• Tribology and Lubricants
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• v.12 no.3
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• pp.39-47
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• 1996

The magnetic fibrous polymeric oil filter elements for industrial lub-systems were obtained by pneumoextrusion processing prepared from thermoplastic pqlymer (polyamide) containing a magnetic particulate filler (Ba ferrite), and treated subsequently in a magnetic fields. Using the standard laboratory oil filtration test rig, metallic particle quantifier and image analyser system, the dependence of filtration charateristics of the magnetic filter media on the parameters of porosity and magnetic properties was investigated. The pressure drops and efficiencies of lubricating filter elements were measured on the packing density and magnetised filler content of filter element. Also, the industrial lub-systems such as lubricant filters for gear test rig and electric discharge processing machine were used for testing the flitrational characteristics of tl, c magnetised filter elements. The magnetic fibrous polymeric filter material was shown to possess a highly filtration efficiency in filtering the fine ferrous particles with increasing the magnetic force of filter element. Therefore, it is expected that the magnetic fibrous polymeric filter material should be used for effective oil filrers on the industrial lub-systems.

• Membrane and Water Treatment
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• v.5 no.2
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• pp.147-170
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• 2014

This paper focuses on the study of the most recent ultra-filtration techniques, based on porous polymer membranes, used for the treatment of wastewater from oil, mine and hydrometallurgical industries. The performance of porous membranes used in separation and recovery of oil and heavy metals from wastewater, was evaluated by the polymer composition and by the membrane characteristics, as it follows: hydrophobicity or hydrophilicity, porosity, carrier (composition and concentration), selectivity, fouling, durability, separation efficiency and operating conditions. The oil/water efficient separation was observed on ultra-filtration (UF) techniques, with porous membranes, whereas heavy metals recovery from wastewater was observed using porous membranes with carrier. It can be concluded, that in the ultra-filtration wastewater treatments, a hybrid system, with porous polymer membranes with or without carrier, can be used for these two applications: oil/water separation and heavy metals recovery.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.12
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• pp.873-878
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• 2014

The applicability of carbon nanotube (CNT) to slow sand filtration for the removal of bacteria was studied using scanning electron microscope and column experiments. The morphology of CNT were investigated using scanning electron microscope and the CNT looked like a skein serving bacteria favorable site for adhesion. Column experiments were performed over a range of CNT filter depth, pH, and ionic strength. Bacteria removal efficiency was found to increase from 44.15% to 99.95% as the CNT filter depth increased from 1 cm to 5 cm, and 3 cm of CNT filter depth was required for significant removal of bacteria. pH increase from 5.5 to 8.5 decreased the bacteria removal efficiency, due to the electrostatic repulsion between bacteria and CNT at higher pH. Bacteria removal efficiency decreased from 97.25% to 70.90% as the ionic strength increased from 0 mM to 50 mM. This study demonstrated that the CNT can be applied to slow sand filtration for treating microbially contaminated water.

• Particle and aerosol research
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• v.12 no.3
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• pp.51-56
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• 2016

Due to recent development in nanotechnology and increasing usage and production of nanomaterials, numerous studies related to environment, sanitation and safety handling of nanoparticle are being conducted. Since nanoparticles can be easily absorbed into human bodies through breathing process, based on their toxic substances and their large specific surface, these particles can cause serious health damage. Therefore, to reduce nanoparticle emissions, nanofiltration technology is becoming a serious issue. Filtration is a separation process during which a fluid passes through a barrier by removing the particles from the stream. Barrier filters can be made of various materials and shapes. One of the most common type of barrier filter is the fibrous filter. Fibrous filters are divided in two types: nonwoven and woven fabrics. Polypropylene is a thermoplastic material, used as a base material for melt blown nonwoven fabric. In this study, we examined filtration property of KCl nanoparticles with a mean particle diameter of 75 nm using multilayer meltblown filter samples. These experiments verify that the penetration of nanoparticle in the filter correlate with pressure drop; the meltblown layer MB1 has the greatest effect on dust collection efficiency of the filter. Among all tested samples, dust collection efficiency of 2-layer filter was best. However, when considering the overall pressure drop and dust collection efficiency, the 4-layer filter has the highest quality factor for particles smaller than 70 nm.

• Journal of Korean Society on Water Environment
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• v.21 no.4
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• pp.337-346
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• 2005

An MSBR using a membrane for not only filtration but also aeration (MA-MSBR) was designed to reduce membrane fouling and to enhance water quality, and compared with an MSBR using a membrane for only filtration (BA-MSBR). COD removal efficiency of the MA-MSBR was similar to that of the BA-MSBR, but membrane performance of the MA-MSBR was better than that of the BA-MSBR. The MA-MSBR had more small particles in mixed liquor, so the specific cake resistance of flocs in the MA-MSBR was higher than that in the BA-MSBR. However, in the aerobic reaction step of the MA-MSBR, air went through membrane pores and out of the membrane surface, so cake layers on the membrane surface and a portion of organics adsorbed on membrane pores could be removed periodically. Therefore, cake resistance, $R_c$, and fouling resistance by adsorption and blocking, $R_f$, for the MA-MSBR increased more slowly than those for the BA-MSBR. Additionally, in order to compare the energy efficiency for two MSBRs, oxygen transfer efficiency and power to supply air into the reactor by a membrane module and a bubble stone diffuser were measured using deionized water. From these measurements, the transferred oxygen amount per unit energy was calculated, resulting that of MA-MSBR was slightly higher than that of BA-MSBR.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.2
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• pp.135-143
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• 2005

It was evaluated that the effect of turbidity removal by Pore Controllable Fiber Filter(PCF) installed in NS(Naksang) small water treatmant plant(system) using under flow water as raw water in the study. The results of the study are as the followings. Firstly, the removal efficiency of turbidity by PCF without coagulation(in operation mode not using coagulants) was mostly below 20 percent. On the other hand, when operation using proper coagulants, that of turbidity was mostly over 80 percent. Secondly, slow sand filtration after PCF, total turbidity removal efficiency of final treated water was 84.3 percent, and the contribution by PCF was 57.1 percent and that of slow sand filtration was 27.7 percent. Therefore the introduction of PCF as pre-treatment process would be helpful to reduce the loading of high turbidity of slow sand filtration. Thirdly, the results of particle counter measurements showed that when operated PCF with coagulants, fine flocs captured or adsorbed at the pore of PCF were flow out into the effluents from 120 minutes after backwashing because of the increase of headloss of PCF. Therefore the decision of backwashing time should made consideration into the outflow of fine flocs from PCF. Fourth, coagulant dosages on PCF at the same turbidity was largely variable because of the effect of the raw water characteristics and the turbidity increase velocity at rainy days, therefore flexible coagulant dosages should be considered rather than fixed coagulant dosage by the influent jar-test result.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.5
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• pp.179-186
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• 1996

The magnetic fibrous polymeric oil filter for automotive was obtained by pneumoextrusion processing prepared from thermoplastic polymer(polyamide) containing magnetic particulate filer (Ba ferrite), and treated subsequently in a magnetic fields. Using an oil filter tester and particle quantifier, the dependence of filtrational characteristics of the magnetic oil filter on the parameters of mean pore sizes and magnetic properties were analyzed. Also experimental engine-bed test of oil filters was investigated. The magnetic fibrous polymeric filter was shown to possess a highly filtration efficiency in filtering the fine metal particles with increasing the magnetic force of filter element. In this study, we knew that efficiency of magnetic fibrous polymeric filter was dependent on the magnetic strength of the filter elements.

• 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 Korean Society of Water and Wastewater
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• v.13 no.2
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• pp.41-46
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• 1999

Backwashing is an important process for the efficient operation of granular filters, and the efficiency of the surface washing among the backwashing processes can affect the filtrations rate and filter run-time. In this study, the efficiency of surface washing is evaluated using real filters for three cases: with surface washing (with and without drainage of water to the surface of filter bed) and without surface washing. As a result, in the case of adopting both the drainage and surface washing, the filter of which condition is initially worse than those of the other filters shows improvement in head-loss development, filtration velocity, filter run-time, and total filtration volume. On the other hand, the conventional method of surface washing rarely has an effect on the filter washing.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.1
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• pp.79-86
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• 2019

In order to measure the filtration characteristics of a cotton ball shape filter, the experiments of suspended solids(SS) surrogate material selection and filtration performance have been carried out in this study. Between the two materials of powdered activated carbon(PAC) and powdered red-clay, PAC is more suitable surrogate material in terms of experimental criteria and particle size distribution in the non-point source pollutants removal system. As a result of the filtration experiments with the cotton ball shape filter, the initial headloss was about 8 cm, and the headloss slightly increased over filtration time. The Kozeny-Carman equation was used to analyze the changes of pressure and porosity during the filtration. The initial porosity was calculated as 0.945 and it decreased to 0.936 at the end of design filtration time. As the filtration continued, the SS concentration of the filtered water gradually increased and the SS removal rate gradually decreased. When the SS target removal efficiency is assumed to be 80%, the cumulative SS removal capacity is expected as $28.8kg/m^2$. This means the volume loading rate of the cotton ball shape filter can be $115m^3/m^2$ when the typical SS concentration of non-point source water pollution is assumed as 250 mg/L.