• Korean Chemical Engineering Research
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• v.51 no.6
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• pp.745-754
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• 2013

This study evaluated the optimal soil washing conditions for toxic metals considering the removal efficiency of toxic metals from contaminated soils as well as from soil washing effluents. In the contaminated soils, As was the major contaminant and extracted by sodium hydroxide solution better than by sulfuric acid. However, in the case of the treatment of soil washing effluents, sodium hydroxide was less effective extractant because soil organic matter extracted by sodium hydroxide prevented the solid-liquid phase separation and toxic metal removal. In the treatment of soil washing effluents with sulfuric acid, toxic metals in the effluents were mostly precipitated at the pH above 6.5. In addition, granular ferric oxide (GFO) as an adsorbent enhanced the removal of As and Pb indicating that toxic metals in the washing effluents can be removed almost completely by the use of combined adsorption-neutralization process. This study suggests that soil washing techniques for toxic metals should be optimized based on the physical and chemical properties of the contaminated soils, the nature of chemical extractant, and the removal efficiency and effectiveness of toxic metals from the soils as well as soil washing effluents.

• Journal of Conservation Science
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• v.25 no.2
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• pp.219-231
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• 2009

The purpose of this study is to provide basic information necessary for the cleaning of excavated costumes. For the purpose, these researchers reviewed previous records of the actual cleaning of excavated costumes and then implemented and documented the processes of cleaning the Yeosan Song's costumes excavated at Mokdal-dong, Daejeon, which could date back to the early and mid periods of Choseon Dynasty. The excavated clothes of the family provide good examples for comparing men's costume of the 15th century with men's and women's of the mid and late 16th century. The total quantity of excavated remains were 184 and textiles were cotton, silk, hemp, ramie, and union cloth. The clothing remains were processed through wet or dry cleaning in accordance with their fabric condition and the extent to which they were worn or polluted. In detail, the excavated costumes of the Yeosan Song family were cleaned in two stages. For wet cleaning, both anionic(LAS) and nonionic(Triton X-100) surfactants were respectively used as cleaning agents and for dry cleaning, a mixture of n-hexane and n-decane(the ratio of 4 to 6) and petrolic dry cleaning solvent were used. After first cleaning, some cotton, ramie and hemp which had still the stains were processed bleaching and silk which were good condition was processed dry cleaning with the organic solvent again.

• Journal of Sericultural and Entomological Science
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• v.21 no.1
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• pp.36-44
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• 1979

Those studies were examined rearing two varieties on Japanese descent and two varieties of Chinese descent by feeding polluted mulberry leaves, non-polluted ones and water-cleaned ones respectively to find effects of air-pollution on the economic characters of silkworms and analysis of contents of Sulphur and Cadmium in the mulberry leaves and silkworms as followings; 1) Japanese descent of polluted part was delayed about 2.5 days than non-polluted part, Chinese descent was delayed about 4 days or inequal and water-cleaned part was medium in the silkworm larval duration. 2) Results of maximum weight of 5th instal, cocoon layer weight and cocoon weight were decreased in due order non-polluted, water-cleaned and polluted in the factors of mulberry 3) Pupal ratio of Japanese descent was not shown statistical significance, but Chinese descent was revealed it obviously in the factors of mulberry leaves. 4) In the resistance of polluted mulberry leaves, Chinese descent was feeble obviously than Japanese and there were some difference even through among the same varieties. 5) The content of S and Cd of polluted area mulberry leaves was increased about 30% respectively than non-polluted area. 6) The fed part of non-polluted mulberry leaves was S 0.41% and Cd 0.013 ppm water-cleaned part was S 0.47% and Cd 0.024 ppm and polluted part was S 0.52% and Cd 0.042 ppm in the contents of S and Cd of silkworm larvae. 7) The contents of S and Cd didn't make visible injury in mulberry leaves but made it seriously in silkworm larvae. 8) The injury of dust on mulberry leaves was more serious than that of quality of mulberry leaves by air-pollution in the economic characters of silkworm. 9) As above results, Chinese descent should avoid contaminated area and it rearing by water-cleaned mulberry leaves can get noticable results in inevitable case on selection of parents silkworm rearingzone.

• Journal of Food Hygiene and Safety
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• v.22 no.3
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• pp.192-198
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• 2007

Kimchi is one of the representative traditional foods in Korea, which is recognized as a kind of wellbeing foodstuffs. However, as increasing foreign-made Kimchi, its safety as food is at the forefront of public health concerns. We analyzed the washing methods of Chinese cabbages, which are the main materials in Kimchi, to prevent parasite contamination during preparing it. To decontaminate parasite eggs from Chinese cabbages, discard the discolored outer leaves from cabbages, spread the space of leaves with fingers and rinse more than 3 separate water tanks with streaming water (velocity more than 0.8m/sec). At each tank, Chinese cabbages were rinsed with more than 3 strokes upward and downward within the streaming water followed by moving back and forth more than 3 times, with 20cm in height and 30cm in width, respectively. Decontamination efficiency increased higher in parallel with streaming velocity of water, and with adding the vegetable detergent to the tank water.

• Journal of Soil and Groundwater Environment
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• v.10 no.1
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• pp.58-64
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• 2005

Several tests were conducted to determine the optimum operational conditions of soil washing techniques for floe-forming arsenic-contaminated soils, collected from D abandoned Iron-mine in Korea. The optimum cut-off size was 0.15 mm $(sieve\;\#100)$, about $94\%$ of the mass of soils. Both sodium hydroxide and hydrochloric acid were effective to remove arsenic and the optimum mixing ratio (soil [g] : washing solution [mL]) was 1:5 for both washing agents. Arsenic concentrations, determined by KST Methods, for the dried floe solids obtained from flocculation at pH 5-6 were $990\~1,086\;mg/kg$ dry solids, which were higher concentrations than at the other pH values. Therefore, batch tests for sequential washings with or without removing floc were conducted to find the enhancement of washing efficiencies. After removing floe with 0.2 M HCl, sequential washings of 1 M HCl followed by 1 M NaOH showed the best results (15 mg/kg dry soil). The arsenic concentrations of washing effluent from each washing step were about $2\~3\;mg/L$. However, when these acidic and basic effluents were mixed together, arsenic concentration was decreased to be less than $50\;{\mu}g/L$, due to the pH condition of coagulation followed by precipitation for arsenic removal.

• Applied Chemistry for Engineering
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• v.19 no.1
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• pp.98-104
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• 2008

This research was performed to evaluate the extraction characteristics of heavy metals for soil washing of mine tailings-contaminated soil according to particle size distribution and the chemical distributional existence of the metals. As the soil particle size was decreased, the extracted concentrations of heavy metals was increased except Fe and Mn. Most of all heavy metals were extracted within 6 h by soil washing with 0.05 M EDTA. Extraction efficiency of metals was decreased for Pb, Cu, and Zn with decreasing of particle size. Significant difference was not observed in extraction efficiency for Cd according to particle size distribution. Extraction efficiency for Cd was the highest as 86~91%, while the lowest as 5~14% for Fe. Most metals of the soil without soil washing was distributed as reducible, oxidizable, and residual fractions. Pb, Zn, and Cd existed as reducible (Fe/Mn oxide) and residual fractions and Cu existed as oxidizable and residual fractions after soil washing treatment with 0.05 M EDTA. As the soil particle size was decreased, residual fraction was increased for Pb and Cu. About 90% of reducible fraction in Pb, Zn, and Cd was removed by soil washing with 0.05 M EDTA. As the results, it was founded that soil particle size was the important parameter to effect on distributional fraction and extraction efficiency of metals in mine tailings-contaminated soil.

• Journal of Soil and Groundwater Environment
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• v.8 no.1
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• pp.17-26
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• 2003

The sorption experiment of cobalt was performed after the TRIGA soil was intentionally contaminated with cobalt was found that the sorption equilibrium coeficiency of soil decontamination was high when the ratio of soil mass to the volume of citric acid becomes 1:5 The TRIGA soil contaminated with 0.01 M, 0.001 M, and 0.0001 M of cobalt solution were decontaiminated with 0.01 M citric acid. The cobalt concentrtion in the wastewater were measured to be correspondingly 36.0, 14.0, 1.5 ppm. The results of wastewater recycling experiment by chemical precipitation method revealed that corresponding cobalt removal efficiency were 97% 88%. It was shown that the removal efficiency decreases as the cobalt concentration in the wastewater decreases. During the decontamination experiment, a lot of NaOH had to be added, and the volume of final solid waste reached almost 10% of that of the contaminated soil. The result of wastewater recyling experiment by ion exchange resin meted rethod revealed that to more the strong acid resins are used, the higher the cobalt removal efficiency becomes and the cobalt removal efficiency becomes and the lower the pH of recycling wastewater become. In order to obtain more than 95% removal efficiency, more than 0.625 g of strong acid resin was necessary in each of 3 experiments. There was an unexpected problem that a lot of strong acid resin waste was produced which amounts to 9.2% (volume) of the contaminated soil.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.283-286
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• 2002

유류로 오염된 부지에 토양세정기법을 적용하기 위한 전 단계로, 실험실 규모의 컬럼실험을 통하여 pilot 규모 현장 적용을 위한 설계인자 및 최적 운전조건을 규명하고자 적정 세척제 종류와 농도, 배합비 및 세정용액 주입유량을 고찰하였다. 회분식실험 결과 POE$_{14}$와 SDS(1:1)를 1%로 적용한 흔합계면활성제의 효율이 가장 우수하였으나, 예비실험 결과 음이온계 계면활성제인 SDS는 미생물에 독성을 끼치는 경향이 있는 것으로 나타나 같은 농도에서 효율이 거의 유사한 POE$_{5}$와 POE$_{14}$ 혼합계면활성제를 이용하여 실험하였다. 선정된 혼합계면활성제를 적용하여 디젤 오염토양 세척능력을 검토한 결과 세척제 농도 1%까지는 효율이 증가하다가 1% 이상의 농도에서는 다시 감소하는 경향을 나타내었으며, 계면활성제 배합비는 1:1로 혼합하였을 경우 세척효율이 가장 우수하였다. 따라서 POE$_{5}$와 POE$_{14}$ (1:1) 1% 혼합계면활성제를 세척제로 선정하였다. 컬럼실험 결과, 주입 flux가 클수록 세정 제거된 총 유류의 양이 증가하였으며, 같은 pore volume의 세정용액 통과 시에는 flux가 작을수록 제거효율이 좋았다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.160-163
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• 2001

유류 오염 토양에 pilot scale 규모의 토앙세척법(soil flushing)과 토양증기추출법(SVE)을 설치하여 운전하였다. 토양세척법의 경우 용매인 알콜류를 주입하고 2일 이후부터 계면활성 재인 Tween 80 용액을 주입 한 후 하부에서 추출된 유출수내의 오염물질의 농도를 측정한 결과 BTEX, Diesel 및 n-Alkane의 농도는 계면활성제 수입 전파 후의 비율이 최대 각각 15배 7.8배 및 47배의 농도 증가를 보였으며 TPH 농도의 증가는 약 10배에 이르는 것으로 조사되었다. 또한 토양증기추출법의 경우 가스 추출로 제거된 가스성분의 누적량을 보면 약 19일의 운전기간동안 BTEX와 TPH 총량 기준으로 약 30 kg 및 708 kg이 제거되었으며 BTEX와 TPH에 대한 최대 제거효율은 각각 4 kg/day 및 90 kg/day 였다.

• Proceedings of the Membrane Society of Korea Conference
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• 1994.10a
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• pp.21-23
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• 1994

무방류폐수처리 시스템 개발에 막분리공정이 핵심적인 기술로 자리잡고 있다. 그러나 막분리기술의 경제성을 높히고 적용범위를 확대하기 위해서는 새로운 막의 개발과 폐수처리에서 항상 문제가 되는 fouling의 원인규명 및 막세척방법의 개발이 절실히 요구되고 있다. 본 연구에서는 염료폐수처리 및 재활용을 위한 pilot 실험에의 막의 fouling 현상과 세척효과를 역삼투막인 BW-30(2540)과 Nanofiltration막인 NF-40(2540) 모듈을 사용하여 조사하였다. RO 투과수에 의한 물리적 세척법인 flushing과 화학적세척을 실시하여 투과율 회복능력을 조사하였다.