• Journal of Plant Biology
• /
• 제12권4호
• /
• pp.9-18
• /
• 1969

In the previous paper(part III), a certian relationships between the changes of chlorinity and organic acid released from organic material were seemed to be concened to each other in saline soil suspension. Such a possibility had been a cause to take this experiments and this experiment was carried out under the treatment of organic acid crystal, oxalic acid and succinic acid, to the soil suspension(soil: water=20g:40cc) directly. The amount of organic acid treated to the suspension were related to the contents of organic material, as amount of organic acid per gram of organic material(391.76mg). The saline soil suspension were grouped and treated with the acids in order of 78.35mg(Group 1), 391.76mg(Group 2) 979.4mg(Group 3), and 1958.8mg(Group 4), respectively. Treated suspension had been incubated at room temperature and extract from suspension was used for analysis. Followings are summary of this report. 1) Changes of pH in soil suspension appeared a little increase after the treatment of organic acid until 168 hours. 2) Total acidity of soil suspension showed a variation, however, the values of total acidity appeared not to be increased or decreased during the period of experiment. 3) Sugar contents of soil suspension was increased until 168 hours after treatment. These results are similar tendency to the previous paper. 4) Addition of organic acid to soil suspension was confirmed not to be effective method for desalination from saline soil. Chlorinity of group 3 and 4 which were treated with high concentration of organic acid showed a decrease comparing to control group.

• Applied Biological Chemistry
• /
• 제40권2호
• /
• pp.128-133
• /
• 1997

유기물 함량이 다른 두 종류의 토양을 선정하여 풍건한 조건, 유기물을 제거한 조건 및 유기물을 제거한 토양에 humic acid 또는 fulvic acid를 첨가한 세 가지 형태로 구분하여 살균제 fluazinam (3-chloro-N-(3-chloro-5-trifluoromethyl-2-pyridyl)-${\alpha},{\alpha},{\alpha}$-trifluoro-2,6-dinitro-${\rho}-toludine$)의 흡착, 탈착, 용탈 및 잔류량의 변화를 조사하였다. Fluazinam의 흡착양상은 Freundlich equation에 잘 부합되었다. 유기물을 제거한 토양에서 fluazinam의 흡착량 및 흡착강도는 유기물을 제거하지 않은 토양에 비하여 감소하였다. 유기물을 제거한 토양에 humic acid 또는 fulvic acid를 각각 2.0%또는 0.5%되게 첨가한 경우, 흡착량은 fulvic acid를 첨가한 토양에서 높게 나타났다. 유기물을 제거한 토양에 흡착된 fluazinam의 탈착율은 증가하였다. Soil column시험에서 토양표면에 처리된 fluazinam은 유출수에 의하여 용탈되지 않았으며, 대부분이 표토층 (5 cm)에 존재하였고 표층 15 cm 이하로는 이동되지 않았다. 토양중 fluazinam의 잔류량변화는 유기물 함량이 적은 토양 보다는 많은 토양에서, 살균조건의 토양보다는 비살균조건의 토양에서, 비담수토양 보다는 담수토양에서 빠르게 감소하였다.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제23권1호
• /
• pp.85-91
• /
• 2018

Arsenic (As) usually is bound to amorphous iron oxides in the soils, and it can be removed via dissolution of iron oxides. Inorganic acid and chelating agent are widely used to extract As in the soil washing. However, the overall performance is highly dependent on the state of As fractionation. In this study, oxalic acid and inorganic acids (HCl, $H_2SO_4$, and $H_3PO_4$) were applied to enhance the dissolution of iron oxides for remediation of As-contaminated soils. Oxalic acid was most effective to extract As from soils and removal of As was two times greater than other inorganic acids. Additionally, 75% of As bound to amorphous iron oxides was removed by 0.2 M oxalic acid. Arsenic removal by oxalic acid was directly proportional to the sum of labile fractions of As instead of the total concentration of As. Therefore, the oxalic acid could extract most As bound to amorphous iron oxides.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2000년도 창립총회 및 춘계학술발표회
• /
• pp.133-136
• /
• 2000

Soil decontamination process was conducted to study adsorption and modeling characteristic of Sr$^{2+}$ ion using citric acid and water system with TRIGA soil. When the concentration of citric acid was increased, the BTC of Sr$^{2+}$ ion was to be closed to the BTC of $^3$$H_2O$ at experiments of soil adsorption. Beside, when the concentration of citric acid was under 0.01M Sr$^{2+}$ ion, BTLs was asymmetry. It was characteristic of nonequilibrium adsorption. R and $K_{p}$ , were decreased to be increased the concentration of citric acid. Asymmetry modeling was nearly the same to be compare with symmetry modeling in decontamination process, when the concentration of citric acid was decreased. Result of experiment was agree with asymmetry and symmetry model, when the concentration of citric acid was increased.eased.

• 한국대기환경학회지
• /
• 제4권1호
• /
• pp.33-44
• /
• 1988

For the purpose of examining the effects of simulated acid rain on the chemical properties of the experimental soil in Pinus densiflora seedlings and Forsythia koreana rooted cuttings, the experimental design of randomized block arrangement with three replications was implemented in the experimental field of Yesan National Agricultural Junior College. One-year-old Pinus densiflora seedlings and Forsythia koreana cuttings were planted in the pots filled the mixed soils (nursery soil: forest soil of siliceous sandy loam = 1 : V/V)in the early spring of 1985. The regime of artificil acid rain, in terms of spray frequency per monthly and spray amount at single treatment per plot, was simulated on the basis of climatological data averaged from 30 years records. Simulated acid rain (pH 2.0, pH4.0, and pH 5.5 as control) containing sulfuric and nitric acid in the ratio of 3:2 (chemical equivalant basis) diluted ground water, were treated on the experimental plants under condition of cutting off the natural precipitation with vinyl tunnel, during the growing season (May 1 to August 31) in 1985. THe results obtained in this study were as follows; 1. Soil acidity was dropped, and exchangeable aluminum contents in the soil was dramatically increased in both species, with decreasing pH levels of acid rain. 2. Exchangeable potassium, clacium, magnesium contents, and base saturation degree of the soil were highly drcreased in two species as the pH levels of acid rain decreased. 3. In two species, sulfate concentrations in the soil were decreased of pH 4.0 treatment, and remarkably increased at pH 2.0 treatment of acid rain in comparison with control. 4. Total nitrogen and available phosphate contents of the soil were not affected by acid rain treatment in the both species, and Fe contents at pH 2.0 treatment were highest among three acid rain treatments.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제15권5호
• /
• pp.23-31
• /
• 2010

For an efficient remediation of Pb-contaminated soil (S-1) in a clay shooting range, a soil washing test was performed with mineral acid, organic acid, chelating agent, and chloride. The Pb extraction efficiency of extractant (0.1 M) used in the washing test showed the order of HCl > $Na_2$-EDTA > NTA > DTPA > citric acid > malic acid > succinic acid > acetic acid > $CaCl_2$ > $MgCl_2$, for S-1 soil. As compared to initial Pb concentration, extraction efficiency by the concentration of extractant was 93.35%, 80.80%, 73.92%, and 24.57% in S-1 soil for HCl (0.5 M, pH 1.10), $Na_2$-EDTA (0.01 M, pH 3.99), citric acid (0.5 M, pH 1.27), and $MgCl_2$ (0.1 M, pH 8.82), respectively. S-1 soil had 56.83% of residue form and 43.17% of non-residue form (18.04% of exchangeable form), respectively. Although the concentrations of these fractions sharply decreased after HCl washing, since the exchangeable forms with relatively large mobility are still distributed as high as 18.78% (to Pb total content in residual soils) in S-1 soil, it is necessary to devise a proper management plan for residual soils after soil washing application.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제22권2호
• /
• pp.33-40
• /
• 2017

In typical remediation practices, separate washing systems have to be applied to clean up the soils contaminated with both oil and heavy metals. In this study, we evaluated the efficiency of successive two-stage soil washing in removal of mixed-contaminants from soil matrix. Two-stage soil washing experiments were conducted using different combinations of chemical agent: 1) persulfate oxidation, followed by organic acid washing, and 2) Fenton oxidation, followed by inorganic acid washing. Persulfate oxidation-organic acid washing efficiently removed both organic and inorganic contaminants to meet the regulatory soil quality standard. The average removal rates of total petroleum hydrocarbons (TPH), Cu, Pb, and Zn were 88.9%, 82.2%, 77.5%, and 66.3% respectively, (S/L 1:10, reaction time 1 h, persulfate 0.5 M, persulfate:activator 3:1, citric acid 2 M). Fenton oxidation-inorganic acid washing also gave satisfactory performances to give 89%, 80.9%, 87.1%, and 67.7% removal of TPH, Cu, Pb, and Zn, respectively (S/L 1:10, reaction time 1 hr, hydrogen peroxide 0.3 M, hydrogen peroxide:activator 5:1, inorganic acid 1 M).

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제23권2호
• /
• pp.23-29
• /
• 2018

This study explored secondary effects of the residual hydrofluoric acid (HF) after a hypothetical acid spill accident by investigating the long-term dissolution of minerals and leaching of pre-existing arsenic (As) from two soil samples (i.e., KBS and KBM) through batch and column experiments. An increase in the HF concentration in both soil samples resulted in a dramatic increase in the release of major cations, especially Si. However, the amounts of mineral dissolved were dependent on the soil type and mineral characteristics. Compared to the KBM soil, relatively more Ca, Mg and Si were dissolved from the KBS soil. The column experiment showed that the long-term dissolution rates of the minerals are closely associated with the acid buffering capacity of the two soils. The KBM soil had relatively higher effluent pH values compared to the KBS soil. Also, more As was leached from the KBM soil, with a more amorphous hydrous oxide-bound As fraction. These results suggest that the potential of heavy metal leaching by the residual acid after an acid spill will be influenced by heavy metal speciation and mineral structure in the affected soil.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2002년도 총회 및 춘계학술발표회
• /
• pp.44-48
• /
• 2002

Washing technique using solubilization and surfactant as a extractant was studied by removing contaminants from the cohesive soil contaminated with heavy metal. For this purpose, the laboratory desorption batch tests were peformed in the kaolinite contaminated with lead by using acetic acid as a solubilization and SDS as a anionic surfactant. In desorption batch tests, the effects of extractant concentration and mixing ratio were investigated and also the coupling effects of acetic acid added with surfactant were considered. Test results show that the removal efficiency of acetic acid as a extractant in the kaolinite contaminated with lead increased with increasing the concentration of acetic acid and the acetic acid was found to be more effective when adding CMC 2 or 3 of surfactant. Additionally, regardless of the initial concentration, the efficiency of lead removal from the contaminated soil increased with increasing shaking ratio.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2000년도 추계학술대회
• /
• pp.298-301
• /
• 2000

Heavy metals are extracted from stream sediments, roadside soils and sediments and soils and tailings from mining area using partial extraction, acid digestion and HF-digestion. Compared to amounts of heavy metals extracted using partial extraction, those extracted using acid digestion are higher by 2.0∼220.9 times in Cu, 2.4∼2806.1 times in Pb, 1.3∼121 times in Cd, 14.1∼1300885 times in Fe, 1.2∼271.5 times in Mn, 1.3∼372.5 times in Zn, 2.2∼1734.5 times in Cr. Although partial extraction, which extracts less amounts of heavy metals from soil compared to acid digestion, is used in domestic standard method for examination of soil, domestic soil standard for heavy metals in non-agricultural and industrial areas is higher than soil standard in foreign countries which use acid digestion, For improvement of the domestic standard method for assessment of soil, it is suggested to lower the domestic soil standard for heavy metals or to change pretreatment method for extracting heavy metals from partial extraction to acid digestion with modifying the soil standard.