA, A_4/6). The organic carbon normalized-sorption coefficients (Koc) for the binding of phenanthrene to the HA fractions were determined by fluorescence quenching and relationship between the sorption coefficients and structural characteristics of the HA fractions were investigated. The elemental analysis and UV-vis spectral data indicated that the HA fractions with higher molecular weights have grater aliphatic character and lower contents of oxygen, while the HA fractions with lower molecular size have greater aromatic character and molecular polarity that correspond to greater SUVA and internal oxidation values (w). The log Koc values (L/kg C) were gradual increased from 4.45 for UF₅ to 4.87 for UF1. The correlation study between the structural descriptors of the HA fractions and log Koc values of phenanthrene show that the magnitude of Koc values positively correlated with $M_w$ and H/C, while negatively correlated with the independent descriptors of the O/C, w, SUVA and A_4/6.

• Asian Journal of Atmospheric Environment
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• 제12권2호
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• pp.153-164
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• 2018

We measured $^1H$ and $^{13}C$ nuclear magnetic resonance (NMR) spectra of Humic-like substances (HULIS) in urban atmospheric aerosols isolated by diethylaminoethyl (DEAE) and hydrophilic-lipophilic balance (HLB) resin to characterize their chemical structure. HULIS isolated by DEAE resin were characterized by relatively high contents of aromatic protons and relatively low contents of aliphatic protons in comparison with HULIS isolated by HLB resin, while the contents of protons bound to oxygenated aliphatic carbon atoms were similar. These results were consistent with the results of the $^{13}C$ NMR analysis and indicate that hydrophobic components were more selectively adsorbed onto HLB, while DEAE resins selectively retained aromatic carboxylic acids. Furthermore, we demonstrated that the chemical structural features of HULIS were significantly different between spring and summer samples and that these disparities were reflective of their different sources. The estimated concentrations of HULIS in spring were found to be regulated by vehicle emissions and pollen dispersion, while the behavior of HULIS in summer was similar to photochemical oxidant and nitrogen dioxide concentrations. The proportion of aliphatic protons for summer samples was higher than that for spring samples, while the proportion of aromatic protons for summer samples was lower than that for spring samples. These seasonal changes of the chemical structure may also involve in their functional expression in the atmosphere.

• 한국물환경학회지
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• 제32권1호
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• pp.98-107
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• 2016

This study examined the effects of environmental conditions and the presence of refractory organic matter on oxidation rates of total organic carbon (TOC) measurements based on high temperature combustion and ultraviolet-sulfate methods. Spectroscopic indices for prediction of oxidation rates were also explored using the UV spectra and fluorescence excitation-emission matrix (EEM) of humic acids. Furthermore, optimum TOC instrument conditions were suggested by comparing oxidation rates of a standard TOC material under various conditions. Environmental conditions included salts, reduced ions, and suspended solids. Salts had the greatest influence on oxidation rates in the UV-sulfate method. However, no effect was detected in the high temperature combustion method. The UV-sulfate method showed lower humic substance oxidation rates, refractory natural organic matter, compared to the other methods. TOC oxidation rates for the UV-sulfate method were negatively correlated with higher specific-UV absorbance, humification index, and humic-like EEM peak intensities, suggesting that these spectroscopic indices could be used to predict TOC oxidation rates. TOC signals from instruments using the UV-sulfate method increased with increasing chamber temperature and increasing UV exposure durations. Signals were more sensitive to the former condition, suggesting that chamber temperature is important for improving the TOC oxidation rates of refractory organic matter.

• 한국물환경학회지
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• 제21권2호
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• pp.125-131
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• 2005

Natural organic matter(NOM) is defined as the complex matrix of organic material and abundant in natural waters. It affects the performance of unit operations for water purification. Several kinds of analytical indicators such as DOC, specific ultraviolet absorbance(SUVA), apparent molecular weight (AMW), fractionation and high performance size exclusive chromatography(HPSEC) have been used to understand characteristics and variations of NOM. This study aims to evaluate the characteristics of NOM in the Geum River system comprising with stream flows and reservoirs. It was identified that SUVA denoting the portion of humic substance in water ranged within 1.60~3.36. Using resin adsorbents, dissolved organic carbon(DOC) was fractionated into three classes: hydrophobic bases(HOB), hydrophobic acids(HOA) and hydrophilic substances(HI). HI dominates in all samples, collectively accounting for more than 62% of the DOC. HOA was the second dominated fraction and it varied considerably but accounted for about 30% of the DOC. The distribution of high molecular weight(HMW) measured by HPSEC being used to determine the molecular weight distribution of aquatic humic substances was 40.1% and 38.7% in reservoir and stream flow, respectively. The distribution of low molecular weight(LMW) in stream flow was 13.2% higher than that in reservoir. And apparent molecular weight less than 1KDa, which include the molecular weight of hydrophilic organic matter, occupied with 69.2% and 68.2% in stream flow and reservoir, respectively. While the molecular weight of 1 to 100 KDa including humic substances ranged with 18.6% and 21.6% in stream flow and reservoir, respectively. Seasonal variation of refractory dissolved organic carbon was similar to that of SUVA.

• 한국환경과학회지
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• 제14권10호
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• pp.965-972
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• 2005

This research studied the effect of factors that are able to form disinfection by-products (DBPs) of chlorination, including natural organic matter (NOM) with sewage, bromide ions, pH and contact time. Trihalomethane (THMs) yield of $0.95{\mu}mol/mg$ was higher than other DBPs yield for the chlorinated humic acid samples. THMs yield of sewage sample was $0.14{\mu}mol/mg$ and haloacetonitriles (HANs) yield in the sewage samples were $0.13{\mu}mol/mg$ but only $0.02{\mu}mol/mg$ for the humic acid samples. As the concentration of bromide ions increased, brominated DBPs increased while chlorinated DBPs decreased, because bromide ions produce brominated DBPs. THMs were highest $(55.55{\mu}g/L)$ at a pH of 7.9 and haloacetic acids (HAAs) were highest $(34.98{\mu}g/L)$ at a pH of 5. Also THMs increased with increasing pH while HAAs decreased with increasing pH. After chlorination, the rate of THMs and HAA formation are faster at initial contact time and then reaches a nearly constant value after 24 hours. This study considers ways to reduce DBP formation by chlorination.

• Environmental Engineering Research
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• 제11권4호
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• pp.181-193
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• 2006

The hydrophilic or hydrophobic characteristics of dissolved organic matter (DOM) from different origins in lake and river waters were investigated using spectrometric and chromatographic analyses of water samples. DOM in a deep, mesotrophic lake (Lake Unmun) was fractionated using three types of ion exchange resins and classified into aquatic humic substances (AHS), hydrophobic neutrals (HoN), hydrophilic acids (HiA), hydrophilic neutrals (HiN), and bases (BaS). The DOM fractionation provided insight into the understanding of the nature of heterogeneous DOM molecules present in different water sources. The UV/DOC ratios were determined for samples from the influent river and lake waters during DOM fractionation and incubation. AHS prevailed over DOM in the lake and river waters. After biodegradation, the relative contribution of AHS in the total DOM became more significant. It indicates that the AHS fraction would increase while water stay long time in the lake.