• 멤브레인
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• 제24권3호
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• pp.201-212
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• 2014

본 연구는 국내 최초로 도입된 Y 정수장의 세라믹막 고도정수처리를 위한 최적 운영 인자를 도출하기 위하여 수행되었다. 경제성과 수질조건을 만족하면서도 세라믹막 여과성능을 지속 유지할 수 있는 최적 운영조건을 도출한 결과, Y 정수장의 평상시 수질 조건에서 막역세척으로 인한 배출수 발생량을 최소화시키면서도 막여과성능을 유지할 수 있는 최적 여과지속시간(역세척 주기)은 시설용량($16,000m^3$/일) 기준 시 4.0시간으로 조사되었다. 또한 화학세척(CIP)에 따른 막차압 회복력을 조사한 결과, 구연산을 이용한 산세정을 통하여 철, 망간, 알루미늄 등의 막 파울링을 일으키는 무기오염물질은 제거되지만 막회복률은 낮았다. 반면 차아염소산나트륨을 사용한 알칼리 세정을 통해서는 막 운영 초기 막차압으로 회복되는 것으로 나타났다. 막차압을 발생시키는 파울링 주요 원인물질은 친수성 고분자 유기오염물인 polysaccharides로 조사되었으며, 화학세척(CIP)시 막성능 회복률은 세척약품 온도에 의한 영향이 매우 크며, 온도가 높은수록 막성능 회복률이 향상되는 것으로 조사되었다.

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

• 청정기술
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• 제6권1호
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• pp.79-84
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• 2000

반도체 세정공정에서 사용되는 화학약품의 소모량을 줄이기 위하여 소량의 전해질 혹은 초순수만을 전기분해 시켜 생성되는 전리수를 이용하여 금속 불순물들이 오염된 실리콘 웨이퍼를 습식세정을 하였다. 전리수는 다양한 범위의 pH 및 산화환원전위(oxidation-reduction potential, ORP)를 형성할 수 있으며, 전리수의 양극수는 pH 및 산화환원전위를 각각 4.7 및 +1000mV의 산화성 수용액을, 전리수의 음극수는 pH 및 산화환원전위가 각각 6.3 및 -550mV를 40분 이상 유지하고 있었다. 실리콘 웨이퍼 세정 전과 후의 금속 불순물 측정은 ICP-MS(Inductively coupled plasma spectroscopy)를 사용하였다. 전리수 가운데 양극수는 구리 불순물 제거에, 음극수는 철 불순물 제거에 효과적임을 확인하였다.

• 한국염색가공학회지
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• 제10권4호
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• pp.1-6
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• 1998

It is important in the durable water and oil repellent finishing for wool fabric what kinds of water-repellent agents will be used. Water repellent agents and its concentration were aleady chosen in the previous paper, one of the crosslinking agents which has less damages(harsh handle or yellowing) to the treated fabrics was a low molecular weight urethane-based resins(eg. Elastron BN-11). In repellent finishing, fabrics were padded in a bath which contained aqueous solution of water-repellent agents, and crosslinking agents, and wetting agents, followed by drying and curing. The most suitable treating condition for excellent repellency and durability to dry-cleaning was as follows ： Fabrics are padded at liquor pick-up ratio of 50%, with aqueous solution which contained $30g/\ell$ of water-repellent agents, and $1g/\ell$ of crosslinking agents, and 40g/s of wetting agents. And the padded fabrics were dried at $110^\circ{C}$ for 1 minute, and cured at $160^\circ{C}$ for 1 minute. For the fabrics, water and oil repellencies and durability to repeated dry-cleanings were observed. For enhancing the durability to dry-cleaning, the role of crosslinking agents was important for they bonds water-repellent agents and fibers to 3-dimensional net structure. Therefore, the most suitable drying and curing conditions should be selected according to the kinds of crosslinking agents.

• 한국산업보건학회지
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• 제33권4호
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• pp.517-527
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• 2023

Objectives: We examine cases of chemical poisoning that occurred in the cleaning of metal parts and the regulations on halogenated solvents in other countries and propose regulations necessary to prevent chemical poisoning from halogenated solvents. Methods: We collected cases of chemical poisoning through the website of the Korea Occupational Safety and Health Agency. A review of the literature was conducted focusing on regulations related to halogenated solvents in the United States and the European Union, particularly for cleaning metal parts. Among the Material Safety Data Sheets submitted to the government, MSDS containing eleven substances were extracted to confirm the composition and product use. We investigated cleaning methods for metal parts used in South Korea. For the hazard classification, the European Chemicals Agency or Japan's NITE's website was used. Results: In the case of poisoning, the cleaning methods involving trichloromethane were dipping and dry, which was not found in the literature. It was confirmed that many halogenated solvents and dimethyl carbonate were used for metal cleaning in South Korea. In vapor degreasing using TCE in the USA, even if the facility is strictly managed, such as by installing cooling coils in open cleaning facilities, the risk of exposure to TCE is considered to be not only carcinogenic but also a concern for acute and chronic effects. In comparison, exposure through Korean work methods such as dipping and drying operations is inevitably much higher. Conclusions: The transition to water-based cleaning with low-hazard chemicals should be a priority in the cleaning process. In the case of metal parts that require precise cleaning, if the use of a halogenated solvent is inevitable, a closed degreasing facility should be used to minimize exposure. The current regulations in the Occupational Safety and Health Act, the Chemical Substances Control Act, and the Air Environment Conservation Act do not require cleaning facilities to minimize emissions. To protect the health of workers using halogenated solvents to clean metal parts, regulations that require a fundamental reduction in exposure will be necessary.

• 한국재료학회지
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• 제25권9호
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• pp.462-467
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• 2015

Pellicle is defined as a thin transparent film stretched over an aluminum (Al) frame that is glued on one side of a photomask. As semiconductor devices are pursuing higher levels of integration and higher resolution patterns, the cleaning of the Al flame surface is becoming a critical step because the contaminants on the Al flame can cause lithography exposure defects on the wafers. In order to remove these contaminants from the Al frame, a highly concentrated nitric acid ($HNO_3$) solution is used. However, it is difficult to fully remove them, which results in an increase in the Al surface roughness. In this paper, the pellicle frame cleaning is investigated using various cleaning solutions. When the mixture of sulfuric acid ($H_2SO_4$), hydrofluoric acid (HF), hydrogen peroxide ($H_2O_2$), and deionized water with ultrasonic is used, a high cleaning efficiency is achieved without $HNO_3$. Thus, this cleaning process is suitable for Al frame cleaning and it can also reduce the use of chemicals.

• 한국물환경학회지
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• 제33권2호
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• pp.123-129
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• 2017

The purpose of this study is to identify potential methodologies to reasonably estimate the effectiveness of road vacuum cleaning in terms of pollution loads reduction. In this context, this study proposes two empirical equations to estimate the amount of diffuse pollution loads removed by road vacuum cleaning. The proposed equations estimate the removed amount of pollution loads respectively taking into consideration of: a) the distance of road vacuum cleaning; and b) the amount of road-deposited sediment(RDS). All of the parameters in these equations were evaluated based on results of field monitoring and laboratory analyses, except for the RDS generation rate. The results of this study suggest that pollutant removal efficiency is 46.3% for $BOD_5$ and 56.4% for TP; discharge ratios for particulate and dissolved $BOD_5$ are 35.0% and 21.2%, respectively; discharge ratios for particulate and dissolved TP are 35.0% and 19.4%, respectively. Average concentrations of pollutants in RDS are $BOD_5$ 977.3 mg/kg and TP 317.6 mg/kg. Some results of a case study imply that both equations can be potentially useful if the adopted parameters are reasonably evaluated. In particular, the RDS generation rate should be evaluated based on monitoring data collected from various road conditions.

• 상하수도학회지
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• 제31권6호
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• pp.539-549
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• 2017

In water treatment process using microfiltration membranes, manganese is a substance that causes inorganic membrane fouling. As a result of analysis on the operation data taken from I WTP(Water Treatment Plant), it was confirmed that the increase of TMP was very severe during the period of manganese inflow. The membrane fouling fastened the increase of TMP and shortened the service time of filtration or the cleaning cycle. The TMP of the membrane increased to the maximum of $2.13kgf/cm^2$, but it was recovered to the initial level ($0.17kgf/cm^2$) by the 1st acid cleaning step. It was obvious that the main membrane fouling contaminants are due to inorganic substances. As a result of the analysis on the chemical waste, the concentrations of aluminum(146-164 mg/L) and manganese(110-126 mg/L) were very high. It is considered that aluminum was due to the residual unreacted during coagulation step as a pretreatment process. And manganese is thought to be due to the adsorption on the membrane surface as an adsorbate in feed water component during filtration step. For the efficient maintenance of the membrane filtration facilities, optimization of chemical concentration and CIP conditions is very important when finding the abnormal level of influent including foulants such as manganese.

• 한국재료학회지
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• 제18권6호
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• pp.307-312
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• 2008

In this study, a new cleaning process with a low cost of ownership (CoO) was developed with ozonated DI water ($DIO_3$). An ozone concentration of 40 ppm at room temperature was used to remove organic wax film and particles. Wax residues thicker than $200\;{\AA}$ remained after only a commercial dewaxer treatment. A $DIO_3$ treatment in place of a dewaxer showed a low removal rate on a thick wax layer of $8000\;{\AA}$ due to the diffusion-limited reaction of ozone. A dewaxer was combined with a $DIO_3$ rinse to reduce the wax removal time and remove wax residue completely. Replacing DI rinse with the $DIO_3$ rinse resulted in a surface with a contact angle of less than $5^{\circ}$, which indicates no further cleaning steps would be required. The particle removal efficiency (PRE) was further improved by combining a SC-1 cleaning step with the $DIO_3$ rinsing process. A reduction in the process time was obtained by introducing $DIO_3$ cleaning with a dewaxing process.

• 한국산학기술학회논문지
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• 제22권6호
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• pp.11-18
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• 2021

나노버블수는 태양광 패널 청소, 도로의 염분 제거, 기계의 정밀 부품 청소 등 다양한 세척 공정에 사용된다. 해양쓰레기 세척 시스템의 전처리에 나노버블을 적용하면 높은 세척 효율과 물 절약이 가능하다. 본 연구에서는 나노버블수의 염분 제거율을 비교하기 위해 NaCl 200,000 mg/L 용액에 목재를 침적시켜 해양쓰레기를 제작하였다. 수돗물과 나노버블수를 이용하여 노즐 종류, 오리피스 직경, 펌프 회전수 및 세척 시간에 따른 목재 표면 염분농도를 비교하였다. 목재 표면 염분농도는 세척시간이 길어질수록 감소하였다. 하지만 물 사용량을 고려한 최적의 세척 시간은 5-10초 사이였다. 노즐의 오리피스 직경이 커질수록 분사압력은 낮아지며, 세척 후 목재 표면 염분농도는 높아졌다. 이는 노즐의 오리피스 직경이 세척 시스템에서 중요한 요인임을 나타낸다. 나노버블수를 이용한 세척 후 목재 표면 염분농도는 수돗물로 세척 후 목재 표면 염분농도에 비해 부채꼴형 노즐은 2.2 %, 원형 노즐은 30.9 % 낮았다. 또한, 나노버블수를 이용한 세척 실험에서 부채꼴형 노즐을 사용하여 세척하였을 때가 원형 노즐을 사용하였을 때보다 목재 표면 염분농도가 약 9.5 mg/L 낮았다.