• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2012.11a
• /
• pp.213-214
• /
• 2012

This study is about the assessment of utilization possibility as a material for cementation of ground which is necessary for the reinforcement of soft ground by making environment-friendly inorganic composite utilizing inorganic recycled resources, and it was verified that it showed higher uniaxial compressive strength than the existing cementitious ground solidifier when it was applied as a combination material for soft ground such as dredge reclaimed land, and since an inorganic composite utilizing recycled resources such as high calcium fly ash and blast furnace slag etc. does never use cement, it is considered that it would be safe in the issue of a hexavalent chromium that was recognized as a problem of a cementitious solidifier.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2002.04a
• /
• pp.233-236
• /
• 2002

다양한 산업활동에 의하여 발생하는 6가 크롬 (Cr(Ⅵ))은 대표적인 토양 및 지하수 오염물질이다. Cr(Ⅵ)은 3가크롬(Cr(III))로의 환원에 의한 침전반응으로 이동성이 저하된다고 알려져 있다. 본 연구에서는 기존의 고형화/안정화 공정에 환원.분해 반응을 추가한 2가철 기반 분해성 고형화/안정화(Degradative Solidification/Stabilization)공정에 의한 Cr(Ⅵ) 처리 특성을 고찰하였다. 회분식 실험결과 cemen/Fe(II) system내에 Cr(Ⅵ)은 환원반응 뿐만 아니라 cement에 의한 침전에 의해서도 제거됨이 밝혀졌다. Cr(Ⅵ)의 제거속도는 Fe(II)의 반응당량에 비례하는 것으로 보여진 반면, cement/solution ratio에 따른 Cr(Ⅵ) 제거동역학의 차이는 그다지 크지 않았다

• Journal of Ginseng Research
• /
• v.14 no.2
• /
• pp.274-278
• /
• 1990

The metabolic disturbance and nephrotoxicity induced by sodium dichromate (20 mg/kg, SC) have been diminished by the administration of Korean red ginseng extract (100 mg/kg, PO). Red ginseng has a powerful potency on the blood urea nitrogen (BUN) increment shown in the early 2h after dichromate intoxication. It normalized the dichromate induced hepatic glycogenolysis. The effect of red ginseng on dichroamte induced nephrotoxicity was investigated by hematological analysis, and urinalysis. Ginseng treatment significantly reduced the increases in the urinary excretion of protein and glucose. These effects were dose dependent. Ginseng protected the accumulation of BUN and creatinine in the blood, caused by dichromate intoxication. Unlike CaEDTA, ginseng did not change the urinary excretion of chromiilm and it could not convert hexavalent chronlium to trialvalent chromium. These results suggest that ginseng treatment is effective in decreasing the metabolic disturbance, one of the earliest signs of dichromate toxicity, resulting in the protective effect of dichromate induced renal damage.

• Journal of Microbiology and Biotechnology
• /
• v.21 no.2
• /
• pp.187-191
• /
• 2011

Microbial fuel cells (MFCs) were successfully enriched using sludge contaminated with Cr(VI) and their characteristics were investigated. After enrichment, the charge of the final 10 peaks was 0.51 C ${\pm}$ 1.16%, and the anodic electrode was found to be covered with a biofilm. The enriched MFCs removed 93% of 5 mg/l Cr(VI) and 61% of 25 mg/l Cr(VI). 16S rDNA DGGE profiles from the anodic electrode indicated that ${\beta}$-Proteobacteria, Actinobacteria, and Acinetobacter sp. dominated. This study is the first to report that electrochemically active and Cr(VI)-reducing bacteria could be enriched in the anode compartment of MFCs using Cr(VI)-containing sludge and demonstrates the Cr(VI) removal capability of such MFCs.

• Proceedings of the Korean Society for Quality Management Conference
• /
• 2004.04a
• /
• pp.298-301
• /
• 2004

European Union Member States shall ensure that, from 1 July 2006, new electrical and electronic equipment put on the market does not contain mercury, cadmium, lead, hexavalent chromium, polybrominated biphenyls(PBB) or polybrominated diphenyl ethers(PBDE) (by Directive 2002/95/EC of The European Parliament and the Council of 27 january, 2003 on the restriction of the use of certain hazardous substances in electrical and electronic equipment ). So, It is important to develop lead free solder and to assure the reliability of appliance. But lead free solder(i.e. Sn-3Ag-0.5Cu) have some problems such as lift off, whisker, migration and crack, etc. In this paper we discuss the reliability assurance method in lead free solder and appliance.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2005.04a
• /
• pp.242-246
• /
• 2005

The heavy metal analysis (Cd, Pb, Cu, Cr, Zn, Ni) with various extraction methods was performed using the certified sample and real soil sample. In case of the certified samples, $10.5{\sim}118%$ of recovery was showed with various ranges depend on the metal kinds and extraction methods. Also, the alkali-digestion method was showed the proper results by applying in hexavalent chromium. In case of real sample, compared to amounts of heavy metals extracted using 0.1N-HCl, those extracted using acid digestion are higher by $3{\sim}24$ times in Cu, $1.1{\sim}1.5$ times in Cd, $2{\sim}23$ times in Pb, $3{\sim}104$ times in Zn, $12{\sim}101$ times in Ni, $30{\sim}202$ times in Cr. There is no considerable difference between four acid digestion methods.

• Journal of Microbiology and Biotechnology
• /
• v.22 no.12
• /
• pp.1767-1775
• /
• 2012

The Cr(VI) removal capability of Acinetobacter junii VITSUKMW2 isolated from the Sukinda chromite mine site was evaluated and enhanced using statistical design techniques. The removal capacity was evaluated at different pH values (5-11) and temperatures ($30-40^{\circ}C$) and with various carbon and nitrogen sources. Plackett-Burman design was used to select the operational parameters for bioremediation of Cr(VI). Three parameters (molasses, yeast extract, and Cr(VI) concentration) were chosen for further optimization using central composite design. The optimal combination of parameters was found to be 14.85 g/l molasses, 4.72 g/l yeast extract, and 54 mg/l initial Cr(VI), with 99.95% removal of Cr(VI) in 12 h. A. junii VITSUKMW2 was shown to have significant potential for removal of Cr(VI).

• Environmental Engineering Research
• /
• v.10 no.1
• /
• pp.1-6
• /
• 2005

Hexavalent chromium in aqueous solutions was successfully removed via sorption and reduction in the presence of waste leaves. Cr(VI) removal followed a first-order reaction, and removal rates were proportional to the amount of waste leaves used in the tests. Most of Cr(VI) were removed via sorption in early stages of the tests, but the reduction reaction played a significant role in Cr(VI) removal later. Solution pHs were continuously decreased due to the microbial activity, which was induced from the microorganisms attached on waste leaves. The decreased solution pHs further enhanced the sorption and reduction of Cr(VI). To characterize the microorganisms found in the tests, a denaturing gradient gel electrophoresis (DGGE) method was used. The majority of microorganisms were composed of Bacillus sp. which can reduce Cr(VI). Thus, waste leaves can be effective reactive media for the treatment of Cr(VI) in the subsurface.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.8
• /
• pp.1519-1525
• /
• 2008

Recently we are limiting use of toxic material of lead, mercury, cadmium, hexavalent chromium, PBB, etc. by a nation environment regulation guidance in Europe, the United States, China and Japan. In this paper, we developed manufacture method and RHD tag of environment material using Hanji, Broussonetia Kazinoki Siebold, and PLOYCABONATE, etc. The developed RFID tag stick to each layer interval using environment material which is minimized environment pollutant.

• 대한예방의학회:학술대회논문집
• /
• 1998.10b
• /
• pp.289-290
• /
• 1998