• 한국분말재료학회지
• /
• 제10권5호
• /
• pp.344-347
• /
• 2003

Pure tantalum powder has been produced by combining Na as a reducing agent, $K_2$TaF$_{7}$ as feed material, KCl and KF as a diluent in a stainless steel (SUS) bomb, using the method of metallothermic reduction. And we examined various types of after-treatment that affect the high purification of powder. A significant amount of impurities contained in recovered powder was removed in various conditions of acid washing. In particular, 20% (HCl + HNO$_3$) was effective in removing heavy metal impurities such as Fe, Cr and Ni, 8% H$_2$SO$_4$ + 8% $Al_2$(SO$_4$)$_3$ in removing fluorides such as K and F from non-reactive feed material, and 2% $H_2O$$_2$ + 1 % HF in removing oxides that formed during reaction. Significant amounts of oxygen and part of light metal impurities could be removed through deoxidation and heat treatment process. On the other hand, because it is difficult to remove completely heavy metal impurities such as Fe, Cr, and Ni through acid washing or heat treatment process if their contents are too high, it is considered desirable to inhibit these impurities from being mixed during the reduction process as much as possible.

• 한국약용작물학회지
• /
• 제6권3호
• /
• pp.216-220
• /
• 1998

시호 입모향상에 대한 기초자료를 얻고자 휴면을 타파하고 발아를 촉진시키는 것으로 알려 진 종자처리방법으로 종피파상, 황산침지, 저온처리, 수세처리, 노천매장 등의 처리를 공시하여 실내 검정에 의한 발아향상효과와 포장에서의 입모, 생육 및 수량에 미치는 영향을 구명하고자 시험을 실시한 결과는 아래와 같았다. 1. 실내상토시험 결과 발아율이 무처리 50%에 비하여 수세처리 62%. 노천매장 77%로 향상되었다. 이 효과는 수세처리에 의한 발아억제물질 용탈과 노천매장 처리에 의한 발아억제물질 용탈 및 미숙 배의 생장이 발아향상의 주원인으로 추정 된다. 2. 볏짚 피복 포장에서 입모율은 무처리 83%에 비하여 수세처리 87%, 노천매장 90%로 향상되었고 출아일수도 무처리 47일보다 수세처리 21일, 노천매장 31일 각각 단축되었다. 3. ha당 건근수량은 무처리 423kg 비하여 입모율이 높아 수확주수가 많고 출아가 빨라 생육기간이 길어 식물체당 생근중이 무거웠던 수세처리와 노천매장처리가 각각 22%, 29% 증수되었다.

• 한국식품영양과학회지
• /
• 제38권5호
• /
• pp.601-604
• /
• 2009

본 연구는 이산화염소수 처리가 식품에서의 잔류농약 제거에 효과가 있는지 조사하기 위해서 수행되었다. 10, 50, 100 ppm 이산화염소수로 채소류에 흔히 쓰이는 농약인chlrpyrifos, diazinon, metalaxyl을 처리하여 GC를 이용하여 농약의 분해율을 측정하였다. 상기 세 가지 농약 성분은 이산화염소수 처리 농도뿐만 아니라 처리시간에 비례하여 분해되었으며 특히 100 ppm 이산화염소수 처리가 가장 효과적이었다. 또한, 인위적으로 농약을 오염시킨 상추를 증류수, 100 ppm 이산화염소수에 각각 침지하여 농약의 제거율을 비교해 보았을 때, 100 ppm 이산화염소수에 10분 동안 침지하였을 때가 가장 효과가 좋았다. 본 연구 결과, 이산화염소수 처리는 신선농산물에서의 잔류농약을 제거하기 위한 세척수로 이용될 수 있을 것으로 판단된다.

• 한국식품저장유통학회지
• /
• 제6권1호
• /
• pp.1-6
• /
• 1999

Fresh gingers, harvested in Seosan, Choongcheongnam-do, were pre-treated by a washing-pasteurizing-drying process, a curing process, and non-treated, respectively. Then they were stored in a lab-scale storage room(12$^{\circ}C$, >92%RH) to investigate the effect of pre-treatment methods on the quality changes during long-term storage. Weight loss of ginger during storage showed ranges in 0.7∼4.3%, and the weight of gingers pre-treated by washing-drying process showed a tendency to change less than those treated by curing. After storage of 130 days, spoilage rates were about 20% in non-treated, 11% in curing treated, and 12% in washing-drying treated ginger,, showing the effect of pre-treatment. The final rate of sprouting was 13∼15% regardless of treatment methods. The firmness of gingers showed a tendency to decrease in stored ginger for the longer period; however, the values were ranged from 1,200 to 1,400 g/$\textrm{cm}^2$, that is hard enough to show a marketable quality. The contents of reducing sugar showed a tendency to increase with the lapse of storage time.

• 대한방사선기술학회지:방사선기술과학
• /
• 제41권3호
• /
• pp.241-247
• /
• 2018

The purpose of this study was to compare the ultrasound gel container washing methods for the sterilization of contaminants and to find the useful methods for the prevention of infection caused by the ultrasonic gel containers. In this experiment, a 250 mL ultrasonic gel container was used, and the ultrasonic gel used was a non-sterile gel (ECO GEL 99, SeungWon Medical, Korea). In order to evaluate the degree of contamination, new 250 mL 15 containers were divided into 5 groups to perform five types of washing by no treatment, washing with water, washing with soap, washing with bottle cleaner and high disinfection level washing. After the washing process, filled the gel container with gel and after 2 weeks, the number of colonies in the gel container was sampled repeatedly twice in the same ultrasonic laboratory and compared before and after washing. As a result of among the five cleaning methods used in this study, 87.2% and 88.9% of the soapy water washing (p = 0.028) and high level washing (p = 0.027) showed significant bacterial reduction rates, respectively. Our findings conclusively an ultrasonic gel container cleaning method for removing contaminants has been found to be an effective sterilization method at a low cost with a soapy water cleaning method. Therefore, it is expected that it will be helpful to prevent the infection caused by the ultrasonic gel container by suggesting the sterilization cleaning method that is practically useful in this study.

• 복식
• /
• 제65권7호
• /
• pp.47-59
• /
• 2015

This paper studies the conservation treatment of Lady Shim's costume, which was excavated in Jecheon Province in 2012. There were the significant problems, which were encountered in the treatment of the costume ; First the Jeogoris were transformed during the excavation, Second fibers were seriously deteriorated, Third most of the fabrics such as Chusa were readily deformed. To overcome these problems and to secure stability in the conservation treatment, we decided to alternate between two different washing methods ; dry cleaning by n-hexane and wet cleaning by water. The costume shape was recovered by steaming and by swelling with Hanji(Korean traditional paper). The combined cleaning method proved to be relatively efficient and stable. In addition, the shape of Chusa was well preserved by dry cleaning.(using n-hexane also solved the problem of bad smell after washing with organic solvents.) The effects of the conservation treatment on the excavated costumes could be seen in the change of Lab color difference. Washing made the distribution of Lab color difference narrower, which may suggest that the impurities on the fiber was removed by washing. In addition, the value of L was greater than a-value and b-value after the treatment. This result indicates that the change of value represents the change of color difference by cleaning.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
• /
• pp.239-242
• /
• 2004

Pilot-scale soil washing facility was developed and operation condition was determined in order to remediate a soil contaminated with As, Ni and Zn. Soil washing facility is composed of soil particle separation, soil washing and wastewater treatment process. Both oxyanionic As and cationic Ni and Zn were effciently removed using HCl rather 0than H$_2$SO$_4$ and H$_2$PO$_4$. This is why oxyanion and cation metals can be extracted simultaneously from the contaminated soil in acidic solution. Further, the contaminated soils include calcite and then demand much acidity, that is consumption of acid solution. Fine particles are enriched with contaminants, and coarse particles are removed effectively rather than fine particles. As, Ni and Zn are strongly associated with minerals, and then the residence time should be increased for a reaction with washing solution.

• 한국의류학회지
• /
• 제34권3호
• /
• pp.448-458
• /
• 2010

Kenaf has a rigid and rough touch that inhibits the use of it as a textile material; therefore, this study developed a novel textile material using kenaf. Kenaf and cotton were blended in the ratio of 3:7 and manufactured as 20' spun yarn that was compared to 20's spun yarn made of 100% cotton. Both kenaf/cotton-blended and 100% cotton spun yarn were constructed as plain woven and knitted fabrics. Four kinds of fabrics were prepared as follows. Plain kenaf/cotton-woven fabrics, plain cotton-woven fabrics, kenaf/cotton jersey, and cotton jersey. A cellulase washing process was carried out to reduce the character of kenaf/cotton-blended fabrics, rigid, and rough touch. All fabrics were pretreated with NaOH. NaOH at the concentrations of 0, 0.25, 1.25, and 2.25mol/L, and cellulase at concentrations of 0, 1, 3 and 5g/L were used since the pretreatment of NaOH has a higher efficiency of weight loss than $Na_2CO_3,\;K2CO_3$ and Triton X-100. The ratio of weight loss, tensile strength, stiffness, drape property, and surface appearance were measured in order to evaluate the efficiency of the washing treatment on fabrics. Kenaf/cotton-blended fabrics exhibited more rigid and rough features than cotton fabrics. A cotton jersey showed significant differences in the degree of stiffness and drape properties. When all fabrics were treated with 1.25mol/L of NaOH and 3g/L of cellulase, kenaf/cotton-blended fabrics showed a higher retention ratio of tensile strength than cotton fabrics after washing despite the increased weight l08s of kenaf-blended fabrics compared to cotton fabrics. The ratio of weight loss for all fabrics was well correlated with flexibility. The washing treatment process made woven fabrics more flexible than knitted fabrics, because the stiffness of woven fabrics made the rubbing actions stronger. Kenaf/cotton-blended fabrics showed a significantly higher ratio of weight loss and more reduction in stiffness than cotton fabrics after the washing treatment. This might be due to the lack of cohesiveness and easy elimination from fabrics. The drape property of kenaf-blended fabrics was superior to cotton fabrics.

• Membrane and Water Treatment
• /
• 제9권3호
• /
• pp.137-146
• /
• 2018

Soil washing is one of the most frequently used remediation technologies for heavy metal-contaminated soils. Inorganic and organic acids and chelating agents that can enhance the removal of heavy metals from contaminated soils have been employed as soil washing agents. However, the toxicity, low removal efficiency and high cost of these chemicals limit their use. Given that humic substance (HS) can effectively chelate heavy metals, the development of an eco-friendly, performance-efficient and cost-effective soil washing agent using a nano-scale chelator composed of HS was examined in this study. Copper (Cu) and lead (Pb) were selected as target heavy metals. In soil washing experiments, HS concentration, pH, soil:washing solution ratio and extraction time were evaluated with regard to washing efficiency and the chelation effect. The highest removal rates by soil washing (69% for Cu and 56% for Pb) were achieved at an HS concentration of 1,000 mg/L and soil:washing solution ratio of 1:25. Washing with HS was found to be effective when the pH value was higher than 8, which can be attributed to the increased chelation effect between HS and heavy metals at the high pH range. In contrast, the washing efficiency decreased markedly in the low pH range due to HS precipitation. The chelation capacities for Cu and Pb in the aqueous phase were determined to be 0.547mmol-Cu/g-HS and 0.192mmol-Pb/g-HS, respectively.

• Korean Chemical Engineering Research
• /
• 제51권6호
• /
• pp.745-754
• /
• 2013

본 연구에서는 유해원소로 오염된 현장토양을 대상으로 물리적 및 화학적 토양세척공법을 적용하였을 경우, 유해원소의 처리효율과 더불어 토양세척공법에서 발생하는 폐수를 중화, 응집, 흡착 반응을 이용하여 처리할 경우를 고려하여 최적 토양세척공법의 선정방법을 평가하고자 하였다. 본 연구에서 사용한 토양에서 주된 유해원소인 비소제거에 수산화나트륨 수용액이 황산 수용액보다 효과적이었다. 반면, 폐수 처리의 경우 수산화나트륨 수용액으로 토양 세척 시 함께 추출되는 토양유기물로 인하여 폐수처리가 복잡하고 유해원소의 제거가 잘되지 않아 세척공정의 세척제로는 산을 이용하여 토양을 세척하는 것이 좋으며, 발생하는 세척액의 pH를 6.5 이상으로 중화시켜 대부분의 유해원소를 제거할 수 있었다. 흡착제로 GFO(Granular ferric oxide)를 이용하였을 경우 비소와 납의 제거율이 뛰어났으며, 중화공정과 결합하였을 경우 대부분의 유해원소를 제거할 수 있었다. 결과적으로, 토양세척 공법 적용 시 토양의 특성에 따라 유해원소의 제거율 및 세척액의 처리 및 재이용 방법이 차이가 있으므로, 세척효율 및 세척수 처리 공정을 고려한 체계적인 최적화를 진행하여야 할 것으로 판단된다.