• Journal of People, Plants, and Environment
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• v.24 no.6
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• pp.609-617
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• 2021

Background and objective: The nanobubbles remain stable in water, and it increased dissolved oxygen (DO) in the water that promotes the seed germination and the plant growth. We evaluated the seed germination and growth of sprouts (radish, wheat, and barley) and leafy vegetables (red mustard and pak choi) when irrigated with various DO of nanobubble water (NB). Methods: The oxygen NB was generated by surface friction and treated in 4 levels: NB 0% (control, DO 9.21 mg·L^-1), NB 20% (DO 15.40 mg·L^-1), NB 33% (DO 20.93 mg·L^-1), and NB 100% (DO 39.29 mg·L^-1). Results: The root length of radish and wheat increased more in NB 33% than the control plot. The fresh weight increased in NB 33% compared to the control plot in radish and wheat, and both fresh and dry weight increased more in NB 20%, NB 33%, and NB 100% than the control plot of barley. The leaf length and width of red mustard decreased more in NB 33% and NB 100% than the control plot and NB 20%, which indicated the leaf compactness. The fresh and dry weight of shoot and root increased more in NB 100% than the control plot in red mustard. In pak choi, the shoot fresh weight increased more in NB 100% than the control plot. In leafy vegetables, the germination rate of red mustard in NB 100% was higher than the control plot, however, it was not significantly different between oxygen NB plots in sprout vegetables. Conclusion: The results showed that the root growth and biomass increased after applying NB 33% in sprout vegetables. The leaf growth properties as the number of leaves and leaf size were not significantly different or decreased in NB treatments compared to control plots, but NB 100% (DO 39.29 mg·L^-1) effectively increased the root growth and plant biomass in leafy vegetables.

• Journal of Environmental Science International
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• v.25 no.7
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• pp.927-935
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• 2016

Dissolved oxygen is necessary for many biological processes as well as many industrial practices. Dissolved oxygen released from water in dissolved air flotation (DAF) systems can be have many different applications. However, DAF systems are very costly to operate. To develop more efficient DAF systems, a deeper understanding of the process of oxygen being released from water is required. In this study, molecular dynamics (MD) simulations were used to simulate 100 oxygen molecules surrounded by 31002 water molecules at temperatures ranging from $0^{\circ}C$ to $100^{\circ}C$. Simulations were carried out for 10 ns, during which, in most cases, all the oxygen molecules were released from the water droplet. With MD simulations, visualization of the molecules escaping the water droplet was possible, which aided the understanding of the interactions between molecules at the nano-scale. The results showed that as the oxygen molecules moved near the edge of the water droplet that the oxygen molecules hesitated before escaping the water droplet or returned to the interior of the water droplet. This was because of the attractive forces between the water and oxygen molecules. Moreover, after most of the oxygen molecules were released from the droplet, some were found to return to the droplet's edge or even the interior of the droplet. It was also confirmed that oxygen molecules were released at a faster rate at higher temperatures.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.33-33
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• 2012

소비자의 기호에 따른 섬유 제품은 고급스러운 감촉 및 착용감, 신축성 등 기능성 측면이 증대되어 의류 및 인테리어용에 니트 제품 및 세데니아 원단의 수요가 급증하고 있다. 그러나 니트 제품은 조직이 복잡하며 장력에 의해 형태 변화가 심해 제품 개발에 대한 문제점이 발생하고 세데니아 원단 또한 장력에 매우 민감하다. 특히 정련/염색시 고부가가치 제품의 품질문제에 영향을 미치며, 제품손상과 불량률이 문제점으로 대두되고 있다. 나노버블은 기포의 크기가 작고 에너지를 보유하고 있기 때문에 생지에 부착되어있는 호제들과 쉽게 결합할 뿐 아니라 생지로부터 쉽게 분리시킴으로써 정련성을 높이는 역할을 수행하게 된다. 정련제와 결합된 나노버블은 정련시 물에 잘 용해되지 않는 스판오일, 방사유제등을 잘 흡착하여 분리시키기 때문에 정련효과를 병행해서 얻을 수 있다. 즉 정련효과가 현저하게 향상됨으로써 정련제의 양도 기존의 정련 방식에 비하여 적게 사용하여도 동일한 정련효과를 얻을 수 있었다. 발생기포의 양을 조절할 수 있어 소포제 없이도 기포발생에 의한 현장사고를 방지함으로써 고품질의 정련제품을 얻을 수 있었다. 또한 기존 정련기술에 비해 정련시간 단축으로 인한 에너지 절감효과 및 이산화탄소 배출량 감소, 나노사이즈의 버블의 높은 분산력으로 과량의 수세공정 생략 등 친환경적 정련/염색 공정이 가능하다.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.6
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• pp.481-490
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• 2017

Water and wastewater treatment has always been a challenging task due to the continuous increase in amount and the change in characteristics of the poorly biodegradable and highly colored organic matters, as well as harmful micro-organisms. Advanced techniques are therefore required to successfully remove these pollutants from water before reuse or discharge to receiving water bodies. Application of ozone, which is a powerful oxidant and disinfectant, alone or as part of advanced oxidation process depends on the complex kinetic reactions and the mass transfer of ozone involved. Micro- and nano bubbling considerably improves gas dissolution compared to conventional bubbles and hence mass transfer. It can also intensify generation of hydroxyl radical due to collapse of the bubbles, which in turn facilitates oxidation reaction under both alkaline as well as acidic conditions. This review gives the overview of application of micro- and nano bubble ozonation for purification of water and wastewater. The drawbacks of previously considered techniques and the application of the hydrodynamic ozonation to synthetic aqueous solutions and various industrial wastewaters are systematically reviewed.

• Journal of Environmental Science International
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• v.26 no.1
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• pp.23-28
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• 2017

This study was aimed at determining the changes in heavy metal removal efficiency at different acid concentrations in a micro-nanobubble soil washing system and pickling process that is used to dispose of heavy metals. For this purpose, the initial and final heavy metal concentrations were measured to calculate the heavy metal removal efficiency 5, 10, 20, 30, 60, and 120 min into the experiment. Soil contaminated by heavy metals and extracted from 0~15 cm below the surface of a vehicle junkyard in the city of U was used in the experiment. The extracted soil was air-dried for 24 h, after which a No. 10 (2 mm) was used as a filter to remove large particles and other substances from the soil as well as to even out the samples. As for the operating conditions, the air inflow rate in the micro-nano bubble soil washing system was fixed at 2 L/min,; with the concentration of hydrogen peroxide being adjusted to 5%, 10%, or 15%. The treatment lasted 120 min. The results showed that when the concentration of hydrogen peroxide was 5%, the efficiency of Zn removal was 27.4%, whereas those of Ni and Pb were 28.7% and 22.8%, respectively. When the concentration of hydrogen peroxide was 10%, the efficiency of Zn removal was 38.7%, whereas those of Ni and Pb were 42.6% and 28.6%, respectively. When the concentration of hydrogen peroxide was 15%, the efficiency of Zn removal was 49.7%, whereas those of Ni and Pb were 57.1% and 42.6%, respectively. Therefore, the efficiency of removal of all three heavy metals was the highest when the hydrogen peroxide concentration was 15%.