• Journal of the Korean Ceramic Society
• /
• v.35 no.4
• /
• pp.399-405
• /
• 1998

The effect of each factor on the porosity and mean pore size of cordierite(2Mg$.$2{{{{ {Al}_{2 } {O }_{3 } }}$.$5{{{{ {SiO}_{2 } }}) ceram-ics which have been mainly used for hot gas filter was investigated by using orthogonal array. The poros-ity was observed to increase with the content of graphite added as pore-forming material and decrease with increasing talc size. The effects of the other factors the graphite size sintering temperature and hold-ing time at sintering temperature were observed to be small relatively. In case of mean pore size the ef-fect of talc size on the mean pore size of cordierity was investigated to be the largest. The mean pore size was observed to increase with increasing talc size.

• Journal of Korean Society for Atmospheric Environment
• /
• v.16 no.4
• /
• pp.381-388
• /
• 2000

Ceramic foam prepared with cordierite as a starting material by foam method was tested to evaluate the feasibility as a filter for the dust collection in hot gas. Two different types of agents Benzethonium chloride (BZTC, C27H42NO2Cl) and Sodium Lauryl Sulfate(SLS, CH3(CH2)11OSO3Na) were used as foaming agents in foaming process. Porosityof ceramic foam was about 80% and mean pore size were 100${\mu}{\textrm}{m}$ for SLS agent and 200 ${\mu}{\textrm}{m}$ for BZTC. It was observed that ceramic foam was composed of continuous macro-pore structure with opening windows interconnecting macro-pores. The surface of ceramic foam support of was coated with cordierite particles ranged from 20${\mu}{\textrm}{m}$ to 50${\mu}{\textrm}{m}$ Meso-pore size in the coating layer on ceramic foam was below 10${\mu}{\textrm}{m}$. While air permeability of the support increased with increasing macro-pore size coated ceramic filters showed a constant permeability without regard to the macro-pore size of the support. The permeabuilities of support varied in the range of 600$\times$10-13m2 to 1000$\times$10-13m2. For the case of coated ceramic filter it was about 200$\times$10-13m2. As a result of particle trapping test by using fly ash the particle removal efficiency was over the 99.9%.

• Journal of the Korean Ceramic Society
• /
• v.51 no.5
• /
• pp.406-412
• /
• 2014

In this study, flat-tubular-type alumina filters were manufactured using alumina powder of two sizes ($2.4{\mu}m$ ALM-44 and $0.4{\mu}m$ AP 400) by an extrusion process. The manufactured alumina filter was sintered at $1200-1600^{\circ}C$ for 1 h. As particle size increased, the largest pore size, average pore size and porosity increased; but density and linear shrinkage decreased. The alumina filter fabricated using ALM-44 powder sintered at $1500^{\circ}C$ was confirmed as the best water treatment filter after investigation of the bending strength, water permeability and impurity-removal efficiency of the experimental filters. This flat-tubular-type alumina filter is expected to be useful not only for direct water treatment, but also for use as a support filter during coating processes, to control pore size.

• Journal of the Korean Institute of Gas
• /
• v.2 no.1
• /
• pp.47-52
• /
• 1998

To eliminate foreign substance like metal rust and sand in natural gas pipeline, 250um strainer filter is used present in Korea Gas Corporation. But particles smaller than 250um passing the filter have bad effects to the valves and the measuring equipments. In order to eliminate small paticle in the pipeline, it is necessary to cut down the pore size of filter When we cut down the pore size of filter, the pressure difference between the front of filter and that of the rear part is increasing and disturb normal condition of gas supply. So it is very important to control the condition between the pore size of filter and the pressure difference. In this study, using head loss coefficient K, the estimation method of efficiency of gas filter according to the pore size and the pressure difference is presented.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.23 no.1
• /
• pp.37-45
• /
• 2021

This study observed the release of microplastics according to washing weights and filtering conditions, measured microplastic generation rates, fiber lengths, and fiber diameters. This study attempted to present data for the development of filters that decrease microplastic generation. For test samples, polyester piled knit fabric (cut-pile) was selected, which currently has the highest amount of consumption in the clothing industry, but can easily cause marine pollution because of its low biodegradability. For test equipment, a drum washer was used and microplastics were collected using two filter pore sizes, 5 ㎛ and 20-25 ㎛. Microplastic fibers weights and lengths were measured. The results of the experiment showed the following: 1) The release of microplastics differed according to the fabric weights and washing process; 2) washing fabric weights showed a differences in the collection amount according to the filter pore size (5 ㎛, 20-25 ㎛); 3) observations of differences in the lengths of the microplastics that occur during the washing process by filter pore size were made. Fibers with shorter lengths appeared with filter pore sizes of 5㎛ in comparison to filter pore sizes of 20-25㎛. The results from this study on microplastic generation by fabric during washing, demonstrated the following conclusions that can be used to reduce the release of microplastics. First, the release of microplastics according to fabric weights and washing courses are affected by physical force. Therefore, it is necessary to reduce the amount of physical force due to water flow, increase the fabric weight, or wash the material in low temperatures. Second, in the manufacturing of washing machines, microplastic filtration can be promoted or legislatation supporting microplastic filtration can be introduced.

• Journal of Environmental Science International
• /
• v.15 no.11
• /
• pp.1027-1034
• /
• 2006

Antimicrobial powder was made by exchanging silver ion on calcined oyster shell. On the purpose of application to water clarifier, bail-type media mixed with antimicrobial powder and $0{\sim}30%$ white kaoline were made. The sterilization effect, pore size distribution and zeta potential was tested to indicate the condition for the media of water clarifier. From these tests, it was confirmed that this media have an excellent sterilization power on $G^-\;and\;G^+$ germs. As the concentration of the exchanged silver ion increased, the surface charge density of the anions on the surface of the media also increased. The surface pore size decreased with the concentration of silver ion and 20% more white kaoline ratio. Consequently, mixing ratio of white kaoline would appear to indicate the optimun condition as media have sterilization power.

• Journal of Korean Society on Water Environment
• /
• v.20 no.4
• /
• pp.346-351
• /
• 2004

Because of being produced a great deal of excess sludges from biological wastewater treatment process, the subject regarding treatment and disposal of them has been significantly handled in real plants. It should be considered the alternative treatment with easy operating and cost effective process in rural areas. For the thickening of wasted activated sludge from small scale wastewater treatment facilities, thus, the provisional sludge thickening system was developed by the application of mesh filter module. Three meshes with different pore size(100, 150, $200{\mu}m$) were prepared for filter modules that were used to withdraw effluent from thickening system. A filter module with $100{\mu}m$ mesh was chosen as the most effective thickening material in the viewpoint of volume reduction and effluent quality: the volume reductions of initially injected sludge with 3,600 mg/L and 9,100 mg/L were 95% and 85%, respectively, and the filtered effluents were enough good to be shown below 1.0 mg/L of SS and 1.0 NTU of turbidity. Since the filtration of thickening was influenced by the cake layer formed on mesh filter module and this system was operated in the combination of sludge thickening with gravity settling, the filter modules with smaller pore size and the larger floc size were required for long term operation safely.

• Journal of the Korean Society of Tobacco Science
• /
• v.16 no.2
• /
• pp.191-197
• /
• 1994

Relationships between surface structure and adsorption properties of smoke components were investigated in surface-modified and un-modified activated carbon filter cigarettes. Commercially available activated carbon was treated with nitric acid and hydrogen peroxide as oxidant, and their pore volume, surface structure, BET surface area, pore type and size were studied. BET surface area and pore volume were decreased by nitric acid treatment, but median pore diameter was 8.1 $\AA$, which showed better development of pore compared with that of un-modified activated carbon, 6.9 $\AA$. In case of hydrogen peroxide treatment, BET surface area and pore volume were increased. Their pore was found to be a slit type based on V-t plot analysis. Neutralization capacities for bases of different strength (NaHCO3, Na2CO3, NaOEt and NaOH) showed that the majority of the acidic surface groups are of weak acidity. Modification of the activated carbon surface led to a slight change in adsorption properties when analyzing the smoke of triple-filter cigarette with surface-modified activated carbon.

• Korean Journal of Materials Research
• /
• v.14 no.7
• /
• pp.470-476
• /
• 2004

The fail safety filter is an assistant filter element to be mounted in order to intercept the particles leaked when the main filter elements are broken. So it should have two contrary functions of being plugged easily to meet the purpose of dust sealing and a high permeability to save the space. The permeability of the metal filter elements were effectively controlled by the following factor: powder size(53-840 ${\mu}m$) and applied pressure(1000-2000 $kgf/cm^2$), and then the compact were sintered for 1 hour at $1200^{\circ}C$ in vacuum sintering furnace. The sintered metal filters was evaluated for the function of the fail safety filter in an experimental unit. The maximum allowable particle size was 420-840 ${\mu}m$, when a CIP pressure of 1500 $kgf/cm^2$ was applied reveals a permeability of about $1.2{\times}10^{10}m^2$ and pore size of about 60 ${\mu}m$. The metal filter produced with stainless steel powder of 480-840 ${\mu}m$ size, which presented excellent permeability than commercial ceramic filter element and plugged with in 3 minutes with the leak of the maximum particle size less than 3 ${\mu}m$.

• Journal of the Korean Ceramic Society
• /
• v.43 no.4 s.287
• /
• pp.199-202
• /
• 2006

In this study, SiC whiskers were grown on a porous SiC diesel particulate filter for nanoparticle filtering. To grow the whiskers at the inner pore without closing the pores, we used chemical vapor infiltration with a solution source and a dilute. As the deposition time increased, the whiskers grew and formed a network structure. After 180 min of deposition, the mean diameter of the whiskers was 174 nm and the compressive strength was 58.4 MPa. The pores shrank from $10{\mu}m\;to\;0.4{\mu}m$ and, because the whiskers filed the inner pores, the gradient of permeability decreased as the deposition time increased. However, by using the network structure of whiskers deposited for 120 min and 180 min, we obtained a diesel particulate filter with pores of $0.98{\mu}m\;and\;0.4{\mu}m$, respectively. Furthermore, the filter shows better permeability than a porous body with pores of $1{\mu}m$. In short, by filtering the nanoparticulate materials, the network structure of whiskers improves the strength, reduces the pore size and minimizes the permeability drop.