• Journal of Wetlands Research
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• v.21 no.4
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• pp.321-333
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• 2019

A primary aspect of low impact development (LID) design that affects performance efficiency, maintenance frequency, and lifespan of the facility is the type of filter media as well as the arrangement or media profile. Several LID guidelines providing media specifications are currently available and numerous studies have been published presenting the effectiveness of these systems. While some results are similar and consistent, some of them still varies and only a few focuses on the effect of filter media type and arrangement on system performance. This creates a certain level of uncertainty when it comes to filter media selection and design. In this review, a synthesis of filter media specifications from several LID design guidelines are presented and relevant results from different laboratory and field studies are highlighted. The LID systems are first classified as infiltration or non-infiltration structures, and vegetated or non-vegetated structures. Typical profiles of the media according to classification are shown including the different layers, materials, and depth. In addition, results from previous studies regarding the effect of filter media characteristics on hydraulic and hydrologic functions as well as pollutant removal are compared. Other considerations such as organic media leaching, clogging, media washing, and handling during construction were also briefly discussed. This review aims to provide a general guideline that can contribute to proper media selection and design for structural LIDs. In addition, it also identifies opportunities for future research.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.56-56
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• 2012

본 연구는 가정용 및 산업용 유해가스제거용 필터여재의 제조에 관한 것으로 핫멜트(hot-melt) 분사 시스템에 의한 다층구조의 부직포와 활성탄 등의 흡착물질로 구성되는 샌드위치 복합시트 및 필터여 재의 제조에 사용되는 구성재료의 최적화에 관한 연구이다. 스프레이 본딩 시스템에 의한 공정은 종래의 유해가스제거용 필터 미디어의 제조하는 방법인 활성탄과 바인더 역할을 하는 핫멜트 수지를 혼합하여 부직포 원단에 도포하여 활성탄을 부착시키는 공정에 비해 도포되는 핫멜트 수지의 양이 감소에 의한 생산비절감과 충분한 활성탄 도포에 의한 기능성 향상 등에 의해 유해가스 포집율을 높일 수 있으며 공정 이후 스프레이에 의해 도포된 핫멜트수지의 자연건조 방식에 의한, 열원이 불필요하며, 에너지가 절감되며, 속도 향상에 의한 생산성 향상, 분진발생 최소화로 인한 제조현장의 환경개선이 가능할 것으로 사료된다. 1차적으로 본 연구의 필터제조의 최적화를 위해서 스프레이 본딩시스템에 효율적으로 사용가능한 다양한 수지를 검토하였으며, 기존 외산 캐빈필터여재의 미세구조 및 성능특성, 다양한 활성탄의 흡착성능검토, 사용 가능한 여재의 특성분석을 통해 다층구조의 필터 여재에 사용 가능한 구성재료의 최적화에 중심을 두었다.

• Journal of the Korean Geotechnical Society
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• v.38 no.6
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• pp.41-47
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• 2022

Permeable pavement technology allows the penetration of rainfall into the roadbed, thereby reducing surface runoff and enhancing water quality. The water quality can be improved by adding a filter layer to the permeable pavement. This study analyzes the permeability performance and particulate-matter removal efficiency of a bottom ash-silica sand filter. The performances of five filters with bottom ash and silica sand as the basic materials were evaluated on particulate matter sized 60 ㎛ or smaller. The pure silica sand sample and pure bottom ash sample delivered an average removal efficiency of around 70%. The removal efficiency of the mixed sample was approximately 90%, exceeding the recommended reduction rate (80%) at non-point pollution reduction facilities. In future work, the filter performance should be further verified on permeable pavement.

• Journal of Wetlands Research
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• v.19 no.3
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• pp.259-270
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• 2017

In this study, field-scale half-saturated bio-filter wetland equipped with recirculation system was operated with stormwater from the paved road, and its operational performance and functions of LID-BMP were analyzed and compared with other facilities. The reduction of TSS, COD, TN, and TP were 92%, 63%, 36%, and 75%, respectively. Comparison of the reduction efficiency were carried out with respect to ratio between surface and catchment areas(SA/CA). In addition, this LID-BMP facility can reduce about 70% of pollutant by treating only 18% of total rainfall runoff. The results show that LID used for this study gave similar efficiency although its ratio was smaller. In addition, comparison study was made between synthetic fiber as a filter media and organic media, which shows that there was not any significant difference between, TSS and TP reduction, but there were large difference in COD and TN removal due to the presence and absence of release of organic carbon. Meanwhile, wetland system in this study equipped with a first-flush capture gave a higher stability in terms of treatment performance.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.6 no.4
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• pp.417-426
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• 1994

Filter media performance was evaluated using monodisperse NaCl particles with Differential Mobility Analyzer and Ultrafine Condensation Particle Counter. Low or medium performance filters show that the most penetrating particles size(MPPS) is around $0.3{\mu}m$ in diameter and is shifted to smaller sizes as the filter face velocity increases. However, HEPA and ULPA filters show MPPS is around $0.15{\mu}m$ in diameter and is also shifted to $0.1{\mu}m$ in diameter as the face velocity increases. In case of electret filter, the MPPS is found around $0.04{\mu}m$ region for Boltzmann charge equilibrium particles. There is a tendency of strong collection efficiency decrease for large particles as the face velocity increases on the contrary to the other filters. One of the medium performance filter efficiency was compared with filtration theory and the good agreetment was found in the experimental range.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.3
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• pp.153-157
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• 2010

We studied the adsorption efficiency of steelmaking slag in removing volatile organic compounds (VOCs) for increasing the recycling rate of steel-making slag. Ceramic filter was prepared by mixing the steel-making slag and the diatomite which is used as adsorbents due to the advantage of the high specific surface area and regular mesopores. The adsorption efficiency for VOCs removal was about 80%, 96% and 85% in acetaldehyde, formaldehyde and ammonia, respectively. The adsorption efficiency over 80% for all The gases showed the practical possibility as the adsorption filter.

• Journal of Korean Society on Water Environment
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• v.32 no.1
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• pp.36-45
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• 2016

Sand filters are widely used in infiltration systems to manage polluted urban runoff. Clogging, which is mainly caused by the deposition of sediments on the filter media, reduces the filter system's infiltration capacity, which further limits its lifespan and function. The physical, chemical and biological clogging characteristics of sand filter, therefore, need to be known for effective design and maintenance. Physical clogging behavior and variations in the characteristics of sand filters according to different media depths are examined in this paper. The variations were observed from laboratory column infiltration tests conducted in a vertical flow and fluctuating head condition. It can be seen that an increase in filter media depth results in a high sediment removal performance; however, it leads to a shorter lifespan due to clogging. In the choice of filter media depth to be used in field applications, therefore, the purpose of facilities as well as maintenance costs need to be considered. At all filter media depth configurations, premature clogging occurred because sediments of 100~250 μm clogged the top 15% of filter media depth. Thus, scrapping the top 15% of filter media may be suggested as the first operational maintenance process for the infiltration system.

• Membrane Journal
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• v.25 no.6
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• pp.503-514
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• 2015

In this study, water purification system without coagulant was consisted of F/A and membrane to produce purified water which only uses physical treatment without coagulant. Because the use of coagulant has a possibility remaining of hazardous aluminum with our health. Especially, the Filtralite was reviewed the possibility to remove turbidity and organic material. It was found that the turbidity removal rate of Filtralite was 83~84%. It show that Filtralite has similar efficiency to sand-filter. But Filtralite has higher 50% removal rate of organic material than sand-filter due to well-developed pore on the surface of it. So, Filtralite could be used to substitute the sand-filter for the F/A process due to higher removal rate. And also coupled with activated carbon in F/A process, TMP was increased by TOC value. To prevent increasing TMP, media that has outstanding organic adsorption ability should be used.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.1
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• pp.8-15
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• 2004

Since the vehicle is regarded as the third living space, the comfortable conditions are required in the passenger compartment. For this reason, customers are concerned about the filtering performances and the importance of filter media has been greatly placed. Therefore the dust holding capacity, the efficiency of these filter media (dry paper, wet paper, non-woven) and the configuration of air filter for vehicle were measured in this study. The following results were obtained on the basis of air filter test. It shows that the thickness and poresize of filter media should be lower for the higher efficiency. The measurement result shows that the performance of round shape filters are higher than the square shape filters. The dust holding capacity of the wet paper and the non-woven paper is higher than the dry paper. As a result, this research can provide an important design parameter and product guidance of the intake air filter for vehicular engine.

• Applied Chemistry for Engineering
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• v.33 no.4
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• pp.444-450
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• 2022

The effect of coated polyester (PET) textiles with metal oxide, chitosan, and copper ion on the antibacterial and antiviral activities was evaluated to investigate the applicability of multi-coated PET textiles as antiviral materials. Compared to coated PETs with a single agent, multi-coated PETs reduced the loading amount of coating materials as well as the contact time with bacteria for a bacterial cell number of < 10 CFU/mL, which was not detectable with the naked eyes. Metal oxides generate reactive oxygen species (ROS) such as free radicals by a catalytic reaction, and copper ions can promote contact killing by the generation of ROS. Chitosan not only enhanced antibacterial activities due to amine groups, but enabled it to be a template to load copper ions. We observed that multi-coated PET textiles have both antibacterial activities for E. coli and S. aureus and antiviral efficiency of more than 99.9% for influenza A (H1N1) and SARS-CoV-2. The multi-coated PET textiles could also be prepared via a roll-to-roll coating process, which showed high antiviral efficacy, demonstrating its potential use in air filtration and antiviral products such as masks and personal protective equipment.